From: Mike Ferguson
Subject: Re: Climate change and Peary caribou
X-To: Kevin Jardine
Dear Mr. Jardine:
In response to some of the issues raised in your email:
1. In my earlier email, I did not directly >>refer to possible increases in the eastern Arctic, as you suggested.
To repeat, >There has been no evidence of a recent decline of Peary caribou on Canada's eastern Arctic islands. In recent winters, Inuit in Grise Fiord on southern Ellesmere Island have seen caribou in areas and on islands where they had not been seen since the 1960s.
Other recent incidental observations of caribou from several sources suggests that other parts of Ellesmere, Devon, Axel Heiberg and smaller islands are also currently occupied. Densities are unknown.
This information could be interpreted as evidence of either a re-distribution into formerly occupied areas, a population increase or both. I can not conclude which may be the case.
2. >The basic point that we make in both the release and the backgrounder is >that a deeper High Arctic winter snow pack is more likely to occur in a >warmer world and that this would make it more difficult for caribou to find >food.
>There is an unusual cooling >>region in the eastern Arctic (especially around western Greenland and >>eastern Baffin Island) that may be due to natural variation but may also be >>related to changes in thermohaline circulation in the north Atlantic. Any >>evidence on how this cooling trend may be affecting wildlife would be of >>great interest to us.
The complexity of on-going regional and seasonal patterns of climate change makes prediction of impacts on any specific wildlife population very difficult. Climatic models of global warming have predicted several parts of the Earth where climate may actually cool (specific areas vary between models). Within that context, the cooling of temperatures since 1960 in parts of the eastern Arctic should not be viewed as unusual, in my opinion. Although some of the western-most Queen Elizabeth Islands (QEI) has seen a warming trend, the vast majority of the QEI saw little overall temperature change during 1961-90 (Hardy and Bradley. 1996. Geoscience Canada 23: 217-224).
The impact on a wildlife population in part will depend on the specifics of the season in which the changes occur. The cooling trend over the past few decades in parts of the eastern Arctic has been largely due to colder winters. Please refer to Ferguson. 1996. Arctic tundra caribou and climatic change: Questions of temporal and spatial scales. Geoscience Canada 23: 245-252. In that literature review, I give some examples in which Arctic caribou populations have increased or decreased contrary to that expected under the warm, wet winter and cool, dry winter hypotheses.
Despite situations that appear inconsistent with, or simply coincidental with (e.g., Ferguson et al. 1998. Arctic 51: 201-209) these hypotheses, the dramatic decline of Bathurst Island caribou during 1995-97 was most probably initiated by loss of accessibility to forage due to severe snow cover conditions. I do not know if any other factors may have been involved.
3. There is a difference between making general recommendations for precautionary steps to reduce risks at a broad scale (e.g., reduction of greenhouse gases because of the potential negative effects of global warming on Arctic wildlife), and making reliable conclusions and predictions of the trends of specific populations of wildlife (e.g., future trends of all populations of Peary caribou).
It is extremely difficult to generalize snow fall and temperature readings from sparse Arctic weather stations to snow cover conditions on the ground that may or may not influence caribou populations (Jacobs. 1989. Arctic. 42: 50-56. ) Weather patterns, terrain ruggedness (Nelleman. 1997. Thesis. Agricultural University of Norway.), caribou distribution and movements, forage resources (Ferguson. 1996), etc. all interact to determine the outcome for each population.
4. "Distinguishing natural from anthropogenic climate change in Nunavut remains an unresolved problem." (Hardy and Bradley. 1996. p. 221)."In the last 200 years..., Nunavut has witnessed a range of environmental change that may be representative of many thousands of years." (Hardy and Bradley. 1996. p. 223). This suggests that Peary and other caribou have survived relatively rapid climate changes over the past two centuries. Ecologists need to consider how the scale at which their studies occur may affect the applicability of the results at other scales (Wiens. 1989. Functional Ecology 3: 385-397). So..."The question remains...: can this adaptable species survive the accelerated climatic changes that man may cause? " (Ferguson. 1996. p. 250)
To me, it seems prudent for both individuals and governments to reduce emissions of greenhouse gases, whether or not we can currently predict the future of Peary caribou, other Arctic wildlife populations, or wildlife and habitats elsewhere.
Mike Ferguson
Pond Inlet, NT
Views expressed above are solely those of the writer.
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