NOAA reports today that May was the globe’s warmest in 134 years of records, besting the previous high mark established in 2010.  Last week, NASA and the Japan Meteorological Agency – in independent analyses – also released data indicating it was our home planet’s toastiest May on record.

May  2014 temperature difference from normal from NASA

Record warm ocean waters helped the planet’s temperature soar to record high levels, NOAA says.  The average temperature of the ocean surface rose to 1.06F degrees above normal – matching the biggest difference from normal in any month dating back to 1880.

The warming of the oceans reveals the symptoms of a developing El Niño event in which sea surface temperatures in the tropical Pacific rise, pumping large quantities of heat into the atmosphere.  The past warmest years on records – 2010 and 1998 – coincided with El Niño events.  NOAA says there is a 70 percent chance El Niño develops this summer and 80 percent chance by late in the fall.

John Christy,  a climate scientist at the University of Alabama in Huntsville (UAH) who curates a satellite-based record of Earth temperature measurements, thinks chances are good 2014 will end up as the warmest year on record: “The long-term baseline temperature is about three tens of a degree (C) warmer than it was when the big El Niño of 1997-1998 began…”, he said in a press release. “With the baseline so much warmer, this upcoming El Niño won’t have very far to go to break that … record.”

May 2014 was the third warmest in the UAH satellite record Christy maintains (dating back to 1978-1979).

The last three months have been unusually warm around the planet. The Japan Meteorological Agency found the March through May period – spanning meteorological spring – was the warmest on record. NOAA’s analysis determined it was the second warmest such stretch, trailing 2010 by a slim margin.

Each of the last three months has ticked up slightly relative to normal in NOAA’s analyses. March was the 4th warmest on record. April (2014) tied April 2010 for the warmest on record. May (2014) then edged ahead of May 2010 by 0.03 degrees F (though that is within the margin of error).

It was the 39th consecutive May above the 20th century average and 351st straight month above average.

Much of the planet was warmer than normal in May, NOAA says. The warmest weather with respect to normal concentrated in eastern Kazakhstan, parts of Indonesia, and central and northwestern Australia. It was the third warmest May on record Down Under.

May 2014 temperature difference from normal from NOAA.

Snow and ice conditions around the world largely reflected the elevated May temperatures:

* Northern Hemisphere and Eurasian snow cover extent was the sixth smallest on record (in 48-years of records).
* Arctic sea ice extent was third smallest on record (since 1979)

The exception to this is in the Antarctic where sea ice set a record high in May – but the behavior of Antartic sea ice is complex and more closely related to wind and ocean patterns – rather than a simple reflection of temperature.