b'Carnegie Science|Fall 2020 13Air Pollution, Climate Effects,and the Global EconomyAerosol pollution might appear to have some upsides, but at the end of the day their profound harm far outweighs their meager benefits. A lthough aerosol emissions from coal and woodThe Carnegie scientists on the team included, (from left to right) lead author Yixuan Zheng, burning are dangerous to human health, it turns out that by cooling the Earth they also diminish global economic inequality, according to a new study by Carnegies Yixuan Zheng, Geeta Persad, and Ken Caldeira, along with UC-Irvines Steven Davis. Nature ClimateGeeta Persad, and Ken Caldeira.published the study. The team noted, however, that aerosolsImages courtesy Carnegie Institution for ScienceChangeare dangerous and that the public health benefits of cleaning them up would far outweigh the economic benefits of continuing toDoes aerosol-related cooling have a similar distribution of release them.economic impacts? Tiny particles spewed into the atmosphere by human activity,The researchers investigated the economic effects of called anthropogenic aerosols, interact with clouds and reflectcooling caused by aerosol emissions in different parts of the some of the Suns energy back into space. They have a short-termworld. They found that, opposite to greenhouse gases, the cooling effect that is similar to how particles from major volcanicaerosol cooling effect benefitted the economies of tropical, eruptions can cause global temperatures to drop. This masks somedeveloping countries and harmed the economies of high of the warming caused by much-longer-lived greenhouse gases,latitude, developed countries. which trap the Suns heat.Although aerosols have many negative impacts, our Estimates indicate that aerosol pollution emitted by humanssimulations demonstrated that aerosol-induced cooling, in is offsetting about 0.7C, or about 1.3F, of the warming due toparticular, could actually diminish global economic inequality, greenhouse gas emissions, said lead author Zheng. ThisPersad said. translates to a 40-year delay in the effects of climate change.However, when you look at the whole world at once, rather than Without cooling caused by aerosol emissions, we would haveregion by region, the net economic effect of this cooling is likely to be achieved 2010-level global mean temperatures in 1970.small due to these effects between latitudes, added Davis. Previous research has shown that climate change providesWe need to understand how human activities affect our some economic benefits to countries in cool regionswhich wouldplanet so we can make informed decisions that can protect the be warmed to temperatures that are ideal for agriculturalenvironment while giving everyone a high quality of life, productivity and human laborand economic harm to countries inCaldeira concluded. Aerosol pollution might appear to have already hot regions. some upsides, but at the end of the day their profound harm far outweighs their meager benefits.Land and air pollution in Amravati, India. Image courtesy Shutterstock/Dipak Shelare'