Warming Sea Water May Be Threatening the Collapse of the Antarctic Thwaites Glacier
One of the challenges of global warming is that its consequences are happening faster than expected. A few years ago, scientists claimed that big changes would happen within centuries, but now they are warning that the climate crisis already has observable effects on the environment.
Ted Scambos, the U.S. lead coordinator for the International Thwaites Glacier Collaboration (ITGC), is one of those experts who’s been testifying to how a warmer planet is already changing the landscape in Antarctica, and he is worried: “In a few parts of Antarctica, there are huge changes due to climate warming; large (city-sized) areas of ice are simply gone; and many glaciers have shrunk in thickness and length.”
For years, Scambos has been studying Antarctica’s Thwaites Glacier, a massive glacier considered the widest in the world, part of the West Antarctic Ice Sheet (WAIS). The area of WAIS is approximately 3,435,000 km. Now, he and a group of scientists are warning that its ice shelves—braces that help prevent the glacier's total collapse—may only last a few more years. When this happens, sea levels could start to rise by several feet, putting millions of people living in coastal cities in danger zones for extreme flooding.
Because they are so distant and in remote areas, people usually don’t pay attention to glaciers, but they play an important role in maintaining the stability of our planet. Glaciers are keystones of life on Earth. As giant freshwater reservoirs, they support the planet’s life systems and influence our day-to-day lives, even for communities who live far from them. “Glaciers are important for many reasons. They are natural reservoirs of fresh water, which is important for agriculture in many arid but mountainous countries. But perhaps more importantly, glaciers and ice sheets represent large amounts of water stored on land, and as such they can be a component of sea level rise,” explains Scambos.
Those massive areas of ice are formed from falling snow. In cold regions, this snow persists, gets thicker, and is compressed by the new snow that falls on top of it, slowly crushing it into ice. When they are about 40 to 60 meters (43-65 yards) thick, they begin to move and generally reach either a warmer climate at lower elevation—where the front of the ice flow melts—or the sea. The formation of a glacier takes millennia, and its size varies depending on the amount of ice it retains throughout its lifespan. They can range from ice that is several hundred to several thousand years old and provide a scientific record of how climate has changed over time.
Since the early 1900s, many glaciers around the world have been rapidly melting, and human activities are at the root of this phenomenon. “Because of global warming, glaciers are shrinking—not just mountain glaciers but the large ice sheets in Antarctica, Greenland, and Patagonia as well. The reason, in general, is warmer air temperatures, warmer ocean temperatures, and in a few areas the reason is less snowfall,” says Scambos.
In a recent study, a team of scientists from the International Thwaites Glacier Collaboration project discovered that the Thwaites Glacier, one of the largest of its kind in Antarctica—covering an area of 192,000 square kilometers (119,303 square miles), almost the size of Florida or Britain—could collapse soon. One third of this massive area consists of large floating ice platforms, or ice shelves. Increasingly, however, these platforms have been fracturing as a warming ocean slowly erases the ice from below. The Thwaites Eastern Ice Shelf, the area of most concern, acts like a dam for the rest of the glacier. According to the team of scientists, within the next three to five years, this 45-kilometer-long (27.9 miles) ice shelf segment could shatter and break like a car window and spell the beginning of the end of the Thwaites glacier.
“This will start a long process of rapid flow, thinning, and retreat into the interior of West Antarctica (the main part of Antarctica in the Western Hemisphere); and, since the ice is thicker in the interior, the ice will flow even faster, and thin faster, in a kind of run-away process,” explains Scambos. Global warming, or the warming of the sea to be specific, is to blame for that. Warm water flowing beneath the ice shelves has caused large sections to thaw, forming glacier caves. This melting process has accelerated tremendously over the past thirty years. If it leads to a collapse, it will have a significant impact on the ocean. Today, the ice shelf contributes up to 4% of global sea level rise, but when it collapses, its contribution to sea level rise could increase by as much as 25%. If the whole glacier collapsed, it could raise sea levels by “2 feet” or more within the next decades or centuries.
“This process is thought to be similar to something that occurred around 110,000 years ago during the warmest period between the ice ages. We are already about as warm as that period; and so, this may be the beginning of a long process that will eventually take away most of the ice sheet we call ‘West Antarctica’,” says Scambos.
The good news is that the worst impacts of this process can still be mitigated depending on how humans respond in coming decades. “It’s unlikely that humans can actually prevent the eventual loss of a large area of Antarctica’s ice sheet, but models of how the ice will evolve consistently show that if we address greenhouse gases and climate warming in the next few decades, by the end of the century we will be slowing the process of Thwaites’ retreat,” explains the scientist.
“In the fastest version of the runaway, the rate of sea level rise becomes hard to manage, hard to adapt to with sea defenses or rebuilding port areas or simply moving people away from the most vulnerable areas. If the rate is too fast, then it is also too expensive. And there would be more disasters and damage as a result.” However, Scambos says that we can make the process so slow that it will be relatively easy to adapt to, pushing much of the disaster a thousand years or more in the future.
*Jacqueline Sordi is a Brazilian journalist and biologist, specializing in science and environmental journalism. She has a master’s degree in environmental journalism at UCLA and is currently a Ph.D. candidate in communications at Federal University of Rio Grande do Sul.
Source: Thwaites Glacier Facts