State of Climate Report Reveals 'Unprecedented' Arctic Melting
Climbing greenhouse gases, rising seas, record-breaking temperatures: all signs of a 'changing and varying climate'
"Our planet as a whole is becoming a warmer place," said Kathryn D. Sullivan, Acting Administrator at the National Oceanic and Atmospheric Administration (NOAA).
Citing climbing greenhouse gases, rising seas, record-breaking temperatures and a rapidly melting Arctic, the American Meteorological Society's (AMS) annual "State of the Climate in 2012," released Tuesday by NOAA, revealed a planet undergoing dramatic environmental change.
“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," added Sullivan. "The findings are striking."
Examining such climate indicators as greenhouse gas concentrations, temperature of the lower and upper atmosphere, cloud cover, sea surface temperature, sea-level rise, ocean salinity, sea ice extent and snow cover, the report was compiled by 384 scientists from 52 countries.
Most notably, the scientists found that the "unprecedented change" occurring in the Arctic was the "major story of 2012."
According to the report, the Arctic continued to warm "at about twice the rate compared with lower latitudes," with the amount of sea ice shrinking to its smallest "summer minimum." At 1.32 million square miles on September 16, it marked the least amount of ice since satellite records began 34 years ago.
Further, more than 97 percent of the Greenland ice sheet showed "some form of melt" during the 2012 summer—four times greater than the 1981–2010 average melt extent.
"The record or near-records being reported from year to year in the Arctic are no longer anomalies or exceptions," said Jackie Richter-Menge, a civil engineer with the US army corps of engineers. "Really they have become the rule for us, or the norm that we see in the Arctic and that we expect to see for the foreseeable future."
Some of NOAA's other highlights from the report include:
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.
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.
Greenhouse gases climb: Major greenhouse gas concentrations, including carbon dioxide, methane, and nitrous oxide, continued to rise during 2012. [...] Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, reaching a global average of 392.6 ppm for the year. In spring 2012, for the first time, the atmospheric CO2concentration exceeded 400 ppm at several Arctic observational sites.
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.