In a typical year, humans are pumping about 51 billion tons of carbon dioxide and other greenhouse gases into the atmosphere — at least, that’s what’s typical at the time we’re making this episode, in 2022.

It’s tricky to imagine what a billion tons of anything looks like. But to give you a sense of scale, this is equivalent to about 8,500 Great Pyramids of Giza or 150,000 Empire State Buildings.

But carbon dioxide is a lot more…airy… than your average Egyptian pyramid, so our emissions take up quite a bit more space. Every year, that mass of gas amounts to about 26 quadrillion liters, enough to fill up the Grand Canyon six times over. The carbon dioxide we’re pumping into the atmosphere is causing unprecedented climate change.

But why do we release so much carbon into the atmosphere? And how easy will it be to change our ways? Hi hi! I’m M Jackson and this is Crash Course Climate and Energy. [INTRO]

In the latter half of the 18th century, Scottish engineer James Watt made some improvements to the design of a coal-powered steam engine. He hoped that his new engine would make it more efficient to pump water out of the bottom of deep coal mines, but it ended up doing a lot more than that. Watt developed the first modern steam engine.

And it set us on course for the Industrial Revolution. After a couple hundred thousand years of doing things by hand or with animals, in just a few decades, we switched to doing pretty much everything with the help of machines. This transition ultimately relied on energy-rich fuels — specifically coal, oil, and natural gas. These collectively are known as fossil fuels, because they form much like fossils do. The story of fossil fuels goes like this.

Once upon a time, some plants or algae died, as they tend to. But instead of decaying away, their carbon-rich bodies were trapped inside sediments that later became rock. Then, over millions of years, those rocks were heated and squeezed by geologic processes, transforming the remnants of those plants and algae into huge, unrecognizable reservoirs of carbon-rich material. Imagine: a disgusting underground soup.

And today, when you fire up your gas stove for mac ‘n’ cheese or hop on a bus, some of that prehistoric material is burned to power your life. Take that in for a second. On a daily basis, you are interacting with matter that’s older than dinosaurs. Rawr!

You’re just the latest in a long line of humans to tap into these reservoirs. We’ve been using fossil carbon as a fuel source since as early as Roman times, when coal was used to heat public baths. That’s because fossil fuels are much more energy dense than the alternatives, meaning they pack a lot more bang for their buck than things like wood or charcoal.

Around the mid-1700s, when engineers figured out how to use all that ‘bang’ to make our lives easier, things got really interesting. The key was to transform the chemical energy tied up in fossil fuels into mechanical energy that could physically move and power machines.

For example, engines do this by burning fuel to turn chemical energy into heat energy. That heat energy is then used to boil water and make steam, which is trapped in a pressurized container. But as that steam is released, it has the power to push a piston, or turn a turbine, creating movement that can power a pump, a wheel, or the entire Industrial Revolution.

That new technology transformed manufacturing, agriculture, and transportation, making it all faster and more efficient, fundamentally reshaping the way we live, work, and play.

And now, these fuels are everywhere. Coal is burned in power plants, diesel runs trucks and trains, natural gas heats homes and businesses, and fossil fuels are even processed to make plastic, used in everything from your toothbrush to your smartphone.

And after seeing how powerful these fuels could be, governments made policies to encourage their use and keep them affordable. But this 260-year love affair with fossilized carbon has come at great cost. Burning these fuels releases carbon dioxide into the atmosphere, and over time, that gas has built up.

Now, it’s helping to trap heat close to Earth’s surface via the greenhouse effect, causing the planet to warm and the climate to change at an unprecedented rate. If we want to slow that rate, and reduce the impacts of climate change, we need to stop releasing so much carbon dioxide. And that means it’s time to break up with fossil fuels.

But even that won’t be easy. In fact, it’s probably going to be one of the messiest breakups of all time. Almost as messy as when Dean left Rory in the middle of the Star's Hollow Dance Marathon. I’m sorry. I just get emotional every time.

Pretty much everything we do ends up releasing carbon dioxide and other greenhouse gases into the atmosphere. Our carbon-emitting habits can be broken down in a number of different ways. If you break out ye olde Google to try to figure out which large-scale human activities contribute to climate change the most, you’ll usually find variations of roughly the same five categories: industry or manufacturing, transportation, electricity, energy use in commercial or residential buildings — aka heating or cooling— and then agriculture. But then you’ll be like — wait, what?

Because across different sources, you’ll see different-sized slices representing how much each of these sectors actually contribute to the global emissions pie. That’s because — well, everything is kind of connected.

For example, we release greenhouse gases when driving our cars, but we also release them when refining the oil into the fuel they use, or when producing the steel they are made of. So, it depends on whether a source is counting all of those emissions towards the transportation slice of the pie — or if it’s counting the steel production and oil-refining parts in a separate manufacturing slice.

For this series, we usually do the latter — try to separate energy that’s used for the purpose of making stuff from the energy that is used for the purpose of getting around. And by that count, making stuff is the biggest category.
Post-industrial materials like steel, concrete, and plastic all have to be heavily processed, and we use so much of them that they account for around 30% of global greenhouse emissions annually.

Next, accounting for about 26% of global emissions, is our thirst for electricity. Lights, appliances, industrial machinery, the internet all rely on a constant flow of electricity, two-thirds of which is still generated by fossil fuels.

Meanwhile, 21% of our emissions come from growing things. The agricultural industry is responsible for the plants and animals we eat, and the plants and animals they eat, and the plants we grow for other purposes, like clothes and paper. And although plants do take carbon dioxide out of the atmosphere, they are outmatched by the land clearance involved in agriculture, and even more so by fertilizers and machinery that rely heavily on fossil fuels.
Are we there yet? Not quite. We’ve still got the transportation industry, which is responsible for about 16% of global emissions. That includes one billion passenger cars. Plus: planes, trucks, trains, and ships in the global trade and transport network.

And finally, 7% of emissions come from heating and cooling our buildings.

The point is, fossil fuel use and greenhouse gas emissions are inescapable to some degree. They’re entangled in so many more stages of so many more of our modern systems than we often stop to think about.

The bright side? If we can learn to decarbonize our energy sources, it will have impacts across all of these industries, and more. Take something as simple as ordering a new cotton T-shirt from an online retailer, which we’ll do in the Thought Bubble.

By ordering online, one less physical storefront needs to be built, lit, or heated, so that’s a start. But your computer and the internet do rely on consistent electricity, which releases greenhouse gases.

Also, the T-shirt you ordered is made from cotton, which was grown on land that’s cleared of its natural vegetation, plus fertilized, planted, and harvested. To do any of that planting, fertilizing, and harvesting, you need processes and equipment.

And then, at the factory, your shirt is spun, sewn, and packaged with the help of steel machinery and plastic materials. In an ideal world, the factory and storage warehouses will also be cooled and heated, to keep workers at a comfortable temperature.

Finally, when it’s ready, the T-shirt will be shipped to your door, via cargo ship, plane, or truck. And with all of these steps: more greenhouse gases. Then, if you ship the shirt back because you got the wrong size or don’t like the color, even more gases are emitted.

It doesn’t end there, either. In a few years, when your T-shirt, or your amazing fringe jacket goes out of style, they’ll end up in landfill where they’ll slowly decompose, releasing greenhouse gases long after you’ve forgotten about them. Thanks, Thought Bubble!

Thought I lost this – it’s a keeper! All in all, the fashion industry releases the equivalent of roughly a billion metric tons of carbon dioxide every year. Hearing stories like this, I know, can make you feel kind of guilty. “I released all those greenhouse gases and all I got was this lousy t-shirt" (or fringe jacket).

And while it can make an impact to shop second-hand, what this story shows us is how climate change is simultaneously about you and so much more than you. Altering the systems involved in fast fashion, which operate on a global scale, will require massive human collaboration. And of course, it’s not just about fashion.

When you add up emission sources from industries all around the world, it’s not hard to see how we’ve made it to 51 billion tons of greenhouse gases per year. And many of these industries put out a lot of good into the world, including manufacturing and industrial agriculture. But, if we stand any chance of reducing the greenhouse gases we put out, we’ll need to decarbonize every one of these major emissions sectors.

That means finding a way to do these things without emitting carbon dioxide. Essentially, we’re talking about another Industrial Revolution, to overhaul how we power our lives. Now, some industries will be easier to decarbonize than others.

For example, the technology to decarbonize electricity is already getting there. It’s why you might see solar panels on the side of the highway, or wind turbines in a field. It’s now a question of making this tech affordable and accessible to everyone, plus solving problems of storage and availability — which we’re gonna talk about more about in the next few episodes.

But other industries will be a lot harder, like the production of cement and concrete. These materials are made by breaking up limestone rock with heat, a process which unavoidably releases carbon dioxide. And we don’t currently have an acceptable substitute for these materials.

An additional challenge is that emissions are a global problem that will need a global solution. Right now, the amount of energy a country uses is very closely linked to its economic wealth. For instance, nations like the US, Canada, and the UK have strong, modern economies that take a lot of energy to sustain.

But they can afford to invest in the infrastructure to make that happen. So they’re also more likely to have the cash to fund more expensive, low-carbon solutions.

But there are still some parts of the world that can’t fund basic access to energy, let alone low-carbon solutions. That means people can’t light or cool their homes, power appliances and computers, or refrigerate food and medicines. At the same time, many of these countries’ populations are growing, increasing the demand for energy, even while the supply is unreliable. More people also means we need more buildings, which means we need more concrete and more steel. Except, the cheapest and quickest way to get that energy and make those building supplies is to use tried and tested, carbon-heavy technologies.

So, many scholars and political leaders argue that the responsibility to decarbonize ultimately falls on the shoulders of those higher-income countries. This requires developing new materials, new processes, and new technologies to curtail greenhouse gas emissions.
When wealthy countries invest in decarbonized technologies, they become more efficient and less expensive for the rest of the world. That could lead to a drop in emissions worldwide, which would help reduce some of the effects of climate change. But if you’ve ever tried to split the bill at a restaurant, you know this is a complicated situation.

Figuring out how much each country should be responsible for reducing emissions, and who is accountable, is an ongoing international challenge. Especially because the higher-income countries that are best poised to lead the charge are the same ones that benefit the most from the fossil-fuel-powered global economy. And in general, we humans have a really hard time accepting short-term economic losses in place of long-term environmental gain.

Remember, we are interacting daily with fossilized carbon from millions of years ago. But we’re often thinking in terms of the next few minutes, the next election, or in my case – the next meal. But this short-term vision, and the short-term policies that sometimes go with it, won’t help us in the long run.

Lower-income countries will certainly feel the worst effects of climate change sooner. But no one is immune to changes happening on a global level. After all, we’re all on the same Earth.

Overall, scientists agree that we have to do something and soon. This won’t be easy, and it certainly won’t happen overnight, but we have to start somewhere. And to help address nearly a third of all of our emissions, decarbonizing electricity might be the first step. But we’ll get more into that in the next episode.

Special thanks to Ben Massengale, our steam engine conductor for this episode. Ben, thanks for keeping us chugging along and helping millions of other learners join the ride too, by supporting us on Patreon.

Crash Course Climate and Energy is produced by Complexly with support provided by Breakthrough Energy and Gates Ventures. This episode was filmed at Castle Geraghty Studio and was made with the help of all these nice people. If you want to help keep Crash Course free for everyone, forever, you can join our community on Patreon.