Dust bowl, the agricultural conditions during the great depression of the 1930s in the US, that helped propel mass migration among drought-stricken farmers are now more than twice as likely to reoccur in the region due to climate breakdown, new research has found. Climate breakdown indicates the conditions could return that wrought devastation across Great Plains.
In the 1930s, dust bowl conditions wrought devastation across the US agricultural heartlands of the Great Plains that passed through the middle of the continental US extended from Montana to Texas. The combined heatwaves, drought, and farming practices caused the conditions replacing the native prairie vegetation.
The misery of the farmers was already enough because of the wider economy caused by those conditions that occurred in the 1930s. However, two record-breaking heatwaves in 1934 and 1936 exacerbated their condition, which is still the hottest US summers on record.
The dust bowl conditions are very rare natural conditions that could be expected to occur naturally about once a century. However, the rising concentrations of greenhouse gases in the atmosphere have made dust bowl conditions likely to become much more frequent events.
As per the projections of an international group of scientists published on Monday in the journal Nature Climate Change, dust bowl conditions are now at least two and a half times more likely to occur, having a frequency probability of about once in 40 years.
In the scenario of global temperatures rise by more than 2C (a rise of 3.6F) above pre-industrial levels, according to the study’s authors, such heatwaves will become one-in-20-year events in the region.
“Even highly industrialized parts of the world are vulnerable to extreme heat and drought,” said Friederike Otto, co-author of the study and acting director of the Environmental Change Institute at the University of Oxford. “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,” she said.
Since the 1930s, farming in the region has changed with the more extensive use of crop irrigation. But groundwater, on which much of that depends, is also being severely depleted.
Huge fields that encourage soil erosion, given over to a single crop such as maize or wheat due to the tendency towards growing monocultures and besides, a lack of natural vegetation, all contribute to the creation of dust bowl conditions.
“If you don’t have trees anywhere, it’s much harder to keep water in the ground,” Otto said. “What crops you grow and how large the fields are have an effect on how the ground is able to hold water.”
The farmers favor huge open fields with few borders for a very long time as they are more efficient for mechanized tilling and harvesting. However, some farmers have changed their practices in recent years to better conserve the soil, mainly after severe droughts in 2017.
Tim Cowan, the lead author and research fellow at the University of Southern Queensland, said although the study concentrated on the impacts of temperature rises, land management would have a big impact too.
However, the damage done by the climate emergency could not be resolved by improving land management. “Even though you have better practices in cropping now, the rises in temperature reduce those benefits, so there would still be a negative impact,” he said.
It was also discovered by the researchers that there was a small but detectable impact from greenhouse gases on the 1930s’ dust bowl conditions.
Gabi Hegerl, co-author, and professor of climate system science at the University of Edinburgh, said: “With summer heat extremes expected to intensify over the US throughout this century, it is likely that the 1930s records will be broken in the near future.”
The researchers developed the climate model at Oxford that runs on the personal computers of volunteers from all over the world.