Thousands of Emperor Penguin Chicks Perished in a 2015 Storm, and Their Antarctic Colony Hasn’t Yet Recovered

British researchers published a study this week indicating that a significant emperor penguin breeding ground in Halley Bay, Antarctica has been essentially barren following a powerful storm in 2015 that decimated a colony of newly hatched chicks. The storm was so strong that it broke up the fast ice that the colony uses as a breeding ground — “fast” referring to sea ice that is fixed or fastened to solid ground — leading to the drowning of somewhere between 14,000 and 25,000 chicks, unpracticed in the water and unable to handle the harsh conditions. Along with the adult casualties, the researchers estimate that approximately 5 to 9 percent of the global emperor population was wiped in the incident; Halley Bay was the second largest breeding ground of emperors.

The population of emperors who typically breed Halley Bay has yet to return. “We’ve never seen a breeding failure on a scale like this in 60 years,” Phil Trathan told AP News. Trathan is one of the authors of the study, sadly but aptly named “Emperors on thin ice.” The fast ice has reformed since the storm, but is no longer stable enough to weather the early storms that hit the area each fall.

While breeding failures have been known to happen, Trathan emphasized the unique nature of the 2015 incident and its aftermath. “It’s unusual to have a complete breeding failure in such a big colony.” He explained to AP that researchers had always thought of Halley Bay as a “climate change refuge” that would help the emperors maintain their population in the coming years. Global warming will likely intensify storms and reshape the emperor penguins’ habitat to great effect: recent studies have projected anywhere from a 20 percent decrease to a 70 percent decrease in the emperor penguin population by the end of the century.

Trathan’s study reported that a nearby colony at the Dawson-Lambton Glacier has experienced exponential growth over the past few years, swelling to ten times its typical size, suggesting that the survivors from Halley Bay were resilient and adaptable enough to relocate and adjust their breeding patterns to a new setting. However, the size of the new Dawson-Lambton colony is not large enough to indicate that the Halley Bay population has fully recovered.

For the experts, the size of the new combined colonies is beside the point. “What’s interesting for me is not that colonies move or that we can have major breeding failures — we know that,” Trathan told BBC News. He explained that he was much more concerned with how long-standing breeding grounds can be disrupted by climate change. He referred to the fact that in 2015 the Earth experienced the strongest El Niño in over half a century, which accounts for the strong season of storms; at the time, sea ice was also at a record low in the region. “[If] we see major disturbances in these [refuges] — where we haven’t previously seen changes in 60 years — that’s an important signal.”