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A newly published research paper co-authored by William Paterson University environmental science professor Nicole Davi predicts that devastating effects of climate change will hit an environmentally pivotal area on Earth “substantially sooner” than previous estimates.
Published in Communications Earth & Environment, the paper points to a likely “tipping point” as soon as the year 2050 in the circumpolar boreal region—the most extensive biome on the planet—which accounts for about one-third of global annual forest productivity. This tipping point, Professor Davi and her team of international co-authors explain, will “dramatically and irreversibly” change the state of the area.
They predict that increased tree mortality of this region will occur over the course of 50 to 100 years and lead to an accelerated ecosystem transition from forest to grassland. Previous studies thought that transition would start decades later and would take several more decades, or even centuries, to be fully realized.
“The boreal forests, which wrap around northern Europe and Asia as well as Alaska and Canada, are the world’s largest source of freshwater, and serve as a major source of carbon mitigation,” says Davi. “Our research indicates that the temperatures we expect to see in these forests will get hotter—for a few days a year—than the trees can tolerate, leading to forest loss much sooner than previously thought.”
Climate change is causing rapid increases in temperatures across the boreal domain, Davi says, noting that areas such as northern Mongolia have warmed two to three times faster than the rest of the planet. Leaf temperature, she adds, is often 5 to 20 degrees warmer than air temperature.
For this study, Davi and her team conducted field experiments on five tree species at a forested site in the Tarvagatai River valley in northern Mongolia, comparing measurements of leaf temperature tolerance (Tcrit) against predictions of leaf temperature derived from models.
In so doing, they found that some trees in the region could experience “lethally high temperatures” two to three days every year by the year 2050 and that such heat waves could get more frequent, more intense, and last longer “if greenhouse gas emissions are not reduced rapidly within the next two decades.” Under both low and high emission scenarios, however, the researchers say the tipping point is inevitable and will happen sooner rather than later.
Other tipping points in our planet’s history include the melting of Greenland and West Antarctic ice sheets and death of low-latitude coral reefs.
Davi, a dendrologist and paleoclimatologist who serves as chairperson of WP’s Department of Environmental Science, is also an adjunct senior research scientist at the Columbia Climate School’s Lamont-Doherty Earth Observatory, where some of the top researchers from across the world collaborate. She serves as lead researcher on this project.
Close to a dozen researchers contributed to the study, hailing from institutions such as Yale University, University of California Davis, Harvard University, Spain’s Ecological and Forestry Applications Research Centre, and the Institute of Forestry at the National University of Mongolia.
Caroline Leland, a post-doctoral research fellow working with Professor Davi at William Paterson University since March 2022, also worked on the study and was a co-author on the paper. Mukund Palat Rao, currently a Marie Skłodowska Curie Fellow at the Center for Ecological Research and Forestry Applications (CREAF), in Barcelona, Spain, was the lead author.
Read the paper, “Approaching a thermal tipping point in the Eurasian boreal forest at its southern margin,” on Nature.com.
08/22/23
