By Donella Meadows

–July 27, 1990–

Dear John Sununu,

I know how smart you are. I know about your engineering degree, and I watched you perform as my governor all those years before you went to the White House. I’ve seen your mind snap up information, quick as a trap. Therefore I was surprised the other day when you made a statement unworthy of your mental abilities.

With all the fossil fuels we burn, you said, humans produce only four percent of the carbon dioxide released on the planet. Nature produces the other 96 percent. Therefore our puny contribution can’t possibly be a problem.

I’m sorry to say, Governor, that environmentalists all over the world are laughing at you for that one. Teachers are turning it into an exam question that begins: Explain what is wrong with the following statement.

When I tell people what you said, however, many of them look blank and ask, “what IS wrong with it?” I guess you’ve made an understandable mistake for a layman. It’s just not one I’d expect from someone who advises the President on environmental policy.

To save you further embarrassment, here’s the story on carbon dioxide.

Your 96 percent and 4 percent are correct. Life on earth emits 110 billion tons of carbon a year from the decay of organic matter and from animals breathing. The human economy adds to that only 5 or 6 billion tons. But you left out one other important number. Green plants on earth ABSORB 110 billion tons of carbon through the process of photosynthesis. Everything was in balance until we came along with our cars and coal burners.

The result is a filling bathtub — you must have used bathtub analogies when you taught engineering. Picture a huge bathtub half full of water. Now imagine 110 gallons of water a minute pouring in through the faucet and 110 gallons a minute pouring out through the drain. Water flows through the tub like crazy, but the level stays constant. Now turn the input flow up by five gallons a minute. What happens? The water in the tub starts to rise. It will keep going up, as long as that extra five gallons is flowing in — until it spills over and makes a big mess.

That’s what’s happening to the CO2 in the atmosphere. It has risen from 270 to 350 parts per million, and it’s still rising. And we’re not leaving the faucet alone; we’re turning it on ever faster. Since CO2 traps heat, that means the earth will gradually warm and our climate will change.

You and I both know, Governor Sununu, that the atmosphere is much more complicated than a bathtub. Other mechanisms open and close CO2 faucets and drains. For example, luckily for us, about half the excess CO2 we produce is dissolving in the ocean. Whether the ocean will keep on helping us out that way is anyone’s guess. We don’t know much about other drains that might open or close either.

You’ve been using that uncertainty very cleverly to block any calls for turning down the faucet of CO2 emissions. Surely, though, a man of your intelligence knows that uncertainty can cut two ways. The planet might come up with new ways of absorbing CO2 (though so far it hasn’t). It might find ways of cooling itself off. And it might not. It might actually enhance the pushes we’re giving it and make them worse, especially since the climate is a chaotic system.

I guess chaos theory has emerged since you went to engineering school, so you might not be familiar with it. In a nutshell, chaotic systems are poised between realms of wildly different behavior, so a slight push can send them shooting off into extreme changes. An ice age is a good example. Just a small shift in the angle and quantity of incoming sunlight cools the earth by a few degrees, and presto, half of North America is covered with ice.

The carbon increase is shoving us the other direction, toward a few degrees of warming. It will take us into temperatures that the earth hasn’t experienced in the last several million years. Will there be a chaotic response? No one knows. How much do you want to bet on it? Because betting is exactly what we’re doing.

By blocking action, you are betting that the planetary response will be stabilizing, not chaotic. You apparently have more faith in the chaotic climate of Earth than you have in the ingenuity of your fellow-engineers to develop new energy systems. But there are smart people — probably as smart as you — who would bet the other way. They’d say earth’s climate is not a system to fool with. And they think that solar energy used super-efficiently will be the central technology of the 21st century.

Governor, the climate is so complex and our understanding of it so incomplete, that there is room for even the brightest people to disagree. The stakes on this bet are enormous. The processes we are setting in motion, whatever they are, will be irreversible, at least over any time span interesting to human beings.

In a situation like this, a mind that’s quick as a trap has to be extra careful to stay open.

Copyright Sustainability Institute 1990