Forests are a good thing, right? And reversing deforestation is a smart approach to climate change – locking all that carbon back up in trees, right?

A new paper out of Lawrence Livermore throws an odd monkey wrench into the conventional wisdom, using model simulations to conclude that grassland cools while forest warms:

We find that global replacement of current vegetation by trees would lead to a global mean warming of 1.3°C, nearly 60 percent of the warming produced under a doubled CO2 concentration, while replacement by grasslands would result in a cooling of 0.4°C. It has been previously shown that boreal forestation can lead to warming; our simulations indicate that mid-latitude forestation also could lead to warming. These results suggest that more research is necessary before forest carbon storage should be deployed as a mitigation strategy for global warming.