American scientists have analyzed the history of the drought in the last two thousand years and have come to the conclusion that in the west and southwest of the United States, a “mega-drought” can occur at any time, which will last at least 30 years.
“Using our model, we were able to better understand the role that” mega-droughts “play in normal fluctuations of the Earth’s climate, and what exactly drives the chances of their occurrence.It is extremely surprising that even such simple calculations show that such cataclysms can easily arise in the coming years and that their strength will not be inferior to the great drought of the past that has occurred in the west of North America in the past 1200 years, “said Toby Ault of Cornell University in Ithaca, USA.
Since 2011, in southern US regions, a drought has raged, affecting 98 percent of California residents and almost all of its forests, many of which have actually completely dried up during this time. To combat it, the California authorities adopted very severe restrictive measures that are comparable to draconian restrictions on water consumption during a drought in the 1970s, which were formulated but not applied in practice.
Scientists estimate that in the last five years alone, California lost about 67 cubic kilometers of water, and before the “super storm” at the end of December last year, the situation was rapidly approaching a critical one. After a powerful series of rains in January, state authorities announced the completion of the drought, but climatologists fear that the situation may again change
Olt and his colleagues tried to find out how often such events could have happened in the past and find a way to predict such a drought in the future by studying the data collected by paleoclimatologists in studying the history of water bodies that existed in the west and southwest of the United States in the last two thousand years.
The authors of the article were interested in one simple question: do prolonged droughts arise by themselves, as a result of “natural” climate variations, or whether they arise only for some external reasons. In their role, there can be dramatic changes in the nature of movements of currents in the oceans, tarnishing or increasing the brightness of the sun, geological disasters and other factors.
To answer it, scientists created a set of climate models in which droughts were driven either by cataclysms or by climate fluctuations, and compared the results of calculations to what the paleoclimatic data showed. Climatologists, as explained by Olt, were not interested in the time and place of occurrence of specific droughts, but their frequency, timing and number of small and large events of this kind.
As these calculations have shown, large droughts do occur mainly due to random fluctuations in the Earth’s climate, but some of their properties depend on “external” events, for example, the probability that several large droughts will begin almost at the same time and will strengthen each other’s action.
All this suggests that the most powerful droughts, lasting for 30 years, can occur in the west of the United States, even if the climate of the planet does not change in the future. Such cataclysms, as scientists say, will affect the territories of many states and their authorities should be prepared that such problems can arise in any next summer or winter season.