The following "climate indicators" present data from each of the datasets featured in the 2009 Climate Assessment Chapter 2 sidebar "How do we know the world has warmed?" by John Kennedy and several other authors. Within each indicator, individual datasets can be toggled off and on for further inspection and zoomed in onto periods of interest. All data used in the sidebar is publicly accessible and the annual data as used in the analysis can be downloaded here.
This set of indicators was selected as we would unambiguously expect them to increase or decrease if the world were warming. In a warming world, based upon simple physical principles we would expect the following indicators to increase: land surface air temperature, sea-surface temperature, marine air temperature, sea level, tropospheric temperature, ocean heat content and specific humidity. Conversely, we would expect the following indicators to decline: snow cover, sea-ice extent, glacier mass, and stratospheric temperatures. Stratospheric temperature decline is also influenced by ozone depletion.
Choose a time series to plot:
For all climate questions, please contact the National Climatic Data Center's Climate Services and Monitoring Division:
Climate Services and Monitoring Division