Climate implications of the sun transition to higher activity mode

Abstract

We analyze the ozone and climate response to the solar irradiance changes caused by the switch of the Sun to higher activity mode which is characterized by the simultaneous decrease of the total and increase of the UV solar irradiance. The results obtained using a chemistry-climate model with an interactive ocean show increase in the stratospheric ozone and temperature caused by higher levels of shortwave (100–380 nm) UV radiation. For the surface climate, the results are not so trivial because we obtained annual mean cooling for most of the globe, but at the same time, we do not observe expected statistically significant cooling over the northern high latitudes. This can be explained by the influence of the stratospheric ozone increase which can enhance the positive phase of the North Atlantic Oscillation bringing more energy to high latitudes. In general, a possible switch of the Sun to a more active state can lead to a slightly cooler climate and some decrease in the surface UV. However, these changes cannot be considered as catastrophic.