Two new studies look at natural declines in cloud reflectivity and subsequent increases in incoming solar radiation as an explanation for warming trends in Europe. CO2 is not even mentioned as a factor in climate change.
Scientists note that for Europe “the decrease in cloudiness is caused by the predominance of high pressure systems in the last two decades of the 20th century and in the second decade of the 21st century.”
Because clouds (and sulfate aerosols) reflect less solar radiation into space, Europe has seen an increase in incoming solar radiation (S) and shortwave radiation (S *) of “1.9 and 2.4 W · m²” per decade – ¹. respectively, from 1983-2015.
These tendencies towards an increase in surface solar radiation by 2-3 W · m² per decade were observed not only in Europe, but also in many countries of the world.
Compared to the scant surface exposure of 0.2 Wm² per decade – ¹ associated with a 22 ppm CO2 increase, it is increasingly clear that the recent global warming has been driven by an increase in shortwave exposure due to declining trends in reflectivity clouds and aerosols.
