A new modeling study led by two NOAA researchers highlights the vast challenges and potentially damaging consequences of solar geoengineering actions large enough to ward off extreme warming by the end of the 21st century.
The study, published in the journal Atmospheric Chemistry and Physics, explored a set of climate model simulations generated by NCAR researchers called the Geoengineering Large Ensemble. This group of 20 simulations projected the climate-forcing influence of hypothetical sulfate aerosol injections in the stratosphere sufficient to reflect enough sunlight to counter global warming from rising carbon dioxide levels throughout the end of the 21st century.
Some scientists and policy makers view climate intervention scenarios, such as reflecting sunlight into space to cool the planet, as a temporary “Plan B” in case humans do not act aggressively enough to tackle the root cause of climate change – fossil fuel pollution.
While the sulfate aerosol injections in the NCAR model runs were carefully designed to keep the annual global-mean surface temperature, the equator-to-pole surface temperature gradients, and the interhemispheric temperature gradients constant as carbon dioxide rose throughout this century, the analysis indicated that potentially unexpected side effects were still possible in different seasons.