NASA study reveals a “greening” Arctic as tundra vegetation thickens

Using 29 years of satellite data, researchers at NASA have found extensive greening in the vegetation across Alaska and Canada, notably in Quebec’s Nunavik region. (IMAGE COURTESY OF NASA)

As the climate warms, Canada’s Arctic is getting greener — but no region quite as intensely as Nunavik over the past 30 years, according to new satellite imagery gathered by NASA.

Using more than 80,000 aerial images of North America taken from Landsat satellites between 1984 and 2012, NASA’s study offers a long-term look at how climate change has encouraged vegetation growth in Arctic regions.

And, as the image shows, one of greener regions is along Nunavik’s Hudson coast, and east through the region into Labrador.

The darker green hue around northern Quebec and into Labrador seems to suggest the region is hardest hit by climate change.

“The map is pretty striking,” said Stéphane Boudreau, a Laval university ecologist who studies vegetation and, more specifically, how plant life is responding to climate change along Nunavik’s Hudson coast.

“When we return to the same places year after year, it’s clear that a significant change has taken place.”

As part of the study, Landsat, a joint program between NASA and the United States Geological Survey, used the amount of visible and near-infrared light reflected by the green, leafy vegetation of grasses, shrubs and trees to monitor vegetation across North America between 1984 and 2012.

Through a program that tracks individual pixels of data over time, researchers could see if more vegetation was growing in a given region, or if individual plants were getting larger and leafier.

But Boudreau warns to be careful in assuming that Nunavik is impacted more by climate warming than other regions.

That’s because NASA’s satellite imagery spans a 29-year period, starting in 1984, largely before sub-Arctic Nunavik started seeing the impacts of a warming climate.

Some Arctic regions started to green even before the 1980s, but not until the 1990s in Nunavik, where it happened quickly and intensively, said Boudreau.

So the NASA map could represent the intense changes in the region over a shorter period of time, he said — although that’s only one theory.

Another hypothesis of Boudreau’s is that the decline in Nunavik’s caribou herds who graze on that vegetation could have encouraged its growth in many parts of the region.

Regardless, Boudreau said researchers in Nunavik see a clear correlation between warmer temperatures and vegetation growth.

“We notice that there’s a very good relationship between the growth of vegetation and summer temperatures,” he said. “The warmer it is, the more these plants grow. So it’s not surprising to see a greening in response to the increase in temperature.”

Nunavik isn’t seeing new species of plant life, however; the vegetation Boudreau studies is all native to the region.

The focus of his research is to find out why those species seem to respond so quickly to warming and what impact that could be having on the ecosystem.

The increase in vegetation is creating even more warming, researchers have found, because plant life accumulates more snow through the winter months.

The snow insulates the ground, making it harder for the cold to penetrate the ground, Boudreau said, and in turn that degrades the permafrost.

Another change researchers have noted is that in berry plants, the larger they grow, the less fruit they seem to produce, Boudreau said.