Warmist "Weepy" Bill McKibben suggests that trace amounts of CO2 will lead to "an Earth with 40% less calories on it"

Bill McKibben on Bill Maher Oct 5 2012 - 12-minute YouTube

Bill McKibben appears on Real Time with Bill Maher, Oct 5-2012.
Fox News's Frank Luntz and Ex-Republican Rep Mark Foley try to put forth some sort of logical sounding arguments to McKibben, but look like children when Maher and McKibben put them squarely in their place. Children vs Adults here. Global Warming is a crisis unequaled in human history.

At the seven-minute mark, McKibben argues that "each degree increase in global average temperature should cut grain yield on this planet by 10%...try to imagine an Earth with 40% less calories on it...what are we gonna develop that replaces Iowa".