PLEA Network

20 March 2018, E&E News, We’re cooling Earth by accident. Now we might try on purpose. Scientists presented a startling revelation in January about air pollution. It can cool the atmosphere and mask some of the warming felt by the Earth. The effect is so strong that if all human-caused air pollution disappeared tomorrow, the Earth could rapidly warm by as much as a full degree Celsius (Climatewire, Jan. 22). The sheer magnitude of the cooling effect was the most dramatic finding of the study, published in Geophysical Research Letters, yet scientists have known for decades that small particles in the atmosphere, known as aerosols, can affect the climate and weather systems. They come from all kinds of sources, everything from volcanoes and wildfires to ships and coal-burning power plants. And depending on the type of particles they are and how high they penetrate into the atmosphere, they can absorb sunlight or reflect it. They can also alter the formation of clouds. Now, research on aerosols is gaining new relevance as concerns about global climate change continue to mount. That’s partly because aerosols can shed new light on how the climate system works and how much warming to expect in the coming years. But it also comes at a time of growing interest among scientists in using aerosols to fight climate change — deliberately, that is. Studying the particles that are already acting on the atmosphere can provide insight into the potential outcomes of intentionally geoengineering the planet to bring global temperatures back down. Read More here