Sun

Sun causing global warming? 2 reasons why not

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C. Alex Young

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EarthSky Voices

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August 23, 2023

bright sun setting over a city in the foreground and large mountainous hills in the background — The next time you enjoy a beautiful sunset like this one, you don’t need to worry that the sun is causing global warming. Image via Pexels / Dajana Reçi.

Is the sun causing global warming? Solar physicist C. Alex Young – who leads EarthSky’s daily sun news post – says no. Read the quick-and-easy-to-understand explanation here. Original article via NASA. Edits by EarthSky.

Is the sun causing global warming?

No. The sun can influence Earth’s climate, but it isn’t responsible for the warming trend we’ve seen over recent decades. We know subtle changes in Earth’s orbit around the sun are responsible for the comings and goings of the ice ages. But the warming we’ve seen in recent decades is too rapid to be linked to changes in Earth’s orbit and too large to be caused by solar activity. Here are two smoking guns that tell us the sun isn’t causing global warming.

1. Since 1978, using sensors on satellites, scientists have been tracking the amount of solar energy that hits the top of Earth’s atmosphere. This measurement tells us that there has been no upward trend in the amount of solar energy reaching our planet.

2. If the sun were responsible for global warming, we’d expect to see warming throughout all layers of the atmosphere, from the surface to the upper atmosphere (stratosphere). But we don’t see that. What we see instead is warming at the surface and cooling in the stratosphere. This is consistent with the warming being caused by a buildup of heat-trapping gases near Earth’s surface, and not by the sun getting “hotter.”

Sun causing global warming? Chart showing a mostly horizontal yellow line wavering up and down and a red line going steadily upward. — View larger. | Is the sun causing global warming? This graph compares global surface temperature changes (red line) and the sun’s energy that Earth receives (yellow line) in watts per square meter since 1880. The thinner lines show the yearly levels, while the thicker lines show the 11-year average trends to reduce the year-to-year natural noise in the data. The amount of solar energy Earth receives has followed the sun’s natural 11-year cycle of small ups and downs with no net increase since the 1950s. Over the same period, global temperature has risen markedly. It is therefore extremely unlikely that the sun has caused the observed global temperature warming trend over the past half century. Image via NASA.

Bottom line: Is the sun causing global warming? A solar physicist with NASA says no. Read the quick-and-easy-to-understand explanation here.

Via NASA

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August 23, 2023

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C. Alex Young

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About the Author:

C. Alex Young is a solar astrophysicist studying the Sun and space weather. Alex is passionate about sharing science with diverse audiences. This led him to start The Sun Today with his designer wife, Linda. First through Facebook and Twitter then adding an extensive website thesuntoday.org, the two work together to engage the public about the Sun and its role in our solar system. Alex led national engagement efforts for the 2017 total solar eclipse. He is the Associate Director for Science in the Heliophysics Science Division at NASA Goddard Space Flight Center.

EarthSky Voices

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Members of the EarthSky community - including scientists, as well as science and nature writers from across the globe - weigh in on what's important to them.