Atmospheric aerosols have counteracted the warming effects of greenhouse gases over the past century. This has provided some “climate protection”, but also prevented the true magnitude of the problem from becoming evident.
Over the coming century, the role of aerosols in opposing global warming will wane, since their lifetime is short, and because there are powerful policy reasons to reduce their emissions. They will, on the other hand, continue to play a role in regional climate change, especially with regard to the water cycle.
The end of significant “climate protection” by atmospheric aerosols, combined with the potentially very high sensitivity of the climate system, make sharp and prompt reductions in greenhouse gas emissions, especially CO2, very urgent.
A recording of the lecture is available at https://phaidra.univie.ac.at/o:429709.
