Mongabay: More than half Antarctica’s penguin colonies are at risk by a 2-degree global rise in temperatures, according to a report released by the environmental group WWF. 2°C is Too Much cites research showing that 50 percent of the emperor penguins and 75 percent of the Adélie penguins are at risk by a 2-degree increase in temperatures. The report says loss of sea ice will impede penguin nesting and diminish krill populations, an important source of food in the Antarctic food …