Using dendroclimatology to investigate megadroughts

Stephen E. Nash in Sapiens:

Recently, with the increasing intensity of anthropogenic climate change, the topic garnering more of my attention is dendroclimatology. This fascinating science uses tree rings to reconstruct ancient precipitation, temperature, and other climatic variables. Unlike various instruments for tracking weather, tree rings provide researchers with a record going back hundreds or even thousands of years.

That is why tree rings make me nervous: The long-term picture these markers paint about megadroughts and climate change in the western U.S., where I live, is deeply troubling.

More here.