Not long ago, my wife and I tried a new diet －not to lose weight but to answer a question about climate change. Scientists have reported that the world is heating up even faster than they predicted just a few years ago. The consequences, they say, could be severe if we don't keep reducing emissions of carbon dioxide (CO₂) and other greenhouse gases that are trapping heat in our atmosphere. But what can we do about it as individuals? And will our efforts really make any difference?
We decided to try an experiment: For one month we would track our personal emissions of CO₂ to see how much we could cut back. The average U. S. household produces about 80 kilos of CO₂, a day by doing commonplace things like turning on air conditioning or driving cars. This is more than twice the European average and almost five times the global average. But how much should we try to reduce?
I checked with Tim Flannery, author of The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth. In his book, he challenged readers to make deep cuts in personal emissions to keep the world from reaching critical tipping points, such as the melting of the ice sheets in
Greenland or West Antarctica. "To stay below that limitation, we need to reduce CO₂ emissions by 80 percent," Tim Flannery said. "That sounds like a lot," my wife said. "Can we really do that?"
It seemed unlikely to me, too. How close could we come to a lifestyle the planet could handle? Finally, we agreed to aim for 80 percent less than the U. S. average: a daily diet of about 13 kilograms of CO₂. Our first challenge was to find ways to convert our daily activities into kilos of CO₂ so that we could change our habits if necessary.
To get a rough idea of our current carbon footprint, I put numbers from recent bills into several calculators on websites. The results that came out were not very flattering. The Environmental Protection Agency (EPA) website figured our annual CO₂ emissions at 24,618 kilos, 30 percent higher than the average U. S. family with two people. Clearly, we had further to go than I thought.
