The evolution of Earth’s climate has many components. New research has shown how important the ozone layer is to the Earth’s surface temperature. Without the ozone layer, our planet would be 3.5 K cooler.
Several feedback and forcing mechanisms play a role in stabilizing and determining global mean global temperature. In its simplest form we receive radiation from the sun. Some of this radiation bounces off the upper atmosphere while the rest travels down. The air and the ground absorb some of this radiation. The rest of the radiation is reflected off the Earth’s surface. Most of that escapes back into space, but some of it is reabsorbed by the atmosphere creating a greenhouse effect that heats our surface to higher temperatures than would be possible without it.
But this is a very simplistic picture. In fact, our temperature and climate depend on everything from the abundance of different particles in the atmosphere to the ocean and atmospheric circulation systems.
While the ozone layer in Earth’s insulating atmosphere is essential to blocking ultraviolet radiation from the sun, most climate models have ignored ozone’s role in studying Earth’s climate. However, researchers have examined the effect of the ozone layer in a new paper that appears on server preprint arXiv.
We didn’t always have an ozone layer. Before the emergence of life, ozone was essentially non-existent in our atmosphere. The Earth has spent billions of years with very little ozone. It has only recently stabilized at the thick levels we see at present. And while molecular oxygen, which makes up a good portion of Earth’s atmosphere, plays a minimal role in climate, so does the ozone layer.
To study the impact of the ozone layer, the researchers used a suite of simulations of Earth’s climate. They changed the amount of ozone in the upper atmosphere and allowed the Earth’s temperature to reach an equilibrium. They found that the presence of ozone has a warming effect on our surface temperatures, increasing, on average, the Earth’s surface temperature by about 3.5 K. If the ozone layer were to disappear, whether through man or other means, it would have a catastrophic effect on our climate.
The primary effect of ozone deficiency is cooling of the upper stratosphere. Cold air cannot hold as much moisture, so the stratosphere becomes drier. Water vapor is an important greenhouse gas, and thus without it, the greenhouse effect on Earth would diminish.
Besides changes in the Earth’s temperature, ozone deficiency will have major impacts on our overall climate. Also, the lack of ozone and the resulting cooling of the stratosphere would destabilize that layer of the atmosphere, which prevents the formation of clouds. This would force clouds to appear only at lower and higher altitudes
Also, some jet streams will strengthen near the equator, while others will weaken near the poles. This will have severe consequences for seasonal weather patterns at all latitudes.
Earth’s atmosphere is a rich and complex system, and this result shows that each component plays an important role.
Russell Detrick et al., Effects of Ozone Levels on Climate Throughout Earth’s History, arXiv (2023). doi: 10.48550/arxiv.2305.15477
the quote: Without Ozone, Earth Could Get Colder (2023, June 14) Retrieved June 14, 2023 from https://phys.org/news/2023-06-ozone-earth-lot-colder.html
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