Tuesday, March 12, 2013

Northern Arctic Becoming More Like The South


Climate Change

Parts Of North Becoming Greener: A significant part of the North is becoming greener, NASA scientists report: "Of the 10 million square miles (26 million square kilometers) of northern vegetated lands, 34 to 41 percent showed increases in plant growth (green and blue), 3 to 5 percent showed decreases in plant growth (orange and red), and 51 to 62 percent showed no changes (yellow) over the past 30 years. Satellite data in this visualization are from the AVHRR and MODIS instruments, which contribute to a vegetation index that allows researchers to track changes in plant growth over large areas."
Photo Credit : NASA's Goddard Space Flight Center Scientific Visualization Studio
Source: NASA


A release by NASA says that the northern Arctic's weather is generally warming up, resulting in a greater abundance of greener vegetation in a significant part of the region (up to 41 percent); This makes those parts of the north look similar to regions south of it. The change is due to, what scientists call, "an amplified greenhouse effect."
An international team of university and NASA scientists examined the relationship between changes in surface temperature and vegetation growth from 45 degrees north latitude to the Arctic Ocean. Results show temperature and vegetation growth at northern latitudes now resemble those found 4 degrees to 6 degrees of latitude farther south as recently as 1982.

"Higher northern latitudes are getting warmer, Arctic sea ice and the duration of snow cover are diminishing, the growing season is getting longer and plants are growing more," said Ranga Myneni of Boston University's Department of Earth and Environment. "In the north's Arctic and boreal areas, the characteristics of the seasons are changing, leading to great disruptions for plants and related ecosystems."

The study was published Sunday in the journal Nature Climate Change.

Myneni and colleagues used satellite data to quantify vegetation changes at different latitudes from 1982 to 2011. Data used in this study came from NOAA's Advanced Very High Resolution Radiometers (AVHRR) onboard a series of polar-orbiting satellites and NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua satellites.

As a result of enhanced warming and a longer growing season, large patches of vigorously productive vegetation now span a third of the northern landscape, or more than 3.5 million square miles (9 million square kilometers). That is an area about equal to the contiguous United States. This landscape resembles what was found 250 to 430 miles (400 to 700 kilometers) to the south in 1982.

"It's like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years," said co-author Compton Tucker of NASA's Goddard Space Flight Center in Greenbelt, Md.
There is no certainty that this warming trend will continue, NASA's computer models say. Yet, there is certainty that things are now generally heating up in the Arctic, leading to climate change. The data is unmistakeably clear.

What is equally interesting, however, is what the data also shows: that the increased vegetation growth is not universal, that is, common to all regions. As the NASA release says, "3 to 5 percent showed decreases in plant growth (orange and red), and 51 to 62 percent showed no changes (yellow) over the past 30 years." If you look carefully at the image above, you'll note the orange and red patches are evident throughout the north.

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You can read the rest of the release at [NASA].

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