EQUATORIAL lands that are home to hundreds of millions of people will become uninhabitable as food and water run out due to climate change, scientists will warn this week.

A report from the Intergovernmental Panel on Climate Change (IPCC), to be published on Friday, will warn that the temperature rises of 2-3C predicted by 2050 spell global disaster for both humanity and the environment.

It will say that up to 40% of animal and plant species face extinction as rising temperatures destroy the ecosystems that support them. And it will point out that the 29 billion tons of carbon dioxide poured into the atmosphere each year are acidifying the oceans – threatening to destroy coral reefs, plankton and many commercial fish species.

By the middle of the century, the report will warn, more than 200m people could have been forced from their native lands by rising sea levels, floods and droughts, with many more facing early deaths from malnutrition and heat stress.

The report comes amid government embarrassment over the latest figures for Britain’s greenhouse gas emissions. Last week David Miliband, the environment secretary, admitted they had risen by 1.5% last year despite repeated Labour pledges to cut them.

“The picture that emerges from the research is quite appalling,” said Rachel Warren, of the Tyndall Centre for Climate Change Research, and one of the IPCC’s senior authors. “It is just horrendous realising what damage climate change can do to ecosystems.”

The IPCC report is a collation of the best peer-reviewed scientific research into the impact of climate change, published over the past five years or so.

It will say that many of the worst effects on humans will be caused by water – or lack of it – in the form of floods, drought, melting glaciers, rising sea levels and ocean acidification.

Nearly a third of the world’s land surface may be at risk of extreme drought by 2099, compared with about 1%. Such a change would destroy farmland and water resources and lead to mass migrations of “environmental refugees”.

The IPCC will also warn that the Amazon rainforest could be in danger. Professor Diana Liverman, director of the Environmental Change Institute at Oxford University, said the region was already experiencing an alarming reduction in rain.

“The warming of the oceans seems to be changing the water cycle,” she said.

In lands close to the equator, especially in Africa, declining crop yields could leave hundreds of millions of people unable to grow food.

In Europe, one of the most obvious early impacts will be the destruction of Alpine ski resorts, with about 70% losing snow cover by 2050.

The IPCC will say it is “too late” to avert some degree of climate change.

It will call on humanity to cooperate on adapting to the changes – while trying to limit them by cutting emissions.

Times Recommends

• Foxy Knoxy snared by her lust and her lies
• Britain is the land of the shrinking family
• Zac Goldsmith: Not such a green god