The National Climate Assessment (NCA) is a central component of the U.S. Global Change Research Program (USGCRP). Every four years, the NCA is required to produce a report for Congress that integrates, evaluates, and interprets the findings of the USGCRP; analyzes the effects of global change on the natural environment, agriculture, energy production and use, land and water resources, transportation, human health and welfare, human social systems, and biological diversity; and analyzes current trends in global change, both human-induced and natural, and projects major trends for the subsequent 25 to 100 years. A draft of the Third National Climate Assessment report is available on the Federal Advisory Committee website. The final report is slated to be released in 2014.
This scientific visualization of annual minimum sea ice area over the Arctic from 1979-2012 is one element of the NCA that highlights findings conveyed in the "Our Changing Climate", the "Alaska and the Arctic" and the "Impacts of Climate Change on Tribal, Indigenous, and Native Lands and Resources" chapters of the draft Third NCA report. This record shows a persistent decline in the minimum extent of Arctic sea ice cover. The satellite observations are from passive microwave sensors and processed using the NASA Team algorithm developed by scientists at NASA Goddard Space Flight Center. The sensors that collected the data are the Scanning Multichannel Microwave Radiometer (SMMR) on the NASA Nimbus-7 satellite and a series of Special Sensor Microwave Imagers (SSM/I) and Special Sensor Microwave Imager and Sounders (SSMIS) on U.S. Department of Defense Meteorological Satellite Program (DMSP) satellites. The data from the different sensors are carefully assembled to assure consistency throughout the 34 year record.
This visualization is similar to another developed by NASA, but is based on a slightly different algorithm to process the same sensor data. Both show similar downward trends in minimum sea ice area coverage over this time period.
Animation depicting Arctic September minimum sea ice extents from 1979 to 2012 (without year annotations). This animation sequence is used as the background for the final composite with the graph overlay.
Animation depicting Arctic September minimum sea ice extents from 1979 to 2012. This animation has a small annotated year in the upperleft corner corresponding with the relevant minimum sea ice extent for that year.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 184.108.40.206.0