Shifting Thinking, Shifting Forests
It’s been a discouraging few weeks for climate change in the news. First, we learned that atmospheric levels of CO2 have reached 400ppm for the first time in three million years. If that milestone wasn’t enough to put climate on your mind, new research out of the Lawrence Berkley National Lab has called into question a widely held prediction, replacing it with a more pessimistic vision of the future.Current thinking based on climate models holds that the boreal forest — that vast expanse of coniferous landscape circling the globe around Canada, Russia and parts of the U.S. — would expand north during the coming century. But Dr. Charles D. Koven, author of a paper published on Monday in Nature Geoscience, argues that the forest will not expand, but rather just shift northward and release more CO2 than current models account for. As other ecosystems also shift north, the boreal would be replaced in some areas by grasslands, which are unable to sequester carbon as quickly as the forests would release it. Koven’s simulations predict that a forest in Alberta will move north 100 miles in the next 90 years.
In the meantime, changing climate would stress trees, leaving forests more vulnerable to natural threats like wildfire, insects and disease. Accounting for these stressors, Koven’s assessment predicts higher carbon loss than the usual models. He writes, “the majority of carbon-climate models — typically without explicit simulation of the disturbance and mortality processes behind such shifts — instead project vegetation carbon gains throughout the boreal region.”
The complex relationship between forests and climate — and the link between deforestation and global climate change — is one of the reasons American Forests is working to protect and restore forests. Climate change may not be stoppable, but its rate can be slowed. We work in all 50 states and 39 countries. Help us in our quest to save the planet’s forests.