With El Niño officially over, new data shared yesterday by NASA’s GISS shows the average surface temperature was 0.93 degrees Celsius (1.57°F) above average for May 2016, the first time in eight months that it was under one degree Celsius. Even the satellite temperature record released this month shows the global average temperature for May 2016 is 0.55 degrees Celsius (0.99°F) above the thirty-year average for that month, down 0.16 degrees Celsius (0.29°F) from last month. The satellite’s average global temperature is for the lower troposphere, which is the air from the ground to about four miles up.
In both cases, satellite and NASA datasets show that rapid cooling is underway now that the 2015-2016 El Niño episode is officially over. Experts now believe we are headed into a La Niña event based on historical precedents. With a La Niña comes cooler temperatures and less precipitation in many areas. NOAA is forecasting a 75 percent chance one will form by September.
Dr. John Christy, who maintains and produces the satellite reports, shows the May anomaly map where much of the Earth is currently cooling off, even as we head into summer (see slideshow). Because of the strong, naturally occurring El Niño that spiked temperatures for the past eight months, the Northern Hemisphere experienced a much warmer winter while South America was inundated with rainfall.
May 2016 was the second warmest May in the satellite temperature record, trailing only May 1998 by 0.11 degrees Celsius (another strong El Niño year), writes Dr. Christy, who is also the director of the Earth System Science Center at the University of Alabama/Huntsville. He also points out that when compared to seasonal norms, “May 2016 was the eighth warmest month overall since the satellite temperature dataset began in December 1978.”
Dr. Christy also says that the 16 warmest months on the record (and 21 of the warmest 25), all occurred during one of three El Niño events. These events occurred in 1997-1998, 2009-2010, and 2015-2016. He notes that the effects from an El Niño are “especially noticeable when comparing temperatures from a specific month,” adding: “In the May data, three El Niño Mays are warmer than the other 35 by an amount that is statistically significant.”