Fact check: Japan Meteorological Agency data shows warming on Japanese island

The claim: A graph made with Japan Meteorological Agency data shows no warming over an 80-year period

The Earth's average temperature has increased by nearly 2 degrees since 1880, according to NASA. Other data corroborate that finding.

However, some Facebook users claim a graph shows a Japanese island has experienced no warming in 80 years.

"This graph – created using data from the Japan Meteorological Agency – shows no warming over an 80 year period," reads a Feb. 9 Facebook post.

The post was shared nearly 300 times in three days. It includes a graph labeled "Hachijojima Mean Monthly Temperature for January 1945-2022."

While the graph appears to show no significant change in overall temperature, the Facebook post lacks context.

That's because the graph singles out the month of January. When looking at annual data, there is a statistically significant warming trend for Hachijojima, according to the Japan Meteorological Agency.

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USA TODAY reached out to the Facebook users who shared the claim for comment.

Data show warming on Hachijojima

Data show the average temperature on Hachijojima increased at a rate of roughly 2 degrees Fahrenheit per century between 1945-2021, according to Wakamatsu Shunya, a science officer at the Japan Meteorological Agency.

When January alone is analyzed, there is no statistically significant trend. But that doesn't mean human-driven global climate change is not occurring, according to Gavin Schmidt, director of the NASA Goddard Institute for Space Studies.

In long-term climate data sets, "you can almost always find a shorter time or more local record to seemingly contradict the long-term global" trend, he told USA TODAY in an email.

"They don’t though," he said.

Elizabeth Maroon, a climate scientist and professor at the University of Wisconsin-Madison, told USA TODAY this is because temperature patterns are informed by both natural variability and the influence of accumulating greenhouse gases.

Fact check: NOAA charts show range of possible sea rise scenarios, don't conflict with observations

"For a single location, the natural variability piece is relatively large," she said in an email. "However, the larger the region you average over, the more the natural variability part is averaged out and the greenhouse gas signal emerges more clearly."

This same idea applies to singling out a certain part of the year – such as January. Looking only at data from one month doesn't tell the whole story.

USA TODAY previously debunked a claim that NASA "admitted" there has been no global warming for 18 years. NASA representatives told USA TODAY agency data shows continued warming over the past 18 years.

Our rating: Missing context

Based on our research, we rate MISSING CONTEXT the claim that a graph made with Japan Meteorological Agency data shows no warming over an 80-year period, because without additional information it may be misleading.

By only looking at the month of January, the Facebook post cherry-picks data from the Japan Meteorological Agency temperature record. Annual data indicate the average temperature on Hachijojima increased at a rate of roughly 2 degrees Fahrenheit per century between 1945-2021.

Our fact-check sources:

• Wakamatsu Shunya, Feb. 14-20, Email exchange with USA TODAY

• Elizabeth Maroon, Feb. 21-22, Email exchange with USA TODAY

• Gavin Schmidt, Feb. 22, Email exchange with USA TODAY

• Japan Meteorological Agency, accessed Feb. 15, Monthly mean air temperature Hachijojima

• Met Office Climate Dashboard, accessed Feb. 15, Annual global mean temperature difference from pre-industrial conditions

• Japan Meteorological Agency, accessed Feb. 15, Home

• NASA, accessed Feb. 15, Global Temperature

• USA TODAY, Jan. 21, Fact check: NASA did not deny warming or say polar ice has increased since 1979

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This article originally appeared on USA TODAY: Fact check: Japanese agency data confirm warming on Hachijojima