Climate Central: This year the hole formed later and lasted two weeks longer than usual, leading to almost 100 percent ozone depletion. While ozone-depleting chemicals are still playing a role, natural factors, such as stratospheric circulation, also helped drive this years widespread thinning. During September we typically see a rapid ozone decline, ending with about 95 percent depletion in that layer by October 1, Bryan Johnson, a researcher at the Earth System Research Laboratory, said in a press release....