How to Avoid a Climate Disaster: The Solutions We Have and the Breakthroughs We Need

by Bill Gates

Fifty-one billion is how many tons of greenhouse gases the world typically adds to the atmosphere every year.

The world needs to provide more energy so the poorest can thrive, but we need to provide that energy without releasing any more greenhouse gases.

making electricity accounts for only 27 percent of all greenhouse gas emissions. Even if we had a huge breakthrough in batteries, we would still need to get rid of the other 73 percent.

Within a few years, I had become convinced of three things: To avoid a climate disaster, we have to get to zero. We need to deploy the tools we already have, like solar and wind, faster and smarter. And we need to create and roll out breakthrough technologies that can take us the rest of the way.

The only solution I could imagine was to make clean energy so cheap that every country would choose it over fossil fuels.

This small decline in emissions is proof that we cannot get to zero emissions simply—or even mostly—by flying and driving less.

We’ve already raised the temperature at least 1 degree Celsius since preindustrial times, and if we don’t reduce emissions, we’ll probably have between 1.5 and 3 degrees Celsius of warming by mid-century, and between 4 and 8 degrees Celsius by the end of the century.

According to research cited by the IPCC, a rise of 2 degrees Celsius would cut the geographic range of vertebrates by 8 percent, plants by 16 percent, and insects by 18 percent.

Where the emissions are. Emissions from advanced economies like the United States and Europe have stayed pretty flat or even dropped, but many developing countries are growing fast. That’s partly because richer countries have outsourced emissions-heavy manufacturing to poorer ones. (UN Population Division; Rhodium Group)

nearly 40 percent of the world’s emissions are produced by the richest 16 percent of the population.

the first Model T that rolled off Henry Ford’s production line in 1908 got no better than 21 miles to the gallon. As I write this, the top hybrid on the market gets 58 miles to the gallon. In more than a century, fuel economy has improved by less than a factor of three.

When crystalline silicon solar cells were introduced in the 1970s, they converted about 15 percent of the sunlight that hit them into electricity. Today they convert around 25 percent. That’s good progress, but it’s hardly in line with Moore’s Law.

1. How Much of the 51 Billion Tons Are We Talking About?

Tip: Whenever you see some number of tons of greenhouse gases, convert it to a percentage of 51 billion, which is the world’s current yearly total emissions (in carbon dioxide equivalents).

2. What’s Your Plan for Cement?

Passenger cars represent less than half of all the emissions from transportation, which in turn is 16 percent of all emissions worldwide.

making steel and cement alone accounts for around 10 percent of all emissions.

How much greenhouse gas is emitted by the things we do? Making things (cement, steel, plastic) 31% Plugging in (electricity) 27% Growing things (plants, animals) 19% Getting around (planes, trucks, cargo ships) 16% Keeping warm and cool (heating, cooling, refrigeration) 7%

Tip: Remember that emissions come from five different activities, and we need solutions in all of them.

3. How Much Power Are We Talking About?

How much power does it take? The world 5,000 gigawatts The United States 1,000 gigawatts Mid-size city 1 gigawatt Small town 1 megawatt Average American house 1 kilowatt

Tip: Whenever you hear “kilowatt,” think “house.” “Gigawatt,” think “city.” A hundred or more gigawatts, think “big country.”

4. How Much Space Do You Need?

How much power can we generate per square meter? Energy source Watts per square meter Fossil fuels 500–10,000 Nuclear 500–1,000 Solar* 5–20 Hydropower (dams) 5–50 Wind 1–2 Wood and other biomass Less than 1

5. How Much Is This Going to Cost?

Here’s a summary of all five tips: Convert tons of emissions to a percentage of 51 billion. Remember that we need to find solutions for all five activities that emissions come from: making things, plugging in, growing things, getting around, and keeping cool and warm. Kilowatt = house. Gigawatt = mid-size city. Hundreds of gigawatts = big, rich country. Consider how much space you’re going to need. Keep the Green Premiums in mind and ask whether they’re low enough for middle-income countries to pay.

Literally: In the United States, leaving a 40-watt lightbulb turned on for an hour costs you about half of one cent.

figuring out how to get all the benefits of cheap, reliable electricity without emitting greenhouse gases is the single most important thing we must do to avoid a climate disaster. That’s partly because producing electricity is a major contributor to climate change, and also because, if we get zero-carbon electricity, we can use it to help decarbonize lots of other activities, like how we get around and how we make things. The energy we give up by not using coal, natural gas, and oil has to come from somewhere, and mostly it will come from clean electricity.

Getting all the world’s electricity from clean sources won’t be easy. Today, fossil fuels account for two-thirds of all electricity generated worldwide. (bp Statistical Review of World Energy 2020)

The share of global power that comes from burning coal (roughly 40 percent) hasn’t changed in 30 years. Oil and natural gas together have been hovering around 26 percent for three decades. All told, fossil fuels provide two-thirds of the world’s electricity. Solar and wind, meanwhile, account for 7 percent.

The typical U.S. household uses 29 kilowatt-hours a day.

(Capacity measures how much electricity we’re theoretically capable of producing when the sun is shining its brightest or the wind is blowing its hardest; generation is how much we actually get, after accounting for intermittency, shutting down power plants for maintenance, and other factors. Generation is always smaller than capacity, and in the case of variable sources like solar and wind it can be a lot smaller.)

How much stuff does it take to build and run a power plant? That depends on the type of plant. Nuclear is the most efficient, using much less material per unit of electricity generated than other sources do. (U.S. Department of Energy)

Making 1 ton of steel produces about 1.8 tons of carbon dioxide.

We emit greenhouse gases (1) when we use fossil fuels to generate the electricity that factories need to run their operations; (2) when we use them to generate heat needed for different manufacturing processes, like melting iron ore to make steel; and (3) when we actually make these materials, like the way cement manufacturing inevitably creates carbon dioxide.

Green Premiums for plastics, steel, and cement Material Ethylene (plastic) Steel Cement Average price per ton $1,000 $750 $125 Carbon emitted per ton of material made 1.3 tons 1.8 tons 1 ton New price after carbon capture $1,087–$1,155 $871–$964 $219–$300 Green premium range 9%–15% 16%–29% 75%–140%

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.

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.

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.

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.

According to the World Bank, the world has lost more than half a million square miles of forest cover since 1990. (That’s an area bigger than South Africa or Peru, and a decline of roughly 3 percent.)

Taking all these factors into account, the math suggests you’d need somewhere around 50 acres’ worth of trees, planted in tropical areas, to absorb the emissions produced by an average American in her lifetime. Multiply that by the population of the United States, and you get more than 16 billion acres, or 25 million square miles, roughly half the landmass of the world. Those trees would have to be maintained forever. And that’s just for the United States—we haven’t accounted for any other country’s emissions.

Although transportation isn’t the biggest cause of emissions worldwide, it is number one in the United States, and it has been for a few years now, just ahead of making electricity.

8.2 billion tons of carbon we produce from transportation today;

Maritime shipping now handles nine-tenths of the goods traded around the world by volume, producing nearly 3 percent of global emissions.

Cars aren’t the only culprit. Passenger vehicles are responsible for nearly half of all transportation-related emissions. (International Council on Clean Transportation)

There are about a billion cars on the road around the world.

Green Premium to replace gasoline with advanced biofuels Fuel type: Gasoline Retail price per gallon $2.43 Zero-carbon option per gallon $5.00 (advanced biofuels) Green Premium 106%

Green Premium to replace gasoline with zero-carbon alternatives Fuel type: Gasoline Retail price per gallon $2.43 $5.00 (advanced biofuels) Zero-carbon option per gallon $2.43 $8.20 (electrofuels) Green Premium 106% 237%