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The Increase of Seasonal Drought in the Greater Horn of Africa

Paper Reviewed
Lyon, B. 2014. Seasonal drought in the Greater Horn of Africa and its recent increase during the March-May long rains. Journal of Climate 27: 7953-7975.

In his review of the atmospheric circulation and sea surface temperature (SST) conditions that are associated with meteorological drought on the seasonal time scale in the Greater Horn of Africa, Lyon (2014) also describes new findings of a post-1998 increase in drought frequency during the region's March-May (MAM) "long rains."

While he writes that "some studies have tied this increase in drought frequency to longer-term upward trends in Indian Ocean SSTs with an anthropogenic contribution (leading to expectations for continued drought)," he cites significant contrary evidence that suggests "the post-1998 decline in MAM is strongly (though not necessarily exclusively) a manifestation of natural multi-decadal variability of SSTs in the tropical Pacific basin, rather than anthropogenic climate change."

A second significant fact to come out of the U.S. researcher's review of the pertinent literature is that "while CMIP5 climate model projections generally show that the Greater Horn will become wetter during this century" - which is just the opposite of what is being observed - "they are also found to do a poor job capturing the annual cycle of rainfall and simulating historical decadal variability of the Greater Horn long rains and their relationship to global SST patterns."

Therefore, as a result of his variety of findings in the pertinent scientific literature, Lyon finally concludes that "overall, whether anthropogenic forcing will lead to a wetter or drier Greater Horn during the current century is seen to remain an open question."

Clearly, the science on this subject is far from "settled," in strong contradiction of incessant claims from the world's climate alarmists that there is nothing left to debate.

Posted 9 March 2015