A new study has measured how much ozone in the atmosphere contributes to the planet’s energy budget—the balance of heat emitted by sunlight received in ways that affect Earth’s temperatures. There are many different things that affect this balance, and it turns out that if you remove the ozone, the planet will likely get colder.
The study uses an Earth climate model to explain how the energy budget is affected by various atmospheric compositions, and says that when ozone decreases, the planet’s average temperature drops as well. At nearly zero ozone, the planet would be 3.5°C cooler than it is today, and the temperature would likely approach those seen in the last ice age. However, this model requires that the amount of carbon dioxide present remains the same.
The energy budget can be explained at a very basic level as follows: “The sun warms the Earth and our planet radiates this heat back into space. But not all of the energy is reflected back. The ocean, the ground, and the atmosphere absorb some of this heat, trap it, and radiate the rest to space. Composition of the atmosphere. “This affects how much of the heat emitted from the surface escapes back into space. For example, greenhouse gases in particular have led to the growing climate crisis because they are so effective at trapping heat.”
Ozone is also technically a greenhouse gas, but its positive or negative impact on the energy budget largely depends on where it is located. The best location it can be found is in the region of the atmosphere called the ozone layer. Located about 50 kilometers in the stratosphere, this region protects life on Earth from dangerous ultraviolet light from the Sun. But the fact that ozone is within 20 kilometers is bad as it absorbs heat and acts purely as a greenhouse gas. At lower altitudes it still helps our planet by removing pollutants, and at ground level it’s still bad as it plays a role in fog formation.
Sometimes the hero, sometimes the “villain”
Ozone can play the role of a hero or a villain for us, depending on where it really is. Given the fact that we’ve destroyed so much of the ozone layer over the past century, you might think that the knowledge that ozone depletion will cool our planet is somehow good news for the climate crisis. Of course, although the rate of skin cancer increases as ozone decreases, it can be thought that we have prevented the climate crisis from getting worse. Unfortunately, this notion is absolutely not true.
Ozone-depleting chemicals, such as chlorofluorocarbons, are tens of thousands of times more powerful than carbon dioxide at retaining heat. The 1987 Montreal Protocol banning them and taking this danger seriously by every country in the world provided significant delays in melting the ice in the Arctic. Thus, the climate crisis could have been much worse had it not been for the world’s efforts to save the ozone layer. In addition, thanks to these measures, the ozone layer began to recover.
The paper describing an ozone-free planet has been accepted for publication in Climate of the Past and is currently on preprint server arXiv.
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