A much reduced covering of snow,
shorter winter season, and thawing tundra. The effects of climate change in the
Arctic are already here. And the changes are
taking place significantly faster than previously thought. This is what emerges
from a new research report on the Arctic.
Margareta Johansson, from Lund
Univ., is one of the
researchers behind the report.
Together with Terry Callaghan, a
researcher at the Royal
of Sciences, Margareta is the editor of the two chapters on snow and
“The changes we see are dramatic.
And they are not coincidental. The trends are unequivocal and deviate from the
norm when compared with a longer term perspective,” she says.
is one of the parts of the globe that is warming up fastest today. Measurements
of air temperature show that the most recent five-year period has been the
warmest since 1880, when monitoring began. Other data, from tree rings among
other things, show that the summer temperatures over the last decades have been
the highest in 2000 years. As a consequence, the snow cover in May and June has
decreased by close to 20%. The winter season has also become almost two
weeks shorter—in just a few decades. In addition, the temperature in the
permafrost has increased by between half a degree and two degrees.
“There is no indication that the
permafrost will not continue to thaw,” says Margareta Johansson.
Large quantities of carbon are
stored in the permafrost.
“Our data shows that there is
significantly more than previously thought. There is approximately double the
amount of carbon in the permafrost as there is in the atmosphere today,” says
The carbon comes from organic
material which was “deep frozen” in the ground during the last ice age. As long
as the ground is frozen, the carbon remains stable. But as the permafrost thaws
there is a risk that carbon dioxide and methane, a greenhouse gas more than 20
times more powerful than carbon dioxide, will be released, which could increase
“But it is also possible that the
vegetation which will be able to grow when the ground thaws will absorb the
carbon dioxide. We still know very little about this. With the knowledge we
have today we cannot say for sure whether the thawing tundra will absorb or
produce more greenhouse gases in the future”, says Margareta Johansson.
Effects of this type, so-called
feedback effects, are of major significance for how extensive global warming
will be in the future. Margareta Johansson and her colleagues present nine
different feedback effects in their report. One of the most important right now
is the reduction of the Arctic’s albedo. The
decrease in the snow- and ice-covered surfaces means that less solar radiation
is reflected back out into the atmosphere. It is absorbed instead, with
temperatures rising as a result. Thus the Arctic
has entered a stage where it is itself reinforcing climate change.
The future does not look
brighter. Climate models show that temperatures will rise by a further 3 to 7
degrees. In Canada,
the uppermost metres of permafrost will thaw on approximately one fifth of the
surface currently covered by permafrost. The equivalent figure for Alaska is 57%. The
length of the winter season and the snow coverage in the Arctic
will continue to decrease and the glaciers in the area will probably lose
between 10% and 30% of their total mass. All this within this century and with
grave consequences for the ecosystems, existing infrastructure, and human
New estimates also show that by
2100, the sea level will have risen by between 0.9 and 1.6 meters, which is
approximately twice the increase predicted by the UN’s panel on climate change,
IPCC, in its 2007 report. This is largely due to the rapid melting of the
Arctic icecap. Between 2003 and 2008, the melting of the Arctic icecap
accounted for 40% of the global rise in sea level.
“It is clear that great changes
are at hand. It is all happening in the Arctic
right now. And what is happening there affects us all,” says Margareta
The report “Impacts of climate
change on snow, water, ice and permafrost in the Arctic”
has been compiled by close to 200 polar researchers. It is the most
comprehensive synthesis of knowledge about the Arctic
that has been presented in the last six years. The work was organised by the
Arctic Council’s working group for environmental monitoring (the Arctic
Monitoring and Assessment Programme) and will serve as the basis for the IPCC’s
fifth report, which is expected to be ready by 2014.
Besides Margareta Johansson,
Torben Christensen from Lund
Univ. also took part in