June 2006 v. June 2023 Arctic sea ice comparison doesn't disprove global warming | Fact check

Kate S. Petersen, USA TODAY
·5 min read
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A young female polar bear on the island of Svalbard wanders the meltwater channels on the sea ice.

The claim: Comparing June 2006 and 2023 Arctic sea ice levels shows 'emissions-driven warming is a hoax'

A June 17 tweet (direct link, archive link) shows Arctic sea ice extent images from June 16, 2006, and June 16, 2023. The sea ice appears to cover roughly the same area in both images from the National Snow and Ice Data Center.

"Not the narrative: June 2023 Arctic sea ice extent about the same as June 2006, despite ~800 billion tons of emissions representing a 41% increase in industrial era CO2," reads the caption. "Emissions-driven warming is a hoax."

The tweet was shared to Facebook more than 100 times in less than a month, according to Crowdtangle, a social media analytics tool. It was also retweeted more than 6,000 times.

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Our rating: False

While Arctic sea ice extent − the area covered by a certain amount of floating ice − was similar in June 2006 and 2023, Arctic sea ice is decreasing overall due to global warming. Multiple lines of evidence show that human CO2 emissions are causing global warming.

Arctic sea ice decreasing overall despite variability

Arctic sea ice is declining overall due to climate change, according to the Environmental Protection Agency. About half of the sea ice cover at the "minimum extent" − the time of year after the summer melt has concluded − has been lost, according to the United Nations Environment Programme.

"We have over 43 years of data now, and the signal of decreasing sea ice is very clear," Walt Meier, a senior research scientist at National Snow and Ice Data Center, previously told USA TODAY.

Fact check: Humans are responsible for a significant amount of CO2 in the atmosphere

However, seasonal weather and short-term climate variations also influence the size of extent, he told USA TODAY in an email. This means that even though sea ice is declining overall, it is still possible for a more recent year or month to roughly match the extent of past months or years.

This is the case for June 2006 and June 2023, which had similar extent sizes throughout the month, according to the National Snow and Ice Data Center Charctic Interactive Sea Ice Graph. However, the extents in both June 2006 and June 2003 were both lower than June extents between 1979-2004 as well as some more recent years.

Overall, June Arctic sea ice extent has decreased by 3.8% per decade since the late 1970s, according to National Snow and Ice Data Center. Other parts of the year, such as the September minimum extent, have sustained much greater losses.

Global warming caused by human greenhouse gas emissions

More than a trillion metric tons of CO2 have been released by fossil fuel burning and land use changes since 1850, according to the 2022 Global Carbon Budget.

Multiple lines of evidence show this CO2 has warmed the planet, Josh Willis, a NASA climate scientist, previously told USA TODAY. For one, CO2 is a known greenhouse gas, which warms the lower atmosphere by slowing the escape of heat into space.

"The amount of warming we see matches what we expect based on the increased CO2 we've added," he said. "The timing of the warming matches the timing of the CO2 increase caused by people."

Additionally, the type of carbon found in fossil fuels can be detected in atmospheric CO2, which confirms the gas was introduced by human behavior.

Fact check: Arctic sea ice declining overall, though level varies by year and season

The post's figures for CO2 emissions since 2006 are in the ballpark, but may be somewhat overstated. Carbon Brief reports that humans released around 660 billion metric tons of CO2 between 2006-2022 through fossil fuel burning and land use changes.

However, the Carbon Brief data (which is from the Global Carbon Project) also subtracts some emissions that were absorbed by the concrete manufacturing process.

The social media user who posted the claim did not immediately respond to questions about the source of the CO2 emissions estimate in the post or which types of emissions are included in the estimate.

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This article originally appeared on USA TODAY: Arctic sea ice declining despite June comparision | Fact check