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FACT CHECK
Fact Check

Earth is warming. May data doesn't show otherwise | Fact check

Kate S. Petersen
USA TODAY

The claim: May 2024 temperature data from the US shows there has been no global warming over the last 128 years

A June 19 Facebook post (direct link, archive link) shows a graph of National Oceanic and Atmospheric Administration data for the U.S. that displays average temperatures for the month of May between 1895 and 2024.

"128 years of global warming down the drain: May 2024 0.1°F cooler than May 1896 in the US, per NOAA data," reads text above the graph. "Ask a climate hoaxer to 'splain that."

The post, which is a screenshot of a post on X, formerly Twitter, was shared on Facebook more than 200 times in five days.

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Our rating: False

Scientists have documented modern global warming by examining temperature trends over long time frames. Comparing average temperatures for two random months is not a valid way to determine whether Earth's climate is changing, according to researchers. While May 2024 was roughly 0.1 degrees cooler than May 1896 in the U.S., NOAA data shows an overall warming trend in the U.S. and globally over the last 128 years.

NOAA temperature data shows 128-year warming trend for US and world

Though the post fails to acknowledge it, NOAA data shows a 128-year warming trend for the month of May in the U.S. NOAA data also shows warming over that timeframe when all months are considered, both in the U.S. and globally.

NOAA is not alone. Multiple independent climate research organizations have documented global warming.

Researchers have also documented ocean warming and the results of both marine and atmospheric warming, such as polar ice loss and sea level rise.

In the U.S., the consequences of warming include:

Modern global warming is caused by an increase in greenhouse gas concentrations in the atmosphere due to human activity, according to NASA.

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Global climate trends can't be determined by comparing two data points

May 2024 was cooler than May 1896 in the U.S. even though average temperatures warmed overall worldwide and in the U.S. during that timeframe, according to NOAA data. This highlights the problem with using two random pieces of temperature data to draw conclusions about long-term climate trends.

Even on a warming planet, weather fluctuations and natural climate variability, such as the  El Niño-Southern Oscillation, cause temperatures to rise and fall from month to month and year to year, according to researchers.

Climate "variability can produce weather patterns that may bring cooler than normal temperatures to some locations for some period of time," Sean Birkel, an assistant professor at the University of Maine and the Maine State Climatologist, previously told USA TODAY. "Meanwhile, the global temperature is still warmer than in decades past."

Gavin Schmidt, the director of NASA Goddard Institute for Space Studies, also previously told USA TODAY that the existence of a statistically significant warming trend does not mean that every single month will be warmer than all previous months.

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Further, while the U.S. is warming overall (consistent with the global trend), the Facebook post is wrong to use U.S. temperature data to draw conclusions about global warming. This is because global warming trends are calculated from temperature measurements taken all over the globe, not just the U.S.

Some places, such as the Arctic, are warming much faster than the global average. Other places are warming more slowly, or even cooling.

"Temperature trends across the entire globe aren’t uniform because of the diverse geography on our planet − oceans versus continents, lowlands versus mountains, forests versus deserts versus ice sheets − as well as natural climate variability," NOAA reports. "When you’re zoomed in on a particular place, you may not be able to see the overall trend."

The U.S. is warming faster than the global average, according to NOAA data.

USA TODAY reached out to the Facebook user who shared the post for comment but did not immediately receive a response.

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