Particles suspended in the atmosphere have decreased the amount of warming caused by greenhouse gases in the Arctic, but this could change as future air pollution is reduced.
Aerosols have a cooling effect by reflecting sunlight back into space. Mohammad Reza Najafi at the University of Victoria in Canada and his colleagues analysed nine climate models running from 1913 to 2012, comparing simulations with and without greenhouse gases, aerosols and other climate drivers. Their results show that aerosols have offset 1.3–2.2 °C of Arctic warming from greenhouse gases, limiting the observed warming to 1.2 °C. With aerosol emissions projected to drop in the coming decades, the rate of the warming is likely to increase.
The team says that its results underscore the reliability of the climate models, which simulate 8.3 °C of warming in the Arctic in a high-emissions scenario by the end of the century.
Nature Clim. Change http://dx.doi.org/10.1038/nclimate2524 (2015)