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

Kate S. Petersen, USA TODAY
Updated ·5 min read

The claim: April and May data shows Arctic sea ice isn't declining

A Facebook post links to an article with a graph that purportedly shows Arctic sea ice extent data for mid-April through mid-May in 2007, 2018, 2021 and 2023.

The graph indicates the Arctic sea ice extent − the area of ocean covered by a certain percentage of ice − was higher in 2023 than in the other listed years and similar to the "17-year average."

"The ice is not disappearing," reads the May 18 post (direct link, archive link).

The post was shared more than 40 times in four days.

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Our rating: False

Data shows Arctic sea ice has declined significantly since at least the late 1970s. Arctic sea ice extent trends cannot be determined by looking at a short time frame over a few years. Experts say the trend is clear when all of the available data is analyzed.

Arctic sea ice has declined for decades

The size of the Arctic sea ice extent has declined since the late 1970s, according to National Snow and Ice Data Center data.

"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, told USA TODAY in an email.

The amount of old ice has also decreased, according to NASA.

"The average age of sea ice is becoming younger," reports the agency. "At the start of the satellite record (in the late 1970s), much of the ice covering the Arctic Ocean was greater than four years old. Today, most of the ice covering the Arctic Ocean is 'first-year ice' − ice that forms in winter and does not survive a single summer melt season."

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Because of this and the thinning of lingering old ice, the remaining Arctic sea ice pack is more fragile, the agency reports.

Data in article does not effectively capture Arctic sea ice trends

The article does not directly state where the data in the sea ice graph came from, but it mentions the Sea Ice Index and MASIE, which both use data from the National Snow and Ice Data Center, according to Meier. The data also appears to roughly match the sea ice extent values shown in the agency's Charctic Interactive Sea Ice Graph tool, which includes data from the Sea Ice Index.

According to this tool, 2023 sea ice extents were slightly higher for mid-April through mid-May than in 2007, 2018 and 2021 as shown in the article. However, 2023 extents during this time frame were also lower than those of many other years, including 1979 through 1988 and 1990 through 2001.

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The Charctic tool does not have a "17-year average" function, and Meier said compiling an average over that amount of time would be inadequate.

"The time series is rather short," he said. "Seventeen years seems like a fairly long time, but we generally look at at least 30 years to study long-term climate trends. Over shorter periods, natural variations in the climate can be large enough to obscure the long-term changes. The 17 years of 2006-2022 have mostly been very low. In fact, starting in 2007, the last 16 years are the lowest 16 years in the Sea Ice Index climate record."

Additionally, the graph in the article highlights a part of the year that has sustained less severe losses than other seasons.

The Arctic sea ice extent in April and May has decreased by around 2.5% per decade, according to the Sea Ice Index. However, in September, which is typically when the ice has finished melting for the summer, the extent has decreased by around 12% per decade.

The article's author did not immediately respond to USA TODAY's questions about the source of the data in the graph.

Loss of Arctic sea ice exacerbates climate change

The loss of Arctic sea ice exacerbates climate change because the bright surface of the ice reflects solar energy, which has a cooling effect. Ocean water, which is darker, absorbs more solar energy, causing warming.

"At the height of summer ... exposed ocean water absorbs nine times as much solar radiation, if not more, than sea ice does," according to the National Snow and Ice Data Center website. "The loss of sea ice warms the Arctic, contributing to a phenomenon known as 'Arctic amplification' where the Arctic warms at a faster rate than lower latitudes."

This increased warming also contributes to increasing ice loss, forming a feedback cycle.

"The more ocean exposed, the larger the potential for absorption of sunlight directly into the ocean, which fuels further ice melt," Bonnie Light, the chair and senior principal physicist at the University of Washington Polar Science Center, previously told USA TODAY.

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USA TODAY reached out to the Facebook user who posted the claim but did not immediately receive a response.

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This article originally appeared on USA TODAY: Arctic sea ice is melting, though amount varies by year | Fact check