August 8, 2012
How bad could it get? A recent study by MIT projects that without "rapid and massive action" to cut carbon pollution, the Earth's temperature could soar by nine degrees this century. "There are no analogies in human history for a temperature jump of that size in such a short time period," says Tony McMichael, an epidemiologist at Australian National University. The few times in human history when temperatures fell by seven degrees, he points out, the sudden shift likely triggered a bubonic plague in Europe, caused the abrupt collapse of the Moche civilization in Peru and reduced the entire human race to as few as 1,000 breeding pairs after a volcanic eruption blocked out the sun some 73,000 years ago. "We think that because we are a technologically sophisticated society, we are less vulnerable to these kinds of dramatic shifts in climate," McMichael says. "But in some ways, because of the interconnectedness of our world, we are more vulnerable."