September 2012: Earth's warmest September on record

September 2012 was tied with 2005 as the globe's warmest September on record, according to the National Oceanic and Atmospheric Administration's National Climatic Data Center (NCDC). Global temperature records begin in 1880. NASA rated September 2012 the 4th warmest September on record. September 2012 global land temperatures were the 3rd warmest on record, and global ocean temperatures were the 2nd warmest on record. September 2012 was the 331st consecutive month with global temperatures warmer than the 20th century average. The last time Earth had a below-average September global temperature was in 1976, and the last below-average month of any kind was February 1985. Global satellite-measured temperatures in September 2012 for the lowest 8 km of the atmosphere were 5th or 3rd warmest in the 34-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH). Wunderground's weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of September 2012 in his September 2012 Global Weather Extremes Summary.


Figure 1. Departure of temperature from average for September 2012, which tied 2005 as the warmest September on record. Parts of east central Russia observed record warmth, as did parts of Venezuela, French Guinea, and northern Brazil. Nearly all of South America was much warmer than average, as were western Australia and central to eastern Europe. Far eastern Russia, a few regions in southern Africa, and parts of China were cooler than average. Image credit: National Climatic Data Center (NCDC) .

El Niño watch continues
Neutral El Niño conditions exist in the equatorial Pacific, where sea surface temperatures were 0.1°C above average as of October 15. NOAA's Climate Prediction Center (CPC) has issued an El Niño watch, and gives a 55% chance that an El Niño event will be in place during the October - November - December period. Temperatures in the equatorial Eastern Pacific need to be 0.5°C above average or warmer to be considered an El Niño. El Niño conditions tend to bring cooler and wetter winter weather to the Southern U.S.


Figure 2. Arctic sea ice extent in September 2012 was the lowest measured, since satellite records began in 1979. Image credit: National Snow and Ice Data Center (NSIDC).

Arctic sea ice falls to lowest extent on record in September
Arctic sea ice extent during September reached its lowest extent in the 35-year satellite record, according to the National Snow and Ice Data Center (NSIDC). As of October 14, Arctic sea extent had set a new record low for the date every day since July 27. I have much more to say about this year's extraordinary loss of Arctic sea ice in my September 20, 2012 post, Earth's attic is on fire: Arctic sea ice bottoms out at a new record low.

Jeff Masters