LITMUS TEST
Why penguins may help us predict the impact of climate change
ANTARCTICA Steve Forrest is trying to count penguins, but progress is slow. Snow is falling in thick, sticky flakes and his target colony is disappearing. Cold waves splash across our boat as the wind picks up, driving white caps across the Gerlache Strait, at the tip of the Antarctic Peninsula.
The chinstrap penguin colony is perched on top of a cliff, and our dinghy, containing several graduate students and two large drones, has no place to land on the rocky shore. One of the students holds up an anemometer to measure the wind speed. The other has the stony face of someone who is about to be sick.
“This is emblematic of what chinstraps do, they are very extreme,” says Forrest, a conservation biologist and 25-year veteran of the Antarctic. We watch as they leap out of the ocean, grip the rock with their claws and trudge up a steep snowbank to get home. “Not a lot is known about chinstraps, compared with some other penguin species — partly because they live in these godforsaken places.”
What seems like bad weather for the penguin-counting team is just a mild day on the coldest, windiest, highest continent on the planet. Antarctica contains 70 per cent of the world’s fresh water and 90 per cent of its ice. If the whole continent melted completely, global sea level would rise by 60 metres. A glance at its ice-encrusted shores makes it obvious why this is the only continent that has never had an Indigenous human population.
On remote islands around the peninsula, Forrest and his team from New York’s Stony Brook University are surveying chinstrap penguin colonies, some of which have not been counted in three decades. They’ve found population declines in several locations: one large colony has shrunk by more than half.
“This is part of a much larger regional decline that we are concerned about,” says Heather Lynch, associate professor of ecology and evolution at Stony Brook. “The alarming part for me is not just that they are declining but that we don’t understand what is going on — and who knows what else is going on, what else is declining, under our noses, that we are unaware of.”
Climate change is the most likely factor behind the declines. The Antarctic Peninsula, where we are, is the fastest-warming part of the continent. It has heated up by about 3 C since 1950, and, in February, a record high of 18.3 C was recorded at Esperanza Base. The pace of change on the peninsula, which is warming more than three times faster than the rest of the planet, means the animal populations there are in the middle of a rapid transformation. Some species are thriving, while others are at risk of extinction.
“The chinstraps are the canary in the coal mine for a whole host of changes that are happening on the Antarctic Peninsula,” Lynch says after the expedition. “Time might be running out to figure this out before these changes are irreversible.”
Although Antarctica can appear to be a barren wasteland, the oceans around it are teeming with life. The giant glaciers and the annual sea-ice formation drive an overturning in the ocean waters, pouring oxygen and nutrients into the sea. Each winter, the continent’s surface area doubles as the ocean freezes around it.
The sea ice nourishes krill, the most abundant species on the planet and the foundation of the ocean food chain. Flocks of birds such as the black-browed albatross and the southern giant petrel, with wingspans of up to two metres, follow our boat wherever we go.
Studying Antarctica is notoriously difficult but, in many ways, it holds the keys for understanding the future of our planet. The rate at which its ice melts will determine whether we see 50 centimetres or 100 cm of sea level rise by the end of the century — the difference between whether or not low-lying cities such as Miami and Bangkok survive in their current form.
Clues to the history of the world, and what the earth’s atmosphere looked like millions of years ago, are also buried deep in the Antarctic ice cap. At a time when humans are trying, and so far failing, to curb emissions, Antarctica reminds us what is at stake.
Even though Antarctica appears to be at the end of the earth on traditional maps, it is at the centre of the world’s oceans. The strongest current in the world, the Antarctic Circumpolar Current, runs clockwise around the continent. It drives the global “conveyor belt” that circulates water through the oceans, a beating heart that pumps life through the seas.