Emperor penguins and three-metre sea level rises: the cost of Antarctica’s warming
By Bianca Hall
Sea levels could rise by three metres and emperor penguins could be extinct in 75 years as large and abrupt changes unfolding in Antarctica pose profound implications for Australia and the Pacific.
These are among the findings of new research undertaken by Australian scientists and an international team from South Africa, Switzerland, France, Germany and the United Kingdom and published today in the prestigious journal Nature.
Emperor penguins care for their chicks in Antarctica. New research shows they could be extinct in 75 years.Credit: Getty Images/iStockphoto
The research shows the accelerating effects of climate change – even if it is limited to two degrees above pre-industrial temperatures – are placing the West Antarctic Ice Shelf in “severe” risk of collapse.
The ice shelf contains enough ice to raise sea levels by three metres, and the “tipping point for unstoppable ice loss from the West Antarctic Ice Sheet could be exceeded even under best-case CO2 [carbon dioxide] emission reduction pathways”, the paper warns.
Lead author Dr Nerilie Abram, chief scientist at the Australian Antarctic Division, said such sea level rises would threaten the world’s coastal cities and communities and result in “catastrophic consequences for generations to come”.
“Rapid change has already been detected across Antarctica’s ice, oceans and ecosystems, and this is set to worsen with every fraction of a degree of global warming,” Abram said.
Changes unfolding in Antarctica are interlinked, placing pressure on the climate, sea levels and ecosystems.Credit: Biosphoto via AFP
“The loss of Antarctic sea ice is another abrupt change that has a whole range of knock-on effects, including making the floating ice shelves around Antarctica more susceptible to wave-driven collapse.”
According to the peer-reviewed paper, there is evidence the “natural behaviour” of Antarctic sea-ice has changed over the past decade, as thinning sea ice and warming oceans create “self-perpetuating” changes.
“As sea ice is lost from the ocean surface, it is also changing the amount of solar heat being retained in the climate system, and that is expected to worsen warming in the Antarctic region,” Abram said.
“Other changes to the continent could soon become unstoppable, including the loss of Antarctic ice shelves and vulnerable parts of the Antarctic ice sheet that they hold behind them.”
A critical threshold for the collapse of the West Antarctic Ice Sheet was estimated to be about two degrees of global average warming above pre-industrial temperatures, but a partial collapse could occur under lower temperatures, the scientists reported.
In 2024, global temperatures reached an average 1.5 degrees above pre-industrial averages, although the Paris Agreement only considers the target breached when average temperatures have been above that level for 20 years.
The 10 warmest years on record have been the past 10 years.
“The decline in Antarctic sea ice and the slowdown of deep circulation in the Southern Ocean are showing worrying signs of being more susceptible to a warming climate than previously thought,” Abram said.
Study co-author Professor Matthew England, from the University of NSW and the ARC Australian Centre for Excellence in Antarctic Science (ACEAS), said the observed changes would lead to profound impacts on Australia without urgent intervention.
“Consequences for Australia include rising sea levels that will impact our coastal communities, a warmer and deoxygenated Southern Ocean being less able to remove carbon dioxide from the atmosphere, leading to more intense warming in Australia and beyond, and increased regional warming from Antarctic sea ice loss,” England said.
Repeated breeding failures linked with diminishing sea-ice coverage could have devastating impacts, including on emperor penguins, researchers found.
A grim outlook.Credit: Matt Golding
Emperor penguins breed on landfast sea ice (known as “fast ice”) between March or April and January. But with many regions of multiyear “fast ice” becoming seasonal, researchers believe emperor penguins are in trouble.
“Of the 60+ known colonies [on Antarctica], 30 have experienced increased or complete breeding failure events since 2016 due to early fast-ice loss, and 16 colonies have suffered two or more such events,” they wrote.
England said emperor penguin chicks relied on stable sea ice habitats before their waterproof feathers grew in.
“The loss of entire colonies of chicks has been seen right around the Antarctic coast because of early sea ice breakout events, and some colonies have experienced multiple breeding failure events over the last decade.”
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