Seeking to downplay the impacts of climate change, Fox News claimed that sea-level rise would only amount to “a few inches over a century” in a “worst-case scenario.” However, just a few days prior, a draft report from the world's top climate scientists showed that the actual number would be around three feet, exacting a great toll on coastal cities.

On Fox News' America's Newsroom Thursday, anchor Gregg Jarrett suggested that former Vice President Al Gore “tends to exaggerate” the consequences of global warming, alleging that Gore said “the sea level would rise 20 feet” (more on that later). Jarrett continued, “Scientists are laughing at that, saying 'wait a minute, okay, maybe, worst-case scenario, a few inches over a century.'”

But if anyone is “laughing,” it should probably be at Gregg Jarrett, who has evidently modeled his own disregard for science on that of the North Carolina general assembly. Earlier this week, a leaked draft of a major report from the U.N.'s Intergovernmental Panel on Climate Change (IPCC) found that sea levels could rise by more than three feet by the year 2100 if greenhouse gas emissions continue to rise rapidly -- in other words, a “worst-case scenario.” Only in a scenario in which “the world's governments would prove far more successful at getting emissions under control than they have been in the recent past” would sea level rise be limited to “as little as 10 inches” in addition to the eight-inch rise we've already experienced, according to The New York Times. Some scientists have said this assessment is “overly conservative,” and there are studies suggesting “the possibility of as much as two meters (six feet) sea level rise by 2100.”

Even if we suddenly and drastically reduced our emissions, greenhouse gases already emitted have left us "locked in" for catastrophic sea level rise for centuries to come.

None of this will be cheap. Recent research suggests that the global cost of flooding in the world's 136 largest coastal cities -- including New York, Miami and New Orleans -- could reach $52 billion a year by 2050, spurred partly by rising sea levels. Climate Desk created a map showing the cities with the 10 highest annual flood costs by mid-century under this scenario:

Recently, a federal task force convened in the wake of Hurricane Sandy recommended that climate change be taken into account for future planning, as rising sea levels intensify storm surges. Sandy, which did more damage as a result of higher sea levels, cost the U.S. between $50 and $70 billion. 

Jarrett's “20 feet” comment was apparently in reference to a statement from the film An Inconvenient Truth, which has often been targeted by conservatives for supposedly exaggerating climate impacts. However, an England and Wales High Court decision largely endorsed the facts of the movie, and scientists Gavin Schmidt and Michael Mann have explained on the blog Real Climate that in it Gore “correctly asserted” that about 20 feet of sea-level rise would occur in the event that the Greenland or West Antarctic ice sheets melted entirely. The movie never claimed that this would occur in the near future (it is not expected to):

Ice-sheet driven sea level rise Gore correctly asserted that melting of Greenland or the West Antarctic ice sheet would raise sea levels 20 ft (6 meters). In the movie, no timescale for that was specified, but lest you think that the 20 ft number is simply plucked out of thin air, you should note that this is about how much higher sea level was around 125,000 years ago during the last inter-glacial period. Then, global temperatures were only a degree or two warmer than today - and given that this is close to the minimum temperature rise we can expect in the future, that 20 ft is particularly relevant. The rate at which this is likely to happen is however highly uncertain as we have discussed previously.