Globally, 2012 was number eight or nine on the list of warmest years on record. For the United States and Argentina, 2012 was their number one hottest year to date.
The American Meteorological Society (AMS), released a "report card" on the state of the environment, the National Oceanic and Atmospheric Administration (NOAA) reported.
"Many of the events that made 2012 such an interesting year are part of the long-term trends we see in a changing and varying climate - carbon levels are climbing, sea levels are rising, Arctic sea ice is melting, and our planet as a whole is becoming a warmer place," Acting NOAA Administrator Kathryn D. Sullivan, Ph.D, said.
Melting Arctic sea ice was one of the major factors for concern. Researchers started monitoring Arctic ice 37 years ago, and haven't seen such a large melt to date. About 97 percent of Greenland's ice sheet showed at least some signs of melting, this is four times higher than the average melt extent from 1981-2010.
The report outlined the status of several other environmental factors.
Air wasn't the only thing to make the "warmest list." Sea surface temperatures were found to be the 11th warmest on record. The presence of La Niña can cool the ocean's surface, which led to the less impressive temperatures between 2000 and 2012.
La Niña was quite weak this year. It dissipated into "neutral conditions." La Niña and El Niño have the ability to greatly affect weather, but neither was prevalent in 2012. The presence of La Niña had kept sea levels at bay, but 2012 saw a record high.
Water from areas with a high evaporation rate were saltier, on the other hand, water from areas of high precipitation had a lower salt content than expected. This could mean the both precipitation and evaporation are intensifying.
Greenhouse gases were found in unusually high quantities, after experiencing a small dip in past years.
"This annual report is well-researched, well-respected, and well-used; it is a superb example of the timely, actionable climate information that people need from NOAA to help prepare for extremes in our ever-changing environment," Sullivan said.
