Ecological consequences of a warming planet – Earth’s Caribou population has collapsed – Foreshadowing ecological trends across the rest of the planet

By November 6, 2009 February 24th, 2013 Extinction events

The International Polar Year resulted in this study by a team of 25 Arctic researchers. Seven degrees of warming in some parts of the Arctic have changed more than just the average temperature. The Arctic biosphere is collapsing. Arctic sea ice is projected to disappear like it has not done in 14 million years (here). As the permafrost melts it is replaced by lakes. The lakes then drain or evaporate and leave a wasteland of huge potholes that do not support the ecosystem that once flourished on top of the ice. Nine of Canada’s eleven caribou herds are in decline.

The Bluenose West herd in the Northwest Territories had a population of 80,000 at the turn of the century; it was under 20,000 animals in 2006.

Northwest territory biologists say that the Bathurst herd of the central barrens had fallen from over 120,000 animals in 2006 to 32,000. This is a  loss of nearly 90,000 caribou in three years.

An aerial survey could not even find enough of the Beverely herd to get statistically valid data for a cow / calf count. This herd of 280,000 in 1995 has almost completely disappeared..

Warmer temperatures in the winter mean more and wetter snow. This makes it more difficult for the caribou to find food as the snow is much more difficult to fling aside with flick of the caribou hoof. Warmer temperatures in winter also mean more chances of ice storms which coat everything in ice making it even more difficult for the caribou to break through to find food. Warmer temperatures in summer mean more insect pest. The caribou spend much of their time trying to evade these pests, running about in fits and starts to get ahead of the slow flying bugs and shaking incessantly.  The results are that they feed less in this time of plenty and expend more energy than normal, weakening the animals already over weakened by the extra exertions and diminished food intake from the winter.  Caribou herds have fluctuated wildly in the historic past, but this is not the historic past. Climate change has moved our planet’s climate out of the range of historic natural variability – beyond what we have experienced in recorded history. Our climate has changed.

Polar amplification has multiplied the change in the Arctic. (More warmth means less snow. Less snow reflects less heat back into space, so there is more warming, which melts even more snow, even sooner, etc.) The environment where Arctic ecology evolved has now abruptly changed. One can not create an organism through evolution, and then abruptly move that organism to a different environment and expect it to thrive, or even expect it to survive in many cases. We are experiencing an abrupt climate change. When abrupt climate changes have happened in ancient prehistory, fossil records have shown us that great extinctions have taken place.  We have come to understand that abrupt climate changes are much more numerous than ever imagined in the past and happen every few thousand years.

The most dire foreshadowing of this journal article however is that the collapse of Earth’s Caribou herds is only one of the first of many. The report warns that the Arctic, because of the polar amplification effect, leads the rest of the world in the impacts of climate change. What occurs in the Arctic today can be expected to occur across the rest of the planet in the future. and if the recent past is any predictor of the future, the changes will happen faster wand with greater impact than we are expecting.

Vors and Boyce, Global declines of caribou and reindeer, Global Change Biology, May 2009

Post, et. al., Ecological dynamics across the Arctic associated with recent climate change, Science, September 2009.