Greenland's Petermann Glacier is shrinking; movement doesn't mean it's growing | Fact check

Kate S. Petersen, USA TODAY
Updated ·6 min read

The claim: Recent advance in Greenland's Petermann Glacier shows climate change is a 'scam'

An Aug. 7 post (direct link, archive link) on X, formerly Twitter, shows two satellite images of Greenland's Petermann Glacier. The images are zoomed in on a channel where the glacier meets the ocean and forms an ice shelf − a formation that floats on the water as opposed to resting on the land.

An image labeled as being from 2023 shows the leading edge of the ice shelf extending farther out in the channel than an image labeled as 2012.

"Greenland's Petermann Glacier has been growing about three meters per day for the past eleven years. This will not be reported by the @nytimes @NPR or @BBCNews #ClimateScam," reads the post's caption.

The post was reposted more than 1,000 times on X.

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Our rating: False

Petermann Glacier has lost significant mass due to global warming but as it shrinks, ice continues to flow out of the channel shown in the images. The 2012 image in the post was captured shortly after two large chunks broke off the glacier. The 2023 image shows glacial ice refilling the channel because of gravity-driven ice flow, not because the glacier is "growing."

Greenland's Petermann Glacier is not 'growing'

Overall, Petermann Glacier is losing mass, not growing, according to researchers. This includes the last 11 years.

A study published in 2019 found that the glacier had a net loss of 56 billion metric tons of ice between 1972 and 2018, according to Eric Rignot, a NASA climate scientist who has extensively studied the Greenland ice sheet. Unpublished data shows that net losses continue to the present, he told USA TODAY.

The region of northern Greenland where Petermann is located lost more than 300 billion metric tons of ice between 2002 and 2018, according to Polar Portal, a Danish polar data repository.

"Petermann is generally thinning, retreating, and its flow is accelerating," NASA reports.

The agency also reports that, overall, Greenland has lost about 5.2 trillion metric tons of ice since 2002.

Alex Gardner, a NASA cryosphere scientist, told USA TODAY that the leading edge of Petermann has advanced in the channel by about 3.3 meters per day for the last 11 years. This is similar to the figure in the post, but the post is wrong to claim that this means the glacier is "growing."

The change is related to "calving," when large chunks of ice break off the glacier and are lost to sea.

"Over the past 11 years, the front of the Petermann Glacier has indeed advanced, following a massive calving event in 2010 in which the glacier lost roughly 250 square kilometers of ice," he said in an email. "This event was followed by another large calving event in 2012 that was roughly 1/3 the size of the 2010 event. Since then the ice front has readvanced and regained some of its lost area but is nowhere near its pre-2010 extent."

Advancement after a calving event does not mean the glacier is gaining mass, Ruth Mottram, a glaciologist and climate scientist at the Danish Meteorological Institute, wrote in a blog post. Advancement is simply a response to gravity.

"After the glacier calves a large iceberg, the glacier behind continues to push ice out through the channel ... and the front eventually moves back to roughly the same position it was in before the calving," she wrote. "However, that does not mean the glacier is 'growing.'"

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She told USA TODAY that all glaciers behave this way.

"They flow from where the ice is thickest down to where it is thinnest under gravity," she said in an email.

She said the claim uses misleading data.

"Why do they only focus on the last 11 years when we have decent observations going back more than 20 years? Even three years earlier, the glacier is much more extensive," she said. "It’s classic cherry-picking. And even if Petermann had proved to be (growing) rather than losing ice, one single outlet glacier from the Greenland ice sheet proves absolutely nothing about the general health of the Greenland ice sheet or indeed the causes and consequences of climate change."

Global climate change is occurring due to greenhouse gas emissions released by human behavior

Modern climate change is caused by the atmospheric accumulation of greenhouse gases released by human activity. The physical process by which these gases delay the escape of heat into space and warm the planet is well understood and has been verified through observations and experiments.

This warming, which has been detected by multiple independent climate agencies, has consequences that include the melting of ice sheets, glaciers and Arctic sea ice, increasing heat wave frequency and sea level rise. Global warming results in sea level rise because warming water expands and melting ice contributes additional water to the oceans.

"The amount of warming we see matches what we expect based on the increased CO2 we've added," Josh Willis, a NASA climate scientist, previously told USA TODAY. "The timing of the warming matches the timing of the CO2 increase caused by people. Not only that, the timing of global sea level rise matches the CO2 increase."

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The X user who posted the claim could not be reached.

The claim was also debunked by Reuters.

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This article originally appeared on USA TODAY: Greenland Petermann Glacier lost ice over past decade | Fact check