Energy equation

In recent years, the amount of CO2 released by humans into the planet has approached 40 billion tons. If you wanted to break that down based on people, we've recently crossed 7 billion people on the planet. So that's going to be approximately 7 billion people times the amount of tons per person. If you work out the math, 40 divided by 7 is going to be roughly 5.7 tons per person.

This might already seem like a lot. You could imagine 5.7 tons of wood just being burned. Actually, it would have to be much more than 5.7 tons of wood because wood contains some water. But it's even more than that. For many of y'all watching, it's going to be a lot more than that because that's the average of the developed and the developing world.

It turns out that the average person in the developed world, or if you're a wealthy person or a middle-class person in even the developing world, your average is going to be closer to 20 tons per person per year. In the developing world, if you're not as wealthy a person or you're living in a rural place and you're not using a car to get to where you need to go, or your house doesn't have electricity, the poor are using closer to 1 ton of CO2 per person per year.

This already leads to something interesting. The number of people on the planet is only likely to increase. We have a little chart here based on data from the U.N. I know the numbers here are a little bit small; it starts in 1800 and goes all the way to 2100. The blue are the actuals. If you want to see where we are right now, we are not quite at 20 yet.

We're going to be roughly right over there, that's where we are right now. We've recently crossed 7 billion people. If you wanted to see where these U.N. predictions have us for 2050, 2050 is right over here. The high U.N. prediction has us getting to a world population of about 10.5 billion. The median prediction has us crossing 9 billion, maybe 9.3 or 9.4 billion. The low prediction still has the population increasing a bit, crossing 8 billion people worldwide.

This number is clearly going to increase. You can also imagine we want it to happen that more people get out of poverty, that they are able to use more goods and services. In that case, they might be using more energy. If we don't change how we produce energy, this has the potential of really going up a lot, which could make this number go up a lot.

To help us think about that a little bit more, Bill Gates gave his famous TED talk a couple of years ago where he talked about his energy equation. It's a pretty straightforward equation that talks about the total sum of CO2 emissions. This is the capital Greek letter sigma right over here—it's shorthand math shorthand for "sum." The annual sum of CO2 emissions is that 40 billion number that I was talking about before.

You can derive this in any given year by taking the product of several things. First, think about the world's population (P). I'll even call that the average population because the population is changing. Then, you can multiply that times the amount of services on average each person is using per year. Let me say so: times the services.

Let me write that down: the average services per person. Really, we could say average services and goods because we're talking about things that need energy. Any good or service pretty much that you look around is going to need energy for you to consume.

There are some obvious things like transportation. Obviously, your car might consume some fuel and needs energy to do that. But even watching this video, I’m consuming energy producing this video for you. I had to eat some food—some energy—which is the reason I eat it is for energy. Some energy was needed even to produce that food and get it to my table.

I’m using electricity on my computer right now, and you would have to use electricity to consume this video. There’s a lot more energy being used in the goods and services you consume than you might realize.

Then you want to take, remember, we want to get to the total sum of CO2. You multiply that times the average energy per service, or you could say per good or service consumed. Average energy per service.

As I said, almost any service you consume is using some energy. When you go to school, your teacher, he or she is consuming energy to just be alive. They had to eat some food. They had to use transportation to get there. Your classroom might be heated, or it might be cooled in some way.

Then finally, to get us to the sum of CO2 released in a year, we have to multiply by the CO2 released per unit of energy. We can think about how all of these dynamics are going to change. If we ever want this thing on the left to get to zero—and unless it gets to zero, things like global warming are only going to get worse—in order for that to get to zero, at least one of these things has to be zero. That’s the only way you’re going to get a product to be zero.

We could look at each of these elements of the energy equation and think about what they are likely to do. The average world population will see what's going on here. Even the median prediction has a population growing by roughly 30 percent. We could say this is going to increase by a factor of 1.3.

These are all predictions and very rough, but we can think directionally where things are going. Now, average goods and services—or average services per person—well, we want the poor to be able to consume more. Maybe some of us in the developed world consume a little too much; that’s a philosophical thing for folks to debate.

On average, we want more people to have better transportation, better access to health care, better access to education, and better access to leisure. This is likely to go up. In fact, this will go up as the world gets richer.

Some of the predictions—what Bill cited in his TED talk—suggest this could go up by a factor of two. This is good. We want the world to become richer; we want more people to consume goods and services.

Now, the average energy per service—well, the good thing is technology is making things more efficient. We might have better insulation, better efficient engines—whether they're electric engines or some other type of fuel engines. Therefore, the average energy per service is likely to go down.

It depends on how optimistic you are; it could go down by 20% or, depending on your timeframe, 50%. Some even more optimistic predictions might be even more than 50%. It’s going to go down, so let’s just say times 0.5—let's just be optimistic.

Even if you multiply this—1.3 times 2, that’s a factor of 2.6—if you take that by half, you still have this entire product increasing. Even if we got really efficient—to decrease our energy usage per service by 80% or even 90%—you still have many tens of billions of tons of CO2 being released every year.

So the only way we're going to be able to get this thing down to zero is if the CO2 released per unit of energy goes to zero. This need to go to zero is a bold statement because we're nowhere close to that right now. But if we're serious about this, it's possible that humanity can get there.

There are energy sources that don’t release CO2 or can get pretty close to being at zero. Just to be clear, even if you're driving an electric car, you have to think about where does that electricity come from? If that electricity was generated using something like coal, that's going to release CO2. Or if it was generated using natural gas, that is going to release carbon into the atmosphere.

So you need to think about, even if you're using something like an electric motor, how is that electricity actually produced? You have energy sources like nuclear. Nuclear has its own set of issues that we think about, like safety and what you do with the waste. But people are working on things like clean-burning nuclear that are much safer and generate a very small fraction of the waste.

You have all your other renewable sources of energy, but this is a big challenge for humanity. If we want this thing on the left to be zero, if we want to slow or stop the heating of the planet, we have to figure out how to do this.

The general sense is that as a civilization, if we put our minds to it, we can do it.