Implications of potential future grand solar minimum for ozone layer and climate

Abstract

Abstract. Continued anthropogenic greenhouse gas (GHG) emissions are expected to cause further global warming throughout the 21st century. Understanding the role of natural forcings and their influence on global warming is thus of great interest. Here we investigate the impact of a recently proposed 21st century grand solar minimum on atmospheric chemistry and climate using the SOCOL3-MPIOM chemistry-climate model with an interactive ocean element. We examine five model simulations for the period 2000-2199, following the greenhouse gas concentration scenario RCP4.5 and a range of different solar forcings. The reference simulation is forced by perpetual repetition of solar cycle 23 until the year 2199. This reference is compared with grand solar minimum simulations, assuming a strong decline in solar activity of 3.5 and 6.5 W m −2 , respectively, that last either until 2199 or recover in the 22nd century. Decreased solar activity by 6.5 W m −2 is found to yield up to a doubling of the GHG-induced stratospheric and mesospheric cooling. Under the grand solar minimum scenario, tropospheric temperatures are also projected to decrease compared to the reference. On the global scale a reduced solar forcing compensates for at most 15 % of the expected greenhouse warming at the end of the 21st and around 25 % at the end of the 22nd century. The regional effects are predicted to be significant, in particular in northern high-latitude winter. In the stratosphere, the reduction of around 15 % of incoming ultraviolet radiation leads to a decrease in ozone production by up to 8 %, which overcompensates for the anticipated ozone increase due to reduced stratospheric temperatures and an acceleration of the Brewer-Dobson circulation. This, in turn, leads to a delay in total ozone column recovery from anthropogenic halogen-induced depletion, with a global ozone recovery to the pre-ozone hole values happening only upon completion of the grand solar minimum.

Investigation of the Vertical Influence of the 11-Year Solar Cycle on Ozone Using SBUV and Antarctic Ground-Based Measurements and CMIP6 Forcing Data

“…Global ozone increases with solar activity due to there being greater incoming UV radiation [27,48,51,74,75]. Local observations at Faraday/Vernadsky show that total ozone increases by about 8 DU between the solar minimum and maximum (Figure 5a,d) during the 21st-23rd solar cycles (sunspot maxima near 1980, 1990, and 2000, Figure 3).…”

“…It is established that polar ozone in the middle and upper stratosphere varies from year to year due to energetic particle precipitation related to solar variability and such events are particularly frequent around the maximum of the solar cycle [46]. Additionally, the 11-year solar cycle effects in the long-term recovery of ozone depletion have been noted [47,48]. Through the absorption of UV radiation by ozone, solar activity-ozone response impacts the stratospheric temperature distribution and, consequently, circulation and climate [49,50].…”

Ozone Layer Evolution in the Early 20th Century

“…The CCM SOCOL3-MPIOM [20][21][22] consists of the following three interactively coupled components: ECHAM5.4 [23] for the calculation of the atmospheric state, the chemistry module MEZON [24,25], and the ocean model MPIOM [26,27]. The CCM SOCOL3-MPIOM has T31 spectral horizontal resolution and covers the atmosphere from the ground to 0.01 hPa (~80 km).…”

UVSQ-SAT, a Pathfinder CubeSat Mission for Observing Essential Climate Variables

“…The exceptionally weak Solar Cycle 24 and the future Solar Cycle 25 (expected to begin in late 2019) are interesting periods in this context as they might possibly imply the beginning of a general negative solar forcing which would be expected to be vastly outweighed by the global anthropogenic positive forcing [27].…”