Conservative groups spend up to $1bn a year to fight action on climate change

The anti-climate effort has been largely underwritten by conservative billionaires, often working through secretive funding networks. They have displaced corporations as the prime supporters of 91 think tanks, advocacy groups and industry associations which have worked to block action on climate change.

The vast majority of the 91 groups on Brulle's list – 79% – were registered as charitable organisations and enjoyed considerable tax breaks. Those 91 groups included trade organisations, think tanks and campaign groups.

Funding also went to groups that took on climate change denial as a core mission – such as the Heartland Institute, which held regular conclaves dedicated to undermining the United Nations climate panel's reports, and the Competitive Enterprise Institute, which tried and failed to prosecute a climate scientist, Michael Mann, for academic fraud.