Study warns that removing aerosols could cause warming
A new study led by researchers at the CICERO Center for International Climate and Environmental Research in Oslo, Norway has warned that the reduction of aerosol emissions – mostly sulfates - that will coincide with reduced greenhouse gas emissions as the world strives to meet the Paris Agreement target could have the perverse effect of adding to global warming.
The study, published in the journal Geophysical Letters, used idealized scenarios simulated by four global, fully coupled atmosphere-ocean-composition climate models to separate the climatic effects of aerosol emission mitigation from those of continued, moderate greenhouse gas-induced warming.
The models simulated an additional global warming of around 0.7°C when anthropogenic aerosols were fully removed, with a model range of 0.5 to 1.1°C. This is comparable in magnitude to the 1°C warming already realized since preindustrial times.
The study found that populated regions where aerosol emissions were mostly generated would see stronger changes in temperature, precipitation, and extremes than the land area mean. East Asia was highlighted as a region where extreme precipitation is particularly sensitive to a reduction in aerosol emissions.
The northern hemisphere was found to be more sensitive to aerosol removal than greenhouse gas warming, because of where the aerosols are emitted today.
“This means that it does not only matter whether or not we reach international climate targets. It also matters how we get there.”
The study emphasised the need for future climate change studies to consider not just the net forcing and resulting global mean surface temperature but also the detailed balance between greenhouse gases and aerosols in emission pathways.
The study, Climate Impacts From a Removal of Anthropogenic Aerosol Emissions, is available here.