In 2100, a warmer climate
will allow the growth of trees and bushes
in large parts of Greenland that are currently
ice-free. This will mean both risks and
opportunities for the Greenlanders, according
to a new analysis led by researchers from
Aarhus University.
By Jens C. Pedersen
Tongass National Forest,
Alaska. Photo: John Schoen, Anchorage.
Tongass National Forest, Alaska. The researchers
predict that forests of this type will be
able to grow in the southern parts of Greenland
in the future. Photo: John Schoen, Anchorage.
Scientists expect the future climate to
become warmer, and that this will apply
to the Arctic in particular. Here the temperature
is expected to increase considerably more
than the average on Earth, according to
the Intergovernmental Panel on Climate Change
average scenario (A1B).
What will this mean
for Greenland? A very significant change
will be the emergence of forests, where
there are currently only four species of
trees and large bushes indigenous to Greenland
– and they only grow in small areas in the
south.
An international research
group including Professor of Biology Jens-Christian
Svenning, Aarhus University, has analysed
which species will be able to grow in the
climate expected in Greenland in 2100. The
analysis shows that a majority of 44 relevant
species of North American and European trees
and bushes will be able to grow in Greenland
in the future.
In fact, the analysis
points to the fact that a considerable number
of species would already be able to grow
in Greenland today. This is supported by
actual experiments, where various species
of trees have been planted in Greenland,
including Siberian larch, white spruce,
lodgepole pine and Eastern balsam poplar.
By the end of the century,
a key species like the Arctic dwarf birch
will probably be able to find suitable habitats
in most areas of Greenland that are currently
ice-free, far beyond its current distribution.
Here we are talking about more than 400,000
square kilometres, or an area almost the
size of Sweden.
Opportunities for Greenlanders
The researchers conclude that southern Greenland
and the area around Kangerlussuaq (Søndre
Strømfjord) already have the potential
to become much greener, with a forest flora
corresponding to that occurring during former
interglacial periods. With the expected
climate change by 2100, scientists expect
that such flora should be able to grow in
large parts of the ice-free areas in the
southern half of Greenland.
“In other words, Greenland
has the potential to become a lot greener,”
says Professor Svenning.
The new opportunities
for trees and bushes may oust Arctic animals
and plants, but could also be beneficial
to the Greenlanders.
“Forests like the coastal
coniferous forests in today’s Alaska and
western Canada will be able to thrive in
fairly large parts of Greenland, with trees
such as Sitka spruce and lodgepole pine.
This will provide new opportunities for
the population of Greenland. For example,
we see that people use wood wherever there
is forest. This could also create new opportunities
for activities such as hunting and the commercial
exploitation of berries. Forest and scrub
will also reduce erosion and affect water
run-off,” says Professor Svenning.
Trees spread slowly
Why are the trees not already in place in
Greenland? Partly because most trees only
spread slowly by themselves, but also because
Greenland is very isolated. The researchers’
models show that it will take more than
2000 years for Greenland’s indigenous species
of trees to spread to all those areas of
the country that will have a suitable climate
by 2100.
In Greenland, some species
arrived relatively quickly after the last
Ice Age, while other species that rely on
dispersal by birds or wind first arrived
a couple of thousand years later. However,
the researchers’ analysis shows that most
plants have not yet utilised the Greenlandic
countryside following the last Ice Age,
and that the man-made climate change will
rapidly create further opportunities for
the plants. Taking advantage of this will
be a slow process on their own, however.
Humans will play a deciding
role
Professor Svenning indicates that humans
will play a crucial role when trees and
bushes naturally spread so slowly.
“People often plant
utility and ornamental plants where they
can grow. I believe it lies in our human
nature. Such plantings could have a huge
impact on the Greenlandic countryside of
the future as a source of dissemination.
This certainly has positive aspects.
But it would also be
wise to be cautious, and thereby avoid some
of the problems we’ve seen at our latitudes
with invasive species such as giant hogweed
and rugosa rose. The Greenlandic countryside
will be far more susceptible to introduced
species in future than it is today. So if
importing and planting species takes place
without any control, this could lead to
nature developing in a very chaotic way,
reminiscent of the Klondike,” warns Professor
Svenning.
The work to implement
the analyses was carried out by Signe Normand.
She was educated at Aarhus University, and
is returning in February 2014 to take up
a position as assistant professor without
a fixed term. She is currently working at
the Swiss Federal Research Institute for
Forest, Snow and Landscape (WSL).
