COP21: Rhone Glacier drone footage shows ice retreat
Diplomats and climate experts are to meet in Paris for the UN Conference on Climate Change, aiming to secure a new global deal that would limit emissions of carbon dioxide.
For many of us the impact of climate change can often seem distant and difficult to visualise - but that is far from the case in Switzerland.
There, a temperature rise of 2C in the last 150 years has led to a rapid acceleration in the melting of the country's glaciers.
If greenhouse emissions continue to rise according to current trends, all of the large masses of ice in the Swiss Alps will have almost vanished by the end of the century, scientists warn.
BBC video journalist Howard Johnson travelled to the Rhone Glacier, which has receded by 30m in the last year alone.
He met glacier expert Dr David Volken who set out the evidence for the ice sheet's retreat - and why the world should sit up and pay attention.