According to a new study, frequent droughts in North America and the Mediterranean are linked to fluctuations in sea temperature.
Researchers from the University of Exeter, University of Montpellier, and University of Wageningen studied seawater data from 1957 through 2002. The team found that sea surface temperatures in both the northern Pacific and Atlantic oceans became more and more variable, with extremes temperatures lasting for longer durations.
The sea temperature changes correlated with increases in land temperature along with the persistence of extreme conditions. Thus, the researched concluded that frequent droughts on land were triggered by the increases in sea temperature.
The research was published in the journal Scientific Reports.
“Our evidence shows that larger and more persistent variations in sea surface temperature have occurred in the North Atlantic and North Pacific and these contributed to more extreme and persistent temperature anomalies on parts of the world’s land surface,” said Professor Tim Lenton from the University of Exeter.
Extended periods of high or low temperatures can have an effect “greater than the sum of their parts,” the study said.
“For instance, a long heatwave can have greater impacts on human mortality than the sum of individual hot days, and multi-year droughts can have greater agricultural economic impacts than the sum of individual dry years,” Lenton said.
One particular drought in the Eastern Mediterranean has been going on since 1998, which NASA calls “worst drought of the past nine centuries.
Source: University of Exeter