he GISS analysis incorporates surface temperature measurements from 6,300 weather stations, ship- and buoy-based observations of sea surface temperatures, and temperature measurements from Antarctic research stations. This raw data is analyzed using an algorithm that takes into account the varied spacing of temperature stations around the globe and urban heating effects that could skew the calculation.
The result is an estimate of the global average temperature difference from a baseline period of 1951 to 1980.
NOAA scientists used much of the same raw temperature data, but a different baseline period. They also employ their own methods to estimate global temperatures.
GISS is a NASA laboratory managed by the Earth Sciences Division of the agency’s Goddard Space Flight Center, in Greenbelt, Maryland. The laboratory is affiliated with Columbia University’s Earth Institute and School of Engineering and Applied Science in New York.
NASA monitors Earth's vital signs from land, air and space with a fleet of satellites, as well as airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.
Related links:
NASA Earth Observatory has posted a somewhat different temperature summation at:
earthobservatory.nasa.gov/NaturalHazards/view.php?id=85083
NOAA's National Climatic Data Center's summary is at:
www.ncdc.noaa.gov/sotc/summary-info/global/2014/12
Additional commentary about the 2014 temperature anomaly is provided by Dr. James Hansen of Columbia University at:
www.columbia.edu/~jeh1/mailings/2015/20150116_Temperature2014.pdf
The data set of 2014 surface temperature measurements is available at:
data.giss.nasa.gov/gistemp/
The methodology used to make the temperature calculation is available at:
data.giss.nasa.gov/gistemp/sources_v3/
For related press briefing images related to the data, visit:
www.ncdc.noaa.gov/sotc/briefings/201501.pdf
For more information about Earth science at NASA, visit:
www.nasa.gov/earth