The signs of climate change—rising oceans, melting Arctic ice and increasing greenhouse gases among them—are continuing inexorably, the U.S. National Oceanic and Atmospheric Administration (NOAA) said in a report issued on Tuesday August 6.
Culling data from 384 scientists hailing from 52 countries, NOAA said in its report, 2012 State of the Climate, that globally 2012 was among the 10 warmest years on record. However temperature was just the tip of the melting iceberg.
"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 Acting NOAA Administrator Kathryn D. Sullivan in a statement summarizing the peer-reviewed report.
Arctic changes, including temperature increases and increased ice melt, were the most marked exhibitors of climate change and were highlighted in the federal study, released online by the American Meteorological Society (AMS).
“Conditions in the Arctic were a major story of 2012, with the region experiencing unprecedented change and breaking several records,” NOAA said in its statement. “Sea ice shrank to its smallest summer-minimum extent since satellite records began 34 years ago. In addition, more than 97 percent of the Greenland ice sheet showed some form of melt during the summer, four times greater than the 1981-2010 average melt extent.”
Oceans’ heat content stayed at its record high in the upper half-mile of depth, with marked temperature increases below that, at 2,300 to 6,600 feet, NOAA said. Although temperatures per se have not warmed significantly over the past 10 years, there have been “remarkable changes in key climate indicators” such as dramatically rising ocean heat content, record summer Arctic sea ice melt and the melting of nearly the entire top layer of Greenland’s ice sheet last summer, said Tom Karl, director of the National Climatic Data Center, to the Associated Press. Sea level was also at record highs.
"It's critically important to compile a big picture," Karl told the news wire. "The signs that we see are of a warming world."
These conditions and trends played out most strongly in the Arctic, which is manifesting the most dramatic symptoms of climate change, NOAA said.
Polarity in the saline content of water was also noted, with high-evaporation areas containing saltier waters and low-evaporation regions showing more fresh water, NOAA said. This suggests that “precipitation is increasing in already rainy areas and evaporation is intensifying in drier locations,” NOAA said.
Although La Niña helped keep ocean levels down during the first half of 2011, NOAA reported, they “rebounded to reach record highs in 2012,” with global sea levels increasing on average 3.2 millimeters per year over the past two decades.
Likewise, greenhouse gas concentrations, the main ones being carbon dioxide, methane and nitrous oxide, continued their increase in 2012, NOAA said. The global economic downturn actually reduced manmade emissions slightly, NOAA said, but 2011 emissions were at a record high, with CO2 in particular surpassing the 400 parts per million mark in at monitoring stations in the Arctic.
NOAA officials emphasized that they were not interpreting the data, merely passing it on, letting the facts speak for themselves.
"This report does not try to explain why we are seeing what we are seeing," Karl told The Wall Street Journal. "The report is focused only on what the observations are telling us."