Climate change: US megadrought ‘already under way’

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Discussion posted by: Arye ben-Shaoul

A drought, equal to the worst to have hit the western US in recorded history, is already under way, say scientists…. 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. The key to this new study is the use of tree ring records to reconstruct soil moisture data for the past 1200 years. The team were also able to use supporting evidence such as medieval tree stumps growing in normally wet river beds, the abandonment of settlements by indigenous civilisations at the peak of the 13th century drought, plus evidence from lake deposits indicating wildfire activity was enhanced during these drought periods.