Study: Even If They All Survived, Planting A Trillion Trees Would Cut Warming By 0.15C By 2100

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But in recent years, climate scientists have grown more skeptical about relying on tree-planting programs. They have warned that heat waves, famines and infectious diseases could claim millions of additional lives by the end of this century unless humanity swiftly phases out the burning of oil, gas and coal. Now, new research finds that planting a trillion trees would have a minimal effect on halting global warming, partly because of the long lag time for trees to reach maturity and absorb large amounts of carbon. The analysis by John Sterman, a professor at the MIT Sloan School of Management, and Andrew P. Jones, executive director of the nonprofit Climate Interactive, found that planting a trillion trees would only prevent 0.15 degrees Celsius (0.27 Fahrenheit) of warming by 2100.

“Trees are great. I personally love to be out in the forests as much as I possibly can,” Sterman said. “But the reality is very simple: You can plant a trillion trees, and even if they all survived, which wouldn’t happen, it just wouldn’t make that much difference to the climate.” The analysis relied on a global climate simulator called En-ROADS, developed by Climate Interactive and the MIT Sloan Sustainability Initiative. It also found that planting a trillion trees would only sequester 6 percent of the carbon dioxide that the world needs to avoid emitting by 2050 to meet the goal of the Paris climate accord: limiting global warming to 1.5 degrees Celsius (2.7 Fahrenheit) above preindustrial levels. “Planting a trillion trees is not a serious solution to the climate crisis,” Jones said. “It is too little, too late.”

Trees do store vast amounts of carbon dioxide in their trunks, branches and roots. But old-growth forests sequester much more carbon than younger forests, and it usually takes 20 to 30 years for trees to reach full maturity. That means a tree planted today would do little to reduce emissions over the next crucial decades.

Trees are also especially vulnerable to drought, wildfires and pests, all of which are becoming more common as the world warms. In Montana, where the average temperature has increased by nearly 2.5 degrees Fahrenheit since 1950, a mountain pine beetle infestation has damaged or killed hundreds of thousands of acres of forests.

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https://www.washingtonpost.com/climate-environment/2023/08/02/trillion-trees-republicans-climate/