Reuters: The biggest icebergs breaking off Antarctica unexpectedly help to slow global warming as they melt away into the Southern Ocean, scientists said on Monday. The rare Manhattan-sized icebergs, which may become more frequent in coming decades because of climate change, release a vast trail of iron and other nutrients that act as fertilizers for algae and other tiny plant-like organisms in the ocean. These extract carbon dioxide from the atmosphere as they grow, a natural ally for human efforts to...