Climate change generates more Arctic tundra vegetation

April 11, 2012, CORDIS
Climate change generates more Arctic tundra vegetation

Researchers in Finland have discovered that climate change has impacted various regions of the Arctic tundra by helping increase the levels of vegetation. Their data suggest that this rise could potentially speed up global warming. The Finnish Meteorological Institute researchers used satellite observations to assess how vegetation impacts snowmelt and, in turn, the terrestrial albedo (i.e. reflectivity) in the Arctic tundra regions. The team gathered the necessary information over a 16-year period during the March to June months.

"The study revealed that vegetation was thicker in Norway," explains Juval Cohen of the Finnish Meteorological Institute. "With the exception of the differences in vegetation, the other prevailing conditions, such as temperature, precipitation and , were almost the same in both countries. The difference in the melting of snow between Finland and Norway affects the albedo on land. During the period, the albedo was almost always higher in Finland."

Keeping the bare tundra, or even limiting vegetation, would delay the melting of snow in spring, according to Dr. Cohen. "This, in turn, could possibly slow down global warming," he says, commenting on the findings.

Experts say global warming has been playing havoc with snowmelts in the last 10 years or so. That is, they are happening earlier in spring than ever before. This earlier melting of snow also affects the reflectivity of . The researchers say the albedo on land plays a role in balancing the energy of Earth because it establishes the ratio between solar radiation reflected by surfaces and radiation absorbed by surfaces.

The albedo of snow is higher compared with the bare ground because snow is bright and reflects most of the back into space. Ground that is free of snow is darker and thus absorbs most of the incoming solar energy.

According to the researchers, has moved the tree line towards the north and has increased vegetation in regions of the Arctic tundra, because plants now have the ability to survive in areas that were once too cold for them.

The team also observed that vegetation growth in the Lapland regions of the tundra are impacted by reindeer husbandry. Vegetation levels decrease when reindeer grazing grows; both consumption and trampling of plants reduces vegetation.

The satellite images also show significant differences in the levels of vegetation on two sides of a fence separating grazing grounds.

The researchers also measured the difference in the solar energy absorbed in both Finland and Norway during the period of melting snow. Based on their observations, the amount of solar radiation absorbed in Norway was greater compared with the one in Finland, and resulted in a lower albedo.

"In April and May in Norway, an area of 100 x 100 kilometres absorbs about 100 000 terajoules more solar radiation than a corresponding area in Finland," the researchers say. "This is enough energy to melt an ice cube roughly 330 x 1 000 x 1 000 metres in size."

Explore further: Vegetation Growth May Quickly Raise Arctic Temperatures

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not rated yet Apr 11, 2012
"In April and May in Norway, an area of 100 x 100 kilometres absorbs about 100 000 terajoules more solar radiation than a corresponding area in Finland," the researchers say. "This is enough energy to melt an ice cube roughly 330 x 1 000 x 1 000 metres in size."

So Albedo change at that latitude, about 60N give or take a degree or two, equal to 100by100 kilometer loss of snow and ice produces enough net forcing to melt a third of a cubic kilomter of extra ice per April and May.

Using that as a baseline, does any deniers care to take a guess how much land area there is on Earth between 58N and 62N?

I found that for the whole earth it comes to about 8,775,475km^2.

Continents at that latitude makes up more of the surface than the global average (see map), about 80 to 85%, so 7 million km area to be fair.

7,000,000 / 10,000 = 700

700 * 0.330km^3 = 231km^3

...NET ice volum LOSS PER April and May PER YEAR, from this subset of albedo feed back alone.

It is only just starting.
1 / 5 (1) Apr 12, 2012
I wouldn't panic too much. It seems the reduction in sea ice in the arctic has lead to an increase in cloud cover which may offset this somewhat.http://www.agu.or...51.shtml]http://www.agu.or...51.shtml[/url]
Also sea ice in the Antarctic has been steadily increasing so there will be an increase in albedo down there

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