The Antarctic has reached the tipping point 40 years earlier than expected and the world can expect drastic changes!
Antarctica may force a reckoning between the choices countries make today about greenhouse gas emissions and the future survival of their coastlines and coastal cities, from Boston, and New York to Shanghai. That reckoning has come much sooner than people expected.
While Arctic ice loss as global temperatures rise is directly affecting lives and triggering feedback loops, the big wild card for sea level rise is Antarctica. It holds enough land ice to raise global sea levels by more than 200 feet (60 meters) – roughly 10 times the amount in the Greenland ice sheet – and we’re already seeing signs of trouble.
Scientists have long known that the Antarctic ice sheet has physical tipping points, beyond which ice loss can accelerate out of control and we have passed one of those points. Current global heating is taking the Earth system across a threshold humans have never experienced, into a climate where Antarctica’s ice shelves and marine ice sheets can no longer exist and one billion people, currently living near the coast, will be drowned by rising seas.
This will be a world where wildfires, heatwaves, atmospheric rivers, extreme rainfalls and droughts – such as those we have seen globally last summer – become commonplace.
The Earth system (oceans, atmosphere, cryosphere, ecosystems etc.) is interconnected. This allows energy flow, enabling physical and ecological systems to remain in balance, or to regain balance. But connections can also mean dependencies, leading to reactions, amplifying feedbacks and consequences. Changes have roll-on effects, much like toppling dominoes.Unless we change our current emissions trajectory, this is what to expect.
By 2050, the climate over Antarctica (Te Tiri o te Moana) will warm by more than 3℃ above pre-industrial temperatures. The Southern Ocean (Te Moana-tāpokopoko-a-Tāwhaki) will be 2℃ warmer.
As a consequence, more than 50% of summer sea ice will be lost, causing the surface ocean and atmosphere over Antarctica to warm even faster as dark ocean replaces white sea ice, absorbing more solar radiation and re-emitting it as heat. This allows warm, moist air in atmospheric rivers from the tropics to penetrate further south.
This accelerated warming of the Antarctic climate is a phenomenon known as polar amplification. This is already happening in the Arctic, which is warming two to three times faster than the global average of 1.5℃, with dramatic consequences for the permanent loss of sea ice and melting of Greenland’s ice sheet.The famous 1.5 ºC figure, widely quoted as the desired 'maximum' for planetary warming, stems from the 2015 United Nations Paris agreement on climate change. This treaty declared the goal of keeping the global average temperature well below 2 ºC above pre-industrial levels, with a preferred limit of 1.5 ºC.