It's easy to get depressed about climate change. We've made so little progress in reducing carbon-dioxide emissions that our previous goal - to limit the rise in global temperature to 2 degrees Celsius - is almost laughable. (See: "UN Climate Report Questions Global Willpower")

But what if companies could make money from carbon dioxide, the heat-trapping gas that's the main contributor to global warming?

We're not actually so far off from turning emissions into commodities, it turns out. In the United States alone, a number of companies aim to convert waste carbon dioxide into chemicals that can be used to make products we buy every day: bleach, baking soda, car seats, diapers, even fuel. What's more, these companies aren't just