In graphs: From Antarctica to the North Pole, the world’s sea ice is shrinking
It can be hard to imagine the scale of change taking place on a warming planet. What does 100 gigatonnes of ice look like? How many millions of Olympic swimming pools can you imagine?
Our charts with this article aim to contextualize the massive changes underway in Antarctica, with data from the US National Snow and Ice Data Center.
Headline: Warm Southern Winters Have Produced Much Less Sea Ice Than Usual, Pointing to Possible Fundamental Change in This Historically Changing Climate.
Why did we write this
This summer’s heatwaves from the United States to Europe and Asia have captured the world’s attention. But it was also an unusually warm Antarctic winter, and that had obvious effects.
By the end of August, the extent of Antarctic sea ice (total area with at least 15% sea ice cover) was about 860,000 square miles less than the average August extent from 1981 to 2010. This is a swath of ocean the size of Saudi Arabia, normally ice-packed but now open ocean, is the lowest in winter since records began 45 years ago.
The general trend of sea ice growth in Antarctica has reversed in the past few years, from growing to slightly declining.
Sea ice loss is also occurring in the northern hemisphere, and has long been a symbol of the climate crisis. Antarctic sea ice has appeared to be more resilient. With sea ice steadily declining in the Arctic, sea ice in the Antarctic has fluctuated between record levels and lowest levels over the previous decades. But in 2016, sea ice in Antarctica began a steady downward trend.
Melting sea ice will not directly raise sea levels, as the ice is already floating in the ocean. But the loss of sea ice means less sunlight is reflected back into space, accelerating warming seas and potentially threatening the ice shelves holding back the continent’s huge glaciers, some of which are melting dangerously quickly. Scientists warn that if the Thwaites glacier in Antarctica collapses, global sea levels could rise by up to two feet – a change that could also put other glaciers at risk.
The stakes are high for polar ecosystems, not just global sea levels and ocean currents. One recent study found significantly reduced survival rates for young emperor penguins, a bird as iconic as the largest of the penguin species. If the ice melts or breaks up too soon, the penguin chicks can die because they have not developed waterproof adult feathers.
The scientists also tracked some unusual breaking of ice shelves, which are formed by glaciers and are much thicker than thin and shifting sea ice.
“It’s still an unknown place,” Katherine Walker of the Woods Hole Oceanographic Institution told Al-Monitor after the sudden collapse of the Konger Ice Shelf last year.