A drought, equal to the worst to have hit the western US in recorded history, is already under way, say scientists. Researchers say the megadrought is a naturally occurring event that started in the year 2000 and is still ongoing. Climate change, though, is having a major impact with rising temperatures making the drought more severe. Some researchers are more cautious, saying that it is too early to say if the region really is seeing a true megadrought.

According to the authors of this new paper, a megadrought in North America refers to a multi-decade event, that contains periods of very high severity that last longer than anything observed during the 19th or 20th centuries.

The authors say there have been around 40 drought events over the period from 800-2018 in the western US.

Of these, only four meet the criteria for a megadrought. These were in the late 800s, the mid-1100s, the 1200s and the late 1500s.(BBC)…[+]