Vegetation feedbacks on atmospheric moisture and heat transport

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Although most often associated with the carbon cycle, terrestrial vegetation can also have a profound influence on the Earth's hydrological and surface energy budgets. Plants release water into the atmosphere via transpiration, and as a result can influence the partitioning of surface energy into sensible and latent heat. Latent heat is a form of potential energy that results in the use of energy for vaporization of water, wherein the latent energy can be moved to distant areas and released upon condensation. Production of latent energy therefore is a means by which atmospheric heat and moisture is transported to cooler places across the globe. Recent research in my lab indicates that if vegetation in northern latitudes, like in the Canadian boreal forest and tundra, were to be more productive (say as a result of increasing atmospheric CO2), then the extra production of latent heat that they would produce could represent a potential positive feedback on Arctic warming. This proposal is aimed at getting a better understanding of how vegetation can influence atmospheric transport of moisture and heat. This research is made all the more critical because satellite research has already shown that northern latitudes are much greener now than they were over a decade ago. If this greening also results in an increase in latent heat production, then we should be prepared for an even greater magnitude of warming. It is unwise of us to overlook positive (warming) feedbacks because they can lead to "climate surprises" and threshold-induced rapid rates of climate change.