The western United States and northern Mexico have experienced increasingly long dry seasons since the beginning of the 21st century, and some climatologists predict that this trend will cause extreme drought in the long term worse than any other that has been documented, according to a study that publishes the journal Science this April 17.
That document classifies the phenomenon as a “mega-drought” and relates it to human activity not only thanks to modern meteorological records but also to the analysis of growth rings in trees that are up to 1,200 years old.
The investigation covered a territory that spans nine US states, from Oregon and Montana to California and New Mexico, and extends into northern Mexico. Park Williams, a bioclimatologist at Columbia University and its lead author says that “we are on the same path as the worst prehistoric droughts.”
His team mapped dozens of droughts in that area starting in the year 800 and estimated that only four deserved the prefix ‘mega’ for presenting extreme aridity that lasted for decades: the first at the end of the 9th century and the last at the end of the 16th century. 1575 to 1603.
Years, decades or centuries of aridity?
When comparing these ‘mega-droughts’ with the soil moisture records from 2000 to 2018, these specialists concluded that the current disaster already exceeds the first three and is a short distance from the last and worst, since the current change affects more areas. more consistently.
The great ancient droughts lasted more than 19 years less than the 12th century, which lasted for almost 100. Today “we may be lucky” because “natural variability will bring more precipitation for a time but, in the future, we will need more and more “, declares Williams who, although he admits that it is not his prediction for this moment, contemplates that this region may remain arid for centuries.
These researchers think that it is a trace of global warming caused by humans since, despite the fact that natural conditions seem to have also influenced the rainfall in recent years, the decisive contribution was the increase in temperatures. because warmer air draws more moisture out of the ground.
Among the most palpable effects are the drastic reduction of two reservoirs on the Colorado River, dry forests teeming with insects that devastate them, and the fact that wildfires in California and the contiguous US territories affect larger areas each year.
Source: RT Noticias
