Discovered: Science hazards its best guesses about what we'll experience in the new year, showing us previews of rising sea levels, soaring temperatures, and a close encounter with a supercomet. 

West Antarctica will melt quickly, causing sea levels to rise exponentially. A new paper in Nature Geoscience finds that West Antarctica is warming much more quickly than scientists had predicted. In the last 54 years, the ice sheet has warmed 4.4 degrees Farenheit, which corresponds to three times the average rate of global warming. The researchers predict that all that ice melting would cause sea levels to rise by a catastrophic 10 feet within the next several hundred years. [The New York Times]

We'll have a close-call with a supercomet as luminous as the moon. If global warming doesn't kill off the planet, an unstoppable supercomet hurtling towards our home planet might. Next year, we're likely to have a close brush with such an impact. But don't worry, astronomers say that a supercomet called ISON will come spectacularly close to Earth, but won't hit us. Discovered by amateur star-gazers in Eastern Europe in September, this supercomet is projected to approach Earth close enough to put out as much light as the moon. Look for its passage in December 2013.  [Time]

Temperatures will rise worldwide, in part due to El Niño. The weather phenomenon known as El Niño is scheduled to return in winter and spring of 2013, perhaps dethroning 2012 as the warmest year on record. If National Weather Service predictions are right, ocean surface temperatures will warm. That—compounded with rising sea levels and a steady temperature incline—could lead to record-breaking global temperatures, reports New Scientist's Stefan Rahmstorf. [New Scientist]

But remember: we can't predict the future with much precision. Keeping all these predictions in mind, don't forget to stay skeptical of anyone who tells you exactly what will besiege the world's ecosystems next year. Predictive climate models work very well in the long-run, but start to break down when the grain gets too fine according to researchers from the University of Arizona. A team led by Xubin Zeng analyzed the powers of foresight amongst many different climate models, finding that weather forecasts within two weeks remain somewhat reliable—as do those trying to predict climates 30 years or more down the road. But scientists aren't yet very good about knowing whether we should pack an umbrella or swimsuits for the new year. "There has to be a simplification," says Zeng. "The models cannot reflect that kind of resolution. That's why we have all those uncertainties in climate prediction." [University of Arizona]