New study on penguins and climate change

A new piece  (open access) published in the Proceedings of the National Academy of Sciences assesses the potential impact of climate change on penguin populations in Antarctica. It could provide an excellent reading in the science section of a climate change course as a case study.  Among the take-aways from the study:

  1. While it had been hypothesized that the populations of Adelie penguins, which favor pack-ice habitat in winter in the West Antarctic Peninsula and Scotia Sea, would decline in the face of warming, while ice-avoiding chinstrap penguins would see population increases, empirical evidence shows that both have declined more than 50% in the last 30 years in the South Shetland Islands, and 75% in the South Sandwich Islands;
  2. The primary reasons that both species have declined is a massive drop in krill populations (with density declining  80% from the mid-1970s and a 38-81% decline in biomass). This is attributable to increasing temperatur5es, and consequent reductions in sea ice necessary to sustain large krill populations, and increasing competition from recovering seal and whale populations;
  3. The decline in the reproductive capacity of the krill population, along with declines in sea ice, may ensure further declines in food resources for penguins and other predators in the West Antarctic Peninsula;
  4. Krill catches in the West Antarctic and South Sandwich Islands have increased four fold in the past  ten years, and may expand further given the Marine Stewardship Council’s recent certification of one company’s krill fishing operations as sustainable, and introduction of new products, e.g. Omega-3 krill oil.

This study is another cautionary tale in the realm of climate science; as the study concludes, a species that was believed to be a “winner” as a consequence of climate chang’may be among the most vulnerable species affected by a warming climate.”

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