Earth’s lower atmosphere is rising due to climate change

Higher temperatures are forcing the upper boundary of the troposphere to expand upward

image of Earth's atmosphere with the troposphere visible in orange

The troposphere (seen here in orange) is the lowest layer of Earth’s atmosphere and where nearly all weather occurs. Over the last 40 years, the boundary between the troposphere and the neighboring stratosphere (pink) has risen as a result of climate change.

Image Science & Analysis Laboratory/NASA Johnson Space Center

Global temperatures are rising and so, it seems, is part of the sky.

Atmosphere readings collected by weather balloons in the Northern Hemisphere over the last 40 years reveal that climate change is pushing the upper boundary of the troposphere — the slice of sky closest to the ground — steadily upward at a rate of 50 to 60 meters per decade, researchers report November 5 in Science Advances.

Temperature is the driving force behind this change, says Jane Liu, an environmental scientist at the University of Toronto. The troposphere varies in height around the world, reaching as high as 20 kilometers in the tropics and as low as seven kilometers near the poles. During the year, the upper boundary of the troposphere — called the tropopause — naturally rises and falls with the seasons as air expands in the heat and contracts in the cold. But as greenhouse gases trap more and more heat in the atmosphere, the troposphere is expanding higher into the atmosphere (SN: 10/26/21).

Liu and her colleagues found that the tropopause rose an average of about 200 meters in height from 1980 to 2020. Nearly all weather occurs in the troposphere, but it’s unlikely that this shift will have on a big effect on weather, the researchers say. Still, this research is an important reminder of the impact of climate change on our world, Liu says.

“We see signs of global warming around us, in retreating glaciers and rising sea levels,” she says. “Now, we see it in the height of the troposphere.”

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