Scientists
have rung another warning bell about changes in the fragile ecosystem
of the Arctic, saying that vegetation found in areas several degrees to
the south of the region 30 years ago was now showing up in parts of the
Arctic due to global warming linked temperature rise.
A Nasa-funded international study published in
Nature Climate Change
on Sunday, used a new 30-year satellite data set and temperature
records to study the effect of temperature rise on vegetation in
the Arctic and regions just below it.
The researchers found a 10% increase in
Arctic plant growth since the early 1980s. This increase was seen in more than one-third of the vegetated lands. During
the same period, the mean temperature of land in the region, excluding ice sheets, rose by 1 to 2 degrees celsius.
The findings were reported by an international team of 21 authors from
seven countries, who used latitude as a yardstick to study seasonality
changes. "Arctic plant growth during the early 1980s equalled that of
lands above 64 degrees north. Today, just 30 years later, it equals that
of lands above 57 degrees north," said co-author Terry Chapin of
University of Alaska.
The study also found that temperature
seasonality the temperature difference between summer and winter — was
reducing in many Arctic regions because the colder seasons were warming
more rapidly than the summers.
The Arctic region is witnessing
some of the most dramatic fallouts of climate change. Changes in
vegetation and seasons may hit availability of food and alter the life
pattern of many animals like the polar bear. These could also hit
migratory birds.
A warmer Arctic has implications for the rest
of the world, too. "The warming reduces polar sea ice and snow cover in
the Arctic land mass, thereby increasing the solar energy absorbed by
the nolonger energy-reflecting surface . This sets in motion a cycle of
positive reinforcement between warming and loss of sea ice and snow
cover, amplifying the greenhouse effect," said lead co-author Ranga
Myneni of Boston University.
end quote from:
Science Recorder
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