2012 PART OF A SUSTAINED LONG-TERM CLIMATE WARMING TREND NASA scientists have shown that 2012 was th

2012 PART OF A SUSTAINED LONG-TERM CLIMATE WARMING TRENDNASA scientists have shown that 2012 was the ninth warmest of any year since 1880, which continues a long-term trend of rising global temperatures. The 132-year record shows that, with the exception of 1998, the nine warmest years have occurred since 2000; 2014, 2010 and 2005 were ranked as the hottest years on record.An updated analysis by NASA’s Goddard Institute for Space Studies (GISS) compared global temperatures in 2012 with the average global temperature from the mid-20th century. This comparison showed that Earth continues to experience warmer temperatures than many decades ago.The average global temperature in 2012 was about 14.6°C (58.3°F), 0.6°C (1.0°F) warmer than the baseline in the mid-20th century. The new analysis shows that the average global temperature has risen about 0.8°C (1.4°F) since 1880.While weather patterns will always carry some fluctuations in average temperature from year to year, the continued increase of greenhouse gas levels in Earth’s atmosphere ensures there will be a long-term rise in global temperatures. Each year will not necessarily be warmer than the previous year, but based on the current increase in greenhouse gases each decade is expected to be warmer on average than the previous decade.The significance lies not in another year of higher temperatures worldwide, but in the fact that this current decade is warmer than the last, and that decade in turn was warmer than the one before. The increasing amount of carbon dioxide in the atmosphere is causing the warming.Carbon dioxide is a greenhouse gas; greenhouse gases trap heat and control Earth’s climate. The gas occurs naturally but also is emitted through the burning of fossil fuels for energy purposes. The level of carbon dioxide in Earth’s atmosphere has been increasing consistently for decades.The first year in the GISS temperature record is 1880, when the carbon dioxide level in the atmosphere was about 285 parts per million. By 1960 the atmospheric carbon dioxide concentration was about 315 parts per million. Today the concentration is over 390 parts per million.The continental U.S. experienced its warmest year on record in 2012. According to GISS director James E. Hansen, this is ‘an example of a new trend of outlying seasonal extremes that are warmer than the hottest seasonal temperatures of the mid-20th century.’ Some seasons are expected to be cooler than the long-term average; however the frequency of unusually warm extremes is increasing. These extremes have the biggest impact on all life on the planet, including humans.GISS compiled weather data from more than 1,000 global meteorological stations, satellite observations of sea-surface temperature and Antarctic research station measurements to produce the temperature analysis. There are other global temperature analyses; the Met Office Hadley Centre in the United Kingdom and the National Oceanic and Atmospheric Administration’s National Climatic Data Center in Asheville, N.C. are two of several used. Though the three primary records use slightly different methods, their trends are in close agreement.The map represents global temperature anomalies averaged from 2008 through 2012. Click the first source listed below to see an animation showing the change in global temperatures from 1880 to 2012.-TELhttp://www.nasa.gov/topics/earth/features/2012-temps.htmlhttp://www.nasa.gov/pdf/719354main_NOAA%20NASA%20Climate%20Briefing.pdfAnimations and maps available for download: http://svs.gsfc.nasa.gov/vis/a000000/a004000/a004030/index.htmlData source: NASA Goddard Institute for Space StudiesVisualization credit: NASA Goddard’s Scientific Visualization Studio -- source link

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