Solar geoengineering could cause unwanted changes in climate, new modelling suggests

Solar geoengineering could cause unwanted changes in climate, new modelling suggests

SOURCE: Physics World DATE: June 20, 2020 SNIP: Using aerosols to reflect sunlight and cool the planet will weaken storm tracks in the temperate latitudes in both hemispheres, an international team of scientists warn. Their modelling suggests that while such solar geoengineering schemes could reduce the severity of winter storms, they would also stagnate weather systems in the summer. This could lead to more intense heat waves, increases in air pollution, and changes in ocean circulation. Solar geoengineering involves cooling the Earth by reflecting incoming sunlight and is seen by some scientists as a way of mitigating the effects of global warming. One popular strategy involves placing reflective aerosols in the stratosphere – using aircraft, balloons or blimps – to block sunlight. But the effects of solar geoengineering are unknown. It would not work as simply as cooling the planet and therefore returning Earth’s climate to pre-industrial levels. Climate under solar geoengineering would be different, as there would still be marked increases in atmospheric carbon dioxide levels. Charles Gertler, a graduate student in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology, in the US, and colleagues were interested in how injecting aerosols into the atmosphere would impact the pole‐to‐equator temperature gradient in both hemispheres, and the effect that could have on extratropical storm tracks. These are regions in the mid and high latitudes with heightened incidences of storms known as extratropical cyclones, which play a significant role in determining the day-to-day weather conditions in many parts of the world. “Our results show that solar geoengineering will not simply reverse climate change,” Gertler explains....
Climate Engineering, Once Started, Would Have Severe Impacts If Stopped

Climate Engineering, Once Started, Would Have Severe Impacts If Stopped

SOURCE: Rutgers University DATE: January 21, 2018 SNIP: Facing a climate crisis, we may someday spray sulfur dioxide into the upper atmosphere to form a cloud that cools the Earth, but suddenly stopping the spraying would have a severe global impact on animals and plants, according to the first study on the potential biological impacts of geoengineering, or climate intervention. The study was published online today in Nature Ecology & Evolution. The paper was co-authored by Rutgers Distinguished Professor Alan Robock, research associate Lili Xia and postdoc Brian Zambri, all from the Department of Environmental Sciences at Rutgers University–New Brunswick. “Rapid warming after stopping geoengineering would be a huge threat to the natural environment and biodiversity,” Robock said. “If geoengineering ever stopped abruptly, it would be devastating, so you would have to be sure that it could be stopped gradually, and it is easy to think of scenarios that would prevent that. Imagine large droughts or floods around the world that could be blamed on geoengineering, and demands that it stop. Can we ever risk that?” The geoengineering idea that’s attracted the most attention is to create a sulfuric acid cloud in the upper atmosphere as large volcanic eruptions do, Robock said. The cloud, formed after airplanes spray sulfur dioxide, would reflect solar radiation and cool the planet. But airplanes would have to continuously fly into the upper atmosphere to maintain the cloud because it would last only about a year if spraying stopped, Robock said. He added that the airplane spraying technology may be developed within a decade or...