Vegetation feedbacks on atmospheric moisture and heat transport

尽管陆地植被通常与碳循环有关，但它也可以对地球的水文和地表能量收支产生深远的影响。植物通过蒸腾作用将水分释放到大气中，因此可以影响地表能量向显热和潜热的分配。潜热是一种势能，其结果是将能量用于水的汽化，其中的潜能可以被转移到较远的区域，并在冷凝时释放。因此，生产潜能是一种将大气热量和水分输送到全球较凉爽地方的手段。我的实验室最近的研究表明，如果北纬地区的植被，如加拿大北部森林和冻土带的植被，能够提高生产力(比如大气中二氧化碳的增加)，那么它们产生的额外潜热可能代表着对北极变暖的潜在积极反馈。这项建议旨在更好地了解植被如何影响大气中的水分和热量传输。这项研究变得更加关键，因为卫星研究已经表明，北纬地区现在比十多年前更绿了。如果这种绿化还导致潜热产生的增加，那么我们应该为更大幅度的变暖做好准备。我们忽视正(变暖)反馈是不明智的，因为它们可能会导致“气候意外”，并导致气候变化的快速增长。

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.