In Lima today, the World Meteorological Organization (WMO) announced that 2014 is on track to be the warmest year on record. The following are five charts that explain the data thus far.
1. 2014’s warming trend has occurred across the globe, throughout the year.
We’re talking about January to October, which WMO customarily discusses in November. (It is expected to finalize its 2014 report early in 2015.) WMO didn’t produce a global temperature map, so here’s one from the National Oceanic and Atmospheric Administration (NOAA):
Red means above the 1981 to 2010 average, and blue means below.
According to WMO, global average temperatures in the first 10 months of 2014 reached 14.57°C. If that average holds, 2014 will be the warmest year on record (although with an error of +/- 0.10°C, 2014 is basically in a statistical tie with several other record years). The above-average warming has been in every ocean and spread across the planet.
Some months this year, including June and October, have set global records outright for average air temperature, says Derek Arndt, chief of the Climate Monitoring Branch of the National Climatic Data Center in Asheville, North Carolina. “The monthly anomalies broke records above the error bars,” he says. “This is very, very unusual.”
Whether the 2014 record, if confirmed, means the end of the so-called warming hiatus is unclear, WMO’s Michel Jarraud told reporters this morning during a teleconference. The hiatus, which began in about 1998, has been typified by a slower rate of increase in average air temperatures than in previous decades.
2. Warming oceans are driving record air temperatures.
The red line on this chart plots 3-month averages of ocean heat content. It shows a record warming spell earlier this year, which continues to drive up the 5-year average of heat content, shown in blue.
3. It’s been a weak El Niño year, which only makes 2014’s warming all the more notable.
Three of the four warmest years since 1900 have been years with El Niño—the phenomenon in which warm water from the western side of the equatorial Pacific sloshes east, increasing global temperatures. Forecasters expected 2014 to be a strong year for El Niño. But it wasn’t, according to dynamicist Kevin Trenberth of the National Center for Atmospheric Research in Boulder, Colorado. Instead, the globe experienced a weak El Niño (the gray bars in the graph below). Still, warming reached record levels.
This observation is “the only significant one” in 2014 temperature data, writes climate scientist James Hansen of Columbia University in an e-mail to ScienceInsider. “The reason that the ocean continues to warm is that Earth is out of energy balance,” Hansen writes. “There is more energy coming in than going out.”
4. and 5. Colder-than-normal temperatures in the eastern United States may be a new feature of global warming.
California and other states in the western United States have set records for high temperatures in 2014, driving an historic drought. But in the central and eastern United States, cold has been the notable development, Arndt says. “We’ve had much cooler than normal conditions in the central U.S.”
The cooler-than-usual temperatures are represented by the big blue blob on the world map below (that’s Florida peeking out at the lower right of the blob), provided by atmospheric scientist Jennifer Francis of Rutgers University, New Brunswick, using NOAA data.
And Francis also provided a chart—again using NOAA data—showing that, in the eastern United States, January to September has been one of the coldest such periods since the 1950s.
Francis has hypothesized that the warming Arctic is altering global circulation patterns, which could make the warm west–cold east pattern more common. (Other scientists, however, dispute some of her ideas.)
Meanwhile, most researchers believe that ever warmer years will become routine as humans pump more carbon dioxide and other warming gases into the atmosphere.