Due to melting ice and the expansion of a warming ocean, the global sea level rose at a rate of 1.7mm/year during the 20th century and at a rate of more than 3mm/year since 1993, according to NASA.
Climate scientist Josh Willis explained that the "pothole" was caused by the dramatic shift in natural climate patterns from El Niño to La Niña, which redistributed the globe's water, dumping much of it on land this year. Willis said the drop in sea level doesn't change the long term trend: "We're heating up the planet, and in the end that means more sea level rise ... But El Niño and La Niña always take us on a rainfall rollercoaster, and in years like this they give us sea-level whiplash."
As you can imagine, that key fact won't stop conservative media from employing the well-worn and always wrong tactic of using short-term changes to dismiss the long-term trends driven by human-induced global warming.
Matt Patterson of the right-wing Capital Research Center wrote in a Washington Examiner column that the "latest science" shows "man-made global warming may be nothing more than a man-made myth." Patterson pointed to a study about cosmic rays by CERN, which has been portrayed by conservative media as a refutation of manmade global warming, but actually "says nothing" about climate change, as the lead author made clear. In the column, which is titled "New climate science vindicates global warming skeptics," Patterson goes on to say, "what about those [sea] levels? Are they in fact, rising? No, at least not now. According to NASA satellite data updated on Aug. 5 of this year, sea levels have actually fallen from 2010 to 2011."
In an August 30 editorial titled "Watching a Green Fiction Unravel," Investor's Business Daily also cited the CERN study, adding, "it's not just the CERN research creating a problem for them," referring to those concerned about climate change. "They also need to explain why sea levels, like presidential approval numbers and consumer confidence, have fallen."
Meanwhile, the National Academy of Sciences states that although projections of future sea level rise vary, "it is clear that global sea level rise will continue throughout the 21st century due to the GHGs [greenhouse gases] that have already been emitted, that the rate and ultimate amount of sea level rise will be higher if GHG concentrations continue to increase, and that there is a risk of much larger and more rapid increases in sea level."