Why Global Climate Change Comes Quickly

This somewhat long and dense article is well worth the wading through, in order to have the bejesus scared out of one, once the realization sets in that the climate has, in the past, changed rather quicker than previously supposed. Also worth a mention are the potentially mischievous possibilities of releasing methane from melting permafrost, increasing the feeback effect dramatically (money quote: "Thresholds may produce unexpected system responses").