Does Arctic sea ice reach its highest level in 21 years? Does this prove global warming is a hoax?

 

Screenshot of the article.

 

News Brief

An article published Jan. 16, 2024 by The Daily Sceptic website claims that Arctic sea ice on Jan. 8 reached its highest level in 21 years. A screenshot of this article was shared April 2, 2024 on Facebook. The caption, written in traditional Chinese, translates, “global warming is a joke.” The Facebook post suggests that the data used in the Daily Sceptic article proves the globe is not warming.

Fact-checking

1. Where does the data come from?

The Daily Sceptic article includes an interactive diagram of the extent of Arctic sea ice published by the National Snow and Ice Data Center (NSIDC). It shows that the Arctic sea ice extent on Jan. 8, 2024 is approximately 13.68 million square kilometers. The Daily Sceptic website was founded by British commentator Toby Young. The website often publishes articles about climate change and vaccine conspiracies, which have been debunked by multiple fact-checking organizations.

The Jan. 8 Arctic sea ice data used in the claim does come from the NSIDC website. The interactive diagram shows that the data point of Jan. 8, 2024 is higher than the same dates in other years since 2004. The data suggests that the Artic ice reaches its highest level on the same date in 21 years.

 

NSIDC’s diagram demonstrates that the Arctic sea ice extent on Jan. 8, 2024 is approximately 13.68 million square kilometers, reaching its highest level on the same date in 21 years.

 

According to the NSIDC website, the aforementioned interactive diagram is part of NASA-funded Arctic Sea Ice News & Analysis (ASINA) project. The sea ice data comes from the NASA Snow and Ice Distributed Active Archive Center.

 

The data of the NSIDC ASINA project is funded by NASA.

 

2. Does the data deny global warming?

The fact checks published by the BBC and Reuters quoted experts saying that the data has been “cherry-picked.” The fallacy of cherry-picking is using incomplete evidence to support an argument while ignoring other significant evidence that may contradict the position, especially for one’s own benefit or gain.

Experts told Reuters that the quoted figures 20 years apart are accurate, but cherry-picking individual dates does not provide a meaningful picture of what is happening in the Arctic. Walter Meier, a senior research scientist at NSIDC, said that ice levels during large parts of February and March 2024 were lower than during the same periods in 2004. Meier adds, “Comparing two specific days from two specific years is not an indicator for or against long-term changes. The sea ice varies from day to day and from year to year.”

The Hong Kong Observatory published a blog article in 2012 in response to climate sceptics’ claim that “the Earth had not warmed for the past 16 years based on monthly temperature data.” The article states that the claim is misleading because it deliberately focuses on short-term fluctuations but ignores the long-term trends. The article adds that in climate change studies, one way to examine the long-term trend is averaging the data over a relatively long period to allow short-term fluctuations to cancel out.

The cherry-picking tactic is often used in global warming denial narrative. As shown in the right diagram  below, the Berkeley Earth Surface Temperature (BEST) project analyzed Earth’s surface temperature records, showing that global warming continues unabated. However, certain global warming skeptics attempt to argue that global warming has stopped by cherry-picking only the short recent time period from the BEST project’s full record (as shown in the left diagram), to hide the incline in global surface temperature.

 

Certain global warming skeptics still attempt to use the BEST record to argue that global warming has stopped.

 

3. What is the long-term trend of sea ice change?

According to the information released by NASA, scientists studying Arctic sea ice trends can rely on a fairly comprehensive record dating back to 1953. Since 1979, a collection of satellites has provided a continuous, nearly complete record of Earth’s sea ice cover. A diagram published by BBC using NSIDC data shows that from 1979 to 2023, Arctic sea ice extent has shown an overall downward trend.

 

From 1979 to 2023, Arctic sea ice extent has shown an overall downward trend.

 

Meier told Reuters that the best indicator of long-term change in sea ice in the Arctic is the lowest level in each year. NSIDC data show those levels steadily declining: from 1979 to 1990, the average for the minimum ice extent was 6.95 million square kilometers; this value dropped to 6.5 million square kilometers (1991 to 2000), and further dropped to 5.39 million square kilometers (2001 to 2010), and finally fell to 4.42 million square kilometers (2011 to 2020).

In addition, the current Arctic sea ice extent this year is lower than the 1981-2010 average, according to data provided by NSIDC.

 

The current Arctic sea ice extent this year is lower than the 1981-2010 average.

 

To sum up, the data quoted in the claim does suggest that the Arctic sea ice extent on Jan. 8, 2024 is higher than the extent on the same dates in other years since 2004. The data demonstrates that the Arctic sea ice reaches its highest level on the same date in 21 years. However, the data have been cherry-picked and cannot reflect the long-term trend of Arctic sea ice change. NSIDC data show that Arctic sea ice extent has shown an overall downward trend since 1979. Therefore, the data quoted in the claim cannot deny global warming.