Earth on Pace for Its Warmest Year on Record
By Jeff Masters
November 2016 was Earth's fifth warmest November since record keeping began in 1880, said NOAA's National Centers for Environmental Information on Monday.
November 2016 was 0.7 C (1.31 F) warmer than the 20th-century November average, but 0.23 C (0.41 F) cooler than the record warmth of 2015. NASA reported that November 2016 was the second warmest November in its database, behind November 2015. The difference between the two data sets is, in large part, due to how they handle the data-sparse areas in the Arctic, which was record warm in November. NOAA does not include most of the Arctic in their global analysis, while NASA does.
Figure 1NOAA / National Centers for Environmental Information
Figure 1. Departure of temperature from average by region for November 2016, the fifth warmest November for the globe since record keeping began in 1880. Record warmth was observed across parts of central and southeastern Canada, some areas across the far northern tier of the U.S. along with a portion of the southwest U.S., parts of western and southern Mexico, sections of eastern and west central Africa, a few parts of northern South America, and regions of some southeastern Asia island nations. Cooler-than-average conditions were observed across much of the central Eurasian continent, with monthly temperatures at least 5 C (9 F) below average in central Russia and parts of northeastern Asia. In South America, central Bolivia experienced record cold temperatures during November.
A weak La Niña event is now underway in the Eastern Pacific and the cool waters present there have helped cool the planet slightly below the record warm levels observed during the strong El Niño event that ended in May 2016. The fact that November 2016 was still the 2nd to 5th warmest November on record despite the presence of La Niña can mostly be attributed to the steady build-up of heat-trapping greenhouse gases due to human activities.
NOAA's global surface temperature for the year so far (January-November 2016) is an impressive 0.94 C (1.69 F) above the 20th-century average and 0.07 C (0.13 F) warmer than the previous January-to-November record, set in 2015. Remarkably, no continental land areas were cooler than average for the year-to-date. It is almost certain that 2016 will end up as the warmest year on record for the planet, giving Earth three consecutive warmest years on record.
Ocean-Only, Land-Only, and Lower Atmosphere Temperatures in November
Ocean-only temperatures this November were the second warmest on record, while land-only temperatures were the 12th warmest on record. (Since most of Earth's surface is covered by ocean, the land-plus-ocean reading is dominated by the ocean-only temperatures, thus keeping November 2016 so warm globally). For the lowest 8 km of the atmosphere, global satellite-measured temperatures in November 2016 and for the January-November year-to-date period were the warmest in the 38-year record, according to the University of Alabama in Huntsville. For the stratosphere, the year-to-date temperatures were the coldest on record. Stratospheric cooling is a classic symptom of an increase in greenhouse gases in the atmosphere—the upper atmosphere must cool to compensate for warming near the surface.
Figure 2NOAA / National Centers for Environmental Information
Figure 2. Departure from the 20th-century average for the global January-through-November temperature for the years 1880 - 2016. This year has seen by far the warmest temperatures on record for the year-to-date period.
Arctic Sea Ice Hits Its Lowest November Extent on Record
November 2016 Arctic sea ice extent was the lowest in the 38-year satellite record, according to the National Snow and Ice Data Center (NSIDC). The record low was due to unusually high air temperatures, winds from the south and a warm ocean. For a brief period in the middle the month, total extent actually decreased by 50,000 square kilometers (9,300 square miles.) The only other November retreat of Arctic sea ice in the 38-year satellite record was a less pronounced and brief retreat of 14,000 square kilometers (5,400 square miles) that occurred in 2013. Seven of the eleven months of 2016 have seen record-low Arctic sea ice and the annual sea ice minimum in September was the second lowest on record.
Sea ice around Antarctic was also extraordinarily low in November—more than 1 million sq km below the previous monthly record, from 1986. The monthly value was 5.7 standard deviations below the long-term average, a mammoth departure and more than twice as large as the previous record. Sea-ice formation processes are largely decoupled between the Arctic and Antarctic, so there is no obvious direct link between the record-low values at the two poles in November.
Figure 3. Daily mean temperatures by Julian day through Dec. 18 over the Arctic north of 80 N, as compiled by the Danish Meteorological Institute. Temperatures for this year (red line) are compared to the long-term averages (green line.) Temperatures in October, November and the first half of December were 5 - 20 C (8 - 36 F) above average. This is by far the warmest multi-month anomaly measured since Danish Meteorological Institute began tracking Arctic temperatures in 1956. According to the 2016 Arctic Report Card, issued last week, the average surface air temperature of the Arctic for the year ending September 2016 was by far the highest since 1900, and new monthly record highs were recorded in January, February, October and November 2016.
No Billion-Dollar Weather Disasters in November 2016
According to the November 2016 Catastrophe Report from insurance broker Aon Benfield, no billion-dollar weather-related disasters hit the planet in November. However, one event from October—Super Typhoon Chaba in South Korea and Japan—accumulated enough damage claims to be rated a billion-dollar disaster by the end of November. From January through November 2016, there were 30 billion-dollar weather disasters globally. This is the fourth greatest number of such disasters in any year since 1990. Only 2013 (41), 2010 (40) and 2011 (35) had more. For the U.S., Aon Benfield counted thirteen billion-dollar weather disasters during January - November 2016, which is the second highest number of such disasters on record since 1980 (the record: sixteen in 2011).