Current sea level rise

Trends in global average absolute sea level, 1870–2008.[1] Changes in sea level since the end of the last glacial episode. Current sea level rise is about 3 mm/year worldwide. Between 1870 and 2004, global average sea levels rose 195 mm (7.7 in), 1.46 mm (0.057 in) per year.[5] From 1950 to 2009, measurements show an average annual rise in sea level of 1.7 ± 0.3 mm per year, with satellite data showing a rise of 3.3 ± 0.4 mm per year from 1993 to 2009,[6] a faster rate of increase than previously estimated.[7] It is unclear whether the increased rate reflects an increase in the underlying long-term trend.[8] Two main factors contribute to observed sea level rise.[9] The first is thermal expansion: as ocean water warms, it expands.[10] The second is from the melting of major stores of land ice like glaciers and ice sheets. On the timescale of centuries to millennia, the melting of ice sheets could result in even higher sea level rise. Overview of sea-level change[edit] Projections[edit]

Change and Sea Level Rise Melting of Glaciers and Ice Sheets One of the most pronounced effects of climate change has been melting of masses of ice around the world. Glaciers and ice sheets are large, slow-moving assemblages of ice that cover about 10% of the world’s land area and exist on every continent except Australia. They are the world’s largest reservoir of fresh water, holding approximately 75% (1). Over the past century, most of the world’s mountain glaciers and the ice sheets in both Greenland and Antarctica have lost mass. One of the best-documented examples of glacial retreat has been on Mount Kilimanjaro in Africa. Image from global-greenhouse-warming.com When researching glacial melting, scientists must consider not only how much ice is being lost, but also how quickly. Image from UNEP In Antarctica, recent estimates show a sharp contrast between what is occurring in the East and West Antarctic Ice Sheets. Impacts The melting back of the glaciers and ice sheets has two major impacts. Sea Level Rise

Sea Levels Rising Fast on U.S. East Coast Charles Q. Choi (Also see "New York, Boston 'Directly in Path' of Sea Level Rise." ) Sea levels worldwide are expected to rise as global warming melts ice and causes water to expand. Now it seems scientists have pinpointed just such a variance. Analyzing tide-level data from much of North America, U.S. Global sea level rise averaged about 0.6 to 1 millimeter annually over the same period. "If you talk with residents of this hot spot area in their 70s or 80s who've lived there all their lives, they'll tell you water is coming higher now in winter storms than it ever did before," said study co-author Peter Howd , an oceanographer contracted with the USGS. "We're now finally getting to the point where we can measure their observations with our highfalutin scientific instruments." (Sea sea level rise pictures .) For residents of New York and cities up and down the eastern seaboard, those numbers should become a lot more than ink on paper. But it's not just cities that are expected to suffer.

Scientists warn US east coast over accelerated sea level rise | Environment A stormy Atlantic ocean hits the coast of Buxton, North Carolina. Photographer: Ted Richardson/Bloomberg via Getty Images Sea level rise is accelerating three to four times faster along the densely populated east coast of the US than other US coasts, scientists have discovered. The zone, dubbed a "hotspot" by the researchers, means the ocean from Boston to New York to North Carolina is set to experience a rise up a third greater than that seen globally. Asbury Sallenger, at the US geological survey at St Petersburg, Florida, who led the new study, said: "That makes storm surges that much higher and the reach of the waves that crash onto the coast that much higher. The hotspot had been predicted by computer modelling, but Sallenger said: "Our paper is the first to focus on using real data to show [the acceleration] is happening now and that we can detect it now." The impacts of the rising seas are potentially devastating, said the scientists.