COP26, which begins on Oct. 31, aims to secure more ambitious action from the nearly 200 countries that signed the 2015 Paris Agreement to limit global warming to well below 2.0 degrees Celsius - and preferably to 1.5C (2.7 degrees Fahrenheit) - above pre-industrial levels.

"COP26 is not a photo op or a talking shop. It must be the forum where we put the world on track to deliver on climate. And that is down to leaders," Sharma said on Tuesday (October 12) at the UNESCO World Heritage Centre in Paris.

Sharma said there must be new commitments on public and private finance to support the countries most vulnerable to climate change and progress on adaptation to the effects of the changing climate.