Global Warming: On Hold? Michael Reilly, Discovery News

March 2, 2009 -- For those who have endured this winter's frigid temperatures and today's heavy snowstorm in the Northeast, the concept of global warming may seem, well, almost wishful.

But climate is known to be variable -- a cold winter, or a few strung together doesn't mean the planet is cooling. Still, according to a new study in Geophysical Research Letters, global warming may have hit a speed bump and could go into hiding for decades.

Earth's climate continues to confound scientists. Following a 30-year trend of warming, global temperatures have flatlined since 2001 despite rising greenhouse gas concentrations, and a heat surplus that should have cranked up the planetary thermostat.