Aerosols and your areaTo scientists who study the atmosphere, an “Aerosol” particle is a tiny partic

Aerosols and your areaTo scientists who study the atmosphere, an “Aerosol” particle is a tiny particle suspended in the air. Products that get sold using the name “aerosol” are things that spray tiny particles into the air – for example, as air fresheners. For atmospheric scientists, aerosols are far more important than those spray cans. They can be made up of a great many things – ash from wildfires, smoke from smokestacks, dust picked up by the wind, and even salts produced by chemical reactions in the atmosphere.Aerosols are extremely important for your weather and for you. In general, breathing in aerosol particles is a bad thing; so many varieties of aerosol particles are considered types of air pollution and are regulated. Aerosol particles high in the atmosphere will reflect sunlight themselves and can also trigger the formation of high-altitude clouds that also reflect sunlight. It is thought that cooling from aerosols have offset roughly 1/3 of the warming effect of the greenhouse gases released over the last century.In particular, a period of time from 1940 through the 1960s showed very little warming globally due to high releases of air pollution from Europe and North America prior to the establishment of air pollution controls to protect people breathing. Today, there are still huge amounts of aerosol pollutants being released, but the location has changed – from Europe and North America to India, China, and other developing countries. A new study suggests that this change in where air pollutants are being released is really important to the earth’s climate.In this study, scientists from the Carnegie Institute of Washington fed different aerosol release patterns into weather and climate models and observed the end results at both local and global scales. Aerosol releases in Europe, the United States, and China turn out to have a much stronger cooling effect than aerosol releases in India or elsewhere in the tropics. Aerosol releases in these areas triggers cooling that also affects the arctic, causing the formation of sea ice that reflects sunlight back out to space. Aerosols in those areas, therefore, have a global cooling effect.However, aerosol release in the tropics, such as from India, leads to only local cooling effects. That can be seen in this graphic; releases from Western Europe, the US, and China, produce global blue patterns, while releases in India only produce a local blue dot, with a very weak global signal (Areas showing the gridlines don’t produce a statistically significant signal across model runs).These results have important implications for dealing with greenhouse gases. In the 1970s, Europe and the US “Cleaned up their act” because the pollutants in their air were literally killing their residents. When those areas cut cut aerosol pollutants, they removed the effect that was offsetting climate warming and the Earth began warming in response. Today, China and India have the same issues – air pollution literally hurting their citizens. Over time, it is likely those countries will establish improving pollution controls to improve the health of their citizens. When this happens in India, they will also affect their local climate, but they won’t export the changes to the rest of the world. China, on the other hand – when that nation works to cut air pollution, it will also remove one of the breaks on how fast the world is currently warming.Finally, because of the potential trillion dollar costs associated with climate change, some scientists have suggested deliberately polluting the atmosphere with large amounts of aerosols to trigger a cooling effect. This research suggests there are only certain places on Earth where this would work – especially in the northern hemisphere where ice can respond to the local cooling. If someone ever were to deploy that tactic, that would mean extra heavy amounts of air pollution would be required in North America, Europe, Russia, and China – something those nations might not want to put up with.-JBBImage credit and original paper:https://www.nature.com/articles/s41467-018-05838-6More about aerosols:https://earthobservatory.nasa.gov/Features/Aerosols -- source link

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