Boreal forests shade permafrost so effectively that summer thaw stays about one metre shallower

Boreal forest canopies reduce summer permafrost thaw by about one metre compared to treeless land.

Tree shade keeps 59 billion tonnes of carbon frozen in permafrost soil, far exceeding carbon stored in living trees.

The natural cooling service has been largely overlooked in standard climate models.

Losing boreal forests removes this protection, risking release of ancient organic matter as greenhouse gases.

The study, published in Nature Climate Change, involved Humboldt University of Berlin, Alfred Wegener Institute, University of Oslo, and Vrije Universiteit Amsterdam.