Antarctica lost 3 trillion tonnes of ice between 1992 and 2017, according to a new analysis of satellite observations. In vulnerable West Antarctica, the annual rate of ice loss has tripled during that period, reaching 159 billion tonnes a year. Overall, enough ice has been lost from Antarctica over the past quarter-century to raise global seas by 8 millimetres.
What will Antarctica look like in the year 2070, and how will changes in Antarctica impact the rest of the globe? The answer to these questions depends on choices we make in the next decade, as outlined in our accompanying paper, also published today in Nature.
Our research contrasts two potential narratives for Antarctica over the coming half-century – a story that will play out within the lifetimes of today’s children and young adults.
While the two scenarios are necessarily speculative, two things are certain. The first is that once significant changes occur in Antarctica, we are committed to centuries of further, irreversible change on global scales. The second is that we don’t have much time – the narrative that eventually plays out will depend on choices made in the coming decade.
Change in Antarctica has global impacts
Despite being the most remote region on Earth, changes in Antarctica and the Southern Ocean will have global consequences for the planet and humanity.
For example, the rate of sea-level rise depends on the response of the Antarctic ice sheet to warming of the atmosphere and ocean, while the speed of climate change depends on how much heat and carbon dioxide is taken up by the Southern Ocean. What’s more, marine ecosystems all over the world are sustained by the nutrients exported from the Southern Ocean to lower latitudes.
From a political perspective, Antarctica and the Southern Ocean are among the largest shared spaces on Earth, regulated by a unique governance regime known as the Antarctic Treaty System. So far this regime has been successful at managing the environment and avoiding discord.
However, just as the physical and biological systems of Antarctica face challenges from rapid environmental change driven by human activities, so too does the management of the continent.
Antarctica in 2070
We considered two narratives of the next 50 years for Antarctica, each describing a plausible future based on the latest science.
In the first scenario, global greenhouse gas emissions remain unchecked, the climate continues to warm, and little policy action is taken to respond to environmental factors and human activities that affect the Antarctic.