Chelsea Harvey in reported in the Washington Post: “Rising global temperatures may be affecting the Greenland ice sheet — and its contribution to sea-level rise — in more serious ways tha[n] scientists imagined, a new study finds.” What’s up with this? The concern is about the “firn”—a porous sheet of snow that slowly freezes into ice over time as more and more snow accumulates atop it but can absorb melt water in the meantime. According to the study, a layer of ice several meters thick has … [Read more...]