Simulations have been used to analyze geoengineering to mimic the cooling effect of volcanic eruptions. Aerosols would be dispersed from balloons or airplanes at approximately 15 and 30 degrees latitude on both sides of the equator. The desired results would be reduced surface warming and a positive change in the temperature gradient.
Researchers ran 20 computer simulations to demonstrate the impact of adding sulfate aerosols to the stratosphere in the proposed manner.
The models showed the desired cooling impact.
But it is not perfect. There would be reduced global rainfall. The models showed that the changes in rainfall would not be uniform, either; some areas would get less than others. And as some of those areas, such as the North Atlantic, received less rainfall, the ocean would experience an increase in salinity, which would make the water denser.
Enhancement of the Earth’s albedo through the injection of sulfate aerosols into the stratosphere has been proposed as an approach to offset some of the adverse effects of climate change. Here we analyze an ensemble of simulations of the twenty-first century climate designed to explore a strategic geoengineering approach. Specifically, stratospheric sulfur injections are imposed at 15° and 30° in both hemispheres with the aim to minimize the changes in surface temperature, both in the global mean and in its gradients between hemispheres and from equator to pole. The approach accomplishes these goals and reduces previously noted adverse impacts of solar radiation management, such as excessive cooling in the tropics and weakening rainfall over land. Nonetheless, hydrological responses over the North Atlantic Ocean lead to an acceleration of the Atlantic meridional overturning circulation and to continued warming of the deep and polar oceans, particularly in the vicinity of southern Greenland. These changes could cause continued, albeit slower, cryospheric melt and global sea level rise. Our simulations demonstrate the complexity of the coupled climate response to geoengineering and highlight the need for significant advances in our ability to simulate the coupled climate system and the continued refinement of geoengineering strategies as a prerequisite to their successful implementation.