Climate change is typically viewed as heavily connected to greenhouse gas emissions, but overall it is driven by an interaction of numerous factors. While greenhouse gases stimulate the warming of our planet, other factors - such as aerosolized particles - produce a cooling effect. However, the ongoing nature of the warming has made it difficult to reveal just how large this cooling effect is.
A new study in Nature Geoscience attempts to measure the aerosol effect quantitatively by examining climate data from three time periods that span from 1964 to 2010 to determine the evolution of global temperatures if carbon dioxide emissions paused at their 1964 values.
The results revealed that the cooling effects created by aerosols masked around one-third of the global warming that is caused by rising greenhouse gas emissions, with the effect at its strongest prior to 1990. However, exactly how these aerosols work is still a matter of debate.
Aerosolized particles achieve their cooling effect by scattering light and reflecting some of it back out into space, causing a decrease in global temperatures. They can also stimulate the formation of clouds, which themselves can act as both insulators and reflectors, meaning they can help heat and cool the planet, complicating the interaction between aerosols and clouds.
An additional study in Nature Geoscience examines the role of aerosols in the accelerated warming that has been observed in the Arctic compared to the rest of the planet. The team found that approximately half of the average Arctic warming is the result of Europe decreasing their sulfate-based aerosols during the periods of 1980 and 2005, which led to a reduction of aerosolized sulfates and, in turn, a decreased cooling effect.
The findings imply that Europe's decrease of emissions, meant to prevent climate change, actually progressed it due to our lack of understanding of the atmospheric relationships that cause it.
Both studies shed light on the large role of human emissions in the process of climate change, as well as the unclear relationship between greenhouse gases, aerosol particles and the clouds that they can form. However, current data seems to point to the detrimental effects of aerosol reduction on our planet's warming.
