Climate change is forcing the boreal forest that covers much of northern Canada to a tipping point, concludes a newly published study.
"The changes could be very dramatic and very fast," said Dmitry Schepaschenko of Austria's Institute for Applied Systems Analysis.
Schepaschenko was one of three authors who collaborated on a detailed review of current research on the boreal forest. Their conclusions were released Thursday in a special edition of the journal Science.
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One of the authors is from Natural Resources Canada, but was unable to speak on the record because of restrictions placed on public servants during the federal election.
The boreal forest is one of the largest ecological zones on the planet. It covers much of northern Canada and extends into Scandinavia and northern Russia.
Although it remains largely intact, it faces the most severe expected temperature increases anywhere on Earth. Schepaschenko said some parts of Siberia are likely to eventually become 11 C warmer.
That will bring greater precipitation, but not enough to compensate for the dryness caused by hotter weather. A drier boreal will suffer new diseases, insect infestations and vast wildfires.
Boreal could become savannah
Nor will the forest simply be able to shift north as warmer temperatures creep up from the south, said Schepaschenko.
"The forests can't go so far to the north. The speed at which forests can move forward is very slow, like 100 metres a decade."
The result, the study concludes, is that the forest is likely to transform from an unbroken canopy of green to a mixed landscape with groves of trees separated by open grasslands.
"This forest will convert to a type of savannah."
The consequences of the shift will be sweeping and affect everything from the billions of songbirds that nest in the forest to industries that depend on its vast reserves to stored carbon now locked in permafrost beneath it.
'There could be big trouble'
The study concludes that better management of the boreal forest is needed. For example, spruce trees that are commonly replanted by forestry companies aren't likely to do as well in a drier environment.
"We really need some form of adaptive forest management," Schepaschenko said.
While much attention is given to the fate of tropical rain forests — often referred to as the "lungs of the Earth" — Schepaschenko said the boreal is crucially important as well, if only for the amount of carbon it stores.
"Boreal forests are underestimated right now. There could be big trouble.
"In our small world, everything is connected."