A 'MEGADROUGHT' is likely to emerge in the southwest of North America driven by climate change

Parts of the US and Mexico have been plagued by a severe drought since 2000, making it the worse one to hit the area in the past 1,200 years.

Researchers are now warning that it is likely to progress into a ‘megadrought’ and climate change is playing a key role in its development.

The experts say the rising temperatures are to blame for about half the pace and severity of the current drought, which ranks the 11th worst to ever be detected.

A team from Columbia University used weather observation, tree-ring data and dozens of climate models to determine a drought more severe than anything from prehistory is likely to progress.

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Parts of the US and Mexico have been plagued by a severe drought since 2000, making it the worse one to hit the area in the past 1,200 years. Researchers are now warning that it is likely to progress into a ‘megadrought’ and climate change is playing a key role in its development

Coauthor Benjamin Cook, who is affiliated with Lamont and the Goddard Institute for Space Studies, said: ‘It doesn’t matter if this is exactly the worst drought ever.’

‘What matters is that it has been made much worse than it would have been because of climate change.’

The team analyzed thousands of tree rings to map dozens of droughts in the area starting in 800 AD, which resulted in the discovery of four megadroughts.

There was one in the late 800s, the mid-1100s, the 1200s and the late 1500s.

The straight horizontal center line indicates average moisture; blue line at bottom shows 2000-2018 mean. Green bars indicate abnormally wet periods, pink ones abnormally dry. The fluctuating red moisture line is based on tree-ring data until it converts to blue at the start of modern instrumental observations

Droughts were found to exist in this area after 1600, but none were as severe.

The four megadroughts were then compared to soil moisture records from observed weather patterns from 2000 to 2018 and the results showed that the current drought is already outdoing the three earliest ones.

The fourth, which spanned 1575 to 1603, may have been the worst of all—but the difference is slight enough to be within the range of uncertainty.

However, the current drought is affecting a larger area than any of the ones on record.

And the previous ones were driving by nature, not by human-made climate change.

Lamont climatologist Richard Seager was one of the first to predict, in a 2007 paper, that climate change might eventually push the region into a more arid climate during the 21st century.

And he speculated at the time that the process might already be underway.

In the Catalina Mountains in southern Arizona (pictured), forests struggle to keep up with recent increases in drought and wildfire activity, which are expected to continue due to human-caused climate change

By 2015, when 11 of the past 14 years had seen drought, Benjamin Cook led a followup study projecting that warming climate would cause the catastrophic natural droughts of prehistory to be repeated by the latter 21st century. 

A 2016 study coauthored by several Lamont scientist reinforced those findings. Now, says Cook, it looks like they may have underestimated. 

‘It’s already happening,’ he said.

The effects of climate change in this area has been witnessed in the reservoirs of Lake Mead and Lake Powell, as well as the Colorado River – all have dramatically loss water over the years.

And California was plagued by deadly wildfires in 2019.