by Bill Gates
Green premium range
9%–15%
16%–29%
75%–140%
Aside from cement, these premiums may not seem like much. And it’s true that in some cases, consumers might not feel any pinch at all. For example, a $30,000 car might contain one ton of steel; whether this steel costs $750 or $950 hardly makes any difference in the overall price of the car. Even for that $2 bottled Coke you bought out of a vending machine the other day, the plastic represents a minuscule share of the overall price.
But the final cost to consumers isn’t the only factor that matters. Suppose you’re an engineer working for the City of Seattle, and you’re reviewing bids to repair one of our many bridges. One bid comes in charging $125 a ton for cement, and another comes in charging $250 a ton, having added on the cost for carbon capture. Which one will you pick? Without some incentive to opt for the zero-carbon cement, you’ll go with the cheaper one.
Or, if you run a car company, will you be willing to spend 25 percent more on all the steel you buy? Probably not, especially if your competitors decide to stick with the cheaper stuff. The fact that the overall price of the car will increase only a tiny bit wouldn’t be much comfort to you. Your margins are already pretty slim, and you’d be unhappy to see the price of one of your most important commodities go up by a quarter. In an industry with narrow profit margins, a 25 percent premium could be the difference between staying in business and going broke.
Although a few manufacturers in a few industries might be willing to bear the cost for the right to say they’re doing their part to fight climate change, at these prices we’ll never drive the kind of system-wide change we need to get to zero. Nor can we count on consumers to drive down the prices by demanding more of these green products. After all, consumers don’t buy cement or steel—large corporations do.
There are different ways to bring the premiums down. One is by using public policies to create demand for clean products—for example, by creating incentives or even requirements to buy zero-carbon cement or steel. Businesses are much more likely to pay the premium for clean materials if the law requires it, their customers demand it, and their competitors are doing it. I’ll cover these incentives in chapters 10 and 11.
But—and this is essential—we need innovation in the manufacturing process, ways to make things without emitting carbon. Let’s look at some of the opportunities.
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Of all the materials I’ve covered in this chapter, cement is the toughest case of all. It’s hard to get around that simple fact—limestone plus heat equals calcium oxide plus carbon dioxide. But a number of companies have good ideas.
One approach is to take recycled carbon dioxide—possibly captured during the process of making cement—and inject it back into the cement before it’s used at the construction site. The company that’s pursuing this idea has several dozen customers already, including Microsoft and McDonald’s; so far it’s only able to reduce emissions by around 10 percent, though it hopes to get to 33 percent eventually. Another, more theoretical approach involves making cement out of seawater and the carbon dioxide captured from power plants. The inventors behind this idea think it could ultimately cut emissions by more than 70 percent.
Yet even if these approaches are successful, they won’t give us 100 percent carbon-free cement. For the foreseeable future, we’ll have to count on carbon capture and—if it becomes practical—direct air capture to grab the carbon emitted when we make cement.
For pretty much all other materials, the first thing we need is plenty of reliable clean electricity. Electricity already accounts for about a quarter of all the energy used by the manufacturing sector worldwide; to power all these industrial processes, we need to both deploy the clean energy technology we already have and develop breakthroughs that let us generate and store lots of zero-carbon electricity inexpensively.
And soon we’ll need even more power, as we pursue another way to reduce emissions: electrification, which is the technique of using electricity instead of fossil fuels for some industrial processes. For example, one very cool approach for steelmaking is to use clean electricity to replace coal. A company I’m following closely has developed a new process called molten oxide electrolysis: Instead of burning iron in a furnace with coke, you pass electricity through a cell that contains a mixture of liquid iron oxide and other ingredients. The electricity causes the iron oxide to break apart, leaving you with the pure iron you need for steel, and pure oxygen as a by-product. No carbon dioxide is produced at all. This technique is promising—it’s similar to a process we’ve been using for more than a century to purify aluminum—but like the other ideas for clean steel it hasn’t yet been proven to work at an industrial scale.
Clean electricity would help us solve another problem too: making plastics. If enough pieces come together, plastics could one day become a carbon sink—a way to remove carbon rather than emit it.
Here’s how we could do it. First, we would need a zero-carbon way to power the refining process. We could do that with clean electricity or with hydrogen produced from clean electricity. Then we’d need a way to get the carbon for our plastics without burning coal. One idea is to remove carbon dioxide from the air and extract the carbon, though that’s an expensive process. Another approach that various companies are working on is to get carbon from plants. Finally, we’d need a zero-carbon source of heat—which would likely also be clean electricity, hydrogen, or natural gas fitted with a device to capture the carbon it emits.
If all these pieces come together, we could make plastics with net-negative emissions. In effect, we’d find a way to take carbon out of the air (using plants or some other method) and put it into a bottle or other plastic product, where it would stay for decades or centuries, with no additional emissions. We’d be socking away more carbon than we were putting out.
Beyond finding ways to make materials with zero emissions, we can simply use less stuff. On its own, recycling more of our steel, cement, and plastic won’t be nearly enough to eliminate greenhouse gas emissions, but it will help. We can recycle more materials and should be exploring new ways to cut the amount of energy needed to recycle stuff. And because reusing something doesn’t require nearly as much energy as recycling it, we should also be looking at ways to build and make things using repurposed materials. Finally, buildings and roads can also be designed with the goal of limiting the use of cement and steel, and in some cases cross-laminated wood—made of layers of timber glued together into a stack—is sturdy enough to substitute for both materials.
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To sum up, the path to zero emissions in manufacturing looks like this:
Electrify every process possible. This is going to take a lot of innovation.
Get that electricity from a power grid that’s been decarbonized. This also will take a lot of innovation.
Use carbon capture to absorb the remaining emissions. And so will this.
Use materials more efficiently. Same.
Get used to this theme. You’ll see it often in the coming chapters. Next up is agriculture, which features one of the great unsung heroes of the 20th century as well as farms full of burping cows.
CHAPTER 6
HOW WE GROW THINGS
19 percent of 51 billion tons a year
Cheeseburgers run in my family. When I was a kid, I’d go on hikes with my Boy Scout troop, and all the guys always wanted to ride home with my dad because he’d stop along the way and treat everyone to burgers. Many years later, in the early days of Microsoft, I scarfed down countless lunches, dinners, and late-night meals at the nearby Burgermaster, one of the Seattle area’s oldest burger chains.
Eventually, after Microsoft became successful but before Melinda and I sta
rted our foundation, my dad started using the Burgermaster near his house as an unofficial office. He’d sit in the restaurant, eating lunch while he sifted through requests we had received from people who were asking for donations. After a while, word got out, and Dad started getting letters addressed to him there: “Bill Gates Sr., in care of Burgermaster.”
Those days are long gone. It’s been two decades since Dad traded in his table at Burgermaster for a desk at our foundation. And although I still love a good cheeseburger, I don’t eat them nearly as often as I used to—because of what I’ve learned about the impact that beef and other meats have on climate change.
Raising animals for food is a major contributor of greenhouse gas emissions; it ranks as the highest contributor in the sector that experts call “agriculture, forestry, and other land use,” which in turn covers a huge range of human activity, from raising animals and growing crops to harvesting trees. This sector also involves a wide range of various greenhouse gases: With agriculture, the main culprit isn’t carbon dioxide but methane—which causes 28 times more warming per molecule than carbon dioxide over the course of a century—and nitrous oxide, which causes 265 times more warming.
All told, each year’s emissions of methane and nitrous oxide are the equivalent of more than 7 billion tons of carbon dioxide, or more than 80 percent of all the greenhouse gases in this ag/forestry/land use sector. Unless we do something to curb these emissions, that number will go up as we grow enough food to feed a global population that’s getting bigger and richer. If we want to get near net-zero emissions, we’re going to have to figure out how to grow plants and raise animals while reducing and eventually eliminating greenhouse gases.
And farming isn’t the only challenge. We’ll also have to do something about deforestation and other uses of land, which together add a net 1.6 billion tons of carbon dioxide to the atmosphere while also destroying essential wildlife habitats.
In keeping with such a wide-ranging subject, this chapter has a bit of everything. I’ll tell you about one of my heroes, a Nobel Peace Prize–winning agronomist who saved a billion people from starvation but whose name is largely unknown outside global-development circles. We’ll also explore the ins and outs of pig manure and cow burps, the chemistry of ammonia, and whether planting trees helps avoid a climate disaster. But before we get to any of that, let’s start with a famous prediction that turned out to be historically wrong.
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In 1968, an American biologist named Paul Ehrlich published a best-selling book called The Population Bomb, in which he painted a grim picture of the future that was not far removed from the dystopian vision of novels like The Hunger Games. “The battle to feed all of humanity is over,” Ehrlich wrote. “In the 1970s and 1980s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now.” Ehrlich also wrote that “India couldn’t possibly feed 200 million more people by 1980.”
None of this came to pass. In the time since The Population Bomb came out, India’s population has grown by more than 800 million people—it’s now more than double what it was in 1968—but India produces more than three times as much wheat and rice as it did back then, and its economy has grown by a factor of 50. Farmers in many other countries throughout Asia and South America have seen similar productivity gains.
As a result, even though the global population is growing, there are not hundreds of millions of people starving to death in India or anywhere else. In fact, food is becoming more affordable, not less. In the United States, the average household spends less of its budget today on food than it did 30 years ago, a trend that’s being repeated in other parts of the world as well.
I’m not saying that malnutrition isn’t a serious problem in some places. It is. In fact, improving nutrition for the world’s poorest is a key priority for Melinda and me. But Ehrlich’s prediction of mass starvation was wrong.
Why? What did Ehrlich and other doomsayers miss?
They didn’t factor in the power of innovation. They didn’t account for people like Norman Borlaug, the brilliant plant scientist who sparked a revolution in agriculture that led to the gains in India and elsewhere. Borlaug did it by developing varieties of wheat with bigger grains and other characteristics that allowed them to provide much more food per acre of land—what farmers call raising the yield. (Borlaug found that as he made the grains bigger, the wheat couldn’t stand up under their weight, so he made the wheat stalks shorter, which is why his varieties are known as semi-dwarf wheat.)
As Borlaug’s semi-dwarf wheat spread around the world, and as other breeders did similar work on corn and rice, yields tripled in most areas. Starvation plummeted, and today Borlaug is widely credited with saving a billion lives. He won the Nobel Peace Prize in 1970, and we’re still feeling the impact of his work: Virtually all the wheat grown on earth is descended from the plants he bred. (One downside of these new varieties is that they need lots of fertilizer to reach their full growth potential, and as we’ll discuss in a later section, fertilizer has some negative side effects.) I love the fact that one of history’s greatest heroes had a job title—agronomist—that most of us have never even heard of.
So what does Norman Borlaug have to do with climate change?
The global population is headed toward 10 billion people by 2100, and we’re going to need more food to feed everyone. Because we’ll have 40 percent more people by the end of the century, it would be natural to think that we’ll need 40 percent more food too, but that’s not the case. We’ll need even more than that.
Here’s why: As people get richer, they eat more calories, and in particular they eat more meat and dairy. And producing meat and dairy will require us to grow even more food. A chicken, for example, has to eat two calories’ worth of grain to give us one calorie of poultry—that is, you have to feed a chicken twice as many calories as you’ll get from the chicken when you eat it. A pig eats three times as many calories as we get when we eat it. For cows, the ratio is highest of all: six calories of feed for every calorie of beef. In other words, the more calories we get from these meat sources, the more plants we need to grow for the meat.
This chart shows you the trends in meat consumption around the world. It’s basically flat in the United States, Europe, Brazil, and Mexico, but it’s climbing rapidly in China and other developing countries.
Here’s the conundrum: We need to produce much more food than we do today, but if we keep producing it with the same methods we use now, it will be a disaster for the climate. Assuming we don’t make any improvements in the amount of food we get per acre of pasture or cropland, growing enough to feed 10 billion people will drive up food-related emissions by two-thirds.
Most countries aren’t consuming more meat than they used to. China, though, is a big exception. (OECD-FAO Agricultural Outlook 2020)
Another concern: If we make a big push to generate energy from plants, we could accidentally spark a competition for cropland. As I’ll describe in chapter 7, advanced biofuels made from things like switchgrass could give us zero-carbon ways to power trucks, ships, and airplanes. But if we grow those crops on land that would otherwise be used to feed a growing population, we could inadvertently drive up food prices, pushing even more people into poverty and malnutrition while accelerating the already dangerous pace of deforestation.
To avoid these traps, we’re going to need more Borlaug-sized breakthroughs in the years ahead. Before we can look at what those breakthroughs might be, though, I want to explain where exactly all these emissions are coming from and explore our options for eliminating them using today’s technology. Just as I did in the previous chapter, I’ll use Green Premiums to show why getting rid of these greenhouse gases is too expensive today, and to make the case that we need some new inventions.
Which brings me to cow burps and pig manure.
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Look inside a person’s stomach and you’ll find just one ch
amber where food starts getting digested before making its way to the intestinal tract. But look inside a cow’s stomach, and you’ll see four chambers. These compartments are what allow the cow to eat grass and other plants that humans can’t digest. In a process called enteric fermentation, bacteria inside the cow’s stomach break down the cellulose in the plant, fermenting it and producing methane as a result. The cow belches away most of the methane, though a little comes out the other end as flatulence.
(By the way, when you get into this subject, you can end up having some weird conversations. Each year, Melinda and I publish an open letter about our work, and in our 2019 letter I decided to write about this problem of enteric fermentation in cattle. One day, as we were going over a draft, Melinda and I had a healthy debate about how many times I could use the word “fart” in the letter. She got me down to one. As the sole author of this book, I have more leeway, and I intend to use it.)
Around the world, there are roughly a billion cattle raised for beef and dairy. The methane they burp and fart out every year has the same warming effect as 2 billion tons of carbon dioxide, accounting for about 4 percent of all global emissions.
Burping and farting natural gas is a problem that’s unique to cows and other ruminants, like sheep, goats, deer, and camels. But there’s another cause of greenhouse gas emissions that’s common to every animal: poop.
When poop decomposes, it releases a mix of powerful greenhouse gases—mostly nitrous oxide, plus some methane, sulfur, and ammonia. About half of poop-related emissions come from pig manure, and the rest from cow manure. There’s so much animal poop that it’s actually the second-biggest cause of emissions in agriculture, behind enteric fermentation.