This episode of SciShow is supported by NordVPN.  You can head to nordVPN.com/SciShowVPN for a   special offer and 30 day risk free trial. [♪ INTRO]  If we’re going to find our way out of this  climate crisis that we’ve created, we’ll need   radical ideas.

And right now, lots of these ideas  are aimed at getting our emissions down to zero,   to keep the Earth from getting catastrophically  warmer, which would be great. But we also need   to deal with the amount of climate change that’s  already locked in.

And to do that, we also need   to think big. One consequence we’re already seeing  is sea level rise, as glaciers and ice sheets melt   into the ocean. That’s why some scientists  are exploring ways to geoengineer glaciers   on a massive scale in the hopes of slowing down  the rising water.

Geoengineering is the idea of   intentionally manipulating the environment on  massive scales. Like, putting giant mirrors in   space to reflect some sunlight away from Earth  so things can cool down a bit. Or scattering   little particles throughout the atmosphere to keep  some light from getting through.

But many of these   ideas are pretty controversial, so the whole thing  is more concept than practice, at least for now.   It’s not like we haven’t already been manipulating  the climate for centuries by pumping greenhouse   gases into the air and cutting down trees. But  tinkering with our one and only home planet on   purpose is not something everyone can get behind.  Still, massive problems call for massive proposed   solutions. And one massive problem is melting  ice.

Water that’s currently locked into ice   in Antarctica and Greenland could lead to over 20  meters of sea level rise if it melts into the sea.   That’s enough sea level rise to cover a six-story  building and wash a bunch of islands and coastal   cities straight off the map. So, while it comes  with risks, scientists and governments have been   talking about using geoengineering to deal with  melting glaciers. And one idea is to keep glacial   ice cold by putting a blanket on it.

That’s  because, in some glaciers, a lot of the melting   happens at the top, where warmer air touches the  ice. And when melting begins, it tends to set up   a vicious cycle: It creates a pool of water, and  since water is darker than ice, it absorbs more   sunlight, getting even warmer. And that makes it  melt more readily and the cycle continues.

Even   after these melted pools drain away or dry up,  they can leave behind dark debris that absorbs   more sunlight than the surrounding ice. And once  again, that darker area is more likely to warm   up the ice enough that it melts. And that’s why,  in Italy and Switzerland, people have literally   covered some glaciers with blankets to reflect  sunlight and keep the glaciers from getting too   toasty and melting.

Unfortunately, there’s  just no way we’re going to put blankets over   all of Greenland and Antarctica. So scientists are  thinking about other ways of “blanketing” ice. And   some have come up with a sand-like material that  reflects sunlight back into space.

In one study,   they tested this out on a pond in Minnesota, and  it actually worked! Ice that was treated with   this special “sand” stayed frozen much longer than  untreated ice. The sand could be spread by hand,   or using an agricultural seed sower.

But even if  we’re using sand instead of physical blankets,   covering large parts of Greenland and Antarctica  would still be a huge practical challenge. So in   the meantime, some geoengineering research  is looking at the other side of glaciers:   the part scraping along the ground. Like rivers,  many glaciers drain into the ocean, so fast-moving   glaciers lose ice more quickly than slower ones.  And many of the fastest-moving glaciers slide out   to sea on a layer of liquid water.

That water  can come from the bottom of the glacier if the   ground is warm enough to melt some ice, or if  the friction from sliding heats things up. Other   times, water slips under glaciers through cracks.  Either way, it basically creates a slip-n-slide   that slides the glacier out to sea. So, if we  could just get rid of that water, it might slow   glaciers down like a slip-n-slide without the  water.

One way we might do this is actually   inspired by the very industry that got us into  this mess in the first place: oil. The idea is if   we could drill down into glaciers and extract this  water, using very similar technology to what’s   used in oil drilling, we could slow down these  glaciers and keep them from draining so quickly   into the ocean. We wouldn’t do this for all of the  world’s hundreds of thousands of glaciers, but we   could potentially use this approach to stabilize  the ice sheets that are contributing the most to   sea level rise.

As with blanketing glaciers,  extracting water from underneath enormous ice   sheets comes with a ton of practical challenges,  so no one is ready to try this just yet. But if   we do end up drilling a bunch of boreholes in  glaciers to drain them, there might be several   ways to use them such as essentially refrigerating  the glacier. The idea is this: If we could inject   cold substances into these boreholes, we could  potentially freeze any water under the glacier.   This is basically the same idea as draining the  glacier, but a different flavor: it would make the   bottom dry and eliminate the slip-n-slide.

And  just maybe we could even use the same gas that   caused most of the planet’s warming to cool things  down. I’m talking about CO2. Now, when you think   of CO2, there’s a good chance you automatically  think “warming.” That’s because CO2 in the   atmosphere is famous for trapping heat and making  our planet hotter and hotter.

But CO2 actually   makes a pretty good refrigerant, or substance that  cools things down. In fact, it was even used in   one of the first-ever refrigerators in the 1850s.  The way it works is, you need a machine that   can compress CO2 and turn it into a liquid. Then  when it comes in contact with a warmer substance,   it absorbs some of that heat and turns back into a  gas.

There are various gases that can do this, but   the great thing about CO2 is that it’s relatively  harmless when it’s not off being a greenhouse gas.   So basically, we’d need to build refrigeration  systems that could pump liquid CO2 into glaciers,   then, once it turns back into a gas, liquefy it  again and send it back into the hole. Obviously   this is not a simple job, nor a one-stop shop to  fix everything. But it could end up being one of   the tools in our toolbox.

The thing about all  of these geoengineering ideas is that we won’t   be putting any of them into practice tomorrow.  None of them are feasible yet on a large scale,   and some might just not be possible ever. They all  come with enormous technical challenges. But we   can’t just reverse all the climate change we’ve  already brought upon ourselves.

So ideas like   these give scientists a place to start thinking  about what they could realistically change. You’ve   got to hand it to them they aren’t thinking small. Thanks to NordVPN for supporting this SciShow   video!

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