Temperature (Global)
When assessing temperatures beyond the instrumental record, which only dates back into the 1,800's one must examine what is called paleo evidence. this evidence originates in many types of paleo records including but not limited to ice cores, ocean and lake sediments, fossilized pollen and insects, geologic and chemical isotope analysis and many more. The global temperature assessment is derived form multiple global analysis examining different types of data. It is the composite view and associated confidence levels, including uncertainties and the error range that produces the mean analysis. The confidence on the 'mean' is likely, most likely, or extremely likely to be the more accurate view as opposed to the outliers in the error potential. By collating multiple data sets the confidence interval can be increased based on the individual confidence intervals. It is this remaining confidence level that gives us a more reliable view of the best estimates of the mean temperature of Earth.
More Highs than Lows - A Growing Trend
Source: http://www.ucar.edu/news/releases/2009/maxmin.jsp
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This graphic shows the ratio of record daily highs to record daily lows observed at about 1,800 weather stations in the 48 contiguous United States from January 1950 through September 2009. Each bar shows the proportion of record highs (red) to record lows (blue) for each decade. The 1960s and 1970s saw slightly more record daily lows than highs, but in the last 30 years record highs have increasingly predominated, with the ratio now about two-to-one for the 48 states as a whole.[ENLARGE] (©UCAR, graphic by Mike Shibao.)
Gerald Meehl - NCAR (National Center for Atmospheric Research)
Gerald "Jerry" Meehl is an NCAR senior scientist. His research includes connecting the solar cycle to subtle changes in weather and climate on Earth; examining the consequences of global warming, including heat waves, droughts, storms, and other weather extremes; regional climate change; and El Niño and other influences of the tropics on global climate.
Twice as many record-breaking high temperatures have been set compared to record lows across the U.S. in recent decades (see http://www.ucar.edu/news/releases/200...). For future climate, computer models show the ratio climbing to 20:1 by 2050 and 50:1 by 2100.
Day-to-day variability means we still get record cold days, but the record highs are far exceeding the lows.
NCDC (National Climate Data Center) Analysis
- Background - FAQ
- Global Mean Temperature Estimates
- Gridded Dataset
- The Global Anomalies and Index Data
- Additional Websites
- References
Hadley Met Center
Global Temperature Record
(this graph of HadCRUT3 is also available as Encapsulated PostScript and PDF
suitable for publication and the data are available as Comma-Separated Values)
GISS Surface Temperature Analysis
NASA/GISS Analysis
Analysis Graphs and Plots
Figures on this page were prepared by Dr. Makiko Sato. Please address questions about the figures to Dr. Sato or to Dr. James Hansen.
Click on any graph to view an enlargement of the image. PDF documents require a special viewer such as the free Adobe Reader.
What's New
Feb. 16, 2010: Urban adjustment is now based on global nightlights rather than population as discussed in a paper in preparation.
Nov. 14, 2009: USHCN_V2 is now used rather than the older version 1. The only visible effect is a slight increase of the US trend after year 2000 due to the fact that NOAA extended the TOBS and other adjustment to those years.
Sep. 11, 2009: NOAA NCDC provided an updated file on Sept. 9 of the GHCN data used in our analysis. The new file has increased data quality checks in the tropics. Beginning Sept. 11 the GISS analysis uses the new NOAA data set.
Old News
Comparison of 2010 Temperature to the Two Other Years with the Warmest Annual Means
Global Annual Mean Surface Air Temperature Change
Line plot of global mean land-ocean temperature index, 1880 to present, with the base period 1951-1980. The dotted black line is the annual mean and the solid red line is the five-year mean. The green bars show uncertainty estimates. [This is an update of Fig. 1A in Hansen et al. (2006)]
Figure also available as large GIF, PDF, or Postscript. Also available are tabular data.
(Last modified: 2010-02-18)
Our traditional analysis using only meteorological station data is a line plot of global annual-mean surface air temperature change, with the base period 1951-1980, derived from the meteorological station network [This is an update of Figure 6(b) in Hansen et al. (2001).] Uncertainty bars (95% confidence limits) are shown for both the annual and five-year means, account only for incomplete spatial sampling of data.
Figure also available as large GIF, PDF, or Postscript. Also available are tabular data.
(Last modified: 2010-02-18)
Annual Mean Temperature Change for Three Latitude Bands
Annual and five-year running mean temperature changes, with the base period 1951-1980, for three latitude bands that cover 30%, 40% and 30% of the global area. Uncertainty bars (95% confidence limits) are based on spatial sampling analysis. [This is an update of Figure 5 in Hansen et al. (1999).]
Figure also available as large GIF, PDF, or Postscript, Also available is a table.
(Last Modified: 2010-01-21)
Annual Mean Temperature Change for Hemispheres
Annual and five-year running mean temperature changes with the base period 1951-1980 for the northern (red) and southern (blue) hemispheres.
Figure also available as large GIF, PDF, or Postscript, Also available is a table.
(Last Modified: 2010-02-18)
Global Monthly Mean Surface Temperature Change
Line plot of monthly mean global surface tmperature anomaly, with the base period 1951-1980. The black line shows meterological stations only; redle dots are the land-ocean temperature index, as described in Hansen et al. (1999). The land-ocean temperature index uses sea surface temperatures obtained from satellite measurements of Reynolds and Smith (1994).
[This is an update of Figure 8 in Hansen et al. (1999).]
Figure also available as large GIF, PDF, or Postscript. Also available are tabular data.
(Last modified: 2010-10-13)
Global Mean Surface Temperature vs. Year and Month
Also available as large GIF, or PDF.
(Last modified: 2010-10-13 )
Annual Mean Temperature Change in the United States
Annual and five-year running mean surface air temperature in the contiguous 48 United States (1.6% of the Earth's surface) relative to the 1951-1980 mean.
[This is an update of Figure 6 in Hansen et al. (1999).]
Also available as large GIF, PDF, or Postscript. Also available are tabular data.
(Last modified: 2010-02-16)
Seasonal Mean Temperature Change
Temperature index change (with the base period 1951-1980) since 1950 at seasonal resolution, for the globe (upper line) and for low latitudes (lower line). [This is an update of Figure 7 in Hansen et al. (1999).] Green triangles mark large volcanic eruptions. SST at Nino 3.4 is the 12-month running mean.
Also available as large GIF, PDF, or Postscript. Also available are tabular data.
(Last modified: 2010-09-12)
