Former British prime minister Tony Blair began a tour of China, India and Japan on Friday hoping to rally support for a global pact to cut greenhouse gas emissions by 50 per cent by 2050.

Blair, who stepped down as Britain’s leader in June, said his talks with lawmakers and business leaders are aimed at breaking a deadlock between the developed and developing world on setting new targets for reducing emissions.

In a video posted on his website, Blair warned that the global response to climate change is not up to the scale of the problem, saying a deal must be agreed within two years.

He hopes to develop a framework for an agreement to cut emissions in half by 2050.