﻿Okay, when the weather outside is frightful,
what’s a person gotta do to get some delight up in here?
Well, that depends on where and when you live. We humans have harnessed imaginative ways
of heating and cooling our homes throughout the ages.
For centuries, Korean houses stayed toasty with built-in floor warmers. In ancient Persia,
cooling towers called wind-catchers made the desert a bearable place to live.
And today, here at Crash Course Headquarters, comfort is as simple
as turning up the dial on a thermostat. But that convenience comes at a price.
Heating and cooling homes and commercial buildings leads to about 7% of all global carbon dioxide emissions
every year — which doesn’t sound like that much until you realize that that
translates to more than 3.5 billion tons. And those surges of carbon dioxide
are cranking up the thermostat on our planet at unprecedented rates.
As temperatures soar outdoors, one of our biggest challenges will be
rethinking how we manage temperatures indoors—and making reliable, carbon-free
heating and cooling available to everyone.
Hi hi! I'm M Jackson and this is Crash Course Climate and Energy.
[INTRO]
When I pump up the heat in our studio, I’m tapping into a resource hundreds of
millions of years in the making: natural gas. As a fossil fuel, it’s derived from decomposed
plants and creatures that lived before the dinosaurs, like these cuties. I like to imagine
I owe my piping-hot bubble bath to them. But natural gas consists mostly of methane,
one of the notorious greenhouse gases. And our means of extracting methane
contributes to climate change, contaminates water, and can even cause earthquakes.
I’m talking about fracking. No, not the PG-version of a cuss, hollered
when you stub your toe in front of your parents. Fracking is a way of extracting natural gas or
crude oil from deep below Earth’s surface. It uses high-pressure drilling and fluid to
fracture underground rocks — hence the “frack” — and releases the gas within.
But it also has some big side-effects. Notably, in 2003, a new fracking method
burst onto the scene, just as the U.S. natural gas supply was declining.
By using mostly water instead of expensive gels, and drilling not just down but also horizontally,
this new method made it possible to extract more natural gas than ever before,
and more cheaply, from rock called shale. The fracking boom boosted the U.S. economy.
Extracting gas within U.S. borders instead of importing it helped create 2.8 million jobs
and generate trillions of dollars in revenue. Sounds like a net positive, right! Ah, if only.
The downside is that extracting natural gas from shale is messy. Some methane
inevitably escapes into the atmosphere. It’d be like if whenever you sipped soda
from a straw, some of it came out the side of your mouth. Except here that soda is methane.
This greenhouse gas traps 80 times as much heat as carbon dioxide in its
first 20 years of entering the atmosphere. Global methane levels have spiked since 2007.
The fracking boom, which has since spread beyond the U.S., is a prime suspect in that who-dun-it.
Another problem? Used-up fracking wells keep releasing methane even if they don’t
get plugged up, which costs millions of dollars, and doesn’t always happen.
To make matters even worse, pipelines transporting oil and natural gas from fracking sites leak,
which can threaten nearby communities. For instance, the Standing Rock Sioux Tribe
protested the construction of the Dakota Access pipeline which was built in 2017,
and today runs directly beneath one of the Reservation’s main water sources.
So, overall, natural gas is a major — and majorly complicated — energy source.
But it will also likely play a big part in decarbonizing energy worldwide.
Burning natural gas actually releases significantly less
carbon than burning other fossil fuels. And burning it to generate
electricity or heat makes less air pollution than something like coal.
It also releases fewer pollutants like nitrogen and sulfur oxides — pollutants
that contribute to unhealthy air quality, and form smog and acid rain.
But not everybody has the luxury of clean air and lower-pollution energy.
Billions of people in low-income countries don’t have access to natural gas.
So, they depend on high-polluting, solid fuels to heat their homes and cook dinner, such as coal
or biomass. Biomass includes materials such as charcoal, or wood, or dung from livestock.
These solid fuels release harmful chemicals when burned, including the nitrogen and sulfur oxides
that make smog. And they contribute to four million indoor air pollution-related deaths
each year. Let’s head to the Thought Bubble… Take a wintertime stroll through Ulaanbaatar,
the capital city of Mongolia, and you’ll notice the chill doesn’t just nip at your nose. It mauls it,
with an average January temperature of -20 degrees Celsius. Oooh, delightful. I love the cold.
But before your nose goes numb, you’ll notice the sting in your throat. A thick smog hangs
over the city, trapped at ground level by cold winter air and surrounding mountains.
That smog is full of teeny-tiny
soot particles called PM2.5. These tiniest of polluting particles are 30 times smaller in
diameter than a single strand of human hair. But they pack a mean punch. When someone
breathes them in and these particles get lodged deep in the lungs and bloodstream,
they can cause pneumonia and bronchitis. And Ulaanbaatar’s air can carry 20 times
more of these particles than what’s considered safe to breathe.
Coal is to blame here—Mongolia’s main energy source. For many households, directly burning
coal is the only way to survive winter. And coal fuels 85% of the country’s power production,
so even electricity runs on it. Ultimately, Ulaanbaatar finds
itself in a coal-reliant cycle. Demand for coal drives more coal mining,
which sucks up groundwater and dries grasslands to a crisp.
As grasslands disappear, nomads are pushed to the city. And there,
they join the masses dependent on coal to stay warm—which drives more demand for more coal.
Thanks Thought Bubble!
Stuck in a loop like this, breaking up with coal won’t be easy. Even replacing coal stoves with
coal-fueled electricity just pushes the problem farther up the hill. Like passing
a sizzling ember from one hand to another. Ow. When it comes to reducing
carbon emissions and making our world a cleaner place for everyone, the situation
is messy, and heating is no exception. Increasing access to natural gas might help
Ulaanbaatar and other cities like it, but it’s still a very complicated solution.
And as long as electricity runs on coal, bringing electric heaters to more people won’t be enough
to see cities like this out of the smog—or to see our planet out of rising emissions.
Renewable energy, like solar or wind power, would definitely help with this. But there’s
still another side of the equation we haven’t talked about yet: cooling.
Quick: guess what’s on track to be the most energy-consuming appliance in my house?
Based on my current rate of waffle consumption, it feels like it should be my waffle-maker.
But actually, it’s my air conditioner. Back to my love of frigid temperatures.
Air conditioners are heavy electricity consumers, and it’s mostly fossil
fuels powering that electricity. Air conditioners also have a nasty
way of releasing hydrofluorocarbons, one of the greenhouse gases with the longest name and the
most powerful global warming abilities. But we can’t just ditch the AC altogether:
As the climate warms, the need for air-conditioning rises, too.
Billions of people are facing global warming’s deadliest effects, including more frequent,
severe heat waves. To some, air-conditioning becomes a life-or-death necessity.
The problem is, it’s a necessity that millions of people can’t afford,
so it’s also an issue of justice and equity. And to make things more complicated,
the same air-conditioning that helps people survive blazing heat also exacerbates those
conditions in the first place. But it doesn’t have to be that way.
One thing governments can do is raise the minimum efficiency requirements for appliances, so that
any new AC unit has to meet a certain standard. Moving away from hydrofluorocarbons, and towards
refrigerants with lower greenhouse warming potential, would also help reduce emissions.
And in fact, almost 200 countries have already pledged to decrease the amount
of hydrofluorocarbons they use 80% by 2047. Besides improving existing air conditioner designs
and scaling up carbon-free electricity sources, another option to cool our homes is to ditch AC units
altogether and consider other technologies. And as a big bonus, these solutions could help us
with decarbonizing heating, too, and even help us move away from natural gas.
Take the heat pump. Heat pumps use the same basic mechanism of an air conditioner.
When it’s warm out, both heat pumps and AC units use heat-absorbing liquids called refrigerants to
move heat outside, so your bedroom stays cool. But heat pumps can also do the opposite.
In the winter, they can bring in heat from the cold air outdoors to keep your home warm.
That might sound weird: I know when I’m out waiting for the bus in January, here in the
Northern Hemisphere, my first thought isn’t, “Oh, there’s so much heat in the air right now.”
But for as cold as winter is, the refrigerant in a heat pump is even colder. It can get down
to -50 degrees Celsius depending on the model. So, the refrigerant absorbs and concentrates the
little bit of heat lingering in the snowy air, which turns it into a gas. This refrigerant gas
is then brought inside and pressurized into a warmer gas so that it can transfer the sweet,
sweet warmth of the air in your house. When powered by carbon-free electricity,
heat pumps emit almost no greenhouse gases. And they can even have a negative Green Premium.
That’s the cost difference between an energy source
that releases carbon and one that doesn’t. A negative premium means that, in some places,
it’s already cheaper in the long run to install a heat pump than to run a natural gas furnace.
That said, one barrier to heat pumps is that AC units and natural gas furnaces last a long time.
It’s up to individual homeowners and building developers to install heat pumps in the first place.
And if my very expensive furnace was still kicking, it would be hard for
me to get excited about forking over the cash to replace it with a heat pump.
Government tax incentives and loosening building codes could be one way of
encouraging more people to make the switch. But a third path to decarbonization is to
work with the systems we’ve got—and find new ways of powering them.
And for heating in particular, there are lots of options.
My favorite? Trash. Now, unless you’re me or a racoon, it might seem like not much good can
come out of a steaming pile of trash. But the trash heaps in our landfills
already release gas as they decompose. And that gas can be captured, converted,
and become a low-emission replacement for natural gas in our existing furnaces.
Renewable “drop-in” fuels can also help taper off emissions.
These are basically fossil fuel substitutes made from renewable materials, and they can step in
for natural gas in our heating systems. For example, second-generation biofuels
can be made from non-edible crops that are already being produced alongside our food,
such as straw and corn husks. Meanwhile, electrofuels go a step
further by not requiring crops at all. They’re made by capturing carbon dioxide
and mixing it with the hydrogen from water molecules to create some of
the same molecules found in fossil fuels. Since electrofuels are made of hydrocarbons
just like traditional fossil fuels, burning them would release carbon dioxide. But because that
carbon was just captured from the atmosphere or from a fossil fuel power plant, we wouldn’t be
adding any new emissions to the atmosphere. Then there’s the challenge of that pesky Green Premium.
These drop-in fuels can also carry a high upfront cost compared to fossil fuel energy.
By offering a renewable alternative, they can help us reduce emissions as we wean our heating
systems off the fuels they were built for. Humans have devised ingenious ways of keeping
warm and staying cool, everywhere from the Arctic Circle to the Mojave Desert. Unfortunately,
some of those energy choices have helped bring us to our current mess: the climate crisis.
But that same ingenuity can help us tackle the road ahead.
It won’t be easy to decarbonize heating and cooling. It will involve reducing the
emissions of existing systems, while also working to create better ones.
But in the long run, electrifying heating and cooling will be critical to reducing air
pollution and lowering greenhouse gas emissions. Achieving carbon-free heating and cooling won’t be
the only challenge. It’ll also be critical to make it available to everyone on the planet.
The way we manage the temperature indoors matters a lot. And,
as we’ll find out next time, so does the way we — and our stuff — get from place to place.
Special thanks to Eric Prestemon, this episode’s thermostat monitor.
Eric, thanks for keeping an eagle eye on that dial, and always turning the heat down when we leave
the studio—very energy conscious of you. And thanks for being a supporter 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 the 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.