Despite some miserably cold weather along the eastern half of North America, this January was one of the warmest ever recorded globally.
According to data from the National Oceanic and Atmospheric Administration (NOAA), this was the fourth-hottest January the world has seen since record-keeping began. Meanwhile, NASA’s Goddard Institute for Space Studies (GISS) compiled its numbers and determined this was the third-hottest January since its records started in 1880.
Both institutions essentially work off the same data sets, but analyze them slightly differently. So while they occasionally diverge in their headline findings, their numbers actually sync up very tightly. For instance, when NOAA and GISS declared 2013 the 4th and 7th warmest year on record, respectively, the actual difference between the rankings amounted to just two-hundredths of a degree.
Furthermore, NOAA’s numbers show this was the 38th January in a row with temperatures above the 20th Century average. And the last time any month dipped below that threshold was February of 1985. GISS put January 2014′s global temperatures at an average of 0.70°C (or 1.26°F) above the 1951-1980 average.
Regional temperatures over Alaska, Greenland, and portions of Asia were especially high during January, and a good number of other regions across the globe saw temperatures higher than the 1981-2010 period. This puts the “polar vortex” and the accompanying cold spell that swept the lower 48 states in context: America only covers two percent of the Earth’s surface, temperature fluctuations here are hardly indicative of global trends.
The polar vortex itself wasn’t an expansion of cold temperatures so much as a temporary departure of cold air from the Arctic. In fact, there’s evidence that global warming led to that departure by destabilizing the atmospheric jet stream that governs much of the United States’ weather.
Other records from last month included the third-wettest January on record for Britain, the fifth-wettest for Australia, the fifth-driest on record for the U.S., and the second-warmest since 1961 for China. Arctic sea ice hit its fourth-lowest level on record, while Antarctic ice cover hit its second-highest extent on record — the former being more directly vulnerable to global warming, while the latter is influenced by a more complex set of factors.