Ecoclimate Teleconnections: The Remote Effects of the Interaction Between Ecosystems and Climate (Invited Presentation)

Forest cover has the ability to modify local climate through changes in surface fluxes of carbon, energy, water, and momentum. Changes in forest cover over large spatial areas may also have the ability to alter atmospheric circulation patterns globally, leading to consequences for ecosystems in locations far from the original change in land cover. This can feedback onto climate causing ecoclimate teleconnections. Using global climate model experiments we find the mechanisms responsible for both local and global climate responses to changes in forested area across the northern hemisphere mid-latitudes and the tropics.  We explore the consequences of a range of forest cover changes, as well as the impact of changes in forest characteristics in response to increasing temperatures and atmospheric carbon dioxide concentrations. A local increase in mid-latitude forest cover results in an increase in the absorption of solar radiation at the surface, but surface temperatures only increase when soils are dry. Atmospheric circulation re-distributes the anomalous energy absorbed in the northern hemisphere, in particular towards the south, through altering the Hadley circulation, resulting in the northward displacement of the tropical rain-bands. The magnitude of circulation response to forcing from vegetation scales roughly linearly with area of forest cover added, however local cloud response shows a threshold effect with a drop in cloud cover when soil water can no longer fuel compensating increases in surface latent heat flux.  Atmospheric responses are also triggered by changes in plant functioning in response to climate change.  The ability of vegetation to affect remote circulation has implications for strategies for climate mitigation.