Want to learn what 350 means?
According to NASA’s James Hansen, “the earth’s premier climatologist, has laid out these stakes with some precision. His team found in 2008 that, if the atmospheric concentration of CO2 exceeds 350 parts per million, we won’t be able to have a planet “similar to the one on which civilization exists and to which life on earth is adapted.” We’re at 390 parts per million right now, and, what do you know, the Arctic is melting rapidly, the atmosphere is getting steadily wetter, and the oceans are turning sharply more acid. Follow Hansen’s math a little further: If we wean ourselves from fossil fuels by 2030, then the earth’s CO2 levels will begin to fall, and, by century’s end, we’ll be back near 350. Damage will be done in the meantime, but perhaps survivable damage. And, conveniently, the world’s supply of “conventional,” easy-to-get-at oil is starting to dwindle: The deposits in places like Saudi Arabia, which were built long before anyone had heard of climate change, are nearing the autumn of their lives. We could, in other words, use this moment of declining oil supply as a spur to make the leap toward renewable energy—a gut-wrenching leap, but one that, if we landed successfully, would put us in a new world.”
Recommended reading: Eaarth, Bill McKibben 2011. McKibben is the founder of 350 Organization.