Higher temps in northern Quebec increase “greening,”  scientists show

"Changes in vegetation have been subtle"

Here you can see the satellite images which show how much vegetation has increased in northern Quebec. Landsat 5 captured the false-color images (above) of a study area around Lac La Potherie in northern Quebec in July 1986 and July 2004. The images were made with a combination of near-infrared, red, and green light to bring out details in vegetation. The deeper the red colour in the image, the denser the vegetation. (IMAGE COURTESY OF NASA)

Yellow outlines mark the location of the nine Landsat scenes used in this study. (PHOTO COURTESY OF NASA)

Scientists using a series of images from NASA satellites, have confirmed that warming temperatures in northern Quebec have increased the amount and extent of shrubs and grasses there — an impact of warming which is visible to people who also live on the ground in Nunavik.

By using Landsat’s 30-metre resolution and viewing the same area at the same time for 23 years, researchers were able to see how the vegetation grew denser and more widespread, NASA said in a recent news release.

“It makes sense,” said Jeff Masek, project scientist for Landsat at NASA’s Goddard Space Flight Center, in the release. “This is how shrub encroaching occurs. They increase in size, they increase in density, and then they move northward.”

Computer models have predicted the northward expansion of vegetation due to warming air temperatures.

“But unlike the decline of sea ice, which is a dramatic effect that we’re already seeing as a result of global warming, changes in vegetation have been subtle,” he said.

Scientists typically track vegetation by measuring the “greenness” of a study area.

For this study, researchers, who presented their findings on Dec. 9, 2011, at the annual meeting of the American Geophysical Meeting, focused on greenness measurements during the peak summer growth from 1986 to 2010.