Rapidly warming global temperatures and diminishing sea ice of Antarctica are posing a dire threat to one of the continent's most renowned species: the emperor penguins. Four out of five emperor penguin colonies investigated in the Bellingshausen Sea, located west of the Antarctic Peninsula, suffered catastrophic breeding failures last year due to the loss of sea ice, a groundbreaking study published recently in Nature Communications Earth & Environment revealed.
The comprehensive loss of chicks, labelled as a "catastrophic breeding failure," is the first recorded incident of such magnitude, further validating ominous forecasts that more than 90% of emperor penguin colonies could become quasi-extinct by 2100 due to global warming. Monitoring took place across five emperor penguin colonies in the Bellinghausen Sea, accommodating about 630 to 3,500 pairs, utilizing satellite images from 2018 to 2022. The findings from 2022 indicated that total reproductive failure ensued in four colonies, suggesting almost no chick survival.
Emperor penguins rely on the stability of sea ice connected to the land for nesting and rearing their chicks. The chicks hatch around December and January post egg-laying in May to June and gain independence upon the development of waterproof feathers. However, in 2022, earlier break-up of sea ice observed in regions even led to total loss by November. Satellite imagery typically indicated the presence of black blobs on ice during those months, which suddenly disappeared.
When the sea ice breaks prematurely, chicks can drown if they fall into the water, echoing the sentiments of study co-author and seabird biologist, Norman Ratcliffe, of the British Antarctic Survey. Alternatively, chicks may drift away on floes leading to starvation due to abandonment by adults. He described this adverse experience to the colonies as a "massive loss" and an "early alarm bell."
Antarctica’s sea ice has witnessed a sharp reduction in recent years, sounding the alarm for scientists worldwide. The sea ice reached shockingly low levels in February, at the peak of the Antarctic Summer, and didn't rebound to expected levels even during the harsh winter. In mid-July, the Antarctic sea ice was found to be at its lowest since record keeping began in 1945. It was 2.6 million square kilometers (1 million square miles) short of the 1981 to 2010 average - an area matching the size of Argentina. Many experts believe that the human-induced climate crisis is a substantial contributor to this declining trend.
This diminishing trend of sea ice is especially threatening to Emperor Penguins, states Ratcliffe, claiming, "there’s nowhere else for the birds to go." Although these birds have previously adapted by relocating to nearby sites following breeding failure, this strategy would fail if the complete breeding habitat is impacted. The report reveals that 30% of the known emperor penguin colonies in Antarctica, a total of 62, experienced partial or total sea ice loss between 2018 and 2022.
Cassandra Brooks, University of Colorado Boulder, corroborated that Emperor Penguins face dire risks to their survival, with the study’s findings providing substantial proof. Last year’s study found that if world fails to control fossil fuel pollution, 65% of Antarctica’s indigenous species, primarily Emperor Penguins, might vanish by the end of the century. Worst-case scenarios projected a total wipe-out of Emperor Penguins by 2100.
The loss of sea ice will not only affect the penguins. Seals, microorganisms, and algae, that form the diet of region's major whales, and krill, which depend on sea ice for resting and feeding, would suffer greatly. Sea ice in Antarctica also aids in controlling Earth’s temperature by reflecting back the Sun's energy into space. When this ice melts, the exposed darker ocean absorbs the Sun's energy, thereby contributing to global warming. Ratcliffe concluded that the situation is "quite concerning both for the physical oceanography and biology of Antarctica and the ecosystems that depend on them."
