Straight dope on global warming

Arctic heat wave worries scientists

By Ashley Hall
October 4, 2007 - 3:48PM
Source: ABC
  

Scientists fear the higher temperature will devastate the local Arctic environment

It has been an unusually hot summer in the Arctic. Melting sea ice has
fully opened the North-West Passage, raising the possibility of a new
cheap shipping route between Europe and Asia.

And now Canadian researchers have recorded a heat wave on Melville
Island, high in the Arctic. The island is usually one of the coldest places
in North America, but the mercury soared to a record 22 degrees on
some days in July. That's more than 15 degrees higher than average.

One of the researchers is Scott Lamoureux, a Professor of Geography at
Queen's University in Ontario.

Professor Lamoureux says the jump in temperature may devastate the
local environment, but it's too early to confidently attribute the change
to global warming.

"What we measured this summer were temperatures that were typically
over 10 degrees, and frequently over 15 degrees Celsius," he said.

"The highest temperatures we recorded were 22. So, in all, this really
points to an extremely warm period this past summer in the area."

He says some summers in the past have had not a single day in that
range.

"In the five years we've been working at this site, we've recorded
those temperatures above 10 degrees [on] a few days, in five years," he
said.

Permafrost affected

Professor Lamoureux says the key issue is the effect of the temperature
rise on the frozen parts of the landscape.

"This is an area that is underlaid by what we call permafrost, which is
permanently frozen ground and rock," he said.

"Every summer, we expect typically to see the temperatures warm the
soil surface, and that thaws the ground to typically about 50 centimetres
depth.

"This summer, because it was so warm, we observed measurements of at
least a metre depth, perhaps more, and the result of that is that the
thaw was getting into the ground ice, and this ground ice has been
isolated from these melting temperatures for some period of time, maybe quite
a long time."

He says this means the ground ice melts and water goes to the base of
the soil.

"This actually creates kind of a very unstable situation, and weakens
the soil considerably," he said.

"So what we saw as a result of this was really widespread disruption
and slumping and sliding of the soil and the vegetation on top of it."

Professor Lamoureux says the higher temperatures can cause stress to
some of the animals in the Arctic.

"The largest land animals there are called musk oxen, which are large,
kind of furry, almost like cows really, and there are caribou, and
there's quite a large number of bird species and smaller mammals," he said.

"There are also fox, and some arctic wolves as well.

"Most of the animals are not immediately impacted by the temperatures,
although they can be pretty significantly stressed, as I understand,
from high temperatures, because they have very thick coats, very heavy
fur, because of course they survive year round in that environment, and
winter temperatures can quite routinely go to minus 50 degrees Celsius."

Out of balance

He says the temperature rise is a big problem, even though it makes the
Arctic more pleasant for human visitors.

"Really it's difficult to see an upside, because this is an area that,
again, it should be in the range of five degrees Celsius, and the
vegetation and the animals, everything is really kind of in equilibrium with
that kind of temperature," he said.

"So when it gets exceptionally warm like this, as we saw, we have
tremendous destabilisation of the landscape, and this affected the rivers
quite dramatically.

"We saw a substantial increase in sediment in the water, and we're not
fully sure yet what the impact of that will be."

Professor Lamoureux says the temperature rise may be a consequence of
global warming, although it is too early to be sure.

"I think it's potentially early to call it a trend, but at the same
time it could be signalling the onset of something," he said.

"Given the trend in many areas of the Arctic towards warmer conditions,
this is certainly the concern that this may be the onset of a major
change in the climate regime of the region.

"From a climate standpoint, if we start to see the sea ice become less
persistent - that is, it becomes more open water - this is going to
start to affect the climate really substantially, and it may be possible
that we switch past a threshold where the climate in the summer becomes
considerably different than what we're used to."