January 16, 2013
Long-Term Warming Trend Will Continue: NASA
[ Watch the Video: NASA's Analysis of 2012 Global Temperature ]
April Flowers for redOrbit.com - Your Universe OnlineScientists at NASA report that 2012 was the ninth warmest year on record since 1880. This continues a long-term global trend of rising temperatures. With one exception, 1998, the nine warmest years in the 132-year record have all occurred since 2000. The hottest years on record were 2010 and 2005.
An updated analysis released this past Tuesday by NASA's Goddard Institute for Space Studies (GISS) in New York, which monitors global surface temperatures on an ongoing basis compares temperatures around the globe in 2012 to the average global temperature from the mid-20th century. The findings showed how Earth continues to experience warmer temperatures than several decades ago.
In 2012, the average temperature was about 58.3 degrees Fahrenheit. This is 1.0 F warmer than the mid-20th century baseline, with the global average temperature having risen about 1.4 degrees F since 1880.
The research team emphasizes that weather patterns will always cause fluctuations in average temperatures from one year to the next. The continued increase in greenhouse gas levels in the atmosphere, however, assures a long-term rise in global temperatures. Each successive year will not necessarily be warmer than the last, but if the current trend of greenhouse gases continues unchecked, the team expects that each successive decade will be warmer than the last.
"One more year of numbers isn't in itself significant," GISS climatologist Gavin Schmidt said. "What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before. The planet is warming. The reason it's warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere."
Carbon dioxide is a naturally occurring greenhouse gas that traps heat and, largely, controls Earth's climate. The burning of fossil fuels for energy also emits carbon dioxide. Man-made emissions have driven the levels of carbon dioxide in the Earth's atmosphere higher, rising consistently for decades.
In 1880, atmospheric carbon dioxide was about 285 parts per million. By 1960, however, the atmospheric concentration, as measured at NOAA's Mauna Loa Observatory, was at about 315 parts per million. Today, the measurements exceed 390 parts per million.
Globally, relatively warm temperatures were experienced in 2012, however, the continental US endured its warmest year so far on record, according to NOAA.
"The U.S. temperatures in the summer of 2012 are an example of a new trend of outlying seasonal extremes that are warmer than the hottest seasonal temperatures of the mid-20th century," GISS director James E. Hansen said. "The climate dice are now loaded. Some seasons still will be cooler than the long-term average, but the perceptive person should notice that the frequency of unusually warm extremes is increasing. It is the extremes that have the most impact on people and other life on the planet."
More than 1,000 meteorological stations around the world contributed weather data for the temperature analysis, along with satellite observations of sea-surface temperature, and Antarctic research station measurements. A publically available computer program calculated the difference between surface temperature in a given month and the average temperature for the same place during 1951 to 1980. This three-decade time span serves as a baseline for the analysis, which showed that the last year that experienced cooler temperatures than the 1951 to 1980 averages, was 1976.
One of several global temperature analyses, the GISS temperature record trends shows a close agreement with the other methods used by the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration's National Climatic Data Center.