When people talk about climate change, it's common to envision a slow, drawn-out process that takes decades or longer to unfold. But, looking back through the historical record, rapid Day After Tomorrow-type shifts aren't exactly impossible. A new analysis of Greenland ice cores, led by William Patterson of the University of Saskatchewan, suggests that the Younger Dryas mini ice age, which swept through the Northern Hemisphere 12,800 years ago, engulfed Europe in just a few short months—not decades, as once thought.

That ice age set in after a glacial lake that covered most of northwestern Canada burst and poured into the North Atlantic, where the cold freshwater halted the Gulf Stream and rapidly cooled Europe and North America. Fortunately, although the melting of the Greenland ice sheet could in theory trigger something similar today, the 2007 IPCC report argued that this was "very unlikely" to occur in this century. Still, it's sort of shocking that a change like that could happen so quickly. (Actually, beyond the sensational headline, the real importance of the study is that Patterson and colleagues have developed a new technique to slice carbon isotopes and get more precise readings of the past climate—which, in theory, could help with projections of the future.)

Meanwhile, in other fascinating "climate stuff that happened in a long time ago," two Stanford researchers have an intriguing new theory for the mass extinction that took place 250 million years ago at the end of the Permian-Triassic period—in which 70 percent of all land species, including most dinosaurs, and 90 percent of all ocean species were wiped out.

The scientists, Norman Sleep and Darcy Ogden, argue that the "Great Dying" might've been caused by underground magma that came into contact with Siberia's tar-soaked coal deposits, burning the coal and blasting dust and ash into the stratosphere, along with heaps of carbon-dioxide. The dust would've cooled the planet (as aerosol pollution does), and then, once the ash settled, the CO2 would've heated things back up. Repeated coal explosions could've destabilized the climate. In any case, the theory's intriguing, but still not conclusive (not that the coal industry needs something else to answer for).

(Flickr photo credit: mikelens)