As climate changes, boreal forests to shift north and relinquish more carbon than expected

Dan Krotz at the Lawrence Berkeley National Laboratory News Center: It’s difficult to imagine how a degree or two of warming will affect a location. Will it rain less? What will happen to the area’s vegetation? New Berkeley Lab research offers a way to envision a warmer future. It maps how Earth’s myriad climates—and the ecosystems that depend on them—will move from one area to another as global temperatures rise.

The approach foresees big changes for one of the planet’s great carbon sponges. Boreal forests will likely shift north at a steady clip this century. Along the way, the vegetation will relinquish more trapped carbon than most current climate models predict.

...Boreal ecosystems encircle the planet’s high latitudes, covering swaths of Canada, Europe, and Russia in coniferous trees and wetlands. This vegetation stores vast amounts of carbon, keeping it out of the atmosphere where it can contribute to climate change.

Scientists use incredibly complex computer simulations called Earth system models to predict the interactions between climate change and ecosystems such as boreal forests. These models show that boreal habitat will expand poleward in the coming decades as regions to their north become warmer and wetter. This means that boreal ecosystems are expected to store even more carbon than they do today.

But the Berkeley Lab research tells a different story. The planet’s boreal forests won’t expand poleward. Instead, they’ll shift poleward. The difference lies in the prediction that as boreal ecosystems follow the warming climate northward, their southern boundaries will be overtaken by even warmer and drier climates better suited for grassland. And that’s a key difference. Grassland stores a lot of carbon in its soil, but it accumulates at a much slower rate than is lost from diminishing forests...

This climate model projection shows the movement of climates in Europe. By the end of the century, the climate currently found in France may have moved to northern England. From the Lawrence Berkeley National Lab website