Climate change will "supercharge" forest disturbances

Tree planting is often an environmental solution to offset emissions that contribute to climate change. However, if the trees burn in a forest fire, all of the carbon they store could be thrown back into the atmosphere. When trees die, they also stop scrubbing carbon dioxide from the air due to drought or insect damage.

According to new research from the University of Utah, the likelihood of these threats is increasing worldwide. Relying on forests to absorb carbon emissions could be riskier than previously thought.

“U.S. forests could look dramatically different by the end of the century,” said study lead author William Anderegg. “More severe and frequent fires and disturbances have huge impacts on our landscapes. We are likely to lose forests from some areas in the Western U.S. due to these disturbances, but much of this depends on how quickly we tackle climate change.”

The researchers modeled the risk of tree death from fire, climate stress, such as heat or drought, and insect damage for forests throughout the United States, projecting how those risks could increase overtime. 

The models found that by 2099, United States forest fire risks may increase between four and 14 times, depending on different carbon emissions scenarios. The risks of climate stress-related tree death and insect mortality could double over the same time.

“Climate change is going to supercharge these three big disturbances in the U.S.,” said Anderegg. “We’ve seen devastating fire seasons with increasing severity in the past several years. Generally, we expect the western U.S. to be hit hardest by all three of these. And they’re somewhat interconnected too. Really hot and dry years, driven by climate change, tend to drive lots of fires, climate-driven tree mortality and insect outbreaks.”

In each model, actions to tackle climate change mattered significantly. Reducing the severity of climate change dramatically reduced the likelihood of fire, drought and insect-driven forest die-off. This signals an opportunity – taking action to address climate change now can help maintain healthy forests, and the offsetting of emissions trees provide. 

The study is published in the journal Ecology Letters. The research was supported by the National Science Foundation, U.S. Department of Agriculture, David and Lucille Packard Foundation and Microsoft’s AI for Earth.

Click here to see the findings in an interactive map.

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By Katherine Bucko, Earth.com Staff Writer