NASA GISS Surface Temperature (GISTEMP) Analysis

DOI: 10.3334/CDIAC/cli.001

Graphics    Data

Contributors

R. Ruedy,¹ M. Sato,² and K. Lo¹

¹Trinnovim LLC
²Columbia University
 
Center for Climate Systems Research
NASA Goddard Institute for Space Studies
2880 Broadway
New York, NY 10025 USA

Period of Record

1880-2014 (Anomalies are relative to the 1951-80 base period means.)

Key Finding: The global mean temperature for 2014 was the warmest on record (see Trends section for further details)

Methods

The NASA GISS Surface Temperature (GISTEMP) analysis provides a measure of the changing global surface temperature with monthly resolution for the period since 1880, when a reasonably global distribution of meteorological stations was established. The input data Ruedy et al. use for the analysis, collected by many national meteorological services around the world, are the adjusted data of the Global Historical Climatology Network (GHCN) Vs. 3 (this represents a change from prior use of unadjusted Vs. 2 data) (Peterson and Vose, 1997 and 1998), United States Historical Climatology Network (USHCN) data, and SCAR (Scientific Committee on Antarctic Research) data from Antarctic stations. Documentation of the basic analysis method is provided by Hansen et al. (1999), with several modifications described by Hansen et al. (2001). The GISS analysis is updated monthly, however CDIAC's presentation of the data here is updated annually.

The NASA GISS Web site for the global temperature data of Ruedy et al. is the most comprehensive and direct source of information for these data. Users are strongly encouraged to visit the NASA GISS Web site, where you can specify input for making customized maps, graphs, and subsets of the data, in addition to learning many more interesting details about these data and their analysis. Here, we seek to give users a brief, high-level overview of the GISTEMP analysis and provide you with convenient access to the main time series graphs, data tables, and related references. This brief summary of the methods employed by Ruedy et al. in their analysis is mostly borrowed from their NASA GISS Web pages. Significant updates to the Ruedy et al. methods are described in a 2010 paper. They describe the use of 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. The paper compares alternative analyses, and addresses questions about perception and reality of global warming. Ruedy et al. modify the GHCN/USHCN/SCAR data in two steps to get to the station data on which all their tables, graphs, and maps are based: in step 1, if there are multiple records at a given station, these are combined into one record; in step 2 they adjust the non-rural stations in such a way that their long-term trend of annual means matches that of the mean of the neighboring rural stations. Records from urban stations without nearby rural staitons are dropped.

The analysis includes results for a global temperature index as described by Hansen et al. (1996). The temperature index is formed by combining the meteorological station measurements over land with sea surface temperatures obtained from in situ data before 1982 (Rayner et al. 2003) and from satellite measurements thereafter (Reynolds and Smith, 1994; Smith et al. 1996). Any users of the temperature index data, i.e., the results including sea surface temperatures, should credit Reynolds and Smith (1994) and Smith et al. (1996). (See references.)

The analysis is limited to the period since 1880 because of the poor spatial coverage of stations prior to that time and the reduced possibility of checking records against those of nearby neighbors. Meteorological station data provide a useful indication of temperature change in the Northern Hemisphere extratropics for a few decades prior to 1880, and there are a small number of station records that extend back to previous centuries. However, Ruedy et al. believe that analyses for these earlier years need to be carried out on a station by station basis with an attempt to discern the method and reliability of measurements at each station, a task beyond the scope of their analysis. Global studies of still earlier times depend upon incorporation of proxy measures of temperature change. References to such studies are provided in Hansen et al. (1999).

Trends

Trends in annual mean temperature anomalies for both land and land plus ocean time series show quite a bit of variability from the beginning of the record through about 1920, but no real trend. A significant warming of about 0.3°C is observed in both series from about 1920 through the early- to mid-1940s, followed by a less dramatic cooling in both series through about the mid-1960s. From the 1970s through recent years, rapid warming is observed in both series; on the order of 0.6°C. Global mean surface temperature in 2014 was the warmest since 1880 (read the January, 2015 NASA new release); 0.68°C above the 1951-1980 average. With the exception of 1998, the 10 warmest years in the 135-year record all have occurred since 2000.

The northern and southern hemisphere annual trends series show some general similarities, e.g., little sign of trends before about 1920, an increasing trend ending with a peak in the early 1940s, some cooling from the 1940s through the mid-1970s, followed by strong warming thereafter, with the highest temperatures occurring after 1990. The overall trend for the northern hemisphere is somewhat higher than that of the southern hemisphere. The relatively cool years of the early 1990s (mainly 1992 and 1993) are believed to have resulted from the effects of the dust veil produced by the eruption of Mt. Pinatubo (Parker et al. 1996).

Hansen et al. have also calculated temperature anomaly series for three latitude bands: (1) 90°N to 23.6°N; (2) 23.6°N to 23.6°S; and (3) 23.6°S to 90°S that cover 30%, 40%, and 30% of the globe, respectively. These series reveal that the northern latitudes have warmed much more than either the low or southern latitudes.

References

(Note: All of the references included below are not cited in the above text. Additional references are included because they are described on the GISS Web site as being related to the overall global temperature research of Hansen et al.)

• Christy, J.R., R.W. Spencer, and W.D. Braswell. 2000. MSU Tropospheric temperatures: Data set construction and radiosonde comparisons. J. Atmos. Oceanic Tech. 17, 1153.
• Hansen, J., R. Ruedy, M. Sato and R. Reynolds. 1996. Global surface air temperature in 1995: Return to pre-Pinatubo level. Geophys. Res. Lett. 23, 1665-1668.
• Hansen, J., M. Sato, J. Glascoe and R. Ruedy. 1998. A common-sense climate index: Is climate changing noticeably? Proc. Natl. Acad. Sci. 95, 4113-4120.
• Hansen, J., R. Ruedy, J. Glascoe, and M. Sato. 1999. GISS analysis of surface temperature change. J. Geophys. Res. 104, 30997-31022.
• Hansen, J., R. Ruedy, M. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl. 2001. A closer look at United States and global surface temperature change. J. Geophys. Res. 106, 23947-23963.
• Hansen, J., Mki. Sato, R. Ruedy, P. Kharecha, A. Lacis, R.L. Miller, L. Nazarenko, K. Lo, G.A. Schmidt, G. Russell, I. Aleinov, S. Bauer, E. Baum, B. Cairns, V. Canuto, M. Chandler, Y. Cheng, A. Cohen, A. Del Genio, G. Faluvegi, E. Fleming, A. Friend, T. Hall, C. Jackman, J. Jonas, M. Kelley, N.Y. Kiang, D. Koch, G. Labow, J. Lerner, S. Menon, T. Novakov, V. Oinas, Ja. Perlwitz, Ju. Perlwitz, D. Rind, A. Romanou, R. Schmunk, D. Shindell, P. Stone, S. Sun, D. Streets, N. Tausnev, D. Thresher, N. Unger, M. Yao, and S. Zhang, 2007. Dangerous human-made interference with climate: A GISS modelE study. Atmos. Chem. Phys., 7, 2287-2312.
• Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2010. Global surface temperature change. Rev. Geophys., 48, RG4004, doi:10.1029/2010RG000345.
• Intergovernmental Panel on Climate Change. 2001. Climate Change 2001 (J.T. Houghton et al., Eds.), Cambridge Univ. Press, New York.
• National Research Council. 2000. Reconciling Observations of Global Temperature Change. National Academy Press, Washington, DC, 85 pp.
• Parker D.E., H. Wilson, P.D. Jones, J.R. Christy, and C.K. Folland. 1996. The impact of Mount Pinatubo on worldwide temperatures. Int. J. Climatol. 16, 487-497.
• Peterson, T.C., and R.S. Vose. 1997. An overview of the Global Historical Climatology Network temperature database. Bull. Amer. Meteorol. Soc. 78, 2837-2849.
• Peterson, T.C., R.S. Vose, R. Schmoyer, and V. Razuvaev. 1998. Global historical climatology network (GHCN) quality control of monthly temperature data, Int. J. Climatol. 18, 1169-1179.
• Rayner, N.A., D.E. Parker, E.B. Horton, C.K. Folland, L.V. Alexander, D.P. Rowell, E.C. Kent, and A. Kaplan. 2003. Global analyses of SST, sea ice and night marine air temperatures since the late nineteenth century, J. Geophys. Res., 108, doi:10.1029/2002JD002670.
• Reynolds, R.W., N.A. Rayner, T.M. Smith, D.C. Stokes, and W. Wang. 2002. An improved in situ and satellite SST analysis for climate. J. Climate 15, 1609-1625, doi:10.1175/1520-0442(2002)015<1609:AIISAS>2.0.CO;2.
• Reynolds, R.W., and T.M. Smith. 1994. Improved global sea surface temperature analyses. J. Climate 7, 929-948, doi:10.1175/1520-0442(1994)007<0929:IGSSTA>2.0.CO;2
• Smith, T.M., R.W. Reynolds, R.E. Livesay, and D.C. Stokes. 1996. Reconstruction of historical sea surface temperature using empirical orthogonal functions. J. Climate 9, 1403-1420.