How to Avoid a Climate Disaster

by Bill Gates
11 min read

As someone who isn’t well-versed in climate change, I felt that this book gave me a solid understanding of the topic. It gave a comprehensive overview of the different ways we currently add carbon to the atmosphere, the different ways we can tackle the problem (through innovation), and a little bit on climate policy as well. I like his emphasis on the fact that it’s developing countries that will be hurt the most by a climate disaster, as I think it’s a fact that people in most “rich” countries often forget or disregard altogether.

This book also presents a very optimistic view on us actually being able to tackle climate change, which I guess is not that surprising considering his success with Microsoft and his belief in the power of innovation. I definitely finished this book feeling more optimistic about this issue.

The book did feel a little repetitive towards the end, and it was annoying in some parts to keep hearing about how he invests in all these green companies, etc., so I would say it’s more of a 4.5/5 for me. I’m also aware of all the “controversy” around this book, but I think Jenna’s review on Goodreads summarizes how I feel pretty well.

🥵 The Basics: What is a greenhouse gas?

A greenhouse gas is a type of gas that absorbs heat and traps it in the atmosphere. This phenomenon known as the greenhouse effect is natural and essential to supporting life on earth, however, the burning of fossil fuels, deforestation, and other human activities have intensified the greenhouse effect and led to global warming.

There are multiple greenhouse gases (carbon dioxide, methane, nitrous oxide, and F-gases), but most people combine them all into a single measure known as “carbon dioxide equivalents” (CO₂e). It’s not a perfect measure, because some gases trap more heat than carbon dioxide, but it’s the best method we currently have for counting emissions.

The world’s annual emissions currently stands at 51 billion tons of CO₂e. Here’s roughly what the spread looks like across different activities we do:

ActivityPercentage of global emissions
Making things (cement, steel, plastic)31%
Growing food19%
Transportation of humans and goods16%
Keeping warm and cool7%

🤔 Why do we need to get to zero emissions?

The climate is like a bathtub that’s slowly filling up with water. Even if we slow the flow of water to a trickle, the tub will eventually fill up and water will come spilling out onto the floor. The only way to stop the water from spilling is by stopping the flow of water. The same applies to the climate; unless we stop adding greenhouse gases to the atmosphere, the temperature will keep going up.

In fact, we may even need to reach net negative emissions. To avoid the worst climate scenarios, at some point we’ll not only need to stop adding more gases but actually need to start removing some of the gases we have already emitted. To go back to the bathtub analogy, we won’t just stop the flow of water into the tub. We’ll open up the drain and let water flow out too.

🌏 The global impact

Yes, climate change is bad. But the cruelest part of it all is that even though the world’s poor are doing essentially nothing to cause climate change, they will be the ones to suffer the most from it. Nearly 40% of the world’s emissions are produced by the richest 16% of the population on earth, yet it’s the poorest that will suffer the most.

A warmer climate could lead to a public health crisis. One study found that the number of additional heat-related deaths could approach 10 million each year by the end of the century. As the climate gets warmer, droughts and floods will become more frequent, wiping out harvests more often. Livestock will eat less and produce less meat and milk. The air and soil will lose moisture, leaving less water available for plants (and humans). As food becomes less available, more kids won’t get the nutrients they need, weakening their bodies’ natural defenses and making them much more likely to die of diarrhea, malaria, or pneumonia.

🙋 Bill’s 5 Questions to Ask in Every Climate Conversation

As someone who is only starting to learn about climate change, something I often struggle with when reading articles about new renewable energy innovations is context setting. I found Bill’s 5 Questions really helpful, and will definitely use this going forward.

  1. How much of the 51 billion tons are we talking about? 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? Innovations like electric cars often steal the headlines, so it’s easy to forget that emissions come from various other activities (including building stuff, e.g. using cement), and we need solutions for all of them.
  3. How much power are we talking about? How much energy will this actually produce? Will this be enough to power a house? A city? A country?
  4. How much space do you need? It’s important to consider power density (i.e., how much power you can get from different sources for a given amount of land). If someone tells you that some source of electricity can supply all the energy the world needs, find out how much space will be required to produce that much energy.
  5. How much is this going to cost? Most zero-carbon solutions are more expensive than their fossil-fuel counterparts. The additional cost of an energy alternative compared to fossil fuel is known as a green premium. When you hear about a new energy source, keep green premiums in mind and ask whether middle-income countries can afford them.

⚡️ What do we do about electricity? (27% of emissions)

Electricity has become extraordinarily cheap. In fact, it’s at least 200x more affordable in the year 2000 than 1900. Electricity is so cheap because fossil fuels are cheap, and fossil fuels are cheap because of the following reasons:

  1. They’re widely available
  2. We’ve developed better and more efficient ways to extract them and turn them into electricity
  3. Governments also go to considerable effort to keep the prices of fossil fuels low and encourage their production (e.g. through tariffs, tax exemptions, etc.). In fact, the International Energy Agency (IEA) estimates that government subsidies for the consumption of fossil fuels amounted to $400 billion in 2018 alone
  4. Last but not least, the price of fossil fuels don’t reflect the environmental damage they inflict (which in turn causes economic damage from all the effects of a warmer climate), so they seem cheaper than the alternative. Here’s an interesting fact: oil is cheaper than a soft drink! Oil costs about $1 per gallon while you’ll have to pay $2.85 per gallon for soft drink from Costco

Fossil fuels currently account for two-thirds of the world’s electricity, so in order to get to zero emissions here we need to start using alternative fuels. Thankfully, the green premium (at least for the US) are not too bad. Changing the US’ entire electricity system to zero-carbon sources would raise average retail rates by 1.3 - 1.7 cents per kilowatt-hour, which is 15% more than what most people pay now. This adds up to a Green Premium of $18/month for the average home. Europe’s green premium is also pretty low, about 20% more.

One thing that makes this problem even harder is that we demand reliability from electricity. Two of the most popular sources of renewable energy available now (wind and solar) are intermittent resources, so we’ll either need to store excess electricity in batteries, or add in other energy sources. Unfortunately, battery technology haven’t advanced enough to fix our problems. There are two factors that matter the most here: 1) the cost of batteries, and 2) how long it’ll last before we have to replace it.

One of the things that will certainly need to improve is the grid system in the US. We’ll need to build a unified national grid so that we can ship carbon-free electricity wherever they’re needed from places that have more reliable sources of renewable energy.

🔌 How can we make carbon-free electricity?

Nuclear fission

Nuclear power is the only carbon-free energy source that can reliably deliver power day and night, through every season, almost everywhere on earth, that has been proven to work on a large scale. Unfortunately, there have been a few high-profile nuclear power related accidents that have put people off nuclear as a power source. This is ridiculous though, because extracting electricity from nuclear power is actually one of the safest options! If you’re counting the number of deaths caused per unit of electricity, coal is much more dangerous than nuclear (~351x more dangerous).

Nuclear fusion

Where nuclear fission is the process of getting energy by splitting atoms apart, nuclear fusion involves pushing them together.

This technology is promising, but still at least a decade away from supplying electricity to consumers.

Offshore wind

This process involves putting wind turbines in an ocean or other body of water. It can be advantageous because many major cities are near the coast, so we can generate electricity much closer to where it’s needed and not have to worry so much about challenges with transmission.


Deep underground there are very hot rocks. We can generate electricity by pumping water at high pressure into the rocks, where it absorbs the heat and then comes out another hole, where it turns a turbine. Unfortunately the energy density is quite low. It’s estimated that it can only help supply <2% of the UK’s energy.

🏗 What do we do about how we build things? (31% of emissions)

When we build things, we emit carbon into the atmosphere for the following reasons:

  1. When we use fossil fuels to generate the electricity that factories need to run their operations
  2. When we use fossil fuels to generate heat needed for different manufacturing processes, e.g. melting iron ore to make steel
  3. When we actually make these materials, e.g. the way manufacturing cement inevitably releases CO₂ into the atmosphere.

Currently, these are the things we need to do in order to reach zero emissions in manufacturing:

  1. Electrify every process possible
  2. Get that electricity from a power grid that’s been decarbonized
  3. Use carbon capture to absorb the remaining emissions (this is where we remove carbon from the atmosphere)
  4. Use materials more efficiently so we won’t need to keep creating more

🌳 What do we do about how we grow things, e.g. agriculture & forestry? (19% of emissions)


With agriculture, the main culprits are methane (which causes 28x more warming per molecule than CO₂ over the course of a century), and nitrous oxide (which causes 265x more warming).

Animal rearing

As people get richer, they tend to eat more calories. In particular, they eat more meat and dairy. Unfortunately, to produce more meat and dairy we’ll need to grow even more food. This is how much calories worth of feed we’ll need in order to consume 1 calorie of meat:

  • Chicken 🐓: 2 calories worth of feed —> 1 calorie of poultry
  • Pig 🐖: 3 calories worth of feed —> 1 calorie of pork
  • Cow 🐄: 6 calories worth of feed —> 1 calorie of beef

Not only would we need to grow more food, but cows also release methane, a greenhouse gas, into the atmosphere. The TL;DR here is that they burp and fart it out as a result of digesting their food. We raise roughly a billion cattle globally for beef and dairy, and the methane they burp and fart out every year has the same warming effect as 2 billion tons of CO₂, which accounts for 4% of all global emissions.

In addition to the burping and farting of cows, animal poop also leads to more CO₂. When poop decomposes, it releases a mix of powerful greenhouse gases. There’s so much animal poop that it’s actually the 2nd biggest cause of emissions in agriculture!


Fertilizer is widely used all around the world, and it’s important because it provides plants with essential nutrients. One of the main ingredients of fertilizers is nitrogen. Unfortunately, nitrogen is leads to climate change. The TL;DR here is that fertilizers alone were responsible for ~1.3 billion tons of greenhouse gases in 2010.


When trees are burned down they quickly release all the CO₂ they contain into the atmosphere. On top of that, when you take a tree out of the ground, you disturb the soil… it turns out there’s a lot of carbon stored up in soil (in fact, there’s more carbon in soil than in the atmosphere and all plant life combined). When you start removing trees, that stored carbon gets released into the atmosphere as CO₂.

Deforestation happens for different reasons around the world (e.g. to create new pastureland for cattle, for palm plantations, etc). Since a lot of deforestation occurs to make way for farms and pastureland to create more food, one study by the World Resources Institute (WRI) found that if you account for land-use changes, the American-style diet involving lots of meat and dairy is responsible for almost as many emissions as all the energy Americans use in generating electricity, manufacturing, transportation, and buildings!

At the end of the day though, people don’t cut down trees because they’re evil; they do it when the incentives to cut down trees are stronger than the incentives to leave them alone. This is a political and economic problem.

🚗 What do we do about how we get around? (16% of emissions)

The main culprit here is gasoline. There are two things to keep in mind: it’s very energy dense, and it’s also incredibly cheap

Passenger cars

Passenger cars are responsible for half the transportation emissions. Currently, there is still a modest green premium for cars in the US. For example, the Chevy Bolt EV will cost 10 cents more per mile driven than the Chevy Malibu. If you drive 12,000 miles in a year, then that’s $1,200 extra in gas. This is pretty average for the US, but it can be different in other countries (the main factor being the difference between the cost of electricity and the cost of gasoline). In some parts of Europe gas prices are so high that the green premium for electric vehicles (EVs) has already reached zero.

Garbage trucks, buses, and 18-wheelers

The problem with electrifying large cars is the batteries. You need to carry more batteries to power a large car, but when you add more batteries to the car, the car becomes heavier.

Pound for pound, the best lithium-ion battery available today packs 35x less energy than gasoline. An electric truck capable of going 600 mi on a single charge would need so many batteries that it would have to carry 25% less cargo.

Ships and planes

Getting to zero emissions would do us a lot of good because shipping alone counts for 3% of all emissions. We could switch to other cleaner fuels (e.g. biofuels and electrofuels), but unfortunately the green premiums for those are still quite high.

We could electrify them, but the bigger the vehicle you want to move, and the farther you want to drive it without recharging, the harder it will be to use electricity as your power source. The best all-electric plane on the market today can only carry two passengers, reach a top speed of 210 mi/hour, and fly for three hours before it needs to recharge. In comparison, a fossil-fuel-powered jetliner can fly more than 3x as fast, for 6x as long, and carry nearly 150x as many people as the best electric plane on the market! This disparity also exists for cargo ships.

❄️ What to do about how we keep cool and stay warm? (7% of emissions)

If you live in a typical American home, your air conditioner (AC) is likely your biggest consumer of electricity you own. Ironically, the very thing we’ll be doing to survive in a warmer climate—running ACs—could make climate change worse!

The demand for electricity isn’t the only thing that makes ACs a problem. ACs contain refrigerants (known as F-gases because they contain fluorine) that leak out little by little over time when the unit ages and breaks down. F-gases are extremely powerful contributors to climate change; in fact, over the course of a century they cause thousands of times more warming than an equivalent amount of carbon dioxide.

To warm ourselves in the cold, we often use furnaces and water heaters. These count for a third of all emissions in buildings. Unfortunately, most of them currently run on fossil fuels.

📈 So what can we do to get to zero?

Science tells us that in order to avoid a climate catastrophe, rich countries should reach net-zero emissions by 2050. In order to do this, the government will need to enact more policies to curb emissions and invest in more climate-friendly innovations.

We as individuals can also help by talking to our representatives about the need for climate solutions. We can also impact the demand for zero-carbon alternatives. When you pay more for an electric car, or a plant-based burger, you’re showing that there’s a market for it. If enough people send the same signal, companies will respond. They’ll put more money and time into making low-emissions products, which will drive down the prices of those products, and eventually help them get adopted in bigger numbers. It will make investors more confident in funding new companies that are making the breakthroughs that will help get us to zero emissions.