Trees’ Location Key in Global Warming

According to a new study presented to the American Geophysical Society annual meeting in San Francisco on December 15, trees in the tropical regions do the most to combat global warming while trees in higher latitudes do nothing to cool the temperature. According to a team of US and French climate experts from the Lawrence Livermore National Laboratory, the location of trees is extremely significant as to how they help fight global warming. Tropical forests have a net cooling effect because they take up carbon and release water vapors, which helps cool the planet. Because the tropics receive more sunlight, they have more energy to convert atmospheric carbon dioxide into biomass. And the water vapors that are released increases cloudiness which also helps cool the planet.
While trees in other regions store carbon as well, more heat is absorbed by their leaves from the sun because the leaves are much darker in color. It was recently discovered that at higher latitudes where trees have darker leaves, the warming effect of trees’ foliage outweighs the cooling effect of the CO2 that is stored. So that these trees there can actually contribute to warming the planet rather than the opposite.
Experts predict what global temperatures would be in 2100 if all forests had been removed from the planet in 2000. Unlike previous studies which have only focused on the carbon-storing effects of trees, the team also accounted for the release of water vapor into the atmosphere and the heat that is stored in the leaves from the sun. The team found that if they removed forests from the planet in 2000, global temperatures in 2100 were 0.2°C cooler than if forests were left intact.
Obviously there are many other valuable assets to forests other than their role in global warming, such as preserving ecosystems and biodiversity in addition to timber and fuel. The bottom line is that planting forests in boreal regions may not be the solution to climate change, says Christine Delire, at the Université Montpellier II, France. These findings are significant in understanding how to plant trees with the goal to reduce global warming: focus on the tropical region.