Climate change

The American Enterprise Institute (AEI), which receives funding from oil giant ExxonMobil according to the Guardian, sent letters to scientists in the United States, Britain and elsewhere offering the payments in exchange for articles emphasising the shortcoming of the UN's report.

AEI also reportedly offered additional payments, and to reimburse travel expenses.

It is the first volume of three, which will be drawn together later in the year to make the fourth of the IPCC's assessments.

At a hearing of Congress, scientists and advocacy groups described a campaign by the White House to remove references to global warming from scientific reports and limit public mention of the topic to avoid pressure on an administration opposed to mandatory controls on greenhouse gas emissions.