The time series shows the combined global land and ocean surface temperature record from 1880 to present, with the base period 1951-1980.
How data were collected?
Global surface temperature in more than a century of instrumental data was recorded in the NASA's Goddard Institute for Space Studies analysis. The collected data were from data over land, satellite measurements of sea surface temperature (SST) since 1982, and ship-based analysis for earlier years.
Note: The zero on this chart is the mean temperature from 1961-1990.
The NASA Goddard Institute for Space Studies 2009, Global Annual Mean Surface Air Temperature Change, 2009, The NASA Goddard Institute for Space Studies, New York City, viewed 11th January, 2010, <http://data.giss.nasa.gov/gistemp/graphs/>.
ChartsBin statistics collector team 2010, Historical Global Land-Ocean Temperatures, 1880 to Present, ChartsBin.com, viewed 22nd May, 2013, <http://chartsbin.com/view/upz>.