• NASA compiled 29 years of satellite data to create this map showing the greening of the North American Arctic over time. Green pixels represent areas where peak summertime vegetation has become thicker, while brown pixels indicate a decline in vegetation. (Map: NASA's Goddard Space Flight Center/Cindy Starr)

NASA has produced the most detailed picture to date of the widespread "greening" of the Arctic as a result of climate change.

The map above used data from more than 87,000 images collected over a period of 29 years by NASA's Landsat satellites and clearly shows that the North American Arctic tundra is beginning to resemble warmer ecosystems.

The satellites measured peak summertime vegetation cover, using the amount of visible and infrared light reflected by the grasses, shrubs and trees to determine the type of vegetation present in an area. The map is made up of millions of pixels, each representing a 30 metre square parcel of land.

Green pixels on the map indicate where plants were larger or leafier than in the past, while brown pixels show where vegetation declined. Researchers found that overall, grassy tundra has increasingly given way to shrubland, and shrubs are growing taller and thicker, with the greatest greening occurring in northern Quebec and Labrador.

The video below summarizes the study's findings; NASA scientists will now dive deeper into the data to understand how greening will impact water, energy and carbon cycling in the North American Arctic.