Fact check: Earth's warming well documented, other planets' climate data limited

Kate S. Petersen, USA TODAY
·6 min read

The claim: Earth, Jupiter, Mars, Neptune and Pluto have all warmed during the last hundred years

Greenhouse gas emissions released by human activities are causing Earth's average temperature to warm, according to NASA.

However, some social media users are sharing a post that implies humans are not responsible for this warming, positing instead that Earth is being warmed by a force also causing purported warming on other planets.

"As the Earth has warmed over the last 100 years, so too have Jupiter, Neptune, Mars and Pluto," reads the caption of an Oct. 25 Facebook post.

The post garnered more than 200 shares in a month.

But the claim is wrong.

While Earth has exhibited a clear warming trend over the last 100 years, temperature records for the other planets mentioned in the social media post do not extend that far back, meaning there's no way to prove this claim. Further, there is no evidence of recent warming on Jupiter, Neptune or Mars, according to researchers.

"The simplest problem with these claims is that it is extremely difficult to measure temperatures at other planets remotely," Luke Moore, a professor and planetary scientist at Boston University, told USA TODAY in an email. "Therefore, making any definitive claim similar to what is posted (in the meme) is disingenuous and deceptive."

USA TODAY reached out to the Facebook user who shared the post for comment.

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Jupiter

James Sinclair, a NASA Jet Propulsion Laboratory research scientist, told USA TODAY in an email that there is no evidence to support the claim that Jupiter's temperatures have increased globally over the last 100 years.

In fact, there isn't enough temperature data to show a global trend at all, according to Sushil Atreya, a professor of climate and space science at the University of Michigan, Ann Arbor.

"The first and only systematic measurements of Jupiter's heat balance were done by Voyager spacecraft four decades ago," he told USA TODAY in an email.

Additional conclusive systematic measurements would be necessary to detect a global temperature change since that time, he said.

More limited measurements over the last few decades have shown temperature fluctuations in "different regions of the atmosphere and different parts of the planet," Atreya said. "But they don't represent the planet's temperature as a whole."

Neptune

Contrary to the claim made in the social media post, "there is no evidence to suggest that Neptune has warmed globally in the last 100 years," said Michael Roman, a planetary scientist at the University of Leicester who recently published a paper about temperature trends on Neptune.

Reliable measurements of the planet only began 20 years ago, he said.

"Most of Neptune's observable atmosphere appears to have cooled since reliable measurements began," Roman said.

Glenn Orton, a senior research scientist at NASA Jet Propulsion Laboratory also told USA TODAY in an email that the temperature record for Neptune is too short to determine temperature trends for the last 100 years.

Mars

Likewise, temperature data for Mars only extends back about 50 years, not 100 years, according to Michael Mischna, a NASA Jet Propulsion Laboratory planetary scientist.

Even this record has gaps and shows no long-term warming, according to Richard Zurek, a chief scientist for the Mars Program Office at the same NASA lab.

"While Mars atmospheric temperatures were observed during the Viking missions in the 1970s, there were few observations made after that until the Mars Global Surveyor entered Mars orbit in the late 90s," he said. "While we have much better data coverage since that time, there does not appear to be a general warming trend on Mars."

Pluto

There is also not 100 years' worth of temperature data for Pluto, according to David Tholen, an astronomer at the University of Hawaii.

The first temperature observation for the dwarf planet – derived from atmospheric pressure readings – was in 1988, he told USA TODAY in an email.

Since this time, researchers have detected a warming trend on Pluto, according to Leslie Young, a planetary scientist at Southwest Research Institute.

This warming is thought to be related to physical processes on the dwarf planet's surface that are driven by summertime in its northern hemisphere, she said. And because it takes nearly 250 Earth years for Pluto to orbit the sun, the dwarf planet's "seasons" last for decades.

There is some evidence that warming on Pluto is starting to slow down, but there is not enough data to know for sure, said Young.

Fact check: NASA says modern climate change caused by human activity, not solar orbital cycles

Warming on Earth caused by human behavior

Unlike that of the planets mentioned above, the warming trend on Earth over the last hundred years is well documented and supported by observations from multiple independent agencies dating back to the 1800s.

"The warming the world has experienced is primarily due to CO2 accumulating in the atmosphere," Zeke Hausfather, climate research lead at Stripe, told USA TODAY in an email. "We've long known that CO2 was a greenhouse gas – since the mid-1800s. We know that human activity is causing it to rise because the accumulation in the atmosphere matches the amount we've added through burning fossil fuels."

Fact check: Contemporary, human-driven warming has different ramifications than past warming

Our rating: Partly False

Based on our research, we rate PARTLY FALSE the claim that Earth, Jupiter, Mars, Neptune and Pluto have all warmed during the last hundred years. Earth has warmed over the last 100 years due to human activities that release greenhouse gases. There is no hundred-year temperature record for Jupiter, Neptune, Mars or Pluto. A shorter-term warming trend has been detected on Pluto, but not Jupiter, Neptune or Mars.

Our fact-check sources:

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This article originally appeared on USA TODAY: Fact check: False claim warming similar on Earth, other planets

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