Teaching the Terrifying Math of Climate Change

'The Mystery of the 3 Scary Numbers'

Every now and then an article comes along that takes such a novel approach to an issue, I feel like I'm seeing something with new eyes. Such was the case when I read Bill McKibben's 2012 Rolling Stone article, "Global Warming's Terrifying New Math." It made me see our climate predicament with such clarity that I knew immediately I had to figure out how to turn this article into curriculum.

The "terrifying new math" is pretty simple. McKibben, founder of 350.org and the world's most prominent climate campaigner, proposes that there are just three numbers that we need to pay attention to in order to reach some radical conclusions about the future of fossil fuels.

The first number is 2 degrees Celsius, or about 3.6 degrees Fahrenheit. In the 2009 Copenhagen Climate Accord, 167 countries, including the United States, pledged that "deep cuts in global [greenhouse gas] emissions are required . . . so as to hold the increase in global temperature below 2 degrees Celsius." The Copenhagen Accord was a timid, inadequate document. According to McKibben, even a 2 degree rise in global temperatures is fraught with danger, but it's the only international consensus on a climate target--"the bottomest of bottom lines," he writes. The first scary number.

The second scary number is 565 gigatons--or 565 thousand million tons. That's humanity's carbon "budget"--how much carbon dioxide we can pour into the atmosphere with a reasonable chance of keeping global temperatures to a 2 degrees Celsius increase. That 565 gigatons sounds like a lot until we hear that global carbon dioxide emissions rose by 31.6 gigatons in 2011, and that projections call for humanity to blast through our 565-gigaton quota in less than 16 years.

Which brings us to the final number that makes the other two numbers so frightening: 2,795 gigatons. This number represents the stored carbon in reserves held by coal, oil, and gas companies, and the countries--Kuwait, for example--that act like fossil fuel companies. McKibben notes that this number was first highlighted by the Carbon Tracker Initiative, a group of London financial analysts and environmentalists. In other words, the fossil fuel industry already has plans to exploit five times as much carbon as can be burned without exceeding the 2 degrees ceiling. Burning these fossil fuels would enter the world into a dystopia of climate science fiction--a rise in sea levels not seen in human history, species extinction, droughts, superstorms, heat waves from hell, coral kill-offs, and consequences we cannot yet imagine.

"Here's another way of saying it: We need to leave at least 80 percent of that coal and gas and oil underground," McKibben writes. "The problem is, extracting and burning that coal and oil and gas is already factored into the share prices of the companies involved--the value of that carbon is already counted as part of the economy." This would be the equivalent of these companies writing off $20 trillion.

Not only is the fossil fuel industry not planning to write off any of this $20 trillion, the industry is using its immense wealth to add new reserves. Just as an example, Exxon plans to spend $37 billion this year on increasing oil production.

The simplicity of McKibben's "three scary numbers" helped me put into perspective some of the "softer" responses to global warming. So many environmentalists--and students--want to "be positive" and concentrate on alternatives: everything from buying locally to stepped-up recycling, planting more trees, and developing greener sources of energy. No doubt, it's crucial to imagine and work for alternatives. But for any of this to make a difference, we need to recognize fossil fuels--and those who exploit them--as immediate and staggering threats to life on Earth. One clear implication is that we cannot nice our way out of this. We have to educate and enlist our students in imagining a very different future in terms of energy use and fighting to make that happen.

Yes, a full curricular treatment of climate chaos needs to do more than merely frighten students with scary numbers. But these numbers of McKibben's invest our thinking about the climate with a two-plus-two-equals-four certainty. It's not probable that the route we're on leads to catastrophe--it's for sure.

The Mystery Activity

I love the structure of mixer/tea party activities that get students up out of their seats and talking with one another to figure out a bigger picture. Rather than asking students to assume the roles of individuals in history or around the world, I decided to write clues drawn largely from McKibben's Rolling Stone piece. Through talking with one another, I wanted students to solve the "mystery of the three scary numbers." Well, maybe not solve, but at least come to recognize why these numbers are, in fact, so scary and begin to reflect on their implications. Further activities or discussion about the climate crisis would build from a common recognition of the mathematical fact that we are on an unsustainable trajectory.

My friend and colleague Tim Swinehart, who teaches at Lincoln High School in Portland, invited me into his economics class to teach a couple of "Three Scary Numbers" sessions with him.

I held up a copy of Rolling Stone. "Anyone familiar with this magazine?" Maybe a third of the students raised a hand. "I began reading Rolling Stone in 1968, when I was about your age. Last year, the magazine published an article that generated more interest, more likes, more shares, more Twitter mentions, than any article Rolling Stone had ever published. And here's the thing: The article is about just three numbers, three very scary numbers.

"So we're going to do an activity that we call the 'Mystery of the Three Scary Numbers.' And, basically, you have just two tasks: figure out what the three numbers are and why they're scary. Afterwards, we'll talk about the meaning of these scary numbers and what we can do about them."

We distributed a question sheet to everyone, and each student also received a clue. There were 29 students in the class and I'd written exactly 29 clues. In the clues, each of the three scary numbers was in 16-point bold type so students were sure to spot these "this is a big deal" numerals.

The handout asked questions like:

Find someone who has one of the three "scary" numbers (in large, bold type). What is the number?

List as many details as you can find out about this number (at least three).

Find three other numbers about climate change. What is the number and why is it important?

Some of the clues stuck faithfully to describing something about one of the three scary numbers, for example:

Two degrees Celsius is about 3.6 degrees Fahrenheit. In 2009, 167 countries signed on to the Copenhagen Accord. These 167 countries are the biggest polluters in the world, responsible for 87 percent of all greenhouse gas emissions. The accord states that we cannot raise the Earth's temperature more than 2 degrees Celsius without risking planetary disaster. All 167 countries, including the United States, pledged: "We agree that deep cuts in global [greenhouse gas] emissions are required . . . so as to hold the increase in global temperature below 2 degrees Celsius."

Other clues focused on different numbers:

Over the past 30 years, permanent Arctic sea ice has shrunk to half its previous area and thickness. As it diminishes, global warming increases. This is due to several things, including release of the potent greenhouse gas methane trapped under nearby permafrost, and because ice reflects the sun's energy whereas oceans absorb it. Oil companies see the disappearance of Arctic ice as an opportunity to make more profit by drilling for more oil--which will create even more global warming. For example, Royal Dutch Shell has spent $4.5 billion preparing to drill in the Arctic. One of the world's leading environmentalists, David Suzuki, calls this "insane."

One clue featured the "Keeling curve"--the graph that depicts the inexorable rise in atmospheric carbon dioxide that Charles David Keeling began measuring in 1958 at Mauna Loa in Hawaii. When Keeling first began his measurements there, he recorded 313 parts per million; in 2013, it passed 400 parts per million.

Obviously, the more one knows about basic climate science, the easier time one will have with this activity. When teacher (and Rethinking Schools editorial associate) Adam Sanchez did this activity with 9th graders across town at Madison High School, he realized that his students needed a bit more initial familiarity with the concept of greenhouse gases and the relationship between burning coal, oil, and gas and releasing carbon into the atmosphere.

I introduced the mixer by reminding students that each of them had a different clue and that each clue offered important information that would help them figure out the mystery of what makes these three numbers so scary. Tim and I encouraged the students not to wait until the very end to begin making sense of this, but to talk with one another about the big picture as they circulated throughout the class. The rules of the game were simple: Clues could only be shared verbally--no handing over clues to anyone--and conversations had to be one-on-one (to encourage maximum participation). Finally, this was a get-up-and-mingle activity, so no just hanging out at one's desk waiting for "callers" to arrive.

Students wasted no time: "I need a bold number! Who has a scary number?"

One student encountered 2,795 gigatons. "That's a lot," she said in a quiet voice.

"So what are these numbers saying?" another asked.

"The numbers are important because we only have a couple of years."

"Well, we're already in trouble."

Toward the end of the activity, I watched a student cock her head and ask no one in particular: "So is this saying that we're going to die?"

Students were fully engaged throughout the half hour or so of the clue hunt. When it felt that conversations were winding down, Tim and I asked everyone to form a large circle and continue to discuss the final assignment sheet questions, which asked: Why are these numbers important? What actions should be taken?

We wanted students to feel free to share whatever occurred to them, and so did not over direct the conversation. After this activity, students would continue to study the climate crisis with Tim and connect real human beings with these numbers. For now, we simply wanted to hear how they made sense of this new information.

"These are insane numbers," Matt said. He mentioned the potential species extinction and the rising seas. Cory pointed out that, at current rates, "We're on track to hit 2 degrees quickly, it's not some far-off endpoint"--which was exactly the sensibility we hoped students would draw from the activity: climate change is not about the future, it's about now. Michele was struck by the possibility of widespread desertification. Even James, a confirmed Libertarian, argued that there was no reason to think that the market would somehow on its own be moved by these numbers: "I've never had it quantified like this, or had such a grim picture painted. . . . This has to be a shift that we make."

Not surprisingly, when it came to what "we" should do, students were all over the map. There was the student offering a techno-fix: "NASA is thinking about Mars." Sonia and many other students thought as responsible consumers: We should "use more local products and make permanent changes, not just 'I rode the bus one day'"; we should recycle and compost more; we should cut down on meat and travel; we should walk more; we should stop wasting water. And there were students whose "we" extended to what the government should do: start taxing coal, find alternative sources of energy; "the government should lead a 'war on climate change.'" Interestingly, the more students talked, the more distant their solutions became. When a couple of students began criticizing the Chinese government for its alleged climate crimes, I pointed out how the conversation had drifted from changes that were more in our power to influence to those that weren't.

For homework, we gave the class an abbreviated version of McKibben's "Global Warming's Terrifying New Math" article to reinforce the information they encountered in the mystery activity. McKibben does not write with high school readers in mind, but having encountered much of his argument in the mystery, we knew students would find it more accessible. McKibben's strategic punch-line is the need to launch a campaign to demand that colleges, retirement systems, and cities divest from holdings in fossil fuel companies--borrowing from the important divestment activism of the anti-apartheid movement during the 1980s.

Given the terrifying math McKibben presents, Tim and I did not seek to suggest that there was a single "do this" answer. We wanted to raise the question of what we should do--not answer it. So, in addition to McKibben's divestment proposal, we introduced students to a Huffington Post critique by Christian Parenti, author of Tropic of Chaos, who argues that attacking fossil fuels through the stock market is misguided for a host of reasons and that we need to focus our energies on "the important things government can do, right now, if pressured by grassroots action."

We weren't looking for students to take sides. But we did want them to recognize the urgency of activism. Maria wrote: "The three scary numbers are very scary. What scares me the most is how well this information is known without any action."

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