Half of the world's wetlands have been destroyed in the past century, while melting ice sheets in Greenland and Antarctica contributed to an 11 milimeter rise in sea levels, according to new reports. A study by the Economics of Ecosystems and Biodiversity found that just 12.8 million kilometers remains of the 25 million kilometers of wetlands that existed in 1900, as over-exploitation, aquaculture, and storm damage destroy them at a rate of as much as 80 percent per year in some areas. Wetlands, which can regulate water cycles, act as carbon sinks, and protect coastal land from storms and flooding, usually deliver benefits more cheaply than constructed structures. In the United Kingdom, for instance, wetlands have been found to provide cost savings of up to $1.1 million per hectare, and the Mississippi River Delta provides $12-47 billion in benefits every year. Meanwhile, a global team of scientists announced that Greenland and Antarctica have lost four trillion tons of ice in the last 20 years, leading to an 11 milimeter rise in sea levels. The study also found that Greenland is losing ice mass at five times the rate of the early 1990s. For the story on wetlands, see http://news.mongabay.com/2012/1129-handley-wetlands.html. For the story on ice loss, see http://www.guardian.co.uk/environment/2012/nov/29/greenland-antarctica-4-trillion-tonnes-ice.