By Marianne Guenot and Annie Fu
- Sea levels are rising steadily each year as the planet warms.
- Melting ice could collapse suddenly, raising sea levels abruptly.
- These melting glaciers and ice sheets are the ones scientists are watching most closely.
The Earth’s ice is, rightly, often in the news. As the planet and its oceans warm, our so-called cryosphere is quickly melting away.
There are two factors that lead to sea level rise: the water expanding as it gets warmer and added water from melting ice sheets and glaciers.
Melting ice that could tip sea level rise into catastrophic levels
While it’s easier to plan for a steady sea level rise, scientists are very concerned about what would happen if huge chunks of ice collapse and abruptly change sea levels.
Here are the sites around the world scientists are keeping a close eye on, and why they are important, according to Alex Brisbourne, a Glaciologist at the British Antarctic Survey, and Theodore Scambos, an Antarctic researcher at the University of Colorado.
Glaciers
Glaciers will be the first to go.
Though they will contribute comparatively little to sea level rise — adding about a foot to global mean sea levels if they melt completely — glaciers outside of Greenland and Antarctica have been the main contributors to higher seas over the past century, according to the UN’s Intergovernmental Panel on Climate Change (IPCC).
Catastrophic collapse — Columbia Glacier in Alaska
Glaciers took centuries to freeze over, but they can disappear in a few years. When they start breaking apart, that triggers a negative feedback loop: the meltwater warms the glacier, which creates more meltwater.
The Columbia Glacier in Alaska is one of the most recognizable examples of rapid glacier collapse. This glacier has almost completely disappeared today.
“It’s an example of how this will play out for many coastal glaciers,” Scambos told Insider in an email.
Albedo — Presena Glacier in the Alps, Europe
Glaciers are not only important because they store water away from the oceans. Because they are light-colored, they bounce back a lot of light back into space. This effect, called the albedo of the ice, is crucial because it keeps sunlight from warming the earth.
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