We will most likely see larger than previously expected increases in sea levels over the next century according to a recent study conducted by a team of researchers from the Institute of Arctic and Alpine Research at the University of Colorado, Boulder. They anticipate that the global warming-induced melting of mountain glaciers and ice caps will account for the brunt of that rise, as much as 2-3 times more than the amount originally predicted.
The scientists used satellite monitoring to determine the contribution of all land-based ice (except for Greenland and Antarctica's huge ice sheets) to rising sea levels and found that the volume of ice melting into the sea each year from ice caps and glaciers was 100 cubic miles (or 417 cubic km). They determined, however, that this volume had now increased by a further 3 cubic miles each year, prompted by an acceleration in the rate at which the ice caps and glaciers are melting.Unlike what many other scientists have said — including, most prominently, NASA's James Hansen (who believes that a rise in 17 inches by 2100 will be mainly precipitated by the melting of ice sheets) — the authors of this study believe that the loss of ice from glaciers and ice caps will account for the majority of the expected rise in sea levels. "One reason for doing this study is the widely held view that the Greenland and Antarctic ice sheets will be the principal cause of sea-level rise. But we show that it is the glaciers and ice caps, not the two large ice sheets, that will be the big players in the sea rise for at least the next few generations," said Mark Meier, the study's lead scientist.
These latest results also run counter to the IPCC's own recent estimates, which predicted a rise in sea levels of about 3 inches (7.6 cm) this century (much too low, it now appears). This study, which does not take into account the likely contributions of the thermal expansion of water and the melting of ice sheets, suggests that sea levels will increase by an average of 4 - 9.5 inches and, when those last two events are factored in, by as much as 12 in.
Via ::The Independent: Sea levels may rise by 9 inches this century, scientists warn (newspaper), ::Science Reports: Glaciers Dominate Eustatic Sea-Level Rise in the 21st Century (magazine, sub. required), ::Climate Progress: The Independent blows the sea level rise story (blog)