I’m sure you have read about climate change and maybe studied it in school. You might be worried about how it will affect you. The truth is, the people who will be hit the hardest are the world’s poorest. Millions of the poorest families work as farmers. Changes in weather often mean that their crops won’t grow because of too little rain or too much rain. That sinks them deeper into poverty. That’s particularly unfair because they’re the least responsible for emitting CO2, which is causing the problem in the first place.
Scientists say that to avoid these dramatic long-term changes to the climate, the world must cut greenhouse gas emissions by up to 80 percent by 2050, and eliminate them entirely by the end of the century.
When I first heard this I was surprised. Can’t we just aim to cut carbon emissions in half? I asked many scientists. But they all agreed that wouldn’t be enough. The problem is that CO2 lingers in the atmosphere for decades. Even if we halted carbon emissions tomorrow, the temperature would still rise because of the carbon that’s already been released. No, we need to get all the way down to zero.
That’s a huge challenge. In 2015, the world emitted 36 billion tons of carbon dioxide to produce energy. This is a mind-boggling number. (It’s worth remembering, because it will come in handy. For example, someone may tell you they know how to remove 100 million tons of carbon per year. That sounds like a lot, but if you do the math—100 million divided by 36 billion—you’ll see that they’re talking about 0.3 percent of the problem. Every reduction in emissions helps, but we still have to work on the other 99.7 percent.)
How can we ever reduce a number like 36 billion tons to zero?
Whenever I’m confronted with a big problem I turn to my favorite subject: math. It’s one subject that always came naturally to me, even in middle school when my grades weren’t that great. Math cuts out the noise and helps me distill a problem down to its basic elements.
Climate change is an issue that has plenty of noise surrounding it. There are those who deny it is a problem at all. Others exaggerate the immediate risks.
What I needed was an equation that would help me understand how we might get our CO2 down to zero.
Here’s what I came up with:
That might look complicated. It’s not.
On the right side you have the total amount of carbon dioxide (CO2) we put in the atmosphere. This is what we need to get to zero. It’s based on the four factors on the left side of the equation: the world’s population (P) multiplied by the services (S) used by each person; the energy (E) needed to provide each of those services; and finally, the carbon dioxide (C) produced by that energy.
As you learned in math class, any number multiplied by zero will equal zero. So if we want to get to zero CO2, then we need to get at least one of the four factors on the left to zero.
Let’s go through them, one by one, and see what we get.
The world’s population (P) is currently 7 billion and expected to increase to 9 billion by 2050. No chance it’ll be zero.
Next, services. This is everything: food, clothing, heat, houses, cars, TV, toothbrushes, Elmo dolls, Taylor Swift albums, etc. This is the number that I was saying earlier needs to go up in poor countries, so people can have lights, refrigerators, and so on. So (S) can’t be zero, either.
Let’s take a look at (E). That’s the energy needed per service. There’s some good news here. Fuel-efficient cars, LED light bulbs, and other inventions are making it possible to use energy more efficiently.
Many people, and you may be one of them, are also changing their lifestyles to conserve energy. They’re biking and carpooling to save gas, turning down the heat a couple degrees, adding insulation to their homes. All of these efforts help cut down on energy use.
Unfortunately, they don’t get us to zero. In fact, most scientists agree that by 2050 we’ll be using 50 percent more energy than we do today.
So none of the first three—population, services, and energy—are getting close to zero. That leaves the final factor (C), the amount of carbon emitted per each unit of energy.