Forests, Water Regimes, and Global Warming: The importance of forests, including northern coniferous or boreal forests, for the global water cycle is only slowly becoming apparent

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In several publications, TUM-IAS Fellow Anastassia Makarieva and an international team from various disciplines show how vegetation has a lasting influence on the water cycle. They demonstrate two moisture regimes - one is drier, in which additional moisture causes atmospheric moisture import to decrease, and a wetter one, in which additional moisture increases atmospheric moisture import. Because large-scale deforestation reduces evaporation from forests, the atmosphere is dehumidified, and entire forest areas are transferred to a drier regime in which reforestation has no or even a negative effect. Mature, old forests with many large trees are particularly important because their evaporation capacity is exceptionally high. That is why the protection of the mature forests in the Amazon, Africa, Alaska, Siberia, and Northern Europe is urgent. Anastassia Makarieva says: “The atmospheric water flows do not recognize international borders. Thus, deforestation disrupting evapotranspiration in one region could trigger a transition to a drier regime in another. Our results indicate that natural forests of the Earth, in both high and low latitudes, are our common legacy of pivotal importance as they support the terrestrial water cycle.”

In view of these scientific findings and the dramatic developments in the forest areas, 100+ American scientists supported a request for a moratorium on logging in mature and old-growth forests in their recent letter to President Biden.

Find the articles and summary papers in Nature Water here:

Frontiers | Re-appraisal of the global climatic role of natural forests for improved climate projections and policies (

More than carbon sticks | Nature Water