While this page will no longer be updated, it will stay here for reference.

I hope you've enjoyed reading my blog down the years - I've enjoyed writing it, and have appreciated your comments.

To keep up to date with news and views about the environment, I hope you'll keep reading the science and environment pages of the BBC News website, and my science correspondent colleagues Jonathan Amos and David Shukman.

And here's why.

If Planet Earth is facing a climate "emergency", as some people believe we are, then we should leave no option for combating it unexplored, they argue.

While very few scientists advocate deployment of geoengineering now, many believe we ought to be getting on with research now in order to have technologies ready in 10-20 years when they might be needed.

On the other hand, many environment groups and some scientists argue that diverting attention and research funds towards geoengineering means people will take their eyes off the more important tasks of reducing greenhouse gas emissions and adapting to climate impacts.

Some also argue that politicians and the public will see geoengineering research going on and believe it constitutes a "get-out-of-jail-free" card, reducing the incentive to cut emissions.

Add in the fact that the easiest technical fixes might constrain temperatures but won't tackle the problem of ocean acidification, and you have a rich cocktail of scientific, economic and social issues to discuss.

The arguments were on display this week in a symposium at Oxford University, which recently set up a multi-disciplinary research programme on the issue.

Present were not only physical and social scientists but officials from government departments and funding agencies, representatives from environmental groups and a few journalists.

The hottest current issue in UK geoengineering is the SPICE project.

Its most obvious component, the deployment of a tethered balloon to disperse water into the air, was postponed and probably cancelled earlier this year when some of the team found out that a patent had been lodged on some of the technology.

What was most interesting in the SPICE-related discussions, however, was the question of whether the balloon should be deployed or not.

It's basically a technology test. Researchers want to gather data that could potentially be used in future to make much bigger systems capable of spraying tiny sulphate aerosol particles into the upper atmosphere, mimicking the cooling effect of volcanic eruptions.

The team, led by Matt Watson of Bristol University and Hugh Hunt of Cambridge, have repeatedly stressed that they don't advocate doing this yet and perhaps never will advocate it; they just want the technology to be ready in case it's needed.

Clearly, the SPICE balloon itself would have no climatic impact. Even so, a number of environmental groups lobbied against the research, for reasons enumerated above, with one, the ETC Group, dubbing it the "Trojan Hose".

They and others advocate a tough international regime for all research that would permit laboratory studies but prevent anything happening in the real world.

Others say that's far too draconian, and point to what appears to be the self-contradictory stance of some groups opposing genetically engineered crops - to say there's no research proving they're safe, but then to trash research projects that could provide the proof.

For example, it was pointed out, spraying sulphate particles into the stratosphere might ruin the ozone layer. You'd want to know that before you contemplated using the technology; but how are you going to find out unless you spray a little bit?

Some rules already exist.

By far the most researched technology is ocean fertilisation, where iron is used to stimulate plankton growth in the ocean, increasing uptake of carbon dioxide. Something like 12 large-scale projects have been carried out, with mixed results.

From the regulation point of view, it's also the most advanced field, with the London Convention having agreed rules in recent years that restrict research on the basis of its potential utility and potential risks.

Commercial interests are forbidden, countries must "use utmost caution and the best available guidance to evaluate the scientific research proposals to ensure protection of the marine environment". Deployment - as opposed to research - is not allowed.

Elsewhere, the UN Convention on Biological Diversity in 2010 agreed that for now, "no climate-related geoengineering activities that may affect biodiversity take place... with the exception of small scale scientific research studies... and only if they are justified by the need to gather specific scientific data and are subject to a thorough prior assessment of the potential impacts on the environment".

The ETC Group and others describe this as a "moratorium" on geoengineering. But it isn't a complete one, as much geoengineering research, even on a large scale, would have no impact on biodiversity...

... whereas climate change, of course, will.

If the situation weren't complex enough, another issue's arisen lately - what you might call "dual-use" research.

More than 10 years back, I talked to a US scientist just back from an iron fertilisation experiment who explained that personally, he wasn't interested in geoengineering; really, he wanted to answer more academic questions about iron distribution in the water and derive answers about what the oceans used to look like in the past.

He dressed the funding proposal up in geoengineering language because that was the way to get funds - a tactic scientists in all fields have used down the years in order to ensure their research happens (witness the boom in "bioterror"-related research after the US anthrax scares of 2001).

Fast-forward to the present, and we're seeing the opposite phenomenon - research that could give geoengineering answers, but isn't labelled as such.

Last year, US scientists ran a project on the behaviour of aerosols in clouds.

Such research is standard; what was new about the E-Peace project was the inclusion of "controlled release and atmospheric distribution of three different size ranges of [aerosol] particles in flight and on or by a dedicated ship".

Geoengineering research by another name?

Now, a UK team is proposing "seeding" clouds out at sea to control hurricane strength, and perhaps stop them forming at all.

Clouds would be sprayed with minuscule droplets of seawater. This would make them whiter so they reflect more sunlight back into space, reducing the sea surface temperature - which is the primary driver of hurricanes.

Other researchers, including the UK's Stephen Salter, are proposing using the same apparatus to whiten clouds in order to reflect sunlight and cool the world; in another word, geoengineering.

So when some argued in Oxford that research should be constrained if it's tailored towards geoengineering but permitted if it's not, I wondered: how?

What you might regard as an optimistic note is the degree of thought and debate that's going into the issue of how to regulate geoengineering research before it happens.

Nothing like this went into other controversial but important issues such as genetically engineered crops, shale gas or nuclear power before it began.

But whatever rules are eventually developed, one suspects they're going to have to be applied with common sense.

In 1997, while making a radio series on climate change, I went to a roof-whitening ceremony in Miami.

Attended by marching bands and flags and encouraged by a district mayor, the good burghers of several streets were painting their roofs white, to reflect sunlight and cool the Earth.

They were deploying geoengineering. As far as I know, the world is still turning.

Todd Stern, who leads the US negotiating team in the UN climate convention (UNFCCC) and performed the same role at the recent Rio+20 summit, told an audience at Dartmouth College that insisting on the target in negotiations would lead to "deadlock".

The approach needed more "flexibility", he said.

The negotiations he's referring to concern the Durban Platform - an oddly-chosen name for a process agreed at last year's UN talks in South Africa.

Governments agreed to conclude negotiations by 2015 on a new global deal that would include to different extents every nation, to come into effect in 2020.

As I reported earlier this week, the comment went down very badly with the blocs pushing for faster action on climate change - the Alliance of Small Island States (Aosis) and the EU - with Marshall Islands minister Tony de Brum describing this flexibility as "a death sentence".

Later, the African Group of countries weighed in, spokesman Seyni Nafo saying: "This is not a game with numbers; its a question of people's lives, and so I am not sure there is much space for the 'flexibility' Mr Stern has spoken of."

But Ed King of the Responding to Climate Change website asked whether Mr Stern didn't have a point, given the difficult internal politics of the world's two biggest emitters.

"The aim is to avoid a 2C rise not just for 2015 or 2020 but stretching into the next 100 years," he writes.

"For that to be achieved the USA (and China) has to be on board."

In the middle of this comment storm, Mr Stern's office issued a statement designed to be a clarification.

"Of course, the US continues to support this [2C] goal; we have not changed our policy.

"My point in the speech was that insisting on an approach that would purport to guarantee such a goal - essentially by dividing up carbon rights to the atmosphere - will only lead to stalemate given the very different views countries would have on how such apportionment should be made.

"My view is that a more flexible approach will give us a better chance to actually conclude an effective new agreement and meet the goal we all share."

I say the statement is "designed to be a clarification" because actually, I'm not sure it is.

Certainly, countries have very different views on how "carbon rights to the atmosphere" should be divided up.

We've seen that in abundance at successive UN climate talks dating back at least to 1997 and the agreement of the Kyoto Protocol.

So to that extent, Mr Stern's suggestion of not worrying too much about trying to build a 2C guarantee into the 2015 deal but instead starting "with a regime that can get us going in the right direction and that is built in a way maximally conducive to raising ambition, spurring innovation, and building political will" makes some sense.

However, as he acknowledges: "This kind of flexible, evolving legal agreement cannot guarantee that we meet a 2C goal."

Which begs the question; what use is such an agreement if it doesn't?

It's worth returning at this point to the basic point of the UN climate convention: "The ultimate objective is to achieve... stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."

In some ways it's a badly phrased objective, because greenhouse gas concentrations at a level that are "dangerous" for inhabitants of drought-prone East Africa or low-lying Tuvalu may be absolutely fine in Paris and indeed beneficial in Yakutsk.

But there it is. And the importance of the 2C figure is that it's come to represent a kind of general, averaged-out notion of what "dangerous" means.

Many countries argue it's too lenient. A majority favour 1.5C; a few hold out for 1C.

No government - in public, at least - argues it's too strict.

So as far as there is a general consensus about these things, when Mr Stern advocates a negotiating process that "cannot guarantee" a 2C goal, one way of seeing that is as an acknowledgement that governments shouldn't aim to fulfil the basic objective of the UN climate convention; which is obviously political dynamite.

And yet elsewhere in his speech, he is extremely forthright in arguing that "dangerous anthropogenic climate interference with the climate system" has to be avoided.

For all the protestations of "sceptics", he says: "The atmosphere doesn't care. Its temperature will continue its implacable rise, with all the consequences that entails, unless we act to stop it."

On the evidence of warming - the succession of hot years, the Arctic sea ice melt, ocean acidification, and so on: "They warn of droughts and floods and extreme storms.

"They warn of water shortages, food shortages and national security risk. They warn of what 11 retired generals and admirals wrote about in 2007 - climate change becoming a 'force multiplier for instability in some of the most volatile regions of the world'.

"And they introduce the threat of catastrophic, non-linear change."

... all of which is exactly why most governments are not only supporting the 2C target (if not a smaller figure), but remain determined to get a deal in 2015 that ensures it's achieved.

The most intriguing question - and despite making some enquiries, I've turned up nothing definitive on this - is whether the US is alone in proposing an approach to negotiations that doesn't explicitly aim for 2C.

Since the Copenhagen UN summit of 2009, the US has formed part of what's been dubbed a "coalition of the unwilling", which also, to varying degrees, has included China, India, Russia, Canada, Japan and some of the Gulf states.

Submissions that the US and China sent to the UNFCCC in March, outlining ideas for moving forward on the Durban Platform, don't mention the 2C target at all.

An omission - or something more meaningful?

Meanwhile, submissions from India and Saudi Arabia claim that in order to meet 2C, it's necessary only for the traditional developed countries to restrain emissions - even though the science makes clear that at some stage, all countries will have to take a hit.

The uncomfortable reality is that India, Saudi Arabia and other fast-developing countries can still point at the US and its fellow early industrialisers - the UK, Germany, Japan - and legitimately argue that none has yet been willing to make emission cuts that their historical responsibilities justify.

And without that leadership, they won't follow.

To Mr Stern, the implication of all this is that a process based on slicing up "rights to the atmosphere" can't work.

Politically, he may be right. But it's hard to see any path to a world free of dangerous anthropogenic interference with the climate system unless governments do find a way of apportioning these rights.

Last year, physicist Prof Richard Muller and colleagues published - in the sense of posting material on their website - results from a new project analysing the Earth's temperature record.

The Berkeley Earth (BEST) project basically backed up established temperature records from Nasa and others; the world is indeed warming, and by about as much as we previously thought, it concluded.

Prof Muller was attacked in some quarters for not waiting for the formal process of peer review in a scientific journal before launching the data publicly.

He responded that his method - to put the draft out there openly and let everyone respond who wants to - is increasingly the norm in physics and indeed has always been the norm in string theory, that most arcane of disciplines.

In his view, it's the right way to do things.

A couple of weeks ago, in a New York Times article accompanying the release of five more BEST papers that are being submitted to scientific journals, Prof Muller went further, saying that the majority of 20th Century warming could be laid at the door of greenhouse gas emissions.

By contrast, analysis by established bodies such as the Intergovernmental Panel on Climate Change (IPCC) holds that only after mid-Century did greenhouse gases drive the warming - prior to that, it was predominantly down to natural causes such as solar cycles and a decline in the frequency of large volcanoes.

The original BEST study particularly got up the nose of meteorologist turned sceptic blogger Anthony Watts.

It dismissed the claim he'd made that US weather stations gave an unreliable temperature record because many were badly sited - in places where the extent of heat-reflecting tarmac, for example, had expanded over time.

Also a couple of weeks back, Mr Watts launched a new analysis purporting to show that BEST had it all wrong.

BEST had used an out-of-date methodology for assessing station quality, he argued; use the right one, and you find that US temperatures have risen by only half as much over the last 30 years as Prof Muller and others say it has.

This paper too has been released web-first, on the wattsupwiththat blog, with the aim of formal publication later.

The next development in a busy few days was a Washington Post article penned by Prof James Hansen, the Nasa scientist who has done perhaps more than any other academic down the years to raise the spectre of catastrophic climate change.

It referred to a scientific paper out this week in which he calculates how the incidence of extreme weather events has changed since the middle of the last century.

Using simple statistics rather than computer models, he shows that the frequency of "extreme anomalies" - for the statistically-minded, defined as more than three standard deviations from the mean - has increased 10-fold.

Without climate change, it concludes, last year's drought in Texas and Oklahoma, the 2010 Moscow heatwave, and the 2003 heatwave centred on France wouldn't have happened.

(The article's appearance induced the journal publishing the paper, Proceedings of the National Academy of Sciences, to lift the embargo for reporters, but it doesn't appear to be on their website as yet - sometime this week, presumably.)

Prof Hansen's paper has had a mixed reaction from other researchers.

Prof Andrew Weaver from Canada's University of Victoria said it was an "excellent" piece of work that asked a better-framed question than the one other researchers have posed.

"Rather than say, 'is this because of climate change?' That's the wrong question.

"What you can say is, 'how likely is this to have occurred with the absence of global warming?' It's so extraordinarily unlikely that it has to be due to global warming."

Prof Myles Allen, the Oxford University climate modeller who has spent 10 years developing the science of climate attribution, said it was "broadly in line" with previous analyses, but that the interpretation "goes further than many scientists are comfortable with".

What's perhaps more remarkable about Prof Hansen's paper is the style.

Rarely if ever have I seen a published scientific paper that states the rationale for its existence so baldly in terms of public perception - specifically, "the need for the public to appreciate the significance of human-made global warming".

"Actions to stem emissions of the gases that cause global warming are unlikely to approach what is needed until the public recognises that human-made climate change is underway and perceives that it will have unacceptable consequences if effective actions are not taken to slow the climate change," the authors write.

You'd have to be from another planet not to realise that climate science has been the subject of extraordinarily intense political forces over the last few years.

And many scientists involved feel passionately about it.

At its core, though, climate science has been able to retain its identity partly because researchers generally don't give in to passion, instead sticking to formal processes - publication in peer-reviewed journals and the presentation of data and conclusions in strictly academic terms.

It's rapidly becoming more blurred. And the question arises: is this a good thing?

Prof John Christy, the University of Alabama scientist who has taken a position sceptical of "climate catastrophism" down the years while working in the mainstream discipline of compiling temperature records, believes it could be.

Two years ago, he suggested replacing the monolithic procedures of the IPCC with a "wiki" approach.

And he tells me now that he got involved with the Anthony Watts exercise partly because it "would be an interesting experiment for me in which the paper was 'cloud reviewed' and then rewritten to accommodate important new information before being submitted [to an academic journal]... I'm wondering if this is the way 'review' in the digital age will unfold as time goes on."

Prof Christy makes the distinction - crucial to scientists - between draft papers for discussion and final, complete ones that go into academic journals and become part of the formal literature of science.

But how clear is that distinction to the public that Mr Watts, Prof Hansen and Prof Muller are trying to influence?

And if it's not clear, how does the new model benefit public understanding?

Peer review is far from perfect - especially in a politicised arena such as climate science where some journals exist with a specific, directed slant on the issue.

Energy and Environment, for example, proclaims itself "a forum for more sceptical analyses of 'climate change'".

Creationists have attempted to clothe themselves in scientific garb down the years by establishing publications designed to look and feel like scientific journals.

The Journal of Creation, for example, says it is a peer-reviewed journal but clearly comes with a specific aim - to combat the problem that "creationists cannot publish their creationist ideas in secular journals because the evolutionary worldview has a stranglehold on scientific publishing".

Well, clearly the "evolutionary worldview" ought to dominate scientific journals - because a vast amount of evidence testifies to the fact it's real.

But you can create a parallel world where it isn't, if you really try.

With all its flaws, publication in mainstream peer-reviewed journals is the best mechanism science has yet devised for ensuring that the findings and conclusions reaching the public ear remain above a certain quality threshold.

String theorists can perhaps afford to take a different tack, because - with all due respect - it doesn't make any practical difference to anyone in the wider world who's right and who's wrong in that particular discipline.

But with climate science, it does. It matters a lot.

Is it really time to throw the traditions away? And if it is, whose interests would that serve?

Rio+20: Green Growth or Greenwash? was the title.

As I outlined at the beginning of the debate, it was almost as if Rio de Janeiro hosted two completely different UN sustainable development summits simultaneously in late June.

One was attended by the Brazilian government, several UN institutions, corporations, and people who advise corporations on issues such as supply chain reform.

Their summit was a great success - pledging money for various sustainability initiatives, setting up new partnerships, saving multilateralism and proving that the private sector has raced ahead of governments in their desire for a greener, more equitable future.

Groups such as Oxfam and WWF were evidently at a different event.

Theirs achieved virtually nothing, with Oxfam UK chief Barbara Stocking, for example, saying "it absolutely did not" seize what had been billed as a "once in a generation opportunity" to put the global development path on a sustainable track.

At the time, along with just about every other journalist I spoke to, my impression was more in tune with WWF and Oxfam than the glass half-full contingent.

With hindsight, did I miss something?

Let's begin with the summit organisation itself - properly the United Nations Conference on Sustainable Development. For more than a year beforehand, organisers were clear that this would not be one of those events that delivered a big, binding international agreement on anything.

Rather, they said, we should look at the commitments that governments, companies and civil society groups were prepared to make.

And make commitments they did. The UN summary claims "more than 700".

Sounds a lot - so what are they?

A majority fall in the category of education. Let me pull one out at random from near the top of the list, from Alfred State College in the US.

"Over the next year, we intend to complete an assessment of our sustainability performance using the Sustainability Tracking, Assessment & Rating System (Stars)," it reads.

"We will use the results of this assessment to prepare a comprehensive sustainability plan that includes quantitative targets. Stars will also provide a mechanism for tracking and communicating our progress on sustainability over time."

Near the bottom - for no better reason than I went there once - I select the University of Tampere.

"The University of Tampere has launched a programme for sustainable development, the Sustainability Programme, where it sets the objectives for promoting sustainable development in the teaching, research and everyday operations at the University for the years 2012-2015."

Tampere is also Finland's first Fair Trade university.

The most dynamic-sounding pledge on the register involves planting 100 million trees, mainly in schools, by 2017.

As this initiative has been going since 2004, it's hard to see how it qualifies as "new" - nor, as it's planted seven million trees in those eight years, what guarantees the planting of another 93 million in just five years. Nothing wrong with planting trees, of course. China alone claims to plant more than a billion each year.

On the business side, consultancy firm KPMG - in the shape of its special global adviser Yvo de Boer, former head of the UN climate convention - has highlighted the pledges of the private sector.

"On the sidelines of Rio+20, green economy pledges of more than $500bn have been made," he tweeted.

A KPMG analysis notes that on the governmental level: "Signing something, anything even, was seen as better than signing nothing. That... produced a lowest common denominator document that satisfied almost no-one."

However, while governments were busy saving face, it contends: "There was plenty of action, it just did not come from the multilateral political negotiations. Businesses - and some governments, both national and local - got on with the job either unilaterally or in groups, often in collaboration with civil society and NGOs."

A separate bit of the UN website records pledges made by businesses at Rio+20. Here's a random selection:

Again, nothing much not to like. But is it enough?

At my first UN climate summit, in Nairobi in 2006, I asked an experienced negotiator what to me was the only question that mattered: "What has this event done to curb climate change?"

He gently chided me for it. "That's the one question you're not supposed to ask."

Before Rio+20, just about every environmental indicator was pointing in the wrong direction. Greenhouse gas emissions, loss of biodiversity, ocean acidification, loss of forest and wetland... and at Rio, governments acknowledged it, repeatedly, in speeches.

So in all the voluntary commitments made at Rio, precisely what is there that will turn any of these trends around?

Looking at the social side of the sustainable development agenda, precisely what happened to bring the poorest out of poverty, supply them with proper sanitation, or free them from the burden of eminently treatable childhood illnesses?

What was agreed to insulate the global financial system against further shocks - another issue identified by world leaders in the run-up to Rio as a just subject for discussion?

If the answer to those questions is "very little", then precisely what was the point?

The Chatham House debate didn't produce anything to seriously challenge my initial conclusions.

Panelists with business connections ran through a number of initiatives happening in buildings, energy supply, water efficiency and so on that are curtailing the expansion of industry's footprint.

But they also acknowledged it's not enough.

When big UN set-pieces fail, people come up with apologist answers for a number of reasons. They're desperate to preserve the multilateral process. They're keen to please the hosts. They see other issues as more important than the conference agenda. Or they have a particular line to push.

But I think, overall, with the benefit of five weeks of hindsight and a number of post-Rio discussions under my belt, the conference that I reported on was the one that actually took place.

Probably not, judging by the insights gained by the Norfolk police force during their two-and-a-half-year investigation, which they've just closed.

It's a decision that's caused a fair amount of frustration.

Prof Edward Acton, vice chancellor of the University of East Anglia from where the material was filched in 2009, described himself as "disappointed"; while the Union of Concerned Scientists, which argues for tougher international action on climate change, said it was "a big shame" that whoever stole the material "had got away with it".

At a news briefing in Norfolk Constabulary headquarters in Wymondham, one sensed that the officers running the investigation shared the frustration.

Here was a crime with international ramifications that happened on their patch - the theft and release of more than 6,000 e-mails and other documents that lit a fire under mainstream climate science, perhaps contributing to the torpor in the UN climate process and raising the level of doubt in public minds.

Yet despite engaging help from the UK's specialist e-crime unit, IT security consultants and police forces in other countries, they've identified not a single suspect.

What they have concluded is that there were several "remote attacks via the internet" on CRU's servers between September and November 2009.

Some, but by no means all, of the material was released in two batches - immediately before the UN climate summits in Copenhagen in 2009 and Durban in 2011.

Various internet rumours have it that the hack was performed or commissioned by countries keen to avoid tight constraints on greenhouse gas emissions - or by oil companies, or bloggers with demonstrable IT expertise.

To those hoping that the investigation would at least hint as to whether any of these rumours were true or false, the officer in charge, detective chief superintendent Julian Gregory, gave nothing.

"From the investigation, I can't offer anything at all on that," he said.

"What I can say is there is a high degree of sophistication. That could have rested with one individual, or with some kind of state or commercially sponsored activity; but there was nothing from the investigation that indicates where responsibility lay."

At the outset, three avenues of inquiry presented themselves:

Having decided early on that the first path wasn't practical - "it's not possible to investigate the internet," as Mr Gregory put it, given the elusive nature of proxy servers - police drew a similar blank with the second.

"We've described the hack as 'sophisticated' - that's the view of our experts," he told reporters.

"They identified that as well as achieving the breach, [the perpetrators] concealed their tracks, they laid false trails... the person or persons were highly competent in what they were doing."

Only on the third issue has there been resolution.

After speaking "to everyone" at CRU and looking for signs of entry around the unit, Mr Gregory declared: "There's no evidence to say anybody connected with UEA was involved."

Even here there was a caveat.

"Because we haven't found who is responsible, we can't say categorically that no-one from UEA was involved; but there's no evidence that anyone was, and the nature and sophistication of the attack also suggests no-one from UEA was involved."

On other issues, he wouldn't be drawn.

They'd worked with police in other countries; some had been helpful, others not, but he wasn't prepared to name names.

Nor was he prepared to list people who'd been questioned.

Could the police have done more? Some argue they should have, with ThinkProgress, for example, dubbing the investigation "botched".

The raw figure of £84,000 spent on the investigation over two and a half years doesn't sound very much, although Mr Gregory pointed out this covers only specific spending on the case by Norfolk Constabulary - not routine items such as staff wages, nor what might have been disbursed by specialist national agencies who are not in the habit of divulging information about their activities.

But police forces are supposed to devote "proportionate" amounts of effort to the various cases they're investigating; and given that nobody died or was physically beaten up in the commission of this particular crime, many might argue that no more money should have been spent.

After all, it isn't the police force's job to tackle the tsunami of doubt that "ClimateGate" spewed into the court of public opinion on climate change.

So where do we go from here?

CRU's importance has always lain in the foundations it puts under the edifice of climate science.

If its record of historical global temperatures is flawed - still more if its scientists have wilfully manipulated that record - the edifice tumbles down.

It would invalidate much of the data going into computer models projecting climate change, in turn nullifying arguments that there's a burning need to do something about it.

As an institution, CRU has survived the episode with its main scientific staff still functioning, but with reforms to its operation in terms of increased openness - changes that many mainstream scientists believe will be beneficial to all in the long run.

More importantly, its temperature record has since been broadly validated and corroborated, not least by the Berkeley Earth project.

The foundations of the edifice, then, are still intact. In that sense, identifying the hacker(s) wouldn't make much difference to the world.

What it would do is shed light on who precisely is willing to go to such lengths to shake the edifice, and why.

Police professionally deal in motives as well as evidence.

And here, Mr Gregory was prepared to venture an educated guess.

"You would say that the nature of the data that was taken - quite selectively - and published on the internet appears to have been done with the intention to undermine the science that supports anthropogenic climate change.

"That, combined with the fact that the data was published immediately before global [UN climate] conferences, would lead to the conclusion that it was done with the intention of trying to influence the outcome of those conferences."

Whether "ClimateGate" was as significant in slowing progress in the UN talks as other factors is unclear.

You can argue plausibly that it was less important than a succession of cold winters in North America and western Europe, the burgeoning muscles of emerging economies, paralysis in the US political system, the growing desire of Arctic states to secure mineral resources in the region, and petro-states' domination of the G77/China bloc.

But in the folklore of the sceptical blogosphere, it's achieved cult status; no doubt about that.

Will the perpetrator eventually want to claim credit? Will that, in the end, reveal what the Norfolk police could not?

The Energy and Environmental Science journal paper calculates that total deaths will lie in the range 15-1,300, while cases will number 24-2,500.

These are deaths among the public, not among workers at the plant.

The calculations were done by Prof Mark Jacobson and Dr John Ten Hoeve from Stanford University in California.

One point they raise in the paper is that while these ranges may be big, even the minima are numbers above zero.

This contradicts statements made since March 2010 that the world's worst nuclear accident after Chernobyl would be likely not to produce a single radiation-linked fatality among the public.

(They also predict a small number of cancers - between two and 12 - among workers at Fukushima Daiichi.)

And the academics say the death and case numbers are lower than they might have been because of luck.

Only one-fifth of the radioactive material vented into the air from the stricken power station fell on land; more fallout on land would have meant a higher casualty list.

As intuition would suggest, the vast majority of the cancer cases would arise in Japan itself.

The estimate hasn't yet made any major headlines around the world; and in part, that's presumably because of the uncertainty ranges.

This kind of exercise is fiendishly difficult to do precisely.

The results depend heavily on what you put into your models, and two kinds of model are needed here - one of how radioactive material dispersed, the second relating exposure to that radioactive material with the subsequent risk of disease.

Possibly the biggest uncertainty in all this concerns whether there's any added risk of cancer from exposure to low doses of radioactivity.

Theories that are in circulation encompass the idea that there is a risk but it decreases linearly with declining exposure; that there's no extra risk; and that low doses of radioactivity are actually beneficial, a notion known as hormesis.

The Stanford academics used the first of those ideas - what's called a Linear No-Threshold (LNT) model.

One question I raised with Prof Jacobson was whether, using their methodology, you could say what the rates would have been if there were a threshold - if low doses had no effect.

Currently that's not possible, he said, though the figures probably could be derived, given time.

Perhaps the study's most important point materialises when you hold the numbers up to the light of context.

The paper mentions that evacuating people from the power station's environs resulted in as many as 600 deaths - principally the elderly and seriously ill, for whom evacuation was too arduous.

But more context is given by cancer statistics.

The figures given in Prof Jacobson's paper are for lifetime risk - that is, the number of people who will die of cancer at some point.

If you try to make the effect as strong as you can, by assuming that all those deaths will occur in a 10-year period - which is almost certainly too tight - and take the highest end of the range, Fukushima would add 130 deaths per year.

By contrast, more than 350,000 Japanese die of cancer each year, according to the Japan Cancer Society. The disease will cause the death of about one-third of the population.

Fukushima fallout, then, would be adding less than 0.1% to the total cancer mortality. If the real numbers are at the low end of the Stanford range, it'll add less than 0.001%

The nuclear accident has proven a very big deal for Japan and for nuclear power around the world.

Several reasons for that are all too real. Does the added cancer risk amount to another one, from these numbers, or not?

Often, the answer has been: "very little". But at this year's meeting in Panama City, things were a little different.

Amid all the talk of South Korea's proposed return to "scientific" hunting and whether rules for indigenous peoples' whaling are fair, an agenda oriented towards conservation was taking shape.

Rather than a single striking tone, it's a rainbow of smaller colours.

We now have an IWC programme tackling entanglement of whales in shipping nets.

Delegations discussed problems of marine debris and ocean noise; for the first time, they've agreed to hold a workshop on the noise issue.

There are moves to make the forthcoming Arctic workshop focus on what many consider as the biggest threats to cetaceans in the region, namely climate change and oil and gas exploration.

Perhaps most notably, the IWC's scientific committee, which is widely regarded as the most credible organisation in the world on cetacean science, made its strongest statements yet on the plight of small cetaceans.

One of the big anomalies in the IWC's world is that while the vast majority of talk concerns the big ocean-going beasts, the most pressing conservation priorities are small species living in national waters.

The baiji or Yangtse River dolphin is almost certainly extinct. The vaquita of Mexico, and Maui's dolphin, a New Zealand sub-species of Hector's dolphin, are competing to be next.

The vaquita, an extraordinary-looking porpoise whose silvery-grey sheen and sculpted shape almost make it appear manufactured, has lost about two-thirds of its numbers in 15 years. In 2008 the estimate was 220 individuals, so it's probably under 200 now.

The last survey of Maui's dolphin, meanwhile, found just 55 older than one year.

Both are threatened primarily by accidental catching in fishing nets.

And the IWC scientists were unequivocal. For the vaquita, they say: "If extinction is to be avoided, all gillnets should be removed from the upper Gulf of California immediately."

For Maui's dolphin, "the committee recommends the immediate implementation" of a proposal to expand the current protected area.

The plight of both species was raised in the meeting's political discussions too, with delegates prepared to do more than shelter in the lee of diplomatic alliances.

"Frankly, it's time for diplomatic niceties and strategies to take a back seat to immediate, concrete action," said Austria's Michael Stachowitsch.

"When a bank or a corporation goes under, there is shame and someone takes responsibility. How much greater must the responsibility or shame be when a highly developed mammal species is lost forever?"

In private, some pointed out the contradictions inherent in the position of governments that support a pro-conservation measure somewhere else in the world while allowing a species uniquely under their control to slide to extinction.

Some used a more pungent word: hypocrisy.

Both Mexico and New Zealand voted for the establishment of a whale sanctuary in the South Atlantic ocean - which would have required no action from either.

Ditto India - a strong opponent of whaling in rhetoric, but whose custody of river dolphins in the Ganges and Indus systems leaves them categorised as Endangered on the internationally recognised Red List.

Now, you may have read the words above and wondered how things such as recommending a course of action or holding a workshop can make a difference in the real world. Not enough there, you might well argue, to lighten readers' hearts.

One quick counter-example: The Maui's dolphin comments garnered a headline in the New Zealand Herald newspaper saying the IWC had given New Zealand a "slap".

It caused waves in the New Zealand delegation; and if these tweets become a cacophony, a government that wants to drape its head in a wig of nature's colours will have to take notice.

There's no room to wiggle around a species extinction.

At a more grassroots level, conservation groups have repeatedly issued reports and made recommendations down the years on tackling ocean noise.

They've not had much effect, even when backed up by science.

Similar warnings from the IWC's scientific workshop would carry a lot more gravitas. Their conclusions will find their way into government halls. They'll be taken at official level to bodies such as the International Maritime Organisation (IMO) that have power to act.

This conservation agenda is mirrored by an increasingly conservation-oriented budget.

Governments' core contributions to the IWC have stayed roughly constant, as one would expect given that membership has hardly changed in recent years.

But discretionary contributions from governments and indeed environment groups is rising - from £330,000 in 2010 to £521,000 in 2011.

Just this week, a coalition of nine NGOs contributed just over £10,000 for work on small cetaceans. The Dutch, Italian and UK governments each pledged a similar amount.

The discretionary pot is now about one-quarter of the IWC's total budget, and most of the contributions are directed at specific conservation activities.

Governments that have advocated this and indeed funded it, such as the UK and the US, are of course very happy about the trend, as are environment groups; you wouldn't say their praise is tumultuous as yet, but it's growing.

WWF's Heather Sohl put it like this: "Historically the IWC focused only on whaling, but the biggest threats to cetaceans today are other human activities such as bycatch, ship strikes and expansion of oil and gas developments.

"This year's meeting has taken great strides toward addressing these risks."

Whaling itself won't go away - the commission's official purpose remains the regulation of hunting. Nor will opposition to whaling. Here, South Korea saw that anger renewed.

But slowly, the stoichiometry of the IWC's rich chemistry is changing - the equation is tilting to what for a majority of countries here has long been the right side.

Over the past few years, the International Whaling Commission (IWC) has been starting to address this issue more seriously than before.

At this year's annual meeting in Panama City, I caught up with David Mattila, who's on secondment with the IWC from the National Oceanic and Atmospheric Administration (Noaa) in the US.

Noaa already has a specialist whale freeing team in place, and has even celebrated its work in video.

It all began in the late 1970s with Canadian Jon Lien, who started to free whales caught up in fishing gear off the Newfoundland coast.

David Mattila takes up the story:

"Where I started was in New England a couple of years later. Most of our whales were swimming, and actually it was an old-timer, a fisherman who'd hunted a few whales in the past, who suggested we try 'kegging' them, which is attaching our own rope and attaching buoys and maybe even being towed in a boat to keep them at the surface and slow them down."

The point is that if you can do this, you stand a much greater chance of being able to cut the animals free of whatever they're entangled in.

David and his colleagues have developed a few specialised tools of the trade.

One is a grapple that's thrown on the end of a rope, designed so that when it snares the rope already on the whale, it automatically latches on.

Two types of knife are used, both with a V-shaped blade that cuts as it pulls back, so the whale shouldn't be harmed.

David is now unequivocally a specialist in the art of disentangling whales, his team having freed 1,000 over the years.

Around New England, where he works, 60-70% of right whales and humpbacks show scars typical of entanglement. These ones, of course, have survived and somehow thrown off whatever it was that snared them; how many do not is unclear.

What is clear is that it's not just an issue off the east coast of North America.

Data collected from researchers who have studied humpbacks all over the Pacific showed that in no population were there fewer than 20% that carried entanglement scars; and for most populations, the figure was much higher.

Recently, the IWC decided to start spreading the word and the skills.

A series of workshops has been convened. In March, the show went to Peninsula Valdes in Argentina, a major site for the southern right whale.

One of the people there was Miguel Iniguez, a scientist with the NGO Fundacion Cethus. Some of the session was very practical, he recalls: "Where to stand in the boat, where the rope must be thrown, whether the engine must be kept on."

But more than that, scientists, conservationists, fishermen, vets and others are now thinking about the issue - about how to build a co-ordinated system that can respond to entangled whales, and more importantly, how to stop them being entangled in the first place.

"The ultimate solution is prevention," says David Mattila. "That's the best thing for fishermen and the best thing for the whales."

That might mean different fishing gear. In Maine, for example, lobster fishermen who traditionally left loops of floating rope between their pots now have to use a rope that sinks to the sea bed, reducing the chance of entanglement.

Curious whales have been known to entangle themselves in boat moorings. One solution could be to persuade owners to encase the rope in a stiff plastic sheath - at least for part of the year - that can't be twisted round.

The next part of the IWC plan is to hold a couple of workshops in the Caribbean in a mix of languages. Asia and Africa may follow.

The fact that the IWC is starting to look at this kind of conservation issue rather than just whale hunting has been quietly praised by a number of conservation groups, and by governments that have been encouraging it develop along these lines.

The US and others have put money into the organisation specifically for this kind of project. And it's finding common ground with pro-hunting Norway as well.

David Mattila's last word on disentangling whales is a cautionary one; don't try it yourself. Whales are wild animals, massively stronger than a human being, and may be spooked by attempts to help, especially when people jump in the water to do it.

So it's been refreshing to chat with a few first-timers this year - and confirmatory that some of them, after just three days of what's been a functional meeting by recent standards, already find the waters of hypocrisy and selective memory running deep and strong.

What's got the waters flowing stronger then ever is South Korea's proposal to begin whaling around its coast under regulations permitting hunting for scientific research.

Is science the rationale? South Korea's own statement here suggests it's not, admitting that pressure is coming from fishermen who say whales are eating too many fish, lowering their catches.

These are the same fishermen from communities near the town of Ulsan who routinely snare whales in their fishing nets, accidentally or not - perhaps as many as 150 per year - and are allowed under South Korean law to sell the meat to markets and restaurants.

The logical thing from their point of view would be to regularise what happens anyway, and make the hunting easier.

That was the implication of a submission that South Korea made a few years back as part of the "IWC peace process"; if Japanese villagers were allowed to hunt whales as part of an eventual compromise deal, they said, Koreans would demand the same right.

The peace process came to naught; but it's hard to escape the conclusion that the desire to satisfy a small but genuine whaling community is the real drive behind the scientific whaling proposal too, particularly with an election looming in December.

But whether or not the South Koreans really intend to go ahead with the plan, it's been easy for them to construct a case for it.

In the debate that followed the South Korean revelation here, delegate after delegate from anti-whaling governments cited and lauded the commercial whaling moratorium that their predecessors voted through in 1982.

Strangely, they all forgot to mention the bit of the moratorium wording where they promised to review it.

The South Koreans were happy to remind them; and to help any still suffering from the collective amnesia, it goes like this:

"This provision will be kept under review, based upon the best scientific advice, and by 1990 at the latest the Commission will undertake a comprehensive assessment of the effects of this decision on whale stocks and consider modification of this provision and the establishment of other catch limits".

Whales, gas and climate: A gray tale

Countries like South Korea and Japan are still waiting. Some whale stocks have indeed been re-assessed; but "considering modification" is not on the agenda of most IWC members, and they have no hesitation in making clear that it never will be.

Australia's commissioner Donna Petrochenko, for example, was as forthright as her populace would demand in declaring that "Australia is resolutely opposed to commercial whaling in any form" and "strongly supports the moratorium".

But that statement also makes clear that her government has no intention of honouring the international pledge it made 30 years ago. Nor does the US, UK, Germany, the Seychelles - yes, the Seychelles played a key role - or the rest of the roll call.

From a modern democratic point of view, they're quite right.

The world, as many say, has moved on, and a majority see whales as creatures to be hugged rather than harpooned. Few governments in Europe or Latin America would see their popularity rise by pledging to re-open the global whaling ban.

But what does it say to communities in South Korea, Japan, Greenland and so on who see whale hunting as quite normal?

South Korea mustered other arguments too.

On Tuesday, IWC governments voted to allow the Bequians of St Vincent and the Grenadines to continue hunting whales under "aboriginal subsistence" rules, designed for peoples with an established tradition.

The Bequians' tradition dates back about 130 years, to the time when Yankee whalers taught them how to do it.

Korea's, meanwhile, dates back 8-9,000 years - the oldest documented anywhere on the planet - with ancient rock art showing the unmistakeable coming together of harpoon and whale, and piles of bones testifying to their consumption.

But Koreans, unlike Bequians, aren't allowed to hunt anymore.

Both decisions are made according to the rules; but that's only OK if you think the rules are OK, which the Koreans don't.

The Korean "whales eat fish" argument is one of the most easily debunked in the book, and I'm sure the Koreans know it - as must the Japanese officials who used to deploy it as a justification for whaling.

But when anti-whaling countries here pointed out that it's nonsense, did they also recall that they had a chance four years ago to get Japan's signature on a conference motion saying it was nonsense, and blew it?

One delegate from a government that spoke vehemently in public against the South Korean proposal put it like this in private: "They're just frustrated".

And it makes scientific whaling their only legal option.

Are the Koreans genuinely intending to do it?

It's hard to tell. But what is clear is that the IWC's tangled and often conveniently forgotten history gives them reasons for real frustration, and the wherewithal to construct faux frustration if they choose.

As the Korean proposal puts it: "Good faith and pacta sunt servanda ('agreements must be kept') constitute the two fundamental principles of international relations."

Really?

Go back just three years, and the accepted wisdom was that there were two populations in existence.

The larger one lived on the eastern side of the Pacific Ocean with an annual migration route down the west coast of North America.

A much smaller one dwelt in the western Pacific, off the eastern coast of Russia, migrating south as far as Korea and China.

While the eastern population has regrown after the commercial whaling era to a healthy 20,000+ individuals, the western gray whale is among the world's most endangered cetacean populations, numbering about 150 animals.

Will it follow the population that used to live in the Atlantic Ocean into extinction?

If the answer to that question was unclear three years back, it's now as murky as the sea-bottom sediments in which gray whales feed.

Two years ago, aiming to track western gray whales from their summer feeding grounds off Russia's Sakhalin Island to their unknown winter breeding places further south, researchers tagged a male that they dubbed Flex.

To their surprise, it headed not south but north-east - eventually ending up among the much larger eastern population.

At last year's International Whaling Commission (IWC) meeting, scientists revealed they'd used photos to identify a total of 10 grays that spent time on both sides of the Pacific; and this year, we're up to 14.

That might seem a small number; but it's 10% of the population, so significant.

Yet genetic studies indicate the two populations are pretty much distinct.

You might ask why this matters; aren't the habits of gray whales just a scientific curiosity?

Well - no. It has clear ramifications in at least three areas.

One concerns oil and gas exploration.

The western gray whale feeding grounds close to Sakhalin are also the location of a major gas field.

The company Sakhalin Energy already has two platforms close to shore in Piltun Bay, whose shallow waters are especially used by calves.

A third Piltun platform is mooted, while another company, Exxon Neftegas, has begun work on a facility further offshore near a feeding area used by adults.

There's documentary evidence - some of it obtained through research activities funded by Sakhalin Energy under the Western Gray Whale Advisory Panel - that seismic exploration and platform construction both disturb the whales.

At this year's IWC meeting here in Panama, Russia's commissioner Valentin Ilyashenko caused some consternation among environment groups when he appeared to say that construction of the third Piltun platform was a foregone conclusion.

However, Sakhalin Energy later confirmed to me that it is a "possible eventual development" and that a full environmental impact assessment will be undertaken if and when it was decided to go ahead.

So here's the point. If a significant proportion of what was thought to be the western gray whale population is in fact migrating and breeding in the east, what's the true size of the western population?

The IWC's scientific committee summarised it so: "The number of whales in the western North Pacific population is potentially smaller than the currently estimated ~150 whales that use the Sakhalin summer feeding area.

"Thus, the status of gray whales in the western North Pacific may be of greater conservation concern than is currently recognized."

And the potential impact of oil and gas extraction, therefore, potentially bigger.

The second implication concerns the application by the Makah, a Native American people living on the western coast of the US, to hunt grays under IWC rules on aboriginal subsistence whaling (ASW).

It's already a controversial application for a number of reasons.

But if there's a chance the Makah might take one of the few western gray whales that's strayed to the other side of the ocean, that will be seen by some governments as another reason why the request should be turned down.

The third reason is that gray whales, like many other cetacean species, are already being affected by pollutants in the sea - the so-called "stinky whale" phenomenon - and are likely to be further compromised by climate change, as it alters the seasonal patterns of sea ice growth and retreat and the food supply.

One gray unexpectedly went "walkabout" in the Atlantic and Mediterranean a couple of years ago, with the suspicion being that it navigated the Northwest Passage.

In order to project what these changes will mean for gray whales, it's vital to understand where they currently go - and ideally, why.

The imminent prospect of oil and gas exploration in other parts of the Arctic is another factor that could potentially have grave impacts for grays and other species - again, understanding their current habits is key in making sensible decisions on where, when and how to explore.

Further sighting and tagging projects are planned. They may yet write the natural history of gray whales in black and white.

The Australian minister for sustainability, environment, water, population and communities is due in Panama City for a couple of days to bang the drum for what has been his country's favourite environmental cause - whaling.

But it might be a visit that no-one notices.

When I covered my first International Whaling Commission (IWC) meeting back in 2005, Australian journalists were the second biggest posse in the press room (after the Japanese), and certainly the most entertaining.

Then, ministers such as Ian Campbell (who subsequently went on to join the advisory board of the Sea Shepherd Conservation Society) and Peter Garrett could denounce Japan's whaling "slaughter" from one end of the conference hall to the other, confident that a TV camera would forever be on hand to bring his judgement to the folks back home - not, one sensed, that they needed any convincing.

This year, not a single Aussie camera crew nor even a humble smith of the written word will be there to record Mr Burke, should he similarly declaim.

As I write these words, I'm sitting on a raised rostrum at the back of the main hall here that's been set up for TV crews - power outlets, audio feeds and all.

But I have it to myself.

In recent years, Australia has been the touchstone for public interest in whaling.

The country has pretences to own a giant slice of the Southern Ocean, it has a thriving whalewatching industry, and the zeal of a recently reformed smoker, having quit the harpoon itself only in 1979.

A quick Google News search in advance of this year's meeting for "Australia + IWC" turned up not a single article, and it's far from being the only country where there's a dearth.

So what's happened?

One answer may lie in how the IWC's agenda is effectively changing.

The biggest issue out there for many supporters and opponents of whaling is Japan's programme in the Southern Ocean - closely followed by Japan's coastal whaling programme, Iceland's fin whale hunt and associated whalemeat exports, and the Norwegian hunt.

But despite all the sound and fury of recent years, inside and outside the IWC, those programmes have continued largely unchanged.

Where there have been changes, they've happened in spite of the IWC.

Japan's annual catch has shrunk through the apparently declining appetite of consumers for whalemeat, depleted government finances, and harassment by the Sea Shepherd Conservation Society.

Iceland isn't exporting as much whalemeat as it would like, because, again, of consumer disinterest in Japan.

Added to that, the so-called "peace process" designed to find a compromise between pro and anti-whaling nations concluded in 2010 without agreement, signifying that established official positions are pretty much immutable for the time being.

So IWC discussions have moved on.

This year, aboriginal subsistence whaling (ASW) is top of the agenda.

And despite serious concerns about humane killing and the blurring lines between what constitutes a subsistence need and what is quasi-commercial, hardly anyone connected with the issue disputes the basic point that indigenous peoples who depend on whalemeat should be allowed to hunt them.

Slowly, and almost despite the intergovernmental nature of the top-line discussions here, the IWC is developing programmes of conservation science - I'll be reporting on some of them later this week.

So it's harder to get angry. Words like "slaughter", which once dripped with blood from a Japanese harpoon, have largely been excised from the IWC lexicon.

A few years ago, Japan's deputy commissioner to the IWC, Joji Morishita, observed that in his view, whaling should become "boring" - uncontroversial, flying under the public radar, like most fisheries issues.

Has his wish come true?

You didn't know? I'm not sure government negotiators know either. Certainly US chief negotiator Todd Stern, who usually purveys a smooth brand of spin, waffled more than I've ever heard him when I raised the issue at a news conference.

Here's the key phrase from the declaration:

And the key word is "prevent".

As far as I'm aware, there's no way to "prevent further ocean acidification" other than by turning off the flow of CO2 into the atmosphere.

In fact, you'd have to go further.

A proportion of the extra CO2 already in the atmosphere as a result of humanity's historical carbon emissions will find its way into the sea and contribute to acidification. So that would need to be tackled too, either by absorbing it from the atmosphere or from the sea.

In the environmental movement's terms, that's a result, isn't it?

I'm raising the issue not because I seriously think governments will bring an urgent end to carbon dioxide emissions as a result of this declaration, but because it's absolutely clear they won't.

And that raises the question of what else they will and won't implement coming out of Rio20+.

If the answer is "very little", then that raises the further question of whether these big UN set pieces are really worth it.

What's the point in flying negotiating teams halfway round the world, providing all the five-star hotels and limousines and security details that 130-odd heads of state and government demand, if all you end up with is a piece of paper that will bring little change - especially as it was pretty clear beforehand that many governments weren't really interested in a major adjustment of business-as-usual?

A structuralist analysis of the text's penultimate iteration by WWF turned up some revealing statistics:

That's more than one "reaffirmed" a page, and none taking the world further towards a sustainable era.

There has been agreement on processes coming out of Rio that could lead to something concrete.

Sustainable development goals (SDGs) should be up and running by 2015. The next step is to decide what they should say; and there must be a question of how governments overall will engage with that, given the failure to agree themes in Rio.

Another process should lead to better governance of the high seas: marine protected areas, regulation of illegal fishing, and so on. As a caveat to the general gloom in environmental circles, it's worth noting that some activists specialising in marine issues were pretty happy with the outcome.

Ban Ki-moon will produce a report on how UN processes can better take into account the rights of future generations.

Some governments, and some civil society groups, see these processes as opportunities; if we engage with them properly, the vibe seems to be, we can make them worthwhile.

But the list of things that were not done is far longer:

The halls of these summits are, of course, filled with people who believe in the multilateral system.

But their faith has been shaken this week. One senses that the UN's faith has been a little shaken too.

A year ago, I wrote that the big summit was looking for a big idea.

One of the responses I received then from people close to the organisers was that the event wasn't going to be anything like the 1992 Earth Summit, when legal treaties were on the table encompassing all nations.

This one, it was said, would be more about countries and companies - and indeed groups of countries plus companies - making voluntary announcements on what they were prepared to do to make the world more sustainable.

And they've arrived - 680 at the last count, all listed on the summit website. If you feel like doing a crowd-sourced analysis, why not look at one or two and post a comment?

But as several observers have said, why bring ministers and corporate leaders to Rio, when they can make all the voluntary commitments they want at home?

If voluntary commitments are all governments want to do at this point in time - which appears to be the case, given the nature of the climate change accord made at the Copenhagen climate summit in 2009 and now this - that begs two more questions.

Firstly, is there any point in pretending otherwise? And secondly - and more importantly - can voluntarism ever be enough to sort out the complex mix of social and environmental issues that humanity finds itself facing?

The secretary-general said in a world of plenty, no-one should go hungry.

The final phase of the summit has seen pledges from countries and companies on issues such as clean energy.

But a number of veteran politicians have joined environment groups in saying the summit declaration was "a failure of leadership".

And UK Deputy Prime Minister Nick Clegg described the outcome as "insipid".

The meeting, marking 20 years since the iconic Earth Summit in the same city and 40 since the very first global environment gathering in Stockholm, was aimed at stimulating moves towards the "green economy".

But the declaration that was concluded by government negotiators on Tuesday and that ministers have not sought to re-open, puts the green economy as just one possible pathway to sustainable development.

Mary Robinson, formerly both Irish president and UN High Commissioner for Human Rights, said it was not enough.

"This is a 'once in a generation' moment when the world needs vision, commitment and, above all, leadership," she said.

"Sadly, the current document is a failure of leadership."

The former Brazilian President Fernando Cardoso, who chaired the 1992 Earth Summit, said the declaration did not do as much for environmental protection as for human development.

"This old division between environment and development is not the way we are going to solve the problems that we are creating for our grandchildren and great-grandchildren," he said.

"We have to accept that the solutions to poverty and inequality lie in sustainable growth, not growth at all costs."

Mr Ban had hoped the summit would take firmer steps towards ensuring the poor had access to water, food and energy.

However, his flagship Sustainable Energy for All initiative was merely "noted" in the text, not enthusiastically endorsed.

'Ray of hope'

In the meeting's final phase, he challenged governments to do more.

"In a world of plenty, no-one, not a single person, should go hungry," he said.

"I invite all of you to join me in working for a future without hunger," he told the estimated 130 heads of state and government in Rio.

Currently, it is estimated that almost one billion people - one seventh of the world's population - live in chronic hunger, while another billion do not receive adequate nutrition.

Measures that could help address this include eliminating food waste - about one-third of food is thrown away in rich countries and an even higher proportion in the poorest, for different reasons - and doubling the productivity of smallholdings.

The challenge is partly based on Brazil's own "hunger zero" programme, started by President Lula de Silva.

"Ban Ki-moon's announcement is a welcome ray of hope in a summit that has been shamefully devoid of progress," said Oxfam's chief executive Barbara Stocking.

"Despite the fact that the world produces enough food to feed everyone, there are more hungry people today than when the world last met in Rio in 1992," she said.

However, for the moment, a challenge is all it is.

There is no new money, and no changes to the way the UN organisation itself approaches the issue of hunger.

Outside the main negotiations in Rio, companies and governments have made well over 200 pledges of voluntary action in various areas.

Energy, water and food are all in that mix - though outnumbered by pledges to include sustainability issues in education programmes.

Choosing a word that I hope will work in Portuguese, I ask him for something "ambientale" - environmental - and he begins to declaim.

"Don't want a homeland, don't divide the Earth," he enjoins, quoting the words of Brazilian poet Cecilia Meireles (in Portuguese, with translation brought to you by BBC colleagues).

"Don't divide the sky, don't throw pieces into the sea.

"Don't desire - be born way above - that all things will be yours."

Nelio is an example of local-style micro-capitalism in action at the Cupula dos Povos, the People's Summit.

Half-way across Rio in geographical terms and half a world away in some of its ideology, this alternative gathering is an organic smorgasbord of discussion groups, music, small-scale technology demonstrations, local food, culture, and a few other things as well.

Awnings stretch across discussion areas. Birds sing, children play on the grass, boats sway in the sea next to Flamengo Park, in the heart of Rio.

A band of flutes and drums ambles across the park, people making dalliances with the dance as they pass.

Two things that wouldn't be welcome here are neoliberalism and corporations; they're words that crop up in many of the discussions, and not in a good way.

"The Peoples' Summit in general is the grassroots reaction to what's happening at Rio+20," says Darcy O'Callaghan, who works in Washington DC for the NGO Food and Water Watch.

"We fight against privatisation and commodification of water.

"And in Rio, we're seeing more and more the multinational water corporations as well as multinational water users trying to buy their way into policy spaces so they can secure enough input and enough market for their products."

One of the most persistent criticisms of the United Nations summit here is that it's been "bought" by corporations.

Certainly, scions of the corporate world are everywhere - on panel discussions, making announcements about things like clean energy and sustainable water use - and in some cases, lobbying against bits of the political declaration that they don't like.

And as those at the People's Summit point out, they're on campus, around the dinner table with government delegates and UN officials, rather than a two-hour bus journey across town like the anti-corporates.

The official UN view is that the corporate sector needs to be fully engaged because without it, things aren't going to change.

It's a view endorsed by many governments too, and by some NGOs who choose to work with businesses rather than rail against them.

But it finds short shrift in the Cupula dos Povos.

For Carol Tokuyo, one of a group meeting under the banner "Youth and Environmental Justice", the culture of consumption and private gain is the root of the problem - the reason why humanity is on an unsustainable track.

In their own lives, they're doing things differently.

"We are a network across the whole of Brazil, in every state," she explains.

"We are making profound changes: we are collectives, we live together in big houses with 10 to 20 people, we eat together, we have our own money which we share together."

The sharing extends to education; the group has created an online e-university, Carol tells me, where people swap knowledge with each other rather than having to buy it.

The tent next to hers is rocking to a band whose rhythms and melodies create a kind of mixed African and Latin vibe; and it's with some surprise that I see that the banner on the tent reads Interfaith Dialogue against Religious Intolerance.

But my guess about the music turns out to be spot on.

"We have the African-Brazilian religion people and they're fighting for their rights," an imposing gentleman, whose name I don't quite grasp over the music, tells me.

These are the descendants of slaves brought to Brazil in the late 1700s and early 1800s who've not been assimilated into mainstream Brazilian society.

"They have lots of problems, they face lots of prejudice, and sometimes the state doesn't help.

"Today we have been discussing the creation of special areas inside environmentally protected places that could be set aside for their religious practices."

At the Stockholm environment summit of 1972 - the world's first - and at the Earth Summit here in 1992, the activists' gatherings were acknowledged as the conscience of the meeting.

This time, they're aiming to play the same role, and making much the same arguments. But it's not clear this time who's listening.

On my way out, I see a lot of happy faces - hardly surprising as they've had an afternoon of good food, great music, a bit of dancing and a bit of poetry to leaven the serious messages.

It's a lot more fun than the bigwigs' paw-wow over at Rio+20. But it's still the bigwigs who are running the show.

In some ways, they already do; carbon emissions are assessed on in toto and per capita bases, deforestation rates are calculated.

But is it possible - is it desirable - to put all of this together in a single number?

Matt Prescott, the ex-Oxford University academic who put together the Energy Saving Day initiative a few years back, believes it is.

Just as financial credit ratings agencies such as Standard and Poor's or Moody's rate countries as AAA, A-, C, junk or whatever, on how solid a bet they are for investment, Dr Prescott believes there should be a simple environmental scorecard for countries.

In time for both the Rio+20 summit here and the G20 meeting in Mexico, he's just released his initial analysis under the Environmental Rating Agency (ERA) banner.

It covers the G20 countries (which number 19, as the EU is among the 20).

Each receives a rating on various indicators such as per-capita greenhouse gas emissions, extent of protected area, the net rate at which forests are being planted or chopped down, air quality, the presence of threatened species, and so on.

For each country, these are then combined to produce an overall indicator.

Perhaps unsurprisingly given the strong influence that "Die Gruenen", the Greens, started exerting on politics back in the 1970s, Germany emerges at the top of the G20 table.

But it falls short of an AAA rating, the most coveted in the financial arena, because of sub-maximal performance in terms of forestry and carbon efficiency.

The presence of the US and Canada in fourth and fifth places would raise some eyebrows in the environmental community, given that neither has fulfilled its pledges under the UN climate convention, and that both are ploughing ahead with "unconventional" fossil fuel extraction in the form of tar sands and shale gas.

However, the US has clean air, significant protected areas on land and sea, and efficient power plants, while Canada garners AAA status on power plant efficiency, sustainable use of freshwater, and low corruption.

Bottom of the G20 pile with a B- rating come Saudi Arabia and India.

The Saudi ranking is pulled down by DDD ratings on air quality and water extraction. India receives three DDDs, on carbon efficiency, water extraction and marine protected areas.

While no country gets AAA overall, equally no-one is at "junk" status - which, in the financial world, means "don't touch it with a bargepole".

Three caveats on the ERA approach spring pretty quickly to mind.

Firstly, how do you select your indicators? Various groups of the environmentally-minded would pitch for issues such as nuclear waste, corrosive influence on international negotiations or killing of marine mammals to be included. There are more examples too.

Secondly, how good is the data? There's a very active debate ongoing, for example, on what constitutes effective marine protection - and government statistics on many things aren't always reliable.

Thirdly, on some indicators, nations are either beneficiaries or victims of their geography. Canada can gain a stellar rating on water use, because it has so much of the stuff and relatively few people; it's not the Saudis' fault that their territory is largely arid and barren.

But some of these issues also apply to the financial credit ratings, which, it would appear, have the potential to break a country's economy and bring governments down.

Matt Prescott admits this first report isn't the finished article. Refining will occur, and if others want to come forward to help make this a more comprehensive exercise, they're entirely welcome.

What effect would it have if ERA-style ratings were applied to countries?

Would we ever hear on the news, for example, that "the UK has been downgraded from A to A- after it slashed subsidies for renewable energy"? And if we did, what would it mean?

It could - perhaps should - have some impact on long-term economic investment.

"Every nation's economy is embedded within its environment, and our new environment ratings could provide a useful tool for investors seeking to reduce their exposure to both short and long-term risks," Dr Prescott suggests.

Environmental factors already influence investment decisions to some degree, as corporations and indeed individuals have to take projections of things such as sea level rise and water availability into account.

But the real impact might be reputational. South Korea, for example, is generally regarded as a "green" nation these days, but the ERA analysis suggests it's underperforming against its peers.

Would we see proud Germany getting even greener to maintain its lead? Would South Africa's ecotourism industry suffer as it garners a mere BB rating?

Increasingly, companies vie with each other to be seen as "green". Ratings on things as diverse as the efficiency of electronic appliances and the sustainability of fishing methods are changing consumer behaviour and, therefore, the performance of suppliers.

Could the same thing happen through rating countries? And who'd be first in line for an AAA or a junk rating?

It's hard to credit now, in the age of Sao Paulo, Rio de Janeiro, superhighways and cattle ranching, but the Atlantic Forest once covered more than 1m sq km (385,000 sq miles).

It governed the coast from Recife down through Uruguay and into Argentina, and stood as far inland as Paraguay.

Now, just tiny fragments remain, totalling about 4,000 sq km - struck down, as Maurizio Ruiz tells me, by coffee, charcoal and cattle.

"The coffee plantations came first, in the 1800s," he says; "and what wasn't destroyed by coffee was destroyed by the charcoal industry."

Now, as in the Amazon, cattle ranches have carved out new homes - aided in recent decades by the government, which saw forest simply as land that could be cleared and settled and used for an economic activity.

Stand on the roadside outside the small town of Miguel Pereira, an hour or so north of Rio de Janeiro, and the problem is clear as the sunny day.

The far-off hills are covered in dense forest. But on the slopes immediately below us, it's a different picture.

Grass, fences, a few rather scrawny cattle, the fraying relics of abortive eucalyptus plantations, a rather inviting swimming pool; just the occasional lonely tree still stands.

And as the valley bottom holds a stream, this land clearance isn't entirely legal.

Under current laws, landowners have to keep 20% of their territory under tree cover. Land within 20m (65ft) of a river has to stay forested, as do mountaintops.

The clean-shaven ground here is a problem for any wildlife that might have lived in the forests that once grew here.

But ironically, it's providing a window of opportunity for an organisation that wants to plant trees - ITPA (Instituto Terra de Preservercao Ambiental), the organisation that Mauricio founded 16 years ago, at the tender age of 14.

"When I was a kid, I used to run in the field and I used to think about doing this," he says.

He wanted to reforest the denuded lands but also to provide continuing employment for people who worked as itinerant labourers or farmhands - or as tree-fellers.

Now, ITPA employs about 130 people all year round and a few more during "restoration season", September to November.

By the side of a grassy track, 52-year-old Sebastiao - he doesn't give his surname - is planting yellow lapacho (aka ipe-roxo) saplings.

It's a simple business.

A hole is dug; some hydrogel - water plus a polymer - is put in the hole to provide slow-release moisture during the dry season. The sapling follows, and the roots are covered with soil; that's it.

"When I started, I didn't know anything about planting trees, I only knew about cutting them down, burning them," says Sebastiao.

"Then, I was working on a farm and I heard about these jobs.

"Now, I adore the work - it's been a school to me. I never worked in a legal way with documents before."

The reason behind ITPA's continued existence is that for various reasons, people need trees planted.

If landowners want access to credit, subsidies and grants available for protecting watercourses, they have to stay within the forest law. ITPA can plant enough trees on their land to bring them into legality.

The law says that if a company wants to fell one hectare (2.47 acres) of forest for whatever reason, it has to plant five hectares somewhere else.

ITPA is happy to help them.

Ecologically, the goal is to connect the dots - to join the still-forested fragments in the area north of Rio, known as the Tingua-Bocaina Biodiversity Corridor, in order to provide a piece of forest and a wildlife habitat big enough to form a meaningful ecosystem.

A patchwork of tiny fragments doesn't maintain itself as forest nearly as well as a large expense; it's more prone to drying out, for example.

A fragment may be too small to support native animals. Even if a few do live there, they can't cross to other areas, leading to inbreeding and loss of genetic diversity.

The golden lion tamarin, ITPA's executive assistant Juliana Bustamante tells me, needs a corridor about 40m wide; with that, it'll travel.

Up in the hills, far away from the RioCentro convention complex where government negotiators pore over brackets square, round and curly, ITPA is acting out a central theme of the Rio+20 vision: that the interests of people and nature are not that different.

From here flows the Santa Ana river, a major water source for the teeming millions of Rio.

The authorities spend half a billion dollars each year cleaning up soil that's been washed into the water when rainwater courses down denuded slopes.

Plant the trees, secure the soil, and you save the money, while simultaneously giving people employment and securing the future for animals like the golden lion tamarin.

The International Union for the Conservation of Nature (IUCN) is taking an interest in ITPA because it sees the group as a living example of the green economy in action.

"IUCN along with other partners has launched a target to restore 150 million hectares [globally] by 2020," says forest and climate chanage specialist Carole Saint-Laurent.

"We've done some analysis and have discovered that if we were to restore 150 million hectares, this would generate for local communities more than $84bn (£53bn) per year in net economic benefits.

"Well, you can't be more relevant than that to the agenda at Rio+20."

On the road back to Rio, we stop underneath a spectacular old iron railway bridge - "the first curved iron bridge in the world," Mauricio informs me, with some pride.

But the real pride lies in the forested strip along the river that the bridge straddles.

Planted just three years ago, the forest now teems with life. Trees are at least 6m high, including one with a trunk covered in thorns and another whose crushed leaves smell just like garlic. Insects are everywhere, including several trying to burrow under my skin, and birds caw in the background.

On the hillside above, a few cattle peer down on us with cud-chewing distain.

ITPA hasn't finished, not by a long way. It's re-forested about 800 hectares so far, but the immediate ambition is 18,000.

The controversial recent revisions to the Forest Code, the national law, may yet slow the demand for planting, as they relax the constraints on landowners.

But international money may start to flow through the UN's REDD (Reducing Emissions from Deforestation and forest Degradation) scheme.

Future visitors to Rio will never see the Atlantic Forest in its former full glory; that's impossible.

But they way find enough to give a glimpse of what life was like here before the coffee and the charcoal and the cattle came.

Politics isn't necessarily the best course, nor politicians the best people to plot such a course, to judge by the glacial, boulder-strewn pace of talks here in Rio.

The science is clear on so many of the issues, and ministers acknowledge it - but they see many other factors too, which is why the political response on issues such as climate change often lags way behind the science.

If politics can't get on with it, what about the law?

In 1996, lawyer Mark Gray had a simple vision: make ecocide (destroying nature) a crime.

Well, you might say, any country can do that - and many countries have, in various degrees. Depending on where you live, lighting bush fires, stealing birds' eggs, dumping old motor oil in streams and building on the habitat of a protected newt can all land you in court.

But other nations don't have such laws. Also, activities that harm the natural world sometimes take place beyond national boundaries, such as exploitative high-seas fishing - and some of the worst are performed by companies belonging to one state but operating in the territory of another.

Hence a move several years back by UK barrister Polly Higgins to make ecocide one of the five international "crimes against peace", joining war crimes, genocide, crimes against humanity and the crime of aggression.

The Eradicating Ecocide movement isn't talking about slap-on-the-wrist punishments for law-breaking.

Last year they mounted a "trial" trial - a demonstration, if you will - where two CEOs of fictional Canadian tar sands companies faced a court staffed by real lawyers, a real judge and a real jury.

One was "sentenced" to four years in jail.

As well as bosses of misbehaving corporations, the movement believes ministers and heads-of-government that commit or allow ecocide should also stand trial.

And cases could be brought on behalf of inhabitants, whether human or another species.

The Eradicating Ecocide notion has gained some backing - from environmental activists of course, but also, I'm told, some governments, though I'm not aware of any that have gone public with it yet.

The chances of gaining support from all governments would appear to be infinitesimally small, especially given that a number have chosen not to put themselves under the jurisdiction of the International Criminal Court, the body that can hear cases brought under the four existing crimes against peace.

But maybe that doesn't really matter. The main aim is to prevent ecocidal events from occurring in the first place; and if you have a corporation, say, that operates in many countries, some that are parties and some that aren't, it's going to have to adhere to the standards of those that are.

Given where I came into this article, there's an irony here in that we're talking about lawyers saving the environment from lawyers.

Most countries employ lawyers as negotiators in these UN processes, and that's partly why they get so bogged down.

Working out the legal definition of a tree in the Kyoto Protocol took years.

Yet in the court arena, the law has the capacity to cut through these very same knots. If your neighbour cuts down what any normal person would call a tree that's standing on your side of the fence, he/she can face punishment, with no arguments about the legal definition of said tree.

So what would a normal person put under the heading of ecocide?

The word gained an airing across the world 40 years ago, at the first UN environment summit in Stockholm, when Sweden's Prime Minister Olof Palme levelled the charge against the US over its use of defoliant chemicals during the war in Vietnam.

In Polly Higgins' vision, ecocidal acts during war are not the main target - they'd be covered under some of the other crimes of peace.

The main concern is what happens during normal times.

So the law would presumably cover something like a massive oil leak caused by slack or actively risk-taking management, for example.

Would fishing or hunting a species to near-extinction count? What about:

Clearly there are some difficult issues here.

If a company digs a massive mine, for example, there's going to be significant ecological damage in the area. But with will and the right approach, it can be restored after the mine closes.

So would the initial dig qualify as ecocide for the damage it does?

It'll be interesting to see how far the Eradicating Ecocide idea goes in the next few years.

One senses inevitable resistance ahead from a number of very important countries. And dealing with that would be a matter of politics; which in the environmental arena, as we're seeing here in Rio, is often a long and messy business.

A new environmental summit is about to take place in Brazil, 20 years after 172 nations gathered in Rio, for the Earth summit. To find out more about the issues facing the United Nations Conference on Sustainable Development, or Rio+20, see below.

So given the huge issues facing humanity in terms of sustainability, I was interested to see what thoughts the TEDx event on the fringes of the Rio+20 summit might provide.

Organisers laid on a two-day thinkfest in Forte de Copacabana, a former military base at the southern end of this most famous of beaches that (rather fittingly given its use today) saw rebellion against the established order in 1922.

On the way in, we were invited to sample a number of artistic installations on themes of humanity, biodiversity and sustainability - presenting the problems, you could say, in a more graphical way than the dry reports in which the bad news usually arrives.

The rooftop vantage point gave a nice little vignette of this city's two faces - playgrounds of white sand stretching into the distance, and the endless convoys of enormous cargo ships steaming in and out of port, plying the trade that's helping to enrich this giant nation at some cost to its natural environment.

At the TEDx session I went to, Canadian psychologist Gabor Mate gave an insight into the modern human condition based on his work with addicts.

"If the success of a doctor is measured by how long his patients live, then I have been a failure," he said.

His description of addiction is that it concerns the person much more than the substance; many try drugs without becoming addicted, many enjoy a lifelong relationship with alcohol without becoming an alcoholic.

Dr Mate gave an elegant account of his own struggle against addiction - not to a substance, but to buying classical music CDs, on which he'd once spent $8,000 in a single week and (in a previous medical role) left a woman in labour in order to continue shopping.

Given that the Rio summit (and therefore the TEDx event) is concerned with the state of the world rather than the state of someone's psyche, one could sense there the talk was going - and eventually it did.

Stalin, Hitler, Attila the Hun - all were "quite willing to fight wars and kill people to keep power; power is all about emptiness that you try to fill from the outside.

"Let's not look to the people in power to change things, because people in power are among the emptiest in the world... they're never going to change unless we make them."

Next up was Jean-Michel Cousteau, scion of the famous ocean conservation dynasty and now president of the Ocean Futures Society.

He told us how as a kid he used to bunk off school to catch octopi to sell for a few francs, finding them under rocks in the inshore Mediterranean shallows.

Now, you don't find them there anymore, he said.

A number of conservation groups are hoping Rio+20 will lead to some meaningful outcome for the open oceans, which are in a sense our world's final frontier.

While land and coastal waters belong to nations and therefore stand a chance of being looked after, the high seas are another matter - hardly regulated at all, and therefore increasingly exploited and polluted, with no government obliged to do anything about it.

Ocean Futures Society is arguing that 20% of this area should be set aside for conservation.

It's highly debatable whether the politics exist to make that possible - significant governments such as Japan are determined to preserve fishing access that is only regulated on the basis that it's a food resource, while others such as the US see major riches in the future from minerals exploitation.

And on other issues affecting the oceans - climate change, acidification, plastic pollution - meaningful protection needs to start on the land-based sources of the stuff causing the problems.

Nevertheless, the issue is live in the Rio+20 negotiations.

Laurence Kemball-Cook came on stage to talk about the paving slabs he's invented that generate electricity when they're stepped on.

Each green slab contains a light powered by 5% of the electricity. So what you get isn't only current, but the knowledge that a mere footfall can generate it.

They've already been trialled in schools and other public sites, but the biggest installation so far will be at one of the London underground stations in use for the Olympic Games that begin next month.

Will the slabs survive? Will they thrive? In TEDx language - will they inspire?

Perhaps the most impassioned speech of the day came from someone who wasn't actually in Rio but joined in virtually (the power of the networked world and the information society is a constant TED theme) from her home in Canada.

Severn Suzuki - daughter of the renowned conservationist David - went to the Rio Earth Summit 20 years ago as a 13-year-old to ask her elders to sort themselves out.

That 1992 speech was caught in full on video and it's now one of the most frequently viewed YouTube offerings on environment and sustainability.

What I think caught people's attention was the mood. You might imagine that a 13-year-old girl would talk about emotive things like dolphins and rainbows, and talk in pink generics such as "making the world a better place".

Not a bit of it. Ms Suzuki lays into the delegates: "I've come to tell adults you must change your ways... I'm fighting for my future".

She points out that as yet there is no technical remedy that can clean up mercury pollution or PCBs.

"If you don't know how to fix it - please, stop breaking it," she says.

This year, back via webcam holding one of her own children, Ms Suzuki was no less impassioned, though the message carried a strong flavour of frustration and an occasional hint of despair.

"Twenty years after Rio, we haven't come close to achieving the sustainable society we knew we needed then," she told TEDx delegates.

A while back, she stepped away from big-picture campaigning to work on citizen engagement - trying to generate change from the bottom up.

In Canada, at least, it hasn't worked - maybe not in many other places either. Politically, Canada has shifted away from environmental positions, weakening endangered species legislation, backing fuels such as tar sands, and most recently deciding to leave the Kyoto Protocol.

"The collusion between governments and corporations that we've seen in the last 20 years is enough to make anyone lose faith," she said.

But... the next generation demands better: "I'm a parent and I can't afford to be discouraged".

I don't know if Ms Suzuki could hear the applause she received from the TEDx crowd, but it was huge.

As far as I know, none of the government negotiators who will spend the coming few days attempting to patch together an agreement in the official talks were there to hear it.

"It counts napalm and the cost of a nuclear warhead, and armoured cars for police who fight riots in our streets," he told an audience at the University of Kansas.

"It counts Whitman's rifle and Speck's knife, and the television programmes which glorify violence in order to sell toys to our children.

"Yet... it measures neither our wit nor our courage, neither our wisdom nor our learning, neither our compassion nor our devotion to our country.

"It measures everything, in short, except that which makes life worthwhile."

The target of the senator's ire was Gross National Product (GNP), the dominant indicator of US economic well-being.

Forty-four years later, little has changed. Politicians now generally use Gross Domestic Product (GDP) instead of GNP, but it's a technical difference.

If it goes up even by a fraction of a percent, we're supposed to rejoice - the economy is growing and all is right with our world. If it goes down, faces fall - the economy's shrinking - and the bells of doom start to clang.

Some economists have long questioned whether GDP is measuring anything meaningful. And in recent years, enough governments have listened that the issue is now on the agenda of the Rio+20 meeting.

The text in the draft agreement here - which may or may not be agreed, of course - reads:

"We recognise the limitations of GDP as a measure of well-being and sustainable development.

"As a complement to GDP, we resolve to further develop science-based and rigorous methods of measuring sustainable development, natural wealth and social well-being, including the identification of appropriate indicators for measuring progress... [and] use them effectively in our national decision making systems to better inform policy decisions."

So what's wrong with this simple concept whose rise and fall has come to dominate our news headlines?

"GDP is quite simply a measure of all the money we spend on all the stuff we buy - every financial transaction that takes places in the economy, all that adds to growth," says Andrew Simms, a fellow of the New Economics Foundation (Nef) and author of several books on the subject.

And it is the indiscriminate nature of GDP that gives him, as well as Robert F Kennedy, a problem.

"Say you had a crime wave, and everybody felt insecure and rushed out to buy more locks for their windows and doors; that would look good on the balance sheet, but it wouldn't tell you the story that something bad was happening in society."

IN GDP-world, a society that drives is richer than one that cycles, as more money is spent.

The faster that mobile phones are traded in for new models, the richer we are; chopping down a forest adds to the national economy. The more alcohol, cigarettes and petrol that are sold, the better off we are.

Criticisms of GDP include:

Defenders of the status quo point out that it was never meant to measure environmental or social well-being.

But by dint of being measured constantly and referred to constantly by politicians, business leaders and newspaper editors, others would argue it has become society's weather vane - just about the only simple number in daily use that can be cited as evidence that things are getting better or worse.

Organisations such as Nef have developed composite indicators that they believe are more comprehensive and more valid.

The European Commission has put together a handy compendium, listing and explaining concepts such as the Genuine Progress Indicator, Environmentally Sustainable National Income and the Happy Planet Index.

The tiny South Asian nation of Bhutan famously uses the Gross National Happiness indicator, which combines issues such as children's health and educational status with measures of environmental protection, cultural values and good governance.

But many other countries are starting down the same road.

Oxford University economist Dieter Helm has just been appointed to lead the UK's Natural Capital Committee.

Its role is to assess the financial worth locked up in trees, clean water, insect pollinators and every other part of the ecological kingdom, and present this set of accounts to the Treasury - which should then be able to make better informed decisions.

It's worth recalling that the UN-backed Economics of Ecosystems and Biodiversity (Teeb) project calculated the value of forest lost globally around the world at $2-5 trillion (£1.3-3.2 trillion) each year.

But Prof Helm also hopes to shine a light on other questions.

"If you peel back and ask 'how well have we been looking after our assets in the British economy?' rather than just saying 'has GDP gone up or down a bit?', we'd have to ask some difficult questions.

"Why did we use up all the North Sea oil and gas [revenue] for the benefit of just one generation? Why did we set nothing aside for future generations? Why haven't we been maintaining our roads and railways properly?"

The implication is that an indicator more sophisticated than GDP should catch such things.

Not everyone is convinced by the arguments for going "beyond GDP".

"Everybody knows that the GDP figures are not perfect," says Lord Lawson, Chancellor of the Exchequer under Margaret Thatcher.

"But nevertheless they are extremely useful, and anybody who tried to pretend they were not useful I think would be laughed at."

And he has little time for natural capital accounting.

"It is all a lot of nonsense, because there is no way that you can introduce objectivity into this and it is just used for political campaigning of one kind or another - you just make it add up to whatever you would like it to add up to."

So far, most governments are with Lord Lawson; GDP remains the economic indicator that makes newsreaders sound happy when it rises by half a percent and funereal when it falls. Bhutan is in the minority.

But ministers in Rio will be reminded of the words of Simon Kuznets, the economist who invented GNP 80 years ago: "The welfare of a nation can scarcely be inferred from a measure of national income".