Fact Check: EPA Data Confirms, Not Denies, the Link Between Emissions and Extreme Heat

A recent tweet by Steve Milloy claims that greenhouse gas emissions have no connection to extreme heat or heat waves, citing an EPA chart as supposed evidence. He also accuses World Weather Attribution (WWA) of deliberately ignoring this data to push a false narrative. However, both the EPA’s findings and widely accepted climate science directly contradict these claims.

Claim Post:

Data show that emissions have zero to do with extreme heat and heat waves — see, e.g., the attached EPA chart. So Jeff Bezos-funded scammers at World Weather Attribution @WWAttribution ignore the data and pretend the opposite. https://t.co/qu4i1X9OdH pic.twitter.com/6SoofUwZNL
— Steve Milloy (@JunkScience) June 21, 2025

Claim 1: “Data show that emissions have zero to do with extreme heat and heat waves, see, e.g., the attached EPA chart.”

Fact: The claim is misleading and scientifically incorrect. The EPA’s Heat Wave Index, which covers U.S. data from 1961 to 2021, shows that heat waves have become more frequent, longer, and more intense, the average number per year has tripled since the 1960s, with seasons extending about 46 days longer and heatwave intensities increasing by ~0.5 °F above local thresholds. The agency’s analysis highlights that this increasing heatwave trend is consistent with global warming driven by greenhouse gas emissions.

Additionally, multiple studies from the Intergovernmental Panel on Climate Change (IPCC) and other scientific bodies confirm that rising emissions are a key driver of extreme heat events. Global temperatures have already risen by approximately 1.1°C since pre-industrial levels, significantly increasing the likelihood and intensity of heatwaves worldwide. The EPA chart cited by Milloy does not disprove this relationship. It supports the well-established link between greenhouse gas emissions and worsening heat extremes.

Claim 2: “So Jeff Bezos-funded scammers at World Weather Attribution @WWAttribution ignore the data and pretend the opposite.”

Fact: False. The accusation against World Weather Attribution (WWA) is unfounded and baseless. WWA is an established scientific consortium comprising top institutions, including Imperial College, KNMI, NCAR, and ETH Zurich, that utilises peer-reviewed attribution techniques to assess how human-caused climate change influences extreme weather. Their studies are openly published and routinely cited in scientific literature and major climate assessments. There is no credible evidence to support accusations of fraud or bias.

WWA’s recent study on the June 2025 England heatwave concluded that the event was made approximately 100 times more likely due to human-caused climate change. This finding is consistent with numerous previous studies that show human emissions significantly increase the likelihood of extreme heat waves. Attribution science is a crucial component of climate research and is widely supported by the broader scientific community. Personal attacks do not undermine the validity of this body of work.

The Growing Threat of Heat Waves in a Warming World

Heatwaves are becoming more frequent, intense, and longer-lasting as global temperatures continue to rise. This is not just a scientific projection; it is already happening. The EPA’s data clearly show this alarming trend in the United States, while global research confirms similar patterns worldwide. Human-caused greenhouse gas emissions are at the heart of this growing threat, driving extreme heat events that were once considered rare to become increasingly common and dangerously so.

Ignoring scientifically backed evidence and spreading misinformation about climate science only delays meaningful solutions. Attacks on credible scientific groups, such as World Weather Attribution, do not alter the facts; they merely divert attention from the pressing need for climate action. The link between emissions and extreme heat is well-established, and addressing this crisis requires informed public discourse grounded in verified data, rather than misinterpretation or personal agendas.

References:

https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves