Depending on what source of data you use, 2012 will go down as either the 9th or 10th warmest on record globally, according to NASA and NOAA's National Climatic Data Center (NCDC).
According to NASA, the average temperature globally for 2012 was 58.3 degrees F. (14.6 C.) which is 1.0 F. (0.6 C.) warmer than the mid-20th century baseline, putting 2012 as the 9th warmest on record.
Global temperature anomaly changes from 1880-2012. Video courtesy of NASA and YouTube.
According to the NCDC, the average temperature globally for 2012 was 58.03 F. (14.5 C.), which is 1.03 F. (0.57 C) above the 20th century average, putting 2012 as the 10th warmest on record.
The two warmest years on record globally are 2010 followed by 2005. Official records go back to 1880.
2012 was also the warmest "La Nina" year on record. Image below courtesy of the NCDC.
Key excerpt from the NASA GISS release.......
"One more year of numbers isn't in itself significant," GISS climatologist Gavin Schmidt said. "What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before. The planet is warming. The reason it's warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere."
Scientists from NASA have determined that the drought of 1934 was the driest and most widespread drought in North America over the past 1,000 years.
September 2014 was the warmest September on record globally for land/ocean combined, according to NASA.
While climate change has been responsible for a long-term increase in global temperatures there have been unanswered questions in regards to it's impact on temperature variability.
A recap of the 2014 Arctic melt season.
Scientists from the Lawrence Livermore National Laboratory have concluded the the warming of the top 700 meters of the Southern Hemisphere oceans has been underestimated since 1970.
Changes in the layering of ocean water temperatures surrounding Antarctica are eerily similar to what took place 14,000 years ago.