In the future, Santa's reindeer might have trouble finding enough to eat. As
this ScienCentral News video reports, it's a result of global warming.
The North Pole is a cold place, and that's just the way reindeer like it. But
climatologists say global warming is affecting their snowy world.
"One of the impacts that scientists are most convinced is going to happen
as the earth warms up, is a change in the ratio of snow to rain," says
Gleick, president and co-founder of the Pacific
Institute. "As the earth warms up, weâ€™re going to get more
rain and less snow."
That's a problem for the reindeer because, in cold climates, rain falling on
snow creates ice; scientists call this a rain-on-snow
event. If it's thick enough, the ice can keep the reindeer from their
main food supply, small plants beneath the snow.
"In the winter, the animals have to dig thru
the snow and access these lichens and mosses or their food sources right at
the soil surface," says Jaakko
Putkonen, a professor at University of Washington's Quaternary
Research Center. "If you put an ice layer either on top of the snow
or right at the soil surface, there is no way that the animals can get thru
the ice layer. It's just physically impossible. They cannot access their food."
|image: ABC News|
While the reindeer might not starve right away, they do have to work harder
to get to their food or find non-icy areas to eat, which drains the energy
they usually have stored away to survive the long winter. This also causes
both physical and mental stress, and would take its toll on the younger and
weaker animals first.
Effects like these would be most problematic for reindeer which live in
environment"—like a vast snowy tundra without much else. Animals
in areas with "heterogeneous environments"—with trees and
shrubs, etc.—might not fare as bad.
"A single environmental event has a diversity of effects on a heterogeneous
landscape. All are not bad," says Greg
Finstad, program manager of the Reindeer
Research Program at the University of Alaska Fairbanks. "If a rain-on-snow
event occurs on the coast it snows in the higher elevations, if the rain-on-snow
occurs in the high elevations the rain in the lower elevations melts the snow…
As every reindeer herder worth his salt knows: if it rains on top of the snow
[in a heterogeneous environment] and forms a crust you move your deer to the
trees or tall shrubs because the vegetation intercepts the rain, the snow
is deeper to absorb the rain. And your reindeer, although they must dig through
deeper snow to find food, will do just fine until the wind at the higher elevations
sublimates the ice."
More Rain, Less Snow
Putkonen developed a climate model of soil heat generation
and snow to predict the effects of climate change on reindeer-heavy areas
like northern Alaska and Canada. "Basically what this model was showing
to us is that the area affected by rain-on-snow is going to increase by about
40 percent in about a hundred years, which is a huge change," says Putkonen.
"Not only will we get more of these rain-on-snow events in the future,
based on the best models that are available these days, but also that area
where you get the rain-on-snow is going to shift further north. Basically,
what is going to happen to reindeer and caribou is that they are pushed further
|image: ABC News|
Such a forced migration would not only affect the reindeer, but the people
who depend on them for food, shelter, and business. And migrating south isn't
much of an option. Reindeer survive where they do because they can exploit
a niche in the food supply—the lichens and mosses under the snow that
other animals did not evolve to survive on. If they had to live in an area
where they were not exploiting this food niche, there would be more competition
from other animals that live in warmer climates.
It's also important to note that global warming is neither the only nor even the
most important stress on reindeer these days. Population
growth of people is a much more immediate concern.
Putkonen's research was published in the February, 2003 issue of Geophysical
Research Letters, and was funded by the National