Experts say Earth was cooler, not warmer, 55,000 years ago | Fact check
The claim: Earth was 2 degrees Celsius warmer 55,000 years ago
A June 14 Facebook video (direct link, archive link) shows businessman Dan Peña talking about climate change during an episode of "The Joe Rogan Experience" podcast.
In the edited video, Peña describes a purported meeting with scientists during a trip to the South Pole.
"We're talking with all the goofball scientists and he said .... '55,000 years ago, it was 2 degrees warmer Celsius than it is today,'" Peña says. "What? Stop. Fifty-five thousand years ago, it was 2 degrees warmer than it is today? And I said, 'What about global warming?' Simultaneously, all 10 scientists started laughing. All 10 PhDs from MIT, Caltech, Stanford started laughing."
"Why'd they laugh?" Rogan asks.
"Because global warming is a joke," Peña responds.
The post was shared 18,000 times in less than two weeks.
More from the Fact-Check Team: How we pick and research claims | Email newsletter | Facebook page
Our rating: False
Earth was cooler 55,000 years ago than today, according to researchers.
Earth was cooler 55,000 years ago
Gisela Winckler, a paleoceanographer at Columbia Lamont-Doherty Earth Observatory, told USA TODAY that evidence from sediments and ice core analysis shows that average temperatures on Earth were cooler 55,000 years ago.
"It is not true that Earth was 2 degrees Celsius warmer 55,000 years ago than today," she said in an email. "Fifty-five thousand years ago the Earth was pretty much in the middle of the last glacial cycle, and temperatures were certainly colder than today."
An article from Darrell Kaufman, a paleoclimatologist at Northern Arizona University, published in The Conversation includes a graph that shows global temperature change over the last 150,000 years. The graph, which includes temperature reconstructions from multiple studies, shows that temperatures were cooler 55,000 years ago.
In 2021, the Intergovernmental Panel on Climate Change reported that average global temperatures are now higher than they've been in the last 100,000 years.
Fact check: Earth is warming. May data doesn't show otherwise
Earth is warming rapidly
Global warming has been detected by independent climate research organizations worldwide. Researchers have also documented the consequences of this warming, which include:
An increase in the frequency of extreme weather events, such as heat waves
Changes in the migration patterns, geographic range and behaviors of certain animal species
Fact check: Arctic sea ice is in decline. Data from two April days doesn't show otherwise
While Earth's climate has always warmed and cooled, the rapid pace of modern warming − driven by human greenhouse gas emissions − is unique in the climate record, Ashleigh Hood, a sedimentologist and paleo-environmental scientist at the University of Melbourne, previously told USA TODAY.
"Even though CO2 has varied substantially through Earth’s history, it has generally changed on relatively long timescales (millions or billions of years) compared to the rate of our current warming," she said. "If you look at events in Earth’s history which have environmental and climate change at the same rapid rate of today’s change, these are basically all mass extinction events."
USA TODAY reached out to the Facebook user who shared the post for comment but did not immediately receive a response.
Lead Stories also debunked the claim.
Our fact-check sources:
USA TODAY, Aug. 29, 2023, Climate skeptic's claim about CO2 levels, ice ages and animals misleads
NASA Vital Signs of the Planet, accessed June 26, Causes
NASA Vital Signs of the Planet, accessed June 26, Ice sheets
NASA Vital Signs of the Planet, accessed June 26, Sea level
NASA Vital Signs of the Planet, accessed June 26, Arctic sea ice minimum extent
Intergovernmental Panel on Climate Change, Dec. 13, 2022, Climate Change 2021: Summary for All
The Conversation, July 21, 2023, Is it really hotter now than any time in 100,000 years?
Environmental Protection Agency, July 2022, Climate Change Indicators: Heat Waves
NOAA, Aug. 17, 2022, Climate change: spring snow cover in the Northern Hemisphere
NOAA, April 19, 2022, Climate Change: Global Sea Level
National Park Service, accessed June 26, How Wildlife are Responding to a Warming Climate
Joint Nature Conservation Committee, accessed June 26, Climate change and migratory species a review of impacts, conservation actions, indicators and ecosystem services
Science, Aug. 19, 2011, Rapid Range Shifts of Species Associated with High Levels of Climate Warming
Ecology, Feb. 10, 2021, Unusually large upward shifts in cold-adapted, montane mammals as temperature warms
Carbon Brief, April 20, 2021, Melting glaciers drove ‘21% of sea level rise’ over past two decades
Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or e-newspaper here.
USA TODAY is a verified signatory of the International Fact-Checking Network, which requires a demonstrated commitment to nonpartisanship, fairness and transparency. Our fact-check work is supported in part by a grant from Meta.
This article originally appeared on USA TODAY: Earth was cooler 55,000 years ago | Fact check
