When you hear about melting glaciers in Greenland, you probably think this a result of manmade global warming. But more and more scientists are coming to an understanding that Greenland’s ice sheet has been naturally melting for millennia, and far from being a bad thing, may actually be helping the ocean’s marine life. The reason is that Greenland’s thaw is washing about 300,000 metric tons of nutrient iron into the north Atlantic each year, and studies have shown that blooms of algae coincide with peak runoffs. Since algae is also known to absorb carbon dioxide, some scientists now think, believe it or not, that this modest melting of Greenland’s glacier may actually be slowing global warming.