The Thwaites Glacier is located in western Antarctica and is about the size of Great Britain. Due to climate change, the meltwater from this glacier currently accounts for 4 percent of the sea level rise.
Crack in the windshield
An increase in the rise is not yet on the agenda, because the ice shelf in front of the glacier is slowing down the melting. But on new satellite images shows that this ice shelf is getting more and more cracks.
The cracks can be compared to a crack in the windshield of your car, write the researchers who published the images in their report. “Such a crack weakens the window pane and a small shock can cause the window to fall apart into hundreds of shards.”
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The American scientists write that the ice shelf will shatter within five to ten years. If this happens, the glacier could melt three times faster. The glacier is also known as ‘Doomsday Glacier’ because the sea level would rise more than half a meter if it completely melted.
Sea level will rise
The eastern ice shelf itself will not directly cause sea level rise, explains Stef Lhermitte. He is a glaciologist at TU Delft and studies polar caps using satellite images. “An ice shelf is a piece of floating ice and is therefore already in the water.” Lhermitte compares it to ice cubes in a glass of cola: when the ice cubes melt, there is not suddenly more liquid in the glass.
The problem is with the glacier held in place by the ice shelf. “A glacier is on land. If the ice from the glacier melts and enters the water, the global sea level will rise.” Just like when you put an ice cube in a glass of Coke.
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Horizontal Gravity
The melting of the entire Thwaites glacier will have a major impact on sea levels, especially in the Netherlands. “That’s because of horizontal gravity,” explains glaciologist Lhermitte.
Ocean water is attracted to large ice masses, such as those in Antarctica. As a result, the sea level around the ice caps is higher. “If a large piece of ice disappears there, Antarctica loses some of that attraction, so that the water there flows away.” The sea level at the ice caps then falls, while the sea level rises thousands of kilometers away. “And because the Netherlands is on the other side of the world, relatively more water is coming our way.”
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The bad news is that we can’t stop the ice shelf shattering right now. Even if the entire world stops emitting greenhouse gases today, the temperature will continue to rise and the ice will melt. “It’s a process that cannot be stopped overnight,” explains Lhermitte.
Irreversible process
The IPCC report from earlier this year already showed that some changes in climate are irreversible. For example, the sea level will continue to rise in the coming thousands of years, and the melting of glaciers on mountains and in the Arctic can also continue for centuries.
The good news is that the complete melting of the Thwaites Glacier will take decades to come. “It is unstoppable, but it is happening very slowly. That gives us the opportunity to adapt and prepare as best as possible. The sea level continues to rise, but depending on the choices we make now, the sea level will rise more or less.”
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