EPA Chief: 'World will listen' to US on climate
President Obama unveiled a sweeping program for combating climate change, saying there is no greater threat to the future and future generations.
His plans involve cutting US greenhouse gas emissions by a third within 15 years, and relying more heavily on wind and solar power.
"We're confident we got this right," says Gina McCarthy, Administrator of the US Environmental Protection Agency.
She spoke to the BBC's Laura Trevelyan following the announcement.