WASHINGTON — Miami would be a memory, Bangkok a soggy shadow of its former self and the Maldive Islands would vanish if melting polar ice keeps fueling a faster-than-expected rise in sea levels, scientists reported on Thursday. In an issue of the journal Science focusing on global warming, climate scientist Jonathan Overpeck of the University of Arizona reported that if global trends continue, Earth could ultimately see sea levels 20 feet higher than they are now. By the end of this century, Earth would be at least 4 degrees F (2.3 degrees C) warmer than now, or about as hot as it was nearly 130,000 years ago. Back then, significant portions of the Greenland and Antarctic ice sheets melted, pushing the global sea levels to about 20 feet higher than current levels. A similarly dramatic, and in some cases catastrophic, rise in ocean levels could happen by the year 2500, Overpeck said in a telephone interview, but he noted it could come sooner. ‘We know when the sea level was that high in the past, and we know how much warming is necessary to get that amount of sea level rise from both Greenland and […]