The air above Antarctica is also heating up, causing surface melting that can trigger the collapse of ice shelves. In March 2022, East Antarctica was hit by the most extreme heatwave ever recorded on Earth, with temperatures soaring 38℃ above normal. If this heatwave had occurred in the summer, temperatures above melting point would have been reached in the coldest place on the planet for the first time.

The shape of the land under the ice affects its vulnerability. The West Antarctic Ice Sheet, which could raise global sea level by over three metres, depends on the Thwaites Glacier’s stability. This part of the ice sheet rests on a downward-sloping submarine bed, making it prone to irreversible retreat.

The far-reaching implications of Antarctic ice melt encompass a broad spectrum of global environmental and climatic repercussions. The most obvious impact is the rise of global sea level, which threatens hundreds of millions of people living in coastal areas around the world. Even a few centimetres of sea level rise can increase the risk of flooding, erosion, storm surges and saltwater intrusion, damaging homes, infrastructure and farmland. A 2020 study found that a global mean sea level rise of one metre by 2100 would cause annual flood damages to increase by two to three orders of magnitude, affecting up to 20.3% of global GDP. However, this may be an underestimation as we cannot rule out two metres of global mean sea level rise by 2100.

The loss of Antarctic ice poses a significant threat to our planet’s climate system, as it can set off a feedback loop that exacerbates global warming. As the sea ice in the Antarctic region diminishes, it unveils larger stretches of open water. The darker water absorbs a greater amount of solar radiation, trapping more heat within the Earth’s system. The Arctic has been exhibiting such change since the 1970s, and if the Antarctic is starting to behave like the Arctic, both polar regions would act to accelerate further warming.

Antarctic melt also threatens the disruption of ocean circulation, which carries heat and nutrients around the world. As the ice sheet melts, it dilutes the seawater with fresh water, making it less dense and less likely to sink. This could slow down the great conveyor belt that drives global ocean circulation, changing nutrient distribution, global weather patterns and threatening food security.

Some sea level rise from Antarctica is now inevitable, but we can still avoid the worst impacts by urgently cutting greenhouse gas emissions. The Sharm El-Sheikh Implementation plan, adopted at COP27, recognized the impacts of climate change on the cryosphere. Negotiations at COP28 need to build on this momentum and recognize that limiting global warming to 1.5C is a physical necessity to prevent the irreversible collapse of West Antarctica. Therefore, we must rule out any possibility of reaching 2C of warming, which would be catastrophic for both Antarctica and the rest of the world.

We can achieve this by triggering positive tipping points for societal change. These are rapid shifts in human behaviour, technology, policy or markets that can lead to large-scale transformations that reduce emissions and enhance resilience. Powerful tipping points are reached when new clean technologies reach cost parity with old polluting alternatives.

Figure 1. Renewable energy is projected to overtake fossil fuels by 2030

Source: RMI

The deployment of new technologies follows a well-known pattern of “S curves” of exponential uptake. The more we make something, the better we get at it and costs fall in a predictable way, leading to accelerating growth in deployment of the new technology. Models show that renewable energy is growing exponentially and is projected to provide over one-third of global electricity by 2030 and overtake fossil fuels.