The cost of reducing China’s total greenhouse gas emissions is likely to reach $438bn a year within 20 years, and developed economies will have to bear much of that cost, according to a group of Beijing’s leading climate economists.

The figure, equivalent to about 7.5 per cent of China’s estimated gross domestic product in 2030, is likely to be deployed to support Beijing’s argument at December’s climate change summit in Copenhagen that industrialised nations must share the cost of cutting emissions in developing countries.