Despite it’s usually depicted as reaching 97%, the consensus among researchers on human-caused global warming has grown to 100%, based on a review of more than 11.000 peer-reviewed articles on “climate change” and “global warming” that were published between January and August this year.

University of Florida researcher James Powell looked at 11,602 articles, analyzing their titles, abstracts, and content. Initially, he only found a few handfuls whose titles left an open possibility of their authors rejecting man-made climate change. Then, on closer analysis, none did.

For example, Powell looked at the article “Has Global Warming Already Arrived?” by Varotsos and Efstathiou (2019), a title that suggests discrepancies with man-made global warming. But then, looking further, the article accepts the responsibility of human activities in the growing atmospheric emissions.

Powell’s work, published at SAGE, looks at the beginning of the construction of a consensus on anthropogenic global warming, which he claims began with the work of Manabe and Wetherald in 1967 – using a computer model to show that the increase of emissions would lead to global warming of 2 degrees Celsius.

Computer models later improved and global temperatures continued increasing, which lead to a growing consensus. As researchers, the government started showing their concern, reflected in the creation of the UN’s Framework Convention on Climate Change and its objective to stabilize emissions.

“Because the use of fossil fuels has become so embedded in the world economy, it was clear that “stabilizing” greenhouse gases might require large-scale government intervention and regulation, anathema to some, including some scientists,” Powell said.

This is not the first time such an analysis is done, but it is the first time that it shows a 100% agreement among researchers. In 2013 Cook et al looked at almost 1,000 articles from 1991 and 2011 and estimated a consensus of 97.1%, looking at the terms “global climate change” and “global warming”.

Then, in 2017, Powell did his second analysis of over 5,400 peer-reviewed papers and found a 99.94% consensus about human-caused climate change – just a small difference with Cook’s work that put us a step closer to the 100% consensus.

For Powell, his new findings show that climate change denialists “have long run out of excuses for inaction,” as well as that “humanity has almost run out of time.” The researcher urges countries to step up their game on climate action.