This journal article talks about the possibility of a disturbing situation where climate change starts to kill trees, which are then no longer able to absorb carbon dioxide, which causes more climate change, and so on in an accelerating feedback loop.

Trees Can Limit Climate Change—Unless It Kills Them First

Scientists have considered forests a potential barrier to climate change, since plants on land take up about 25 percent of our carbon dioxide emissions. As trees in colder areas are exposed to warmer temperatures and more CO2 emissions, they will grow faster and absorb more emissions, helping to mitigate the effects of a primary greenhouse gas, the theory goes.
But, in an alarming twist, global warming is likelier to limit forests’ capacity for absorbing emissions in many parts of the continent, a study released today in the journal Ecology Letters finds. After combining climate projections with the tree records, researchers found no evidence for the boreal greening hypothesis. In fact, they found a risk of a negative feedback loop, as trees in their model reacted poorly to warmer temperatures due to drought and other disturbances.
That means as trees die faster than they can take up CO2 emissions, releasing trapped carbon, forests could become a net source of carbon, accelerating climate change. The study found that we could reach such a tipping point as early as 2050.