Summary
Brazilian and South African researchers modelled how solar radiation modification (SRM) could affect Southern Hemisphere extratropical cyclones. SRM is projected to reduce the intensity of these cyclones compared to unchecked global warming, keeping them closer to current levels. Cyclone frequency is expected to decline by the end of the century in both scenarios, but less so under SRM. SRM also shifts cyclone patterns poleward, increasing intensity near Antarctica. The study highlights SRM’s potential to moderate climate impacts, but calls for further research into its complex effects on cyclone behaviour.
Abstract
The Degrees modelling team in Brazil, which is an international collaboration between researchers in Brazil and South Africa, has been exploring how solar radiation modification (SRM) and climate change might affect extratropical cyclones. These cyclones are low-pressure systems that play a crucial role in atmospheric circulation, moving heat from the tropics to the poles. They can cause extreme weather events in South America and elsewhere, damaging coastal ecosystems, impacting maritime navigation and infrastructure.
In this study, the first SRM modelling paper from Brazil, scientists led by Michelle Simões Reboita investigated the expected impact of SRM on Southern Hemisphere extratropical cyclones under different warming scenarios. By comparing future scenarios where SRM is deployed with those where global warming continues, the team found that SRM could influence the frequency, intensity, and spatial patterns of cyclones.
The paper concludes that extratropical cyclones would be less affected by climate change if SRM were used. They are expected to become increasingly intense under global warming, and the Brazil team finds that SRM could lessen their intensity, resulting in a similar intensity to the current period. Cyclone frequency is projected to decrease towards the end of the century in both SRM and climate change scenarios, but this decrease is also less pronounced under SRM.
The study highlights that while SRM could mitigate some impacts of global warming on cyclone frequency and intensity, it would also introduce complexities in cyclone behaviour that require further study. For instance, the spatial patterns of cyclone density and intensity in the models suggest a shift towards the poles under both SRM and global warming scenarios, with cyclones becoming more frequent and intense towards Antarctica and less so in mid-latitudes.
The study highlights the importance of carefully considering the broader climatic impacts and uncertainties associated with SRM. Prof. Reboita and her co-authors recommend further research to better understand the physical differences in cyclone behaviour under SRM and climate change. Her team is also analysing other aspects of extratropical cyclones and the impacts of SRM on the South Atlantic Subtropical Cyclone. Their research will be crucial for informed decision-making on this topic.