The Greening of the Arctic


Temperatures in the north are starting to resemble those much further south. A new study suggests it's time to get ready for the arctic to bloom.

Last week we reported on an extensive new study showing that today’s global temperatures are warmer than any point in at least the last 4,000 years. Now, a separate study published in Nature Climate Change is demonstrating the dramatic impact this is having on the north’s growing season. After analyzing satellite and ground-based data, the researchers found that temperature and vegetation growth at northern latitudes now resemble those typically found four to six degrees of latitude further south — a distance of about 250 to 430 miles (400 to 700 km).

The researchers, an international team consisting of university and NASA scientists, focused their attention on the region from about 45 degrees north latitude to the Arctic Ocean.

Their analysis showed that all the conditions for a greenhouse feedback loop are being met, including diminishing Arctic sea ice and less snow cover. At the same time, as the northern latitudes get warmer, the growing season is getting longer and plants are thriving over a wider geographical area. These changes are having a dramatic impact on the boreal areas, leading to significant disruptions in the various ecosystems.

And indeed, we’re talking about a considerably large area.

"It's like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years," said co-author Compton Tucker through a NASA statement. Vegetation now grows in areas that were ecologically off limits only a few decades ago — a region that covers a jaw-dropping 3.5 million square miles (9 million square kilometers). For perspective, that’s an area equal to the continental United States.

The Greening of the Arctic


In this image, 34-41% of the area in question (i.e. above the 45 degree latitude mark) shows increases in plant growth (shown in green and blue), 3-5% shows decreases in plant growth (orange and red), and 51-62% show no changes (yellow) over the past three decades. Interestingly, the Arctic’s newfound greenness is most prominent in Eurasia.

To conduct the study, the researchers used data gathered over the past 30 years to quantify vegetation changes at different latitudes. Much of the information was brought in 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.

The Greening of the Arctic


Equally disturbing is what the study’s authors are calling an amplified greenhouse effect. Global temperatures are increasing, they say, owing to positive feedbacks.

Specifically, the accumulation of heat-trapping gasses — like CO2, water vapor, and methane — cause the planet’s surface, ocean, and atmosphere to warm. All this warming reduces polar sea ice and snow cover, resulting in darker oceans and land surfaces which hold on to more solar energy. And that in turn causes the air above those regions to get warmer.

From there, the greenhouse effect gets further amplified as soils in the north being to thaw — a process that releases significant amounts of CO2 and methane into the atmosphere.

Read the entire study at Nature Climate Change.

Supplementary source: NASA.

Images: NASA's Goddard Space Flight Center Scientific Visualization Studio.