Most experts agree that the key to avoiding worsening effects from a changing climate is to cut greenhouse gas emissions to zero. Explore how scientists approach the challenge, and discover the technologies that can help get us there.
Cutting our Greenhouse Gas Emissions to Zero
Published: June 22, 2020
Narrator: We’re in the early stages of a global climate crisis. But it’s still early enough that most scientists agree we can prevent a lot of damage if we stop creating the problem. In academic circles, this is called "mitigation."
But how do we do it?
Onscreen: "Preventing" Climate Change
Narrator: Humans emit about 37 metric gigatons of CO2 per year. I know, what the heck does that mean? Think of it this way: if you extracted all the carbon from that carbon dioxide gas and put it into the form of solid coal, it would form a pile of carbon four miles across and over a mile high. And that’s just one kind of greenhouse gas, in one year!
So, how can we make this pile of pollution disappear? If we want to solve climate change, we have to get our net greenhouse gas emissions to zero.
The majority of greenhouse gases—about 70% of them—come from combusting fossil fuels for energy, everything from lighting your bedroom, to fueling cars, trains, and planes, to powering massive industrial plants. This is a good place to start bringing down emissions.
First, we could use less energy. Stuff like LED lighting, and efficient heating and cooling of buildings can help us reduce the amount of energy we need in the first place. These measures will help, but they can only go so far, because, let’s face it: our civilization runs on energy. And some efficiency measures are expensive and not that accessible to those with fewer resources.
Since no one wants to stop using energy, the next trick is to find alternative, affordable clean energy sources. Surprisingly, there is some good news here:
Stephen Pacala: Renewables now are the cheapest form of electricity on two thirds of the Earth's surface and it's going to be everywhere.
Joseph Berry: The sun is the biggest energy source we've got access to. And if you look at how large that resource is in comparison to what we use, it dwarfs it.
Jereme Kent: There's enough wind energy, if you could capture it, to light the world.
Pacala: Wind and solar are much further ahead than anybody ever thought they would be 10 years ago. They're growing impossibly rapidly.
Narrator: And wind and solar aren’t the only games in town. Nuclear power also produces carbon free energy—though many believe that nuclear is a less safe alternative. There’s also geothermal power. All of these alternatives can contribute to replacing fossil fuels. It is already much cheaper to make electricity without burning fossil fuels. But creating an electric grid that runs on clean energy still presents a challenge: it’s very easy to dial up or down the output of a power plant that runs on, let’s say, natural gas, but not so easy to control how much the sun shines or the wind blows. We'll have to innovate ways to distribute and store energy regardless of the weather. And then, we’ve got to get everything we possibly can to run on that grid!
That might be a tall order for some sectors of our economy. The hydrocarbons from fossil fuels cram a lot of energy into a small package—and that’s crucial for things like airplanes. While electric flights for small commercial planes may be on the horizon, longer-haul flights will need something else. All sorts of innovations are being developed to make jet fuel from renewable sources.
And while energy production is responsible for most of our greenhouse gas emissions, there are a lot of other sources, which can be hard to eliminate. Industrial processes—like the production of cement—also release carbon dioxide as a chemical byproduct. Cement alone accounts for about 8% of annual CO2 emissions.
And then, there are the greenhouse gases that are not carbon dioxide. Methane, Nitrous Oxide, and other molecules like industrial refrigerants account for about 25% of our emissions. So, while preventing further climate change would likely be the cheapest and most straightforward solution, simply switching to all renewable energy won’t be enough. And, because the shift won’t happen overnight, it’s already too late to actually “prevent” more climate change, especially for some populations that are already feeling the effects.
So, in addition to crucial mitigation efforts, we may need other sets of solutions for tackling climate change—ones that might help us “undo” or adapt to some of the damage.
Follow us on social to watch our other episodes that explore these solutions.
Narrated by: Caitlin Saks
Produced by: Ana Aceves
Research & Production: Haley Apicella, Sukee Bennett, Ari Daniel, Robin Kazmier, Christina Monnen, and Caitlin Saks
Science Advisor: Scott Denning
Footage: Storyblocks, NASA, Flikr/oatsy40
Animation: Mitch Butler & UNIT
Sound Effects: Freesound
© 2020 WGBH Educational Foundation