The idea that our planet's climate is changing is nothing new, says environmentalist and writer Bill McKibbon—in fact, the first person to theorize that our planet was warming was a 19th-Century Swedish chemist. But because the issue didn't hit home until recently, we've already altered the state of our planet so significantly that our civilization is in peril.

In his Big Think interview, McKibbon, who founded the international environmental advocacy group 350.org, worries about the effects that we might now start to see. The symptoms of our planet in crisis are already surfacing—from rising sea levels to tropical storms, to melting glaciers. And while no other source of renewable energy could take the place of fossil fuels, it's vital for us to start investing our resources to develop alternatives.

Now is the time for the government to make carbon emissions expensive, says McKibbon. It's a tax that he says wouldn't bankrupt anyone: "There are good proposals in Congress right now to take the money generated by the tax on carbon, and rebate it directly to taxpayers with a check every month. Most people would actually come out ahead unless they were using insane amounts of energy," he says.

But that's not all we need to do, he argues. America needs more farmers. Right now, only one percent of U.S. citizens farm, and the average bite of food travels 2,000 miles to reach your lips. He admits we won't likely get back to the days when 50% of the country farmed, but he thinks that the more local farmers we do have, the better it will be for everyone.