Annual State of the Climate Report Outlines Data Behind Climate Change, 2012 Warmest Year on Record for US

The 23rd annual State of the Climate report released Tuesday indicates that the world is getting warmer, with 2012 among the 10 warmest years ever recorded and new records set for sea level rise and melting ice in Greenland and the Arctic. Last year was the warmest on record in the US and Argentina. 

The report is the product of 384 scientists from 52 countries, with experts at NOAA's National Climactic Data Center serving as lead editors. The data within the report provide an annual update of global climate indicators, notable weather events and other facts collected by environmental monitoring stations and instruments on land, sea, ice and sky.

"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," said NOAA Acting Administrator Kathryn D. Sullivan, who is listed as a lead author of the study, which is published in collaboration with the American Meteorological Society, the US Army Corps of Engineers and the Met Office Hadley Centre in the UK.

"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 likened the report to an "annual checkup on the planet's health," however, it is no climate physician, the report only provides data and makes no assessment of the causes of the observed changes.

The full report can be viewed here, and a 14-slide PowerPoint presentation is available here. Some of NOAA's selected highlights from the report are below:

• Warm temperature trends continue near Earth's surface: Four major independent datasets show 2012 was among the 10 warmest years on record, ranking either 8th or 9th, depending upon the dataset used. The United States and Argentina had their warmest year on record.
• La Niña dissipates into neutral conditions:  A weak La Niña dissipated during spring 2012 and, for the first time in several years, neither El Niño nor La Niña, which can dominate regional weather and climate conditions around the globe, prevailed for the majority of the year.
• The Arctic continues to warm; sea ice extent reaches record low: The Arctic continued to warm at about twice the rate compared with lower latitudes. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June each reached new record lows. Arctic sea ice minimum extent (1.32 million square miles, September 16) was the lowest of the satellite era. This is 18 percent lower than the previous record low extent of 1.61 million square miles that occurred in 2007 and 54 percent lower than the record high minimum ice extent of 2.90 million square miles that occurred in 1980. The temperature of permafrost, or permanently frozen land, reached record-high values in northernmost Alaska. A new melt extent record occurred July 11-12 on the Greenland ice sheet when 97 percent of the ice sheet showed some form of melt, four times greater than the average melt this time of year.
• Antarctica sea ice extent reaches record high: The Antarctic maximum sea ice extent reached a record high of 7.51 million square miles on September 26. This is 0.5 percent higher than the previous record high extent of 7.47 million square miles that occurred in 2006 and seven percent higher than the record low maximum sea ice extent of 6.96 million square miles that occurred in 1986.
• Sea surface temperatures increase: Four independent datasets indicate that the globally averaged sea surface temperature for 2012 was among the 11 warmest on record.  After a 30-year period from 1970 to 1999 of rising global sea surface temperatures, the period 2000-2012 exhibited little trend. Part of this difference is linked to the prevalence of La Niña-like conditions during the 21st century, which typically lead to lower global sea surface temperatures.
• Ocean heat content remains near record levels: Heat content in the upper 2,300 feet, or a little less than one-half mile, of the ocean remained near record high levels in 2012. Overall increases from 2011 to 2012 occurred between depths of 2,300 to 6,600 feet and even in the deep ocean.
• Sea level reaches record high: Following sharp decreases in global sea level in the first half of 2011 that were linked to the effects of La Niña, sea levels rebounded to reach record highs in 2012. Globally, sea level has been increasing at an average rate of 3.2 ± 0.4 mm per year over the past two decades.