2013 Was Either the 4th or the 7th Hottest Year Ever. Either Way, It's Warming Up
This week’s big climate news isn’t that half of America is shivering through another cold snap brought on by the second coming of the polar vortex. It’s that the entire planet continues heating up in spite of it.
The National Oceanic and Atmospheric Administration just released climate data for 2013 showing that last year was the fourth warmest since record keeping began in the 1800s. That makes 2013 the 37th consecutive year global temperatures were above the 20th-century average.
This week NASA also released global temperature data identifying 2013 as the seventh warmest recorded by its scientists. NOAA and NASA have slightly different ways of measuring temperatures at the poles, which can change readings. But the agencies arrived at the same conclusion: Higher concentrations of man-made greenhouse gases in the atmosphere are warming the planet.
Last year “adds to the evidence for ongoing climate change," said NASA climatologist Gavin Schmidt. "While one year or one season can be affected by random weather events, this analysis shows the necessity for continued, long-term monitoring."
Schmidt’s point about long-term trends is essential. There’s an old maxim: Climate is what you expect; weather is what you get. Yes, climate influences weather, but no single weather system tells us much about the climate. This is a key distinction to make as Americans in the Midwest and the East Coast slog through a winter fraught with Arctic temperatures and multiple snowstorms. Just because it is cold today does not mean the planet has stopped heating up; it’s just as easy to find contrary fodder for debate, especially if you are in Australia right now.
Shortly before NOAA and NASA scientists released their data, public opinion researchers unveiled findings that demonstrate the importance of communicating the difference between climate and weather.
A November 2013 poll conducted by the Yale Project on Climate Change Communication found that 23 percent of Americans don’t believe in global warming, up from 16 percent in April 2013. The uptick came after a mild fall for temperatures and a slower year for natural disasters. (There were only seven billion-dollar natural disasters in the U.S. last year, compared with 11 in 2012.) “Last year in the United States was relatively calm with no land-falling hurricanes, fewer tornadoes, and drought relief in the Great Plains,” reported the Yale researchers. “In turn, fewer Americans say they experienced an extreme weather event last year.”
In a previous Yale study, conducted in December 2012 after a brutally hot summer, a warm fall and winter, and a string of weather disasters, researchers found that 74 percent of Americans agreed that “global warming is affecting weather in the United States.” But the November 2013 survey found that only 56 percent of Americans agreed with that statement.
The change was significant but not all that surprising. People naturally respond to the conditions around them. And considering the range of nonscientific opinions about the lack of global warming force-fed to them by television pundits every time snow falls from the sky, the drop was even more understandable.
But it’s important to remember that the scientific community is not changing its position in the same way. True, climatologists debate just how much influence global warming has on individual droughts, heat waves, and hurricanes—but there is near unanimous agreement that greenhouse gas emissions from human activity are “juicing” the climate, making extreme weather more severe and frequent.
Scientists are even investigating whether the polar vortex that's freezing America has been influenced by the accelerating melt of Arctic sea ice, which may be impacting atmospheric circulation.
In that case the freak cold snap will be strong evidence that global warming is occurring.