The Claim: The ‘Climate History’ graph shows recent temperatures at the ‘low end of the historical range’

A January 14 Twitter post (direct connection, archive link) contains a chart labeled “Climate history over 9,500 years”. It purportedly shows temperature changes from year to year, with the latest data showing relatively cool temperatures compared to the rest of the chart.

“Recent global temperatures are at the low end of the historical range,” the chart reads.

“How can anyone see this chart and be seriously brainwashed into believing that we are at the end of days? It’s very basic stuff,” the post’s caption reads.

According to Crowdtangle, a social media analytics tool, the post has garnered more than 11 million views on Twitter and more than 100 shares on Facebook in three weeks. A similar graphic with German subtitles led to hundreds of additional interactions on Facebook.

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Our rating: Wrong

The graph cannot show the modern global temperature change as no data after 1885 is shown. Modern global warming began around this time and escalated significantly in the 1980s, according to data from the National Oceanic and Atmospheric Administration. The graph is also based on data from a single location in Greenland and is not representative of global temperatures, experts say.

Chart data from one location does not represent global temperatures

The chart cites a 2004 publication based on limited data from 1997 by a group of scientists including Gary Clow, now a senior research fellow at the Institute for Arctic and Alpine Research at the University of Colorado.

“This chart is based primarily on data from a single location in Greenland,” Clow told USA TODAY in an email. “I must stress that this site does not represent the entire planet.”

Temperatures at a single location are much more variable than average temperatures over larger areas, like “all of Greenland or the northern hemisphere,” he said.

“To conclude that these data reflect global temperature changes…is really misleading,” Clow said.

The data referenced in the chart is also not based on direct temperature measurements, he said. Instead, temperatures are derived based on the types of oxygen trapped in the ice core samples.

Fact check: Contrary to what is claimed, global temperatures and atmospheric CO2 levels are correlated

Although the ice cores were collected in the 1990s, the nature of the analysis means the resulting temperature records only go back to the late 1800s, Clow said.

In other words, even if the ice core dates listed — going as far back as 1885 — represent the entire planet, they exclude dates for the last 140 or so years.

This is the time frame in which most of the recent warming trends have occurred, Carrie Morrill, director of the World Data Service for Paleoclimatology at NOAA’s National Centers for Environmental Information, told USA TODAY in an email.

Despite these inaccuracies, versions of the graph have circulated online for years, according to Richard Alley, a professor of geosciences at Pennsylvania State University and lead author of the 2004 paper cited in the graph.

“I get a few requests for this every year and have for well over a decade,” he said.

Studies show that the earth is warmer now than it has been in the last 10,000 years

Despite the claims in the social media post, recent studies have concluded that global warming, driven by human behavior, has contributed to rising global temperatures that are now warmer than in the past thousands or tens of thousands of years. According to a Rutgers press release, this research contrasts with previous work that suggests Earth has had warmer temperatures over the past 10,000 years.

Fact check: Current human-caused warming has different effects than past warming

“The (earth) climate has changed for many reasons, but mainly because of the CO2 change, which draws special attention to our release of CO2 into the atmosphere from burning fossil fuels and other activities,” said Alley.

USA TODAY has debunked a variety of claims about climate change, including that the oceans are more likely to cause global warming than CO2 and that the greenhouse gas effect is a hoax.

USA TODAY reached out to social media users who shared the post for comment.

The graphic was also debunked by AFP.

Our fact check sources:

• Richard Alley, Jan. 9, email exchange with USA TODAY

• Gary Clow, Jan. 19, email exchange with USA TODAY

• Matthew Osman, December 30, 2022, email exchange with USA TODAY

• Carrie Morrill, 14-19 December 2022, email exchange with USA TODAY

• Scott Wing, December 29, 2022, email exchanges with USA TODAY

• Theodore Scambos, December 14, 2022, email exchange with USA TODAY

• Brian Huber, 29-30 Dec 2022, email exchange with USA TODAY

• Samantha Bova, April 27 – May 13, 2022, Telephone interview and email exchange with USA TODAY

• Laura Larocca, 17-18. April, email exchange with USA TODAY

• Carbon Brief, March 5, 2019, Fact Check: What Greenland ice cores tell us about past and present climate change

• Carbon Brief, December 13, 2017, Analysis: Why scientists believe 100% of global warming is human-caused

• Nature (Journal), 10 November 2021, Global resolved surface temperatures since the last glacial maximum

• NOAA, June 18, 2020, What was the hottest Earth ever?

• NOAA, September 17, 2014, What was the hottest thing the earth has been “recently”?

• NOAA, March 2004, GISP2 Ice Core Temperature and Accumulation Data

• National Centers for Environmental Information, Accessed January 9-30, Palaeoclimatology

• National Centers for Environmental Information, accessed Jan. 9-30, National Centers for Environmental Information

• NASA, March 25, 2021, The Raw Truth on Global Temperature Records – Climate Change: Vital Signs of the Planet

• NASA Vital Signs of the Planet, accessed Jan 27, Global Temperature

• NASA Vital Signs of the Planet, accessed January 27, Causes

• History.com, April 1, 2021, How Did Humans Evolve?

• USA TODAY, May 30, 2022 Fact Check: Current human-caused warming has different effects than past warming

• Rutgers University, February 16, 2021, Major Climate Change Mystery Solved by Scientists

• The University of Arizona, November 10, 2021, Global temperatures over the past 24,000 years show today’s warming is “unprecedented.”

• AFP, Jan 19, Ice core plot used to make misleading claims about global warming

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This article originally appeared on USA TODAY: Fact Check: False Claim Shows Earth Was Colder 1,000 Years Ago

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