Emperor penguins could be wiped out by unchecked climate change within 80 years as their icy habitat shrinks, a study has warned.
The fate of the birds - some of the most striking and charismatic creatures on Earth - is largely tied to the fate of sea ice on which they breed.
Emperor penguins will only build their colonies in very specific conditions.
Ice must be locked in to the shoreline of the Antarctic continent, while close enough to open seawater for the birds to access food for themselves and their young.
As the climate warms, this sea ice will gradually disappear - robbing the birds of their habitat, food sources and ability to hatch chicks.
'If [the] global climate keeps warming at the current rate, we expect emperor penguins in Antarctica to experience an 86 per cent decline by the year 2100,' said seabird ecologist Stephanie Jenouvrier of Woods Hole Oceanographic Institution.
'At that point, it is very unlikely for them to bounce back.'
In their research, Dr Jenouvrier and colleagues combined two existing computer models.
The first - a global climate model created by the National Centre for Atmospheric Research (NCAR) - contributes projections of where and when sea ice is likely to form under different climate scenarios.
The other, a model of the penguin population itself, calculated how colonies might react to such changes in their icy habitat.
'We’ve been developing that penguin model for 10 years,' said Dr Jenouvrier.
'It can give a very detailed account of how sea ice affects the life cycle of emperor penguins, their reproduction and their mortality.'
'When we feed the results of the NCAR model into it, we can start to see how different global temperature targets may affect the emperor penguin population as a whole.'
The researchers ran their model with three different scenarios.
The first considered a future in which average global temperatures only increased by 1.5°C (2.7°F) - the goal set out by the Paris climate accord.
The other two scenarios explored average rises of 2°C (3.6°) and around 5-6°C (9-10.8°F) - the latter being the predicted temperature increase in the 'business-as-usual' case where no action is taken to mitigate climate change.
Under the first scenario, the study found that five per cent of sea ice would be lost by the year 2100, causing a 19 per cent drop in the number of penguin colonies.
If the planet warms by 2°C (3.6°), however, those numbers increase dramatically, with sea ice loss nearly tripling and more than a third of existing emperor penguin colonies disappearing by the end of the century.
The ‘business-as-usual’ scenario is even more dire, Dr Jenouvrier noted, with the extinction of almost all penguin colonies all but guaranteed.
'Under that scenario, the penguins will effectively be marching towards extinction over the next century,' she said.
The full findings of the study were published in the journal Global Change Biology.