Trump's campaign leans on climate change denial: Six misleading claims debunked
Former President Donald Trump and Vice President Kamala Harris are both campaigning on climate as the 2024 presidential race enters its final days.
While Harris has repeatedly referred to climate change as a "crisis," Trump has pushed back against the existence of climate change and promoted climate science misinformation, including claims previously debunked by USA TODAY and other fact-checkers.
Trump is seeking to return to the White House, where his first-term climate actions included withdrawing the U.S. from the Paris Agreement, an international effort to limit global warming through greenhouse gas emissions reductions. He also reversed or weakened domestic rules that limited greenhouse gas emissions – a move one 2020 analysis estimated would result in an extra 1.8 billion metric tons of greenhouse gases being released into the atmosphere.
Harris is seeking a promotion after four years under a President Joe Biden administration in which climate actions included casting the tie-breaking vote to pass the Inflation Reduction Act – landmark legislation to combat climate change. However, the vice president has also spoken favorably of provisions in the bill that expand fossil fuel leasing on federal land and also the Biden-Harris administration’s historic expansion of domestic oil production.
To analyze climate narratives from this election cycle, USA TODAY reviewed climate science-related comments both candidates made in speeches archived on Rev.com and C-SPAN between 2022 and September 2024. USA TODAY also reviewed climate science-related media coverage and the candidates' campaign websites.
This review did not uncover any climate science misinformation promoted by Harris, who consistently references the topic with general statements rather than specific scientific assertions. Trump's statements, however, have repeatedly been at odds with evidence assembled by scientists.
Claim: Climate change is a hoax
“One of the most urgent tasks, not only for our movement, but for our country is to decisively defeat the climate hysteria hoax. ... It’s a hoax. The whole thing is a total … It’s so crazy.” ? Donald Trump, April 21, 2022
An overwhelming amount of evidence shows Earth's climate is changing and that the change is being driven by human behavior. A significant long-term warming trend has been detected by multiple independent climate agencies around the globe.
This warming has been detected in both the atmosphere and the ocean.
Researchers have documented the consequences of this warming, which include:
Melting ice sheets in Antarctica and Greenland
Changes in the ranges of animal species
An increase in the frequency of heat waves
Shrinking snowpack in the western U.S.
Changing plant bloom times
An increase in flooding events due to sea level rise
Scientists are confident these changes are caused by greenhouse gas emissions from human activity, Twila Moon, a climate scientist at the National Snow and Ice Data Center, told USA TODAY.
"Even by 1900 scientists understood the fundamental physics and chemistry that is creating today’s warming," she said in an email. "We can measure how much heat-trapping gas there is in the atmosphere and where it is coming from, and we can measure Earth’s temperature."
The amount of observed global warming matches the amount that would be expected given the quantity of greenhouse gases, such as CO2, humans have emitted, USA TODAY previously reported. The timing of the warming also matches the timing of increased greenhouse gas emissions.
USA TODAY asked Trump spokesperson Steven Cheung for evidence supporting this and the other climate claims detailed below. Cheung did not provide any.
Related fact checks:
Claim: Modern climate change is just natural variation or weather
"In my opinion, you have a thing called weather. You go up and you go down ... The climate's always been changing." – Donald Trump, when asked if climate change was due to human activity, March 2022
While Earth's climate has always changed, modern climate change is caused by human behavior, threatens human infrastructure and is proceeding more rapidly than past climate change events, according to researchers. It is not a weather fluctuation.
"Climate and weather both describe phenomena in the Earth’s atmosphere, but the basic difference between them is time," the National Oceanic and Atmospheric Administration reports. "Weather describes the atmospheric conditions at a specific point in time. It can be measured hourly, daily, weekly, monthly or yearly. Climate is the average or typical weather over a long period of time."
Scientists have documented this long-term change. While there are natural phenomena that can alter Earth's climate, such as volcanic eruptions or changes in orbital cycles, scientists have ruled these out as a cause of modern climate change, USA TODAY previously reported.
The speed at which humans are changing Earth's climate is also unprecedented. While natural climate change typically occurs on very long-term scales, humans are changing Earth's climate on a scale of decades ? a pace more rapid than anything that has occurred in the last roughly 500 million years, according to a recent study.
Rapid rates of climate change in Earth's history have typically caused mass extinction events, paleoclimatologist Ashleigh Hood previously told USA TODAY.
Related fact checks:
Claim: Scientists project average global sea levels may rise 1/8 an inch over 500 years, but also might recede
“And I say that the thing that’s an existential threat is not global warming, where the ocean will rise, maybe, and it may go down also, but it may rise 1/8th of an inch in the next 497 years they say, 1/8th.” ? Donald Trump, June 28, 2024
There is no evidence that sea levels will only rise 1/8 inch over the next 500 years, Howard Diamond, a National Oceanic and Atmospheric Administration climate scientist, told USA TODAY. Instead, NOAA projects average global sea levels rising around 1-12 feet (compared to sea levels in 2000) by 2150, depending on factors such as the amount of CO2 released into the atmosphere by humans.
Diamond said the agency has not projected that average global sea levels could drop in the next 500 years, nor was he aware of any climate agency that had made such a projection.
"At the rate that CO2 is being emitted today, and coupled with its long life in the atmosphere, a projection like that has absolutely no basis in science," he said in an email.
While global average sea levels are rising, there are some places on Earth where relative sea level ? the elevation of the ocean in relation to the land ? is falling, USA TODAY previously reported. This is due to glacial isostatic adjustment ? land that was once compressed under the weight of ice age glaciers is now rebounding and moving upwards.
Other phenomena such as current and wind patterns or gravitational force changes also cause relative sea level rise to vary depending on locale. Average global sea level rise estimates are based on measurements from across the globe that account for these differences.
Related fact checks:
Claim: If global warming is happening, there wouldn't be cold weather events
"Climate change is one of the greatest con jobs ever because global warming didn’t work because … Remember when they sent the boats out to the Arctic, freezing, freezing cold, and the scientists were in the boat, a big ship, and they were worried about the icebergs because they were melting. And they had a little cold wave that lasted for about two days. And it was so vicious and so cold that the ice formed around the ship and started crushing the ship like it was a little … Remember? We had to send helicopters in to get them. The ship was just engulfed in ice. And they’re talking about global warming." ? Donald Trump, Dec. 11, 2023
Cheung did not clarify what purported incident Trump was referencing in this statement. Regardless, unexpected freezing events can and do occur even on a warming planet and do not mean that global warming isn't occurring.
"Cold waves in the Arctic, and elsewhere, still occur on a warming planet because of natural variability in the day-to-day weather," Michael Mann, a University of Pennsylvania climate scientist, told USA TODAY. "But over time, there are fewer and shorter-lasting cold extremes and more frequent and more long-lasting heat waves."
While still subject to freezing polar weather, the Arctic has warmed four times faster than the global average since the late 1970s, resulting in sea ice loss. The loss of sea ice results in less solar radiation being reflected back to space and more being absorbed by darker ocean water, creating a warming feedback loop.
Because weather is variable, examining a small number of weather events is not enough to detect changes in climate, researchers have previously told USA TODAY. Instead, the entire climate record must be examined.
Related fact checks:
Claim: Scientists changed the phrase 'global warming' to 'climate change' because Earth started cooling
“They used to call it different things. Global warming, remember? That wasn’t working because it was getting a little bit cooler. So they said, 'What are we going to do? We’ll call it 'global cooling.'' No. So, they came up with the words 'climate change' because that takes care of everything.” ? Donald Trump, Sept. 3, 2024
While natural climate variability can result in temporary cooler time periods, there has been an overall global warming trend that has persisted for decades. Scientists have not stopped using the expression "global warming," though the phrase means something slightly different than "climate change."
"Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period ? between 1850 and 1900 ? due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere," NASA reports.
The phrase "climate change" is used more broadly to describe warming as well as other phenomena like shifting rainfall and drought patterns, melting ice and altered wind and ocean currents, Mann said.
However, there is a history of climate terminology being manipulated for political gain. In a 2002 memo, Republican strategist Frank Luntz advised the George W. Bush administration to refer to "climate change" rather than "global warming" because it was "less frightening" than the phrase "global warming."
Bush seemed to take Luntz's advice, avoiding the term "global warming," though he had previously used it often, according to media reports of the time.
The memo was a "key part of the conscious, documented Republican strategy, going back to the 1990s, of trying to downplay the reality of global warming or even deny it entirely," Naomi Oreskes, a historian of science at Harvard University, told USA TODAY. She said Trump's statement "is the pot calling the kettle black."
Claim: In the 1920s, there was a scientific consensus that the Earth was going to freeze
“So they used to have, in the 1920s you know they thought the planet was going to freeze. They had a thing, global cooling. They had a picture, I think it was on Time magazine of the Earth very cool,1920s, it was a global cooling thing, but now they got smart.” ? Donald Trump, June 28, 2024
There was no scientific consensus in the 1920s that the planet would freeze, according to Oreskes, who called Trump's claim "bogus." She said some scientists of the time realized the Earth was in a period between ice ages and that there could eventually be another ice age, “but this was quite speculative at that time.”
Cheung did not respond when asked which Time Magazine cover Trump was referencing, but USA TODAY has previously debunked a suite of social media posts featuring a doctored Time Magazine cover that purportedly reported a "coming ice age." There was no such Time cover in the 1920s, when the magazine only featured artwork of people.
Trump’s statement echoes a common climate change denial myth that there was a scientific consensus in the 1970s that Earth would cool instead of warm. This is also wrong.
In the 1970s, researchers were investigating a slight cooling trend that began in the 1940s (which was eventually found to be a result of cooling from sulfate pollution overriding warming from greenhouse gas emissions). Researchers were also continuing to develop their understanding of natural ice age cycles, Richard Alley, a Pennsylvania State geoscientist, told USA TODAY.
Due to these factors, some papers were published suggesting that more cooling could be on the horizon, and Newsweek published an article covering some of this work in 1975. But 1970s papers projecting a warming trend driven by human greenhouse gas emissions outnumbered "cooling" papers, Alley said.
The National Academy of Sciences also published a 1979 report that referred to (and affirmed) the "consensus" that "increasing carbon dioxide will lead to a warmer Earth."
This article originally appeared on USA TODAY: Debunking six of Trump's climate science claims in 2024 campaign