Fig. 5: Conceptual representation of the SLH influence on atmospheric composition and radiative feedbacks within the climate system.
From: Natural short-lived halogens exert an indirect cooling effect on climate
Halogens influence the climate system through direct changes in O3 and OH radical chemical cycling, which in turn regulate the abundance of radiatively active SLCF such as CH4, aerosols and stratospheric water vapour (H2O). The widening (thinning) of the semi-circular arrows within the chemical process layer represents an enhancement (reduction) of the efficiency of the direct SLH-driven (light blue) and indirect OH-driven (dark blue) chemical recycling of CH4, H2O and O3. The green, grey and black upwards arrows within the precursor’s layer are the direct emissions of natural SLH, anthropogenic SLH and anthropogenic air pollutants, respectively. The U-shaped arrows show natural atmospheric cycling processes of halogenated (greenish tail) and anthropogenic (greyish tail) chemical reservoirs, respectively, both of which have been anthropogenically amplified (orange head) and altered the baseline state of the climate system. The length variation of the curly yellow and pink arrows on the uppermost SLCF layer represents the effect induced by SLH on Earth’s radiative balance. The individual warming and cooling effect of each individual SLCF, as well as the net SLH-driven cooling RE, are synthesized as coloured thermometers. Figure 5 was created by NorArte Visual Science (https://www.norarte.es/en/) upon request.
