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(via Orange Tree of Life Sapphire Opal and Citrine Ring. | Etsy)

Tree rings reveal historical megadroughts in US West

While some chunks of california are dying for rain, evidence has emerged that even the worst drought to strike the region, the Dust Bowl of the 1930's was a pipsqueak compared to some relatively recent events. A team from Brigham Young University in Utah used dendrochronology (the study of tree rings) to tease out records of droughts past from sensitive tree species. How it works is simple, if the tree is drought sensitive, it produces wide rings in years of plenty, and thin ones during dearth.

Their record now extends back to 1429, before the 'discovery' and settlement of America by Europeans. Some of the work involved trees by streams, allowing a gauge of past stream flows to be established. Focussing on the Weber river basin of Utah (though surrounding areas will have been experiencing similar conditions), they discovered several worrying multi-year events that imply much worse than currently experienced is possible. For example, in 1703, a 16 year drought started, that's a long time for even a resilient society like the modern USA to endure. The worst era was that of Columbus's lifetime, with 4 of the 5 worst recorded.

If climate change aggravates the situation further, we could start seeing events that go further than these already scary historic droughts. The work has revealed that the climate oscillates much more strongly in this area than we thought, since the 19th century, when the area was settled was wetter than the average. Water resource management workers will be using this research to help build the sort of resilience into the water use system that will take account of the newly revealed reality.

Our recent post on the current drought: https://www.facebook.com/TheEarthStory/posts/689930364401344 Loz

Image credit, galaxy above bristlecone pine: Rogelio Bernal Andreo (DeepSkyColors.com)