2011-01-28: The NASA/GSFC Scientific Visualization Studio has produced a new animation of the rolling five-year mean of the global surface temperature anomaly. 2011-01-13: NASA has issued a second news release discussing global temperature and how GISS results compare to those of other institutions. 2011-01-12: NASA has issued a news release about the 2010 average global temperature. 2010-12-13: Our paper "Global surface temperature change" was published today in Reviews of Geophysics. A summary (PDF) is also available. 2010-12-11: We have posted a webpage discussing that 2010 produced the warmest November in spite of a European cold spell and a strong La Niña. See also the Updates to the analysis process.
Time Series of Zonal Means
Seasonal Cycle of Zonal Means
The basic GISS temperature analysis scheme was defined in the late 1970s by James Hansen when a method of estimating global temperature change was needed for comparison with one-dimensional global climate models. Prior temperature analyses, most notably those of Murray Mitchell, covered only 20-90°N latitudes. Our first published results (Hansen et al. 1981) showed that, contrary to impressions from northern latitudes, global cooling after 1940 was small, and there was net global warming of about 0.4°C between the 1880s and 1970s.
Current Analysis Method
The current analysis uses satellite observed nightlights to identify measurement stations located in extreme darkness and adjust temperature trends of urban and peri-urban stations for non-climatic factors, verifying that urban effects on analyzed global change are small. A paper describing the current analysis was published (Hansen et al. 2010) in Reviews of Geophysics in December 2010. The paper compares alternative analyses, and address questions about...