Arctic could by ice-free in Summer 2040

Further increases in the atmosphere of so-called greenhouse gases may lead to global warming that causes the already- retreating ice to begin melting four times faster in about 20 years' time, a team led by U.S. National Center for Atmospheric Research scientist Marika Holland says today in research published in the journal Geophysical Research Letters.

``We have already witnessed major losses in sea ice, but our research suggests that the decrease over the next few decades could be far more dramatic than anything that has happened so far,'' Holland said yesterday in a statement posted on the NCAR Web site. ``These changes are surprisingly rapid.''

Using climate-change models, Holland's team forecast that by 2040, ``only a small amount of perennial sea ice'' could be left, according to the statement.