Global warming could cut the world's annual economic output by as much as 20%, an influential report by Sir Nicholas Stern is expected to say.
Environmental issues have jumped to the top of the political agenda
While that is a worst case scenario, the report claims that at the very best the cost of tackling global warming would be 1% of annual economic output.
Sir Nicholas's comments are expected to form the core of The Stern Review that is due to be released on Monday.
It is important because it looks at economic, not environmental, arguments.
According to BBC business correspondent Hugh Pym, the report will carry weight because Sir Nicholas, a former World Bank economist, is seen as a neutral figure.
Unlike earlier reports, his conclusions are likely to be seen as objective and based on cold, hard economic fact, our correspondent said.
It also may help win over sceptics in the US, where climate change has often been accused of being based on shoddy science.
Sir Nicholas has looked at the impact of global warming on economic output, or gross domestic product (GDP), until 2100.
His report was commissioned by the Cabinet Office and the Treasury in July 2005 and was aimed at better understanding the economic challenges presented by global warming and how they could be met in the UK and around the world.
Sir Nicholas's approach has not been without its critics, however.
Some experts argue that climate change is beyond human control and the best way to tackle it is to drive forward economic growth so that development picks up pace and nations will be rich enough to pay for adaptation in the future.
Analysts said that they expect the Stern Review to argue that economists have under-estimated the costs that climate change will impose and over-estimated the costs of cutting emissions.