Latest posts by H. Sterling Burnett (see all)
- CO2 Science: Carbon Dioxide Not Temperature Driver - October 12, 2018
- EPA’s Non-Politicized Science Benefits Americans - October 11, 2018
- Proposed Endangered Species Reforms: Good but Not Good Enough - October 4, 2018
A new study from the Global Warming Policy Foundation (GWPF) finds polar bears are thriving, with the population growing or stable despite summer sea ice having dropped significantly after 2006.
Based largely on American biologist Steven Amstrup’s assertion polar bear populations would decline if summer sea ice fell sharply, many scientists were surprised when polar bear counts showed the various subpopulations were stable or growing modestly despite summer sea ice levels falling by nearly 40 percent after 2016. In a separate article, biologist Susan Crockford, author of GWPF’s study, notes ringed and bearded seals (the primary prey of polar bears) north of the Bering Strait thrived in a longer summer open-water season, which improved their access to fish.
“More food for seals in summer means more fat seal pups for polar bears to eat the following spring. … [A]s long as polar bears have lots of baby seals to eat in spring, they get fat enough to survive even a longer-than-usual summer fast,” writes Crockford.
A 2007 study by Christine Hunter et al. said if summer sea ice levels dropped by as much as they did after 2006 “for eight out of ten years (or four out of five years),” which climate model projections suggested might occur as soon as 2050, 10 of 19 vulnerable polar bear populations would be extirpated, leaving fewer than 10,000 of the animals worldwide. Despite sea ice hitting the danger levels feared by Hunter’s team 44 years sooner than projected, just the opposite has occurred. The U.S. Geological Survey estimated there were approximately 24,500 polar bears in the world in 2005, before sea ice levels dropped by as much as 38 percent after 2006. In 2015, the Polar Bear Specialist Group of the International Union for the Conservation of Nature estimated the polar bear population at approximately 26,000, with a second survey estimating as many as 28,500 polar bears roam the Arctic. This is the largest population count since polar bears were first protected by international treaty in 1973.
In addition, Crockford notes there is no evidence polar bear weights have fallen significantly or the percentage of deaths from starvation has increased.