World leaders gather for climate change summit in New York
World leaders are being asked to make bold pledges to address climate change at a one day summit in New York.
UN Secretary General Ban Ki-moon said the global response to climate change will "define our future" and that a "clear vision is needed."
The summit aims to build momentum for a new world treaty on reducing greenhouse gas emissions next year.
David Shukman reports.
24 Sep 2014
- From the section Science & Environment