TREE RING

Growth patterns in tree rings record changes in soil moisture over time. A new analysis reveals that moisture levels in many parts of the world have shifted since 1900, due to human influence on global climate.

https://www.theglobeandmail.com/canada/article-tree-rings-show-human-effect-on-climate-goes-back-more-than-a-century/

The scientists found that after centuries of normal variations during which some places alternately became wetter or drier relative to each other, an additional effect on moisture emerged around 1900 that is consistent with climate change. Overall, the data show that much of North America, Australia and the Mediterranean have been getting drier over the past 120 years while parts of Asia, including India and western China, have been getting wetter.