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This animation examines the change in the vegetation trend over Canada and Alaska between 1984 and 2012. || High-latitude regions have been warming rapidly since the last century, at a rate higher than the global average. At continental scales, satellite data since the 1980s have indicated increased vegetation productivity (greening) across northern high latitudes, and a productivity decline (browning) for certain areas of undisturbed boreal forest of Canada and Alaska. These remote sensing results have been corroborated by in-situ evidence. This research provides a spatially complete view of the vegetation greenness change for all of Canada and Alaska by calculating per-pixel NDVI trend from all available 1984–2012 peak-summer Landsat-5 and -7 surface reflectance data. By incorporating observations from overlapping scenes, researchers obtained up to 160 valid NDVI values for certain areas from this 29-year period, establishing the mid-Summer greenness trend. This animation shows the resulting greenness trend over Canada and Alaska with special attention focused on the regions of Quebec and northern Alaska. || The colorbar applied to the vegetation productivity trend data. Green colors indicate an increase while brown colors indicate a decrease. || A print resolution image of the greening trend over Quebec, Canada. || A print resolution image of the greening trend over Canada and Alaska.

NASA scientists used almost 30 years of data from the NASA/USGS Landsat satellites to track changes in vegetation in Alaska and Canada. Of the more than 4 million square miles, 30% had increases in vegetation (greening) while only 3% had decreases (browning). This is the first study to produce a continent-scale map while still providing detailed information at the human scale.Music: by Janik Riegert [GEMA], Josh Tapen [GEMA]Watch this video on the NASA Goddard YouTube channel. || The northern reaches of North America are getting greener, according to a NASA study that provides the most detailed look yet at plant life across Alaska and Canada. In a changing climate, almost a third of the land cover – much of it Arctic tundra – is looking more like landscapes found in warmer ecosystems. With 87,000 images taken from Landsat satellites, converted into data that reflects the amount of healthy vegetation on the ground, the researchers found that western Alaska, Quebec and other regions became greener between 1984 and 2012. The new Landsat study further supports previous work that has shown changing vegetation in Arctic and boreal North America. Earlier studies showed increased vegetation was connected to increasing global carbon dioxide and increasing global temperatures. Previous surveys of the vegetation across Alaska and Canada had taken a big-picture view of the region using coarse-resolution satellite sensors. To get a more detailed picture of the 4.1 million square-mile area, scientists used the NASA/USGS Landsat 5 and Landsat 7 satellites, which take a measurement for each 30-by-30 meter (98-by-98 foot) parcel of land.Using the detailed Landsat data, NASA scientists found that there was extensive greening in the tundra of western Alaska, the northern coast of Canada, and the tundra of Quebec and Labrador. While northern forests greened in Canada, they tended to decline in Alaska. Overall, the scientists found that 29.4 percent of the region greened up, especially in shrublands and sparsely vegetated areas, while 2.9 percent showed vegetation decline.With the large, continental-scale map complete, researchers will focus on the more human scale – looking at local conditions to see what might control the greening patterns, whether it’s local topography, nearby water sources, or particular types of habitat. They also plan to investigate forested areas, particularly in the greening Quebec.

Animation of the Landsat 8 (formerly known as LDCM, the Landsat Data Continuity Mission) spacecraft in orbit around the Earth. The satellite will travel at 7.5 km/second, circling the globe every 99 minutes at an altitude of 438 miles. LDCM will image a swath 185 km in width and complete about 14 orbits each day, thereby imaging Earth s rendering of LDCM showing the calibration ports of the instruments (TIRS and OLI). || Schematic line drawing of Landsat 8 spacecraft.