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Earth Matters

Earth Matters: Life on a (Carbon) Budget

Earth Matters focuses on conservation, sustainability, recycling and healthy living. This weekly series is brought to you by Maria Luisa Boutique, Strawtown Studio and Summer Play Camp at Blue Rock School
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by Susan Hellauer

As she wrapped up a recent talk on the current state of polar ice, Lamont-Doherty Earth Observatory geophysicist Dr. Robin Bell spoke of the need for us all to live sustainably. As a shining example, she cited her own husband, environmental law professor Karl Coplan, who works hard to live on a carbon emissions “budget” of four tons a year. “He does it,” said Bell. “I try really hard . . .”

Coplan blogs about his endeavor to live within his ambitiously low budget of carbon dioxide and other greenhouse gases, and is working on a book about living sustainably on a tiny fraction of the typical American’s annual 44-ton carbon output.

Earth Matters spoke to Coplan by phone last week about his quest to curb his carbon footprint. The interview has been edited and condensed. 

EM: What inspired you to start tracking your carbon budget?

It wasn’t anything sudden. It was more of an evolution than an epiphany.

I’ve taught environmental law at Pace College Law School since 1994, in the Environmental Litigation Clinic. Before that, I worked at a law firm that did a lot of public-interest environmental work. So I’ve always been sensitive to our environmental footprint. I always got the smallest, best-mpg car to get to work and back, and all the rest. Climate change seemed like something way off in the future, and not something we have to fight right now, like Indian Point dumping radioactive tritium into the Hudson River, or nitrogen coming from NYC sewage treatment plants (to give examples from cases I worked on).

We have environmental laws because people make business and personal decisions without considering  environmental impact. We justify coming in and taking action, and wag our fingers at people who choose to pollute to make a dime. But if you look at your own choices—how you get to work or where you go on vacation—you realize that, like the old Walt Kelly comic, we have met the enemy and he is us: every one of us with a high-emissions lifestyle, especially in the U.S.

So, I came back from a sabbatical ten years ago and thought: What can I do? I realized that I should start keeping track of my own carbon footprint with trackers that were beginning to appear online.

Why four tons?

About three years ago, environmentalist Bill McKibben was popularizing the idea that the whole globe could only afford to burn another 570 gigatons of carbon dioxide (CO2) if we were to have a good chance of meeting the two-degree centigrade global warming target. Well, I took that 570 gigatons and divided it by the 37 years remaining to 2050, and then divvied that up among the seven billion people in the world, and that came out to about two tons per person per year.

carbon budget

Sustainable spouse Lamont-Doherty research professor Robin Bell loads the e-car for a cross-country ski outing. Photo courtesy Karl S. Coplan

I don’t believe there will ever be a system where everyone on the planet would get the exact same allocation of limited resources. So, while I couldn’t justify going to ten times the global average, I thought I could justify going to maybe twice. So I came up with the four-ton footprint as a goal.

It was in September 2015 that I started actually keeping track on a daily, weekly and monthly basis, and I’ve been doing that ever since. I wanted to write a book about it, so I began keeping a diary, to keep track of the big carbon-emitting activities in my life, how I’m doing on my budget, and how this all works out.

What carbon emissions do you track?

First off, I’m not trying to keep track of every single ounce of carbon dioxide emissions, because that’s not practical. I’ve tried to take what are, generally speaking, the biggest items. These are gasoline, if you are driving a gas powered car; electricity, if you are getting it from non-renewable sources; your heating and cooking, if you are burning natural gas for these; and air travel. I also keep track of any time I eat beef or lamb because these are the meats with the highest carbon footprint per pound.

What carbon budget calculators do you use?

I’m a critical person. I don’t take anything, like an online carbon calculator, at face value. So for most of these big things I’m tracking, I actually went to the U.S. Environmental Protection Agency (EPA) website, which has good numbers. I made up my own spreadsheet that calculates the impact of, say, gasoline when I’m driving in [my wife’s] Prius. I take the number of miles we drive and divide it by the car’s 50-mile fuel economy rating and multiply it—I’ve been doing this so long I can rattle these numbers off in my head—by the 20-pound CO2 emissions “cost” of a gallon of gas. I have a similar conversion for natural gas, for which I check my meter or my bill. A pound of beef “costs” about 27 pounds of CO2—more expensive than gasoline, if you can believe it.

carbon budget

Carbon-free commuting: view from the kayak. Photo: Karl S. Coplan

Do you include other emissions besides CO2?

I’m using a carbon equivalence. The EPA website generally includes non-carbon greenhouse gases. So, for example, beef is not just CO2; most of the impact is from livestock methane.

What about the commuting and traveling?

When I started all this I didn’t have a car of my own. I had an electric motorcycle (and still have one), so I was either riding my electric motorcycle or taking the bus to get to work in White Plains. Since then, I found a great deal on a little Smart fortwo electric car, only $130 per month on a three-year lease.

A couple of times a week from April through October I paddle my kayak across the Hudson River, and leave it at a friendly boat club, where I pick up my bike and ride from Tarrytown to work. I do that for exercise and for fun, with the side benefit of emitting zero carbon and zero fossil fuel—but it takes a long time too. Of course, this year they are supposed to open the bicycle lane on the bridge so I can bike to work then.

carbon budget

Rendering of new bridge bike path. Rendering NY State Thruway Authority

Part of this is figuring out a way to live with only one car in a household. We are lucky to live in an area that’s fairly well served by public transport and the options are improving. And now there are quite a few electric vehicles on the market at good prices for leased and used.

I fly less than once a year, and only for a really important reason, like a Waterkeeper Alliance conference, which is very important to me. Occasionally, to enrich my life, I’ll go someplace that I wouldn’t otherwise go if I can stay there for a couple of weeks. Or, even better, I’ll combine such a trip with a Waterkeeper conference.

What about the big one: powering and heating your home?

Electric was the easiest thing to take care of. I looked into solar panels but our house is surrounded by big trees and the solar company people just laughed. But I did sign up for a 100% renewable energy contract, with Green Mountain Energy, providing contracts from Pennsylvania wind farms. The carbon calculators give you credit for this. I’ve got about another year on my contract, but will switch to community solar, which directly feeds our local grid. Community solar is by far the best option for those like me who can’t have solar panels installed.

robin bell

Coplan’s wife, world-renowned polar ice researcher Robin Bell travels frequently to Antarctica. Yet she sometimes asks her carbon-skimping husband to turn up the heat. Photo courtesy Lamont-Doherty Earth Observatory

For heat, we’ve got a big fireplace in our house, which I converted to a wood stove insert. We live in a wooded area in West Nyack, so we’ve got all these old trees. Every year, at least one falls down, so I’ve got a free source of firewood. That ends up being our primary heat, saving us about $300 per winter month. I keep the house quite cool — that’s one sacrifice I make. I do often hear “Can’t we turn the heat up?” from my wife.

Not all wood is sustainable, and if everyone tried to heat with wood it would be a disaster. But, for now, I can do this and it works. In the long run, we will look at geothermal heat, or electric heat with renewable energy.

Has calculating your carbon budget pushed you to achieve more?

Yes, it’s helped me be aware and keep track of big items, and figure out creative ways to live well and have fun without adding to the carbon footprint.

carbon budget

The Mabel Rose near Hook Mountain. Photo courtesy Karl S. Coplan


Like any other budget, if you economize on the basics, you can have a little bit left over for some fun. If you look at my blog you’ll see that we sailed our boat to the Bahamas last spring, and we’ve sailed across the Atlantic, and to Africa. Sailing is one of my passions, and has very little carbon impact. I never say never—I might get on a plane if I someday win the lottery for a rafting permit on the Colorado River. But I encourage people to save the flying for those once-in-a-lifetime, really important things.

Look for Prof. Karl S. Coplan’s Live Sustainably Now: A Carbon-Sustainable Vision of the American Dream, from Columbia University Press as early as Fall 2019.

What’s the best way for people to get started on this with minimum pain?

The first thing to do is to to calculate your carbon footprint by using a website like or Nature Conservancy. Just become aware, for the next time you make a big choice, like where you’re going to live, or how, or even whether, you will replace your car. And be aware that, if you fly to the Caribbean for spring vacation, that’s like the entire carbon footprint that the average person in the world has to live with for a whole year. You have an ethical obligation to live within a sustainable carbon footprint. So just think, and incorporate this into the choices you make.

Learn more:

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Earth Matters  focuses on conservation, sustainability, recycling and healthy living. This weekly series is brought to you by Maria Luisa Boutique, Strawtown Studio and Summer Play Camp at Blue Rock School.

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