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The worst is yet to come: expected in prolonged forms in the future

A new study based on an analysis of climatic data conducted by researchers at the Hebrew University of Jerusalem and Columbia University in the USA: "Global warming is expected to cause mega-droughts and even more widespread fires across America, already in the near future"

Aqueduct in California that dried up due to prolonged drought. Illustration:
Aqueduct in California that dried up due to prolonged drought. Illustration:

In the last month we were exposed to the terrible results of drought, a heat wave and strong winds that caused many fires throughout the country and the world. The scientists of the Intergovernmental Panel on Climate Change (IPCC), among them Prof. Daniel Rosenfeld from the Institute of Earth Sciences, are already warning that droughts and extreme heat waves will cause great suffering for millions of people in the coming decades and will lead to even more widespread fires than those we have seen in the Jerusalem mountains or overseas , in the USA (California) and in Europe (Greece). Similarly, severe droughts have occurred in the last decade in central Chile and in the southwest of North America and lead to extensive agricultural losses.

A new study led by Dr. Natan Staiger from the Institute of Earth Sciences at the Hebrew University, Reveals future risks to major agricultural regions in North and South America. The study, published a few days ago in the international journal Nature Geoscience from Nature, Traces the temperature changes following the "La Niña" phenomenon, whose climate pattern in the last thousand years has repeatedly led to prolonged mega-droughts in North and South America at the same time. The findings reveal that the climate changes in these regions, which include the California region in the USA and central regions in Chile and Argentina, have devastating ecological, agricultural and social consequences.

Dr. Staiger and his colleagues from Columbia University in the USA based themselves on the analysis of extensive databases from archives, which record rainfall and temperatures in the past that showed that in prolonged forms they occurred regularly in the Americas. "We combined geological records and computer simulations of the global climate in order to locate the occurrence patterns of droughts in North and South America throughout history. We discovered that the most severe types of droughts, known in French as "mega-droughts", occurred repeatedly in the southwestern regions of North and South America at the same time. Our findings show that such consecutive forms are more than just a coincidence.", explains Dr. Staiger.

12 mega forms in a thousand years

"We found that during the last millennium, about 12 extreme megaforms occurred in both southwestern North America and southwestern South America. These are very extreme droughts that on average lasted about three decades in North America and about two decades in South America in a row", the researchers add. In this context, it is important to note that 7 of these events occurred simultaneously in both regions as a result of the unusually cold temperatures in the center of the Pacific Ocean caused by the "La Nina" phenomenon. "'La Nina' conditions create huge atmospheric waves that push storms further towards the poles, moving them away from places like central Chile and southwestern North America", explains Dr. Staiger.

The results indicate that in the future extreme drought that will last for decades may affect all the western regions of America. Under global warming, the western regions of North and South America are expected to become even drier. According to the researchers, this will lead to even more severe and extreme droughts in these regions, which we now know can be synchronized by temperature changes in the tropical Pacific Ocean.


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