Global warming will affect the strength of weather systems differently in the Northern and Southern Hemispheres.
Long-term warming is likely to influence the energy available to drive large-scale weather systems, with different effects north and south.
Paul A. O'Gorman at the Massachusetts Institute of Technology in Cambridge, Massachusetts, used 11 climate models to assess how long-term warming will influence the atmospheric energy available to drive large-scale weather systems in mid-latitude regions of each hemisphere. For the last two decades of the twenty-first century, high- and low-pressure systems will be stronger in the Southern Hemisphere throughout the year than they were between 1981 and 2000, the analyses suggest. But in the Northern Hemisphere, O'Gorman found, changes depend on the season: in a warmer world, mid-latitude systems will be, on average, stronger in winter but weaker in summer, largely due to where in the atmosphere warming occurs.
Fewer or weaker weather systems during Northern Hemisphere summers could cause air pollution there to build up more readily, says O'Gorman. On the other hand, stronger systems in the Southern Hemisphere may boost winds, possibly affecting ocean circulation.
References
O'Gorman, P. A. Understanding the varied response of the extratropical storm tracks to climate change. Proc. Natl Acad. Sci. 10.1073/pnas.1011547107 (2010).
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Perkins, S. North–south divide. Nature Clim Change (2010). https://doi.org/10.1038/nclimate1009
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DOI: https://doi.org/10.1038/nclimate1009
