Fact check: Human-driven global warming increased Larsen ice shelf melt

ice shelf
Credit: Unsplash/CC0 Public Domain

The claim: Study shows that 'CO2 emissions play no role' in Antarctic Larsen ice shelf melt

The Larsen C ice shelf of the Antarctic Peninsula is considered to be vulnerable to collapse under certain global warming scenarios, according to researchers. The loss of ice shelves—the part of a land-based ice sheet that floats on the ocean—allows land-based ice to flow into the ocean more quickly, contributing to sea-level rise.

Some social media users are sharing an article that claims a new study minimizes the potential impact of human activity on the ice shelf.

"New study: Man-made CO2 emissions play no role in Larsen ice shelf melt," reads the article's headline in an Oct. 5 Facebook post.

The article, which was published on a website called Climate Change Dispatch, was shared on Facebook more than 850 times in less than two weeks, according to Crowdtangle, a social media metrics tool.

But the article misrepresents the new research, which does link Larsen C ice shelf melt to human-driven global warming, according to Ella Gilbert, the study's lead author and a climate modeler at the British Antarctica Survey.

USA TODAY reached out to Climate Change Dispatch and the Facebook user who shared the claim for comment.

New study lists causes of ice shelf melt that are exacerbated by global warming

The study referenced in the article is titled, "A 20-Year Study of Melt Processes Over Larsen C Ice Shelf Using a High-Resolution Regional Atmospheric Model: 2. Drivers of Surface Melting" and was published in the Journal of Geophysical Research, a peer-reviewed scientific journal, in April. It sought to "identify and rank, for the first time, the most significant causes of melting over the recent past."

The study identified a number of causes of ice melt on the shelf, including solar radiation; warm, dry wind events (called foehn); cloud behavior and large-scale atmospheric circulation patterns.

The Climate Change Dispatch article takes this to mean that human activity and CO2 emissions are not the cause of the melting of the Larsen C ice shelf. But that is not the case, according to the study's lead author.

"On the contrary, the paper explicitly notes that climate change is causing temperatures to rise, making melting more common and changing which drivers of melting happen most frequently," Gilbert told USA TODAY in an email.

The Climate Change Dispatch article correctly notes that the list of melt factors in the paper does not include the phrase "CO2 emissions," but this does not mean caused by anthropogenic CO2 emissions has no role in Larsen ice shelf melt, Gilbert told USA TODAY in an email.

"As noted in the paper, melt occurs only when are at 0 degrees Celsius," she said. "Rising temperatures (caused by increased CO2 emissions) mean this threshold is reached more frequently. This increases the impact of all drivers of melt."

Erin Pettit, an ice sheet researcher and professor at Oregon State University, also told USA TODAY that human-driven warming influences melt factors on the Larsen C ice shelf.

She explained that, for example, increasing global temperatures change global wind patterns because wind redistributes heat between Earth's higher and lower latitudes. These changes likely increase the frequency of foehn wind events on the Larsen ice shelf, which then increases melting.

"CO2 emissions definitely play a role in this," Pettit said.

Our rating: False

Based on our research, we rate FALSE the claim that a recent study shows that "CO2 emissions play no role" in the Antarctic Larsen C ice shelf melt. The study lists causal factors for Larsen C melt, the effects of which are influenced by human CO2 emissions and resulting global , according to the study author.

Journal information: Journal of Geophysical Research

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Citation: Fact check: Human-driven global warming increased Larsen ice shelf melt (2022, October 20) retrieved 28 January 2023 from https://phys.org/news/2022-10-fact-human-driven-global-larsen-ice.html
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