There's no longer any real doubt about it: Global warming is happening. The average temperature of the Earth's surface has risen about 1 degree Fahrenheit over the past hundred years, and overwhelming evidence suggests that most of the increase is due to greenhouse gases, particularly carbon dioxide released by humans. Though a 1-degree increase might not seem like much, even a small rise in global temperature significantly changes the climate, potentially resulting in major storms and droughts, disruption of the food supply, and the catastrophic spread of disease.
Human carbon-dioxide emissions come mainly from two sources: burning fossil fuels and changes in land use, such as deforestation. Americans are the climate's worst enemy. On average, each of us is responsible for about 22 tons of carbon-dioxide emissions every year, according to the United Nations, compared with an average of six tons per person throughout the rest of the world. That means the typical U.S citizen emits the equivalent of four cars.
Much of the discussion around climate change involves national and international policy—should the United States sign the Kyoto Treaty or increase auto efficiency standards? But even without major political or legislative changes, there's a lot that concerned individuals can do to make the problem better. To that end, we've created the Slate Green Challenge—a straightforward program to evaluate and reduce your carbon emissions between now and the end of the year.
For the next eight weeks, Slate, in collaboration with eco-Web site treehugger, invites you to consider your own individual contribution to global warming—and challenges you to go on a carbon diet. The goal is to reduce the amount of CO2 that you put into the atmosphere by 20 percent. If you're a carbon glutton who doesn't bother to turn off the lights when you leave the house, you may find this diet pretty painless. (And just think of the fringe benefits—lower heating bills, poorer oil barons.) But even if you're already a svelte recycler or a carpooler, there's a lot more you can do.
Start here by taking this initial quiz to determine your current carbon output. This is like weighing yourself at the beginning of a diet. Then, go straight to the first segment, which asks you to assess your transportation-related emissions and suggests ways to reduce them. Then, come back every week between now and Dec. 11 for the other units we've developed on such subjects as food, clothing, electricity, and holiday shopping.
You'll always take a short quiz, which will point you to a series of "action items"—things you can do to reduce your carbon output. It's only a few hundred pounds here and there, but it adds up. Once you've registered, we'll keep track of the carbon pounds that you lose from week to week, following up with reminders and additional tips while the program continues. We'll also keep track of how much we've lost collectively, shooting for that 20-percent reduction overall. Don't worry if you've missed the launch date; you can get started at any point by taking the initial quiz. And please, spread the word.
If you succeed in losing the full 20 percent, you will be eligible for two rewards. The first is a free Slate/treehugger Green Challenge T-shirt, brought to you by our friends at I'm Organic, which the first 500 people to complete the challenge will receive. The other is the knowledge that you've trimmed down to help the planet.
(Click here to start the Slate Green Challenge.)