Global Warming Isn't Just a Blanket: In the Long Term, It's Tanning Oil for the Planet

When it comes to global warming, we may be dealing with tanning oil rather than a blanket. Scientists have taken a closer look at what happens to the planet under climate change and have found that instead of slow warming, we may be dealing with something a bit more complicated.

"This is a neat study in that it changes the way we think about the climate system," said Aaron Donohoe, the lead author of the new study, in a news release. "We looked at processes that are well captured in the models, but the conceptual understanding of how they work hasn't been fleshed out before."

When CO2 is added to our Earth's atmosphere, it does act like a blanket-at first. It traps long-wave infrared energy coming off of our planet. The atmosphere then emits less of this long-wave radiation to space because the upper atmosphere is cooler than Earth's surface; this is rather like the top of your blanket being cooler than your body. Earth then gradually heats up under this blanket and hotter objects emit more long-wave radiation. This means that after about a decade, the effect of adding the thicker blanket has been canceled by the warmer body emitting more energy.

In the longer term, this changes even more. Earth begins to absorb more shortwave radiation, which are the high-energy rays coming directly from the sun. Less ice on the Earth and more humid air will essentially act like the Earth's own version of tanning oil. It will absorb more of the sun's incoming rays.

"While greenhouse gases trap one type of radiation, it's the other type-visible shortwave radiation-that is really sustaining global warming over the long term," said Kyle Armour, co-author of the new study.

The findings may help people better conceptualize global warming, and also could help researchers better detect climate change in satellite data.

"Our results do not change our overall expectation that the planet will continue to warm due to the burning of fossil fuels, but they do change our fundamental understanding of how that warming comes about," said David Battisti, co-author of the study.

The findings are published in the journal Proceedings of the National Academy of Sciences.