According to the new study, forests in mid- to high-latitude locations – such as boreal forests of Canada, Scandinavia and Siberia -- may actually create a net warming. The study concludes that by the year 2100, these mid- and high-latitude forests may make some places up to 10 degrees Fahrenheit warmer than would have occurred if the forests did not exist.
The research, led by Lawrence Livermore National Laboratory atmospheric scientist Govindasamy Bala, appears in the April 9-13 online edition of the Proceedings of the National Academy of Sciences.
Forests affect climate in three different ways: they absorb the greenhouse gas carbon dioxide from the atmosphere and help keep the planet cool; they evaporate water to the atmosphere and increase cloudiness, which also helps keep the planet cool; and they are dark and absorb sunlight (the albedo effect), warming the Earth. Previous climate change mitigation strategies that promote planting trees have taken only the first effect into account.
"Our study shows that only tropical rainforests are strongly beneficial in helping slow down global warming," Bala said. "It is a win-win situation in the tropics because trees in the tropics, in addition to absorbing carbon dioxide, promote convective clouds that help to cool the planet. In other locations, the warming from the albedo effect either cancels or exceeds the net cooling from the other two effects."
"If we really want to do something about global warming," said JunkScience.com's Steve Milloy, "providing chainsaws to Canadians, Swedes and Russians would seem a better investment than economy-killing greenhouse gas emissions reductions."
The real value of the study, Milloy said, is that it illustrates how little we know about the global ecosystem and climate. "Imagine that folks in Congress are actually contemplating harming our economy by making energy more expensive and more scarce based on exceedingly limited knowledge about the ecosystem and climate," added Milloy.
"I only have one question," said Milloy. "How did this study make it out of the Global Warming Politburo? Is the Minister of Propaganda still on Spring Break?"