Megadroughts in the Common Era and the Anthropocene

Benjamin I. Cook, Jason E. Smerdon, Edward R. Cook, A. Park Williams, Kevin J. Anchukaitis, Justin S. Mankin, Kathryn Allen, Laia Andreu Hayles, Toby Ault, Soumaya Belmcheri, Sloan Coats, Bethany Coulthard (+22 others)
The concept of megadroughts came to prominence with research into Common Era (CE; Year 1-present) palaeo climate droughts over western North America 1-5 . This research documented multi decadal periods of extreme aridity (or various hydrological deficits 1-5 ) before 1600 CE, as well as widespread ecological disturbances [6] [7] [8] and societal disruptions [9] [10] [11] [12] . Although recurrent and persistent droughts are an intrinsic feature of North American hydroclimate variability, these
more » ... egadroughts were primarily distinguished by their much greater per sistence (for example, multiple decades) than even the most extreme decadal length instrumental era droughts during the 1930s and 1950s 13, 14 . Since then, extreme droughts across the globe have been increasingly referred to as megadroughts, despite often large differences in their severity, duration, or spatial extent. These include multi decadal periods of enhanced aridity in Australia 15,16 , South America 17 , Europe 18 , Central Asia 19,20 , and Mesoamerica 21 ; a multi season drought in 1540 CE over Europe 22 ; spatially extensive multi year droughts in India 23 ; the late Ming Dynasty drought in China 24, 25 ; and an early twenty first century decadal drought in Chile and Argentina [26] [27] [28] . As anthropogenic warming is expected to increase drought severity and risk in many regions of the world 29, 30 , the term has also been increasingly applied to droughts amplified by climate change, both in observations 26, 31 and in model projections 32, 33 . The use of the megadrought label has therefore been inconsistent, owing partly to an absence of applicable objective criteria that define when a drought becomes a megadrought, or when a period of moisture deficit
doi:10.7916/sfrt-5j20 fatcat:npwsdwyjkbdlzde32kngjjukhq