The further you get from the equator, the greater difference there is between summer and winter temperatures. It’s not just the cold or the heat that makes the most extreme environments so hostile, but this “seasonality” in the temperature—the range of conditions to which plants and animals living in these areas can be subjected. A thick layer of fat and a heavy coat of fur can keep you warm in winter, but the same insulation can be dangerous if the summer heat is too high.
But, with global climate change, says a new study, that temperature seasonality is going down. And satellite records and other observations from the past 30 years, says NASA, show that this change in temperature seasonality is already affecting plant growth in higher latitudes. Higher temperatures and longer growing season mean that large portions of the Arctic, subarctic and temperate ecosystems are seeing more plant growth than they did in the past.
In practice, that means the Arctic is turning green. NASA:
The Arctic’s greenness is visible on the ground as an increasing abundance of tall shrubs and trees in locations all over the circumpolar Arctic. Greening in the adjacent boreal areas is more pronounced in Eurasia than in North America.
So far, the effect has been only a small shift in vegetation patterns, with plant growth in one location mimicking how it was 30 years ago in a location five degrees latitude to the south. By the end of the century, however, scientists think that the changes will be equivalent to a 20 degree shift. Think Alaska’s capital Juneau, at 58 °North, acting more like Louisville, Kentucky, at 38 °North.
However, rising temperatures aren’t the only thing to take into account, and the other effects of climate change could actually hurt the increasingly lush Arctic.
Researchers note that plant growth in the north may not continue on its current trajectory. The ramifications of an amplified greenhouse effect, such as frequent forest fires, outbreak of pest infestations and summertime droughts, may slow plant growth.
And, if a nice green Arctic sounds like a pleasant consequence of climate change, just try to imagine what a 20 degree shift in climate would do to somewhere further south.
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