A fate tied to sea ice
The concept of a canary in a coal mine – a sensitive species that provides an alert to danger – originated with British miners, who carried actual canaries underground through the mid-1980s to detect the presence of deadly carbon monoxide gas. Today another bird, the Emperor Penguin, is providing a similar warning about the planetary effects of burning fossil fuels.
As a seabird ecologist, I develop mathematical models to understand and predict how seabirds respond to environmental change. My research integrates many areas of science, including the expertise of climatologists, to improve our ability to anticipate future ecological consequences of climate change.
Most recently, I worked with colleagues to combine what we know about the life history of Emperor Penguins with different potential climate scenarios outlined in the 2015 Paris Agreement, to combat climate change and adapt to its effects. We wanted to understand how climate change could affect this iconic species, whose unique life habits were documented in the award-winning film “March of the Penguins.”
Our newly published study found that if climate change continues at its current rate, Emperor Penguins could virtually disappear by the year 2100 due to loss of Antarctic sea ice. However, a more aggressive global climate policy can halt the penguins’ march to extinction.
Carbon dioxide in Earth’s atmosphere
As many scientific reports have shown, human activities are increasing carbon dioxide concentrations in Earth’s atmosphere, which is warming the planet. Today atmospheric CO2 levels stand at slightly over 410 parts per million, well above anything the planet has experienced in millions of years.
If this trend continues, scientists project that CO2 in the atmosphere could reach 950 parts per million by 2100. These conditions would produce a very different world from today’s.
Emperor Penguins are living indicators whose population trends can illustrate the consequences of these changes. Although they are found in Antarctica, far from human civilization, they live in such delicate balance with their rapidly changing environment that they have become modern-day canaries.
I have spent almost 20 years studying Emperor Penguins’ unique adaptations to the harsh conditions of their sea ice home. Each year, the surface of the ocean around Antarctica freezes over in the winter and melts back in summer. Penguins use the ice as a home base for breeding, feeding and molting, arriving at their colony from ocean waters in March or April after sea ice has formed for the Southern Hemisphere’s winter season.
In mid-May the female lays a single egg. Throughout the winter, males keep the eggs warm while females make a long trek to open water to feed during the most unforgiving weather on Earth.
When female penguins return to their newly hatched chicks with food, the males have fasted for four months and lost almost half their weight. After the egg hatches, both parents take turns feeding and protecting their chick. In September, the adults leave their young so that they can both forage to meet their chick’s growing appetite. In December, everyone leaves the colony and returns to the ocean.
Throughout this annual cycle, the penguins rely on a sea ice “Goldilocks zone” of conditions to thrive. They need openings in the ice that provide access to the water so they can feed, but also a thick, stable platform of ice to raise their chicks.