Atmosphere Journal Entry
New Evidence of Global Warming (October 27, 2008)
This map compares average temperatures between 2001 to 2005 to the long-term average. Areas in dark red had the greatest increase. NASA.
A new study shows the decade ending in 2006 was the warmest ten-year period in the Northern Hemisphere in 1,300 years. The temperature was at least 0.5 degrees Fahrenheit warmer than the long-term average and possibly as much as 1.0 degree Fahrenheit higher. Scientists blame the rise on the increase in greenhouse gases from human activities, especially the burning of fossil fuels.
The researchers combined data from different sources. They looked closely at tree ring data over many centuries. Atmospheric data provided clues about levels of gases such as carbon dioxide, methane, and nitrous oxide. They also studied geological data such as sediments and stalactites and stalagmites, mineral structures in underground caverns.
The new study adds to the mountain of evidence that changes in Earth's climate are speeding up at an alarming rate. Each of the years between 1998 and 2007 is ranked in the top twenty-five warmest on record. 2006 was the warmest year in a century, with both 2007 and 1998 running close behind.
