Quantifying climate change
By Paul Ford
Climate people — researchers, ESG administrators, philanthropic organizations — can forget, under the pressure of fact, just how alien statistics can feel to those of us new to Climate World. They come to the conference and put a “419.68” on the screen. Everyone sighs and nods. They speak in fractions or, alternately, trillions — of dollars or trees, depending on the context. These numbers are whole careers, tenure, grants proffered or not. But if you don’t live in Climate World, they don’t quite resonate. You have to learn to appreciate them.
Of course, most of the time what’s on display is worse than numbers; it’s probabilities. I’ve learned to imagine bell curves as waterslides — big ladder on the left, starting at the 5th percentile, the lower tail. You climb it to the median, and hang out a little and enjoy the view. Then you go down a steep, terrifying slide on the right to the 95th percentile, the upper tail.
Illustration: Baptiste Virot
I was looking at some water data showing millimeters of expected precipitation in New York City (where I live) at 2C of global warming(where I do not yet live) during the rainy season. On the left, all good — maybe even less rain! At the median, a little more. And then — whoosh — down the slide we go, to find that, out there in the upper tail, there could be five times more precipitation, per wet season, than the median. Having just watched my neighbors pump out their basements, having planted clover and extended the gutters to mitigate the likely flooding of our old house, I find it does indeed feel like plummeting into a very deep pool at the world’s least fun amusement park.
But that’s how it goes. The world builds border fences and new coal plants. Climate World holds conferences and publishes papers in Nature. The world gets excited about new TV shows and fusses on social media. Climate World gets agitated about United Nations plenaries and permafrost. Like the fox and the hedgehog, the world worries about many things, but Climate World worries about one big thing, and it tries to reduce that big thing to a mixed decimal. And one can, in time, internalize and understand a lot. Besides, I know how water works. It runs downhill. And if it rains more, the sewers will overflow and basements will flood.
Illustration: Baptiste Virot
Numbers describe forces — we learned to think that way in middle school, doing experiments with Epsom salts. Where I’ve been struggling is when the numbers quantify humanity. For example: More than 5 billion people will have inadequate water access at least a month every year by 2050. That’s a projection from the World Meteorological Organization. Countless other people will have too much water, flooding the basement or coming up the riverbanks. For the past decade, I’ve been getting numbers like that via email digests, newsletters and magazines. They tend to bounce off my brain. I can visualize a few inches of rain per wet season, but I can’t visualize everyone on Earth, all 8 billion of us.
If you give everyone on Earth 10 gallons of water a day, an utterly arbitrary number, that’s around 80,000 Olympic swimming pools — they’d stretch most of the way across the US. It would take Michael Phelps 24 days to swim them, assuming he never stopped to eat or drink. Of course, 10 gallons is probably way too low. We use water in countless ways; we spend thousands of gallons to make a few pounds of beef.
It’s hard to find normal things measured in billions. The M1 chip on the Mac has 16 billion transistors, I guess. But it feels gross to compare humans to chips. What if every person were a book — but that’s 8 billion books. More than two Great Pyramids’ worth. And what if every human were a page in a book — no, that’s a stack of paper almost 500 miles high. All right, 8 billion words. I can imagine 8 billion words, because I’ve tried to read the Intergovernmental Panel on Climate Change’s reports.
If everyone on Earth were a single character in a word on a page in a book, you’d need about 20,000 books — the size of a nice small-town library — to hold all those characters. In your life you might meet a page’s worth. Your town might be a few books’ worth. So basically: Every character in all the fiction in the library — not the characters in the story, but the characters on the page — is a human needing more water.
So I rode my bike and thought about water because, as summer faded into fall, my neighborhood in Brooklyn had flooded in a wave of unexpected downpours that led to many social media posts of water bursting through basement doors or whirlpools in the middle of city streets. It wasn’t peak rainy season. It happened on the tail of the bell curve. Headed toward the ocean, I realized I live in a city of almost 9 million people. I know about 1,000 of them. I know the trains, the government and the waterways. I’ve been to almost all the neighborhoods and up to the reservoir. I’ve seen our infrastructure falter, then recover. This is home.
Imagine 1,000 New York Cities. That’s the world population — or it will be, 9 billion people, by around 2037, according to the UN. A thousand makes sense. I’ve worked on projects that had thousands of components. The pandemic started just about 1,000 days ago. Four pages, double-spaced and typewritten, is 1,000 words.
Photographer: Baptiste Virot
For the first time, I do start to see it. Five billion people is almost 600 New Yorks. Almost 600 future New York Cities will need more water. Everyone I pass on my bicycle (including the climate refugees soon to be sequestered next to the old airstrip) will be thirsty. Everyone on the subway, everyone visiting the Empire State Building, everyone in a Broadway audience — thirsty, if they live in the wrong New York City. Repeat that 600 times. Oddly then, I can see the shape of that number. And 5 billion, along with the parts per million and degrees of warming, starts to make sense. To learn this stuff requires new intuitions. The old ones don’t scale.
The next 1,000 weeks (20 years) will tell us who we are as a species and exactly where we sit on the bell curve. Right now, so far, I live in the right NYC — one with too much rain, if the model holds. Many New Yorks — those with the bad luck to be in South America or parts of India — will be simply unlivable. We use the world “unimaginable” a lot, and rarely with optimism. But the world is far, far more imaginable if you see everything as a multiple of home.
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