The “Dust Bowl” phenomenon that occurred in the 1930s across the plains of North America could return and become more usual in the current atmospheric conditions of spiked greenhouse levels. The new study by the University of Oxford’s, Environmental Change Institute published on May 18 said that those heatwaves that occurred in the region years ago would be “much larger” under the present-day levels of greenhouse gases in the atmosphere. It would also lead to the “return period” of the rare devastating heatwave summer.
The study said, “Heatwave activity in similarly rare events would be much larger under today’s atmospheric GHG forcing and the return period of a 1-in-100-year heatwave summer (as observed in 1936) would be reduced to about 1-in-40 years.
“A key driver of the increasing heatwave activity and intensity is reduced evaporative cooling and increased sensible heating during dry springs and summers,” it added.
The “substantial warning” of Dust Bowl drought had caused severe crop failures across North America along with huge dust storms. The harsh weather conditions had also led to “out-migration”. These situations had occurred when the United States was experiencing its “hottest summers” of the 20th century in 1934 and 1936. There were apparently more than 40 heatwave days and the maximum temperatures had even surpassed 44 degree-Celcius in some regions of the country.
However, even though such conditions are expected to come about rarely and that too naturally, the current increase in greenhouse gases in the atmosphere could make the Dust Bowl phenomenon more frequent. According to the study, the probability of it occurring again has risen by two and a half times marking once in every 40 years. If the temperatures in the world rise over 2 degrees Celcius above the pre-industrial levels, the Dust Bowl would become one-in-20-year events in the same region.
The co-author of the study and acting director of the Environmental Change Institute at the University of Oxford Friederike Otto said, “Even highly industrialised parts of the world are vulnerable to extreme heat and drought. This is an important reminder that if we do not want events like the dust bowl, we need to get to net zero [greenhouse gas emissions] very soon.”
Hearing "dust bowl" most think of severe drought, but heat waves played a huge role - our new paper highlights the importance of looking at all aspects of compounding disasters & looks at the role of #ClimateChange https://t.co/waOs6h2YBh pic.twitter.com/f9eug0m6zu— Friederike Otto (@FrediOtto) May 18, 2020