Study mines 16,000 documents from conservative thinktanks for insights into how they “manufacture doubt” on climate change

By Alex Pashley

It’s been 15 years since researchers last ran the numbers on how climate denial is disseminated in public discourse.

A study recently published in the journal Global Environmental Change fills the gap, taking a fine tooth-comb to misinformation pumped out by conservative think tanks from 1998 to 2013.

It analysed almost 25 million words of op-eds, blogs and policy reports available online from 16 US groups such as the American Enterprise Institute, Heritage Foundation and Heartland Institute (who Climate Home met at a parallel event to the Paris climate talks in December).

Here are the main findings.

Climate science denial isn’t over. The volume of output has ballooned from 203 documents between 1990-97 to 16,028 from 1998-2013. The Heartland Institute tops the list, followed by the Science and Public Policy Institute, then Center for the Study of Carbon Dioxide and Climate Change (CO2 Science).

The emphasis has shifted from debating the usefulness of policy to disputing the science, researchers from Trinity College Dublin and Exeter University found. By casting doubt on the scientific consensus, they seek to undermine public support for a range of green policies, rather than fighting them one by one.

Denial is reactive. Content peaked around the time of the Copenhagen summit in 2009, a major attempt to strike a global warming accord. The data similarly shows spikes in attacks on “alarmism” after the release of Al Gore’s Inconvenient Truth and subsequent Nobel Prize awards for him and the Intergovernmental Panel on Climate Change. In response to bills on CO2 regulations in 2008 and 2009, talk of damage to national economy flared similarly.

Attacks on scientists are rooted in politics. Bids to question the integrity of scientists or scientific bodies “appear closer (semantically) to politics than science”. Rather than tackling point-by-point the claims, the language is emotive. A Heartland Institute report accuses climate scientist Michael Mann of being in the business of “spreading myths and misinformation to further their agenda,” for instance.