Blame Canada

According to this Chicago Tribune article, the massive forests in the Great White North are not only not cleansing the atmosphere of greenhouse gases, but rather are pumping out even more of the evil stuff.

Earth's lungs have come down with emphysema. Canada's forests are no longer our friends.

The mountain pine beetle has been able to survive through the comparatively mild winters and continues its destruction of the northern forests. (Editor's note: we don't hear  much about the effects of acid rain on the forests. Instead, we're cautioned not to allow our kids to eat snow.)
Oddly enough, a solution to the plight of the northern forests might be to increase the amount of logging, cutting down old trees that are susceptible to the pine beetle and reforesting with younger and stronger stock.