Washington — The year 2012 was among the 10 warmest on record, according to the 2012 State of the Climate report, compiled by almost 400 scientists from 52 nations. Based on data collected by scientific instruments monitoring land, sea, ice and atmosphere, the report provides an overview of global climate indicators, notable weather events and other meteorological observations.
U.S. scientists at the National Climatic Data Center (NCDC) were the lead editors of the publication, which was issued by the American Meteorological Society. The NCDC reports that dozens of government, academic and private agencies worldwide contributed to the conclusions, providing insights on regional trends sometimes not captured in data alone.
The 2012 trends consistently show a changing, 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 Kathryn D. Sullivan, who is acting administrator at the National Oceanic and Atmospheric Administration, the parent agency of the NCDC.
Now in its 23rd year, the State of the Climate report is offered to public officials as a tool to help them make decisions about their communities. The data provide information for tackling a range of planning considerations: Is the sea level rising into our city? Is it safe to build on that shoreline? How should we prepare for more violent storms?
Besides warming trends, Sullivan said, the report shows that extreme weather events — monsoons and floods, for instance — are “more frequent and more intense than what we have accounted for in the past, what we have presumed in our business plans, our communities, our infrastructure.”
Jessica Blunden, a scientist involved in climate monitoring at the NCDC, pointed out three of the “striking findings” in the report:
• Global average ocean temperature was higher in 2012 than the averages for the 1980s to 2010.
• Heat content — heat stored in the ocean — in the upper 700 meters of the ocean remained near record-high values in 2012.
• Average global sea level reached a record high in 2012 and has been on a steady rise since 1993.
Blunden also pointed out that the ocean’s heat storage is climbing in the deep ocean, “even down to levels a mile [1.6 kilometers] below the ocean’s surface.”
During an August 6 briefing, a research civil engineer said some of “the most compelling evidence of the fact that the global temperatures are warming” emerges from the data collected in the Arctic. Jackie Richter-Menge, a research specialist in cold regions at the U.S. Army Corps of Engineers, said a record low snow cover in Eurasia was noted in 2012. Similar warming trends created record findings in North America, she said.
“Where sea ice cover is declining at a rate of 13 percent a decade, snow cover extent in June is declining at a rate of about 17 percent a decade,” Richter-Menge said.
Observations of the summertime melting season in the planet’s northernmost regions also affirm planetary warming trends. Richter-Menge said satellite observations show one “rare melt event” involving 97 percent of the ice sheet.
“Across the Greenland ice sheet, the ice sheet was relatively dark,” Richter-Menge said. “This relatively dark ice sheet can absorb more sunlight, which can promote more melting.”
In contrast, the Antarctic ice sheet reached a record high in 2012. The ice mass in the planet’s southernmost region is 0.5 percent higher than ever before recorded. U.S. government scientists briefing journalists on the findings said it is beyond the scope of their work to speculate on why that might be happening.
The State of the Climate report shows that greenhouse gases rose again after a slight decline in 2011, presumably caused by the global economic downturn.