NARRATOR: Are rising temperatures driving Earth's ecosystems past a point of no return?
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JANE LONG: We can't go back. There is no path backwards. STEVE PACALA: Every year, the damages are worse.
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NARRATOR: We have promising technologies that put solutions within our grasp,
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but are we reaching far enough? FRANK KEUTSCH: We have to have emissions cut to zero.
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Even if we stop emitting CO2, we still have the CO2 we've already emitted.
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NARRATOR: So scientists are building a new toolkit... ATTICUS STOVALL: It has power. NARRATOR: ...to ensure a prosperous future.
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Our society has to survive. SHEILA JASANOFF: We need to reduce the heating effect. NARRATOR: Cutting-edge solutions...
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ALDO STEINFELD: It's going to be revolutionary. LOLA FATOYINBO AGUEH: It's like science fiction.
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DAVID KEITH: And there's the balloon up there. NARRATOR: ...and high-risk measures... I really hope we'll never have to do this.
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It's really important that humanity has a backstop. NARRATOR: ...in a race to discover:
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can we cool the planet? Right now, on "NOVA."
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JASANOFF: It's a new time in the Earth's history in which we are not just inhabiting our planet,
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we're operating as stewards of the very thing that we're living on.
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NARRATOR: Since the Industrial Revolution, humanity has been running an unintentional experiment
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in Earth's atmosphere, pushing the climate to new extremes. LONG: Things are going to get hot.
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MAN: Boy, you can feel the heat. This is insane! Oh, my God.
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PACALA: Attitudes have changed rapidly because everyone can see for themselves
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the climate change that is occurring. NARRATOR: A child born today will witness, across her lifetime,
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a planet transformed by rising temperature. MAN: I got you, I got you.
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NARRATOR: How did we get here? LONG: Every time you get in your car,
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every time you fly a plane, every time you turn the heat on, all of those things are putting carbon dioxide
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into the atmosphere, and if there's more carbon dioxide in the atmosphere, there's a higher temperature.
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NARRATOR: And now temperatures have started to spike. KEITH: If we keep pumping billions of tons of CO2
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into the atmosphere each year, we really will cook ourselves, literally, in the end. (birds squawking)
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NARRATOR: To stop the worst impacts of planetary heating, we need rapid emissions cuts,
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starting now. PACALA: The developed nations of the world need to go from the energy system they have now
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to one that emits nothing, zero, in 30 years' time.
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The good news is, we know how to do that. Renewables now are the cheapest form of electricity
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on two-thirds of the Earth's surface, and it's going to be everywhere. NARRATOR: A world of carbon-free energy is coming.
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(thunder crackling) But climate impacts are coming faster. KATE MURPHY: Lasers are at power.
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There it is. NARRATOR: So scientists are opening a second front in the battle...
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STOVALL: Sweet. It has power. NARRATOR: Bringing new technologies to bear on the way we fight climate change...
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FATOYINBO AGUEH: We now have so much data. This is going to be a game-changer. PACALA: There are a whole class of solutions
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to actually get this job all the way done. NARRATOR: By removing CO2 from the air...
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SANDRA SNAEBJORNSDOTTIR: This little guy, this is just the beginning. NARRATOR: Converting CO2 from a waste
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to a resource... APOORV SINHA: We see this kind of as a testing ground.
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NARRATOR: Even extreme measures, like shielding us from the sun.
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(machinery whirring) PACALA: There's been a technical revolution in the last few years that's unlike anything we've seen
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in the previous hundred. This is a problem with a solution.
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NARRATOR: Can a new wave of climate tech take us the rest of the way to turn down the global thermostat?
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KEUTSCH: We need to look at everything that's out there-- natural solutions, CO2 sequestration,
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solar geoengineering. There may be this idea out there that nobody has come up with yet
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that could be really transformative.
The Impact of Carbon Dioxide on the Atmosphere
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NARRATOR: Cooling the planet means, first, stopping more CO2 from entering the atmosphere
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and then finding ways to remove it. But just how much CO2 are we talking about?
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Imagine you filled the National Mall all the way from the Lincoln Memorial to the Capitol steps with coal...
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# # ...and you piled it up all the way
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to the top of the Washington Monument ten times.
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That would be a gigaton of coal. "Giga" means billion, so that's a billion tons.
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Now, we actually burn ten times that much carbon every year. People actually go dig that stuff up out of the ground,
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ten billion tons of it, and set it on fire in power plants, in engines,
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in factories all over the world. (imitating combustion)
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And then because that carbon has reacted with oxygen, ten gigatons of carbon is burned, but it creates 37 gigatons of CO2.
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NARRATOR: At our current rate, that's just one year of CO2 emissions.
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To blunt the impacts of heating the planet,
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we need to shrink that number, to zero. # #
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But there's another problem-- the gigatons that came before.
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LONG: The single most important fact about climate change is that the carbon dioxide that we emit into the atmosphere stays there for thousands of years.
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NARRATOR: Year after year, we live with the carbon dioxide we've added over time-- nearly 1,000 metric gigatons
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since the Industrial Revolution began. LONG: Almost everything we emit stays there,
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and it's staying there until you do something about taking it out.
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NARRATOR: Pulling CO2 out of the air. (men speaking on radios)
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NARRATOR: It sounds futuristic, but it's a problem we've encountered before. JAN WURZBACHER: Remember Apollo 13?
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It was all about CO2 filtering, right? That was the big problem, how to get the CO2 out of the air. (indistinct radio chatter)
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NARRATOR: In 1970, following an accident, the crew of Apollo 13 aborted a mission to land on the moon.
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JOHN SWIGERT (archival): Houston, we've had a problem. NARRATOR: Forced to return to Earth in a smaller capsule,
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the astronauts faced a big problem. WURZBACHER: You're in confined spaces. People exhale CO2.
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You need to remove that CO2. (person exhales) NARRATOR: Every exhale caused carbon dioxide to build up,
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making the air increasingly toxic. MAN (archival): Okay, now, let's everybody keep cool.
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Let's solve the problem but let's not make it any worse by guessing.
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NARRATOR: The astronauts survived by modifying their air scrubber to remove more carbon dioxide.
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(air flowing) Inside the scrubber, negatively charged sites
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on the filter polarize and bond with the CO2, removing it from the air.
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Could something like this work in Earth's atmosphere?
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DENNING: There's not a lot of CO2 in the air compared to nitrogen and oxygen. Imagine a box with 10,000 ping pong balls in it
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and four of them are painted black-- those are the CO2 molecules.
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Trying to find those four balls out of that big box full of ping pong balls is hard!
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NARRATOR: Removing CO2 from a spacecraft is one thing. Removing it from our atmosphere poses a much bigger challenge.
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Is it realistic?
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WURZBACHER: Most people to whom we told we are taking CO2 out of the air would say, "You're crazy."
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But here you see a full-scale direct air capture plant. You see it consists of 12 individual modules
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capturing the CO2 out of the air. NARRATOR: Jan Wurzbacher is a co-founder
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of Climeworks, a Swiss start-up specializing in what's called direct air capture.
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Through this side, we suck in ambient air with 400 PPM-- that's 400 parts per million CO2.
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And on the other side, we expel about 100 PPM CO2 content.
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So three-quarters are kept inside. NARRATOR: A filter with highly reactive chemicals called amines
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catches even small concentrations of CO2.
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Heating the filter then breaks the bond. WURZBACHER: You release the CO2 and you can extract pure concentrated CO2.
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And then you start all over again.
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NARRATOR: But generating the energy to do this can produce its own CO2.
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Their solution for that is garbage.
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Here we are on top of the waste incineration plant. The reason why we're here is the main energy source
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for our process of CO2 capture from the air, waste heat from the incineration process.
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NARRATOR: Heat that would have been wasted instead heats the filters inside the array,
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which capture nearly 1,500 metric tons of pure CO2 a year-- about what's expelled from the tailpipes of 300 cars.
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PACALA: Once you've pulled CO2 out of the atmosphere with a direct air capture machine,
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the question is what to do with it. WURZBACHER: The big picture is taking one percent of CO2 out of the atmosphere
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within the next five to ten years-- that is roughly 400 million tons-- and store it underground.
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NARRATOR: Could we put carbon right back where we found it-- underground?
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PACALA: There are lots of rocks near the surface of the Earth that would want to bond spontaneously with CO2.
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There's enough of these kinds of minerals that you could remove all of the atmospheric CO2 many, many times over.
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NARRATOR: One of the best places to try that out is Iceland.
Removing CO2 from the Atmosphere: Where Does it Go?
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SNAEBJORNSDOTTIR: Here we are-- the land of ice and fire. (laughs)
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We have eruptions. We have earthquakes. NARRATOR: Iceland is an island formed out of volcanic rock called basalt.
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We see the basaltic mountains here around me and actually extending several kilometers downwards.
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NARRATOR: Basalt is porous rock that readily bonds with CO2 over centuries.
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Sandra Snaebjornsdottir's team has found a way to speed up that process.
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SNAEBJORNSDOTTIR: CarbFix is the method of capturing CO2 and turning it into stone.
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It's magic, but it's magic that already occurs in nature.
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NARRATOR: CarbFix is turning one-third of the CO2 from this power plant into solid rock in less than two years.
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The key is water. Inside this scrubber, gaseous CO2 is dissolved in water
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