More computer model hype: Adelie penguins face disaster by 2100

adelieA new study published yesterday says Antarctica’s Adelie penguins could face a disastrous population decline if global warming were to affect the continent. When? By 2099. There’s two big problems: Antarctica’s ice cover is actually growing in size, making the continent larger. And it’s based on computer models, which are notoriously prone to error and rarely, if ever, give accurate results. Imagine shooting a bullet from New York to Los Angeles and hitting a pin-sized bullseye on the side of a moving truck. That’s the difficulty with forecasting a region’s climate 83 years from now. Let alone a particular penguin’s population.

Because Adelie penguins populate the continent’s entire coastline, the researchers focused only on West Antarctica, which has seen marginal warming since satellite tracking began in 1979. Interestingly, Adelie penguins rely on bare-rock locations for breeding and chick rearing, so increased sea ice is actually more detrimental to their well-being.

The study used various computer models and the UN IPCC’s climate computer simulations to come up with these new results. In its latest assessment report, the Intergovernmental Panel on Climate Change (IPCC) created numerous scenarios, from not too bad to the very worst. The new study shows that there might be a 60 percent loss in penguin populations when the IPCC’s Representative Concentration Pathway 8.5 was fed into the simulation. But as another study pointed out, global warming is not progressing at the rate suggested by even the worst-case scenarios released by the IPCC.

But Antarctica, like other land masses surrounded by water, isn’t melting like the IPCC predicted or scientists assumed. It’s actually growing. That can also be a problem as Adelie penguins like to breed on rocky outcroppings. Warming periods in the past have actually helped the Adelie populations to grow as more bare rock was exposed.

The study, led by Megan Cimino, also used satellite observations from 1981 to 2010 for sea surface temperature, sea ice, and bare-rock locations to estimate the suitability of penguin chick-rearing habitats. Camino says that more sophisticated models to estimate population trends are still being developed. Because Adelie penguins are doing just fine on the frozen continent, researchers had to extrapolate findings for future estimates.

Overall, the researchers reported that climate change’s effects on penguins in Antarctica will likely be highly site-specific, based on regional climate trends, and may reduce their populations by half by the end of this century. They speculate that there might be a 30 percent drop in Adelie colonies by 2060, or 20 percent of its overall population. The satellite observations didn’t actually count individual Adelie penguins, but rather areas they could breed and raise chicks.

Cimino believes that the recent drop in the overall Adelie population is from increased global warming, something one seasoned ecologist dismisses. As previous cases have illustrated, Adelie penguins are a mobile group that migrate when food runs low or sea ice encroaches. Case in point is Commonwealth Bay, Antarctica, an important feed-and-breed area for Emperor penguins and Adelie penguins.

As a South Wales paper points out, since 2010 the Adelie population has crashed from 160,000 to 10,000 after an iceberg the size of Rome became grounded. The iceberg, called B09B, blocked the passageway from Commonwealth Bay to the sea, forcing the sea ice between the coast and the iceberg to remain unbroken. With the ice unbroken and up to 10 feet (three meters) thick, the penguins were unable to feed and had to walk more than 37 miles (60 Kilometers) to find open water and food.

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