The year was 1915. Bold explorers, led by Earnest Shackleton, were investigating Antarctica by ship. After days of chopping through ice sheets, the boat could go no further. The sailors had to jump ship as the ice overtook the boat and squeezed the wooden planks into splinters. 🧊 They made headlines for surviving a whole year after they abandoned their boat.
Fast-forward to today, and those ice sheets are still making headlines. Cracks in massive glaciers, chunks of ice the size of U.S. states drifting off into the ocean - the ice sheets are looking fragile these days. Scientists are worried that most solutions could take a decade to show any effect. That's why they're looking at some brain-bending possibilities.
They’re focusing on the Thwaites Glacier—aka the “Doomsday Glacier.” It’s the widest glacier in the world, about the size of Florida, and it holds a lot of ice. (Well, technically 480,000 cubic kilometers, but who’s counting?)
Thwaites Glacier interacts in a special way with the ocean floor. There are tall, undersea mountains that sit below the glacier. These mountains act as an underwater dam, preventing warm ocean currents from rushing below the Antarctic sheet of ice.
Naturally, warm temperatures cause glaciers to melt. But what speeds the process along are rivers of warm ocean water wearing away at the ice from below. Fifty years ago, the underwater mountains did a good job at blocking this kind of current.
As the glacier has been melting, though, it has become more buoyant. That makes it float a little higher in the water. This means it separates from the natural sea wall below. Warm ocean currents slip under the glacier, causing the melting to speed up.
It’s one of those vicious cycles: the more it melts, the faster it melts. 🌡️ Ice sheets shrink and grow with the seasons, but lately, the growing during the cold seasons isn't making up for the shrinking in the warm seasons. In fact, scientists say Thwaites is losing 80 cubic kilometers of ice every year. That’s like taking 400,000 Olympic swimming pools... and multiplying it by 80. 😳
This rush toward ice sheet oblivion has scientists looking at some wild possibilities. One option is building a wall 1,000 feet tall that extends for 60 miles to stop the warm ocean water from rushing under the glacier. The problem? The expense and challenge of building such a massive structure under the coldest waters on Earth makes it nearly impossible.
Other options scientists are looking at to save glaciers are also complicated. One idea is using thermosiphons to pull heat away from glaciers. They've even considered pumping water out from underneath glaciers so they don’t slide around so much. None of these options are cheap or easy, but scientists keep searching for solutions to slow the melting.
Researching Antarctica got me thinking; how does the ice on this continent change over the course of a year? Even Shackleton knew it was easier to explore during certain months. Check out the graph below:
If I brought this graph to class, here are some questions I'd ask to go with it:
💡What is the greatest amount of ice that covers Antarctica? During what time of year does this occur?
💡During what times of year would there be 10 million km2 of ice covering Antarctica?
💡Antarctica is in the Southern Hemisphere. Use your knowledge of seasons and Earth's movement to predict how this graph might look if it represented glaciers in the Northern Hemisphere, like in Greenland.