Hypothesis doesn’t have legs to stand on

Editor: Susan J Crockford of the dept. of anthropology, University of Victoria, on March 2 wrote a paper seeking to assess the 2005-06 hypothesis, that originally led to placing the polar bear on the endangered list, that if the Arctic sea ice coverage of 3-5 mkm2 would result in a predicted 30 per cent decline in the population of polar bears.

If the study proved to be the case the hypothesis would be affirmed, if not the hypothesis would be discredited. She did discover that sea ice had declined at a faster rate than the hypothesis had assumed.

However, and this is where the real meat of her survey and analysis challenged and indeed refuted the original hypothesis. She writes:

"Realization of predicted sea ice levels allows the ‘rapid sea ice decline equals population decline’ assumption for polar bears to be treated as a testable hypothesis. Data collected between 2007 and 2015 reveal that polar bear numbers have not declined as predicted and no subpopulation has been extirpated. Several subpopulations expected to be at high risk of decline remained stable and five showed increases in population size. Another at-risk subpopulation was not counted but showed marked improvement in reproductive parameters and body condition with less summer ice.” Crockford concludes: “As a consequence, the hypothesis that repeated summer sea ice levels of below 5 mkm2 will cause significant population declines in polar bears is rejected, a result that indicates the ESA and IUCN judgments to list polar bears as threatened based on future risks of habitat loss were scientifically unfounded.”

The problem in many of the conservation decisions is that they are based upon an untested hypothesis and assumptions.

When scientific observation discovers data from the field that refutes the hypothesis, the hypothesis either needs to be adjusted or thrown out.

In this case, the data from the field refutes the 30 per cent decline hypothesis.

That is not to say something might change in the future, but at present the data does not support a blanket assumption that the polar bears are at risk of severe decline.

Jim Church, Kelowna