Although temperatures have risen throughout the globe, they've gone up most dramatically in the Arctic. Past warm periods indicate that deciduous tree expansion into the Arctic is a common occurrence when the region warms up, so a new study has looked into the impact trees could have on the regional climate. As expected, the increase of the leafy trees would result in less reflective ground, but the study suggests they could also induce more cloud cover and an increasingly warm surface and ocean that have more turbulent weather patterns.
Studies of climate change suggest that deciduous trees will eventually expand into the Arctic region, a notion that is supported by paleontological studies of the region's past warm periods. The currently forested parts don't change from evergreen to deciduous—rather, deciduous trees expand into areas that currently lack other vegetation. The authors of the new paper estimate that the Arctic region could be warm enough to support a substantial population of deciduous trees within the next 10 years.
Although the trees may invade as a result of climate change, it's also expected that they'll influence the local climate, since the foliage will alter the reflective properties and water cycle of the land it will be growing on. The authors used a climate model to study how the albedo (diffusive light reflection) and transpiration of the deciduous trees affected the overall temperature, as well as amount of water vapor in the air.
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http://arstechnica.com/science/news/2009/12/expansion-of-deciduous-trees-could-make-arctic-warm-faster.arsThe trees are in on the conspiracy too. Does Inhofe know?