Microplastics may cool and heat the Earth’s climate

Like ashes Microplastics ejected from supervolcanoes have invaded the atmosphere and circled the earth. These are plastic fragments less than 5 mm in length, and there are two main types of them.Fragments are produced from decomposed bags and bottles (babies drink millions of small particles every day In their formula), and the microfiber will fall off the synthetic fiber clothes during washing and washing Rush out to seaThe wind then sweeps the land and sea, bringing the microplastics into the atmosphere.The air is so bad every year, equivalent to More than 120 million plastic bottles There are 11 protected areas in the United States, accounting for only 6% of the country’s total area.

in a Learn Published in the magazine today nature, For the first time scientists tried to simulate how atmospheric particles affect the climate. This is a strange combination of good news and bad news. The good news is that microplastics may reflect a small portion of solar energy back into space, which actually cools the climate slightly.The bad news is that humans are bringing so many microplastics to the environment (ocean Sediment sample It shows that since the 1940s, the concentration has doubled every 15 years), and the particles themselves are so different that it is difficult to know how the pollutants will ultimately affect the climate.At some point, they may end heating Planet.

The earth absorbs some of the sun’s energy and reflects some of it at the same time. This exchange is called radiative forcing. The model found that, like other aerosols in the atmosphere (such as dust and ash), microplastics interact with this energy. “They are very good at scattering sunlight back into space, so we see the cooling effect,” said atmospheric chemist Laura Revell, the lead author of the new paper. “But they are also very good at absorbing the radiation emitted by the earth, which means they can contribute to the greenhouse effect in a very small way.”

Like snowflakes, no two microplastics are the same-they are made of many different polymers and show rainbow-like colors. Debris breaks up when it rolls in the environment, while fibers break apart again and again. Each particle grows a unique “plastic ball“Bacteria, viruses and algae.”

So when Revell and her colleagues set out to build a model of how they affect the climate, they knew it was impossible to represent so much diversity.Instead, they determined General The optical properties of fibers and debris fall into two broad categories-for example, the degree to which they reflect or absorb solar energy. Their model is based on pure polymers without pigments and assumes that the composition of the atmosphere is 100 particles per cubic meter of air. The researchers then plugged all of this into an existing climate model that told them the estimated impact of atmospheric microplastics on the climate.

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