Minimizing the impact of global warming will take a moral crusade on a par with the 1960s Civil Rights Movement, McKibben said. Though that crusade can't halt global warming, the difference it can make, McKibben said, will be well worth the effort. The one degree increase in global temperature seen over the past hundred years has already been felt. Winter comes on average a week later in the Northern Hemisphere than it did 30 years ago. It leaves a week earlier.
Warm air can hold more water than cold air.
That means when it rains, it rains harder, resulting in more flooding from more severe storms. And where there is no rain, the warmer temperatures means droughts are even more severe. Effects are being felt far from human population centers. Ice caps are thinning so much that polar bears that were hunted and trapped weigh an average of 200 pounds less than they did 20 years ago, McKibben said. Scientists think the weight loss is a result of the bears having less ice from which to hunt seals.