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Any use of the National Center for Atmospheric Research (NCAR)'s Community Climate System Model, version 3 (CCSM3) data should acknowledge the contribution of the CCSM project and CCSM sponsor agencies with the following citation:

"'This research uses data provided by the Community Climate System Model project supported by the Directorate for Geosciences of the National Science Foundation and the Office of Biological and Environmental Research of the U.S. Department of Energy." In addition, the words 'Community Climate System Model' and 'CCSM' should be included as metadata for webpages referencing work using CCSM data or as keywords provided to journal or book publishers of your manuscripts. Users of CCSM data accept the responsibility of emailing citations of publications of research using CCSM data to: ccsm@ucar.edu. Any redistribution of CCSM data must include this data acknowledgement statement.

Please also acknowledge EOS-WEBSTER as the data distributor when using these data in subsequent models or publications.

The Climate Changes in the 21 st Century collection can be ordered from the EOS-WEBSTER Search and Retrieve Tool.

Additional climate change data, links, and resources are available from the Climate Change Resources page.

Summary:

The United Nations and World Meteorological Organization established the Intergovernmental Panel on Climate Change in 1988 to assess the scientific, technical and socio-economic information necessary to understand climate change, its potential impacts and options for adaptation and mitigation. The IPCC provides periodic assessments of the scientific understanding of climate change and its consequences, drawing on the expertise of scientists worldwide. The IPCC is widely recognized as the world's foremost authority on climate change.

The IPCC released three assessment reports in 1990, 1995, and 2001. A fourth assessment report will be released in 2007. The IPCC does not carry out research nor does it monitor climate  related data or other relevant parameters. It bases its assessment mainly on peer reviewed and published scientific literature. Climatological datasets that will be key inputs into the 2007 assessment report are now available through EOS-WEBSTER. EOS-WEBSTER has developed the Climate Changes in the 21 st Century collection from the National Center for Atmospheric Research's Community Climate System Model, version 3 (CCSM3). The Climate Changes collection is intended as an easy-to-use resource for general inquiries into the potential impacts of low, medium and high levels of atmospheric CO₂ and projections about population growth, land-use changes, new technologies, and energy resources. The IPCC calls each set of projections a storyline or a SRES scenario. Scenarios used for the 4th Assessment are described below. Data provided in this collection are averages of several model runs for each scenario, also known as ensembles. Modelers use these ensembles to discover sensitivities within their model. The averaged ensemble values are good representations of the model and are suitable for making comparisons between the past and future and among the different future storylines.

Community Climate System Model, version 3 (CCSM3)

The National Center for Atmospheric Research (NCAR) in Boulder, Colo., has developed a powerful supercomputer-based system to model Earth's climate and to project global temperature rise in coming decades. The model, called CCSM3, is yielding new insight into the complexities of the Earth system and the likely responses of our planet to natural and man-made influences.

CCSM3 is one of the world's leading general-circulation climate models, which are extraordinarily sophisticated computer tools that incorporate phenomena ranging from the effect that volcanic eruptions have on temperature patterns to the impact of shifting sea ice on sunlight absorbed by the oceans. Climate models work by solving mathematical formulas, which represent the chemical and physical processes that drive Earth's climate, for thousands of points in the atmosphere, oceans, sea ice, and land surface. CCSM3 is so complex that it requires about 3 trillion computer calculations to simulate a single day of global climate.

In addition to simulating temperatures over the next century, scientists will use the model to study climate patterns of the past, such as the peak of the last ice age 21,000 years ago. They will also use it to probe chemical processes and the cycling of carbon between the atmosphere, ocean, and land, as well as the localized impacts of sulfates and other pollutants on climate.

Please Note:

EOS-WEBSTER has two collections of IPCC data using the NCAR CCSM3 model. This collection, Climate Changes in the 21st Century, is particularly well suited for educational use and is intended for middle school through college students as well as members of the general public. Our second collection, NCAR Science and Research Data for IPCC AR4, is best suited for scientific and research purposes.

Datasets available from the Climate Changes in the 21st Century collection:

*Are these data identical to those used for the Fourth IPCC assessment?

The data distributed by EOS-WEBSTER have been modified from the original used in the 4th IPCC assessment. These modifications were made to improve ease of using the data and do not alter the results predicted by the models. Modifications include a small change in the shape and size of the global grid. Originally, the data were on a gaussian grid of 1.40625 degrees longitude centered at the prime meridian (0 degrees longitude), with latitudes of 1.40625 degrees at the equator getting farther apart towards the poles. For our GIS-friendly version of these data, we have recast the grid cells onto a regular, 1.40625 deg longitude x latitude grid starting at -180.0 degrees longitude and 90.0 degrees latitude, which results in a slight shift of the grid cells. The actual grid cell center points and areas can be obtained from the collection by ordering the geography file.

If you plan to use these data in peer-reviewed, scientific journal articles, please use the information in the geography file to precisely georeference the data and correctly calculate the area of each grid cell.

Variables available from the Climate Changes in the 21 st Century collection:

*Invalid data locations are designated by -99.0.

The IPCC Scenarios and Storylines: Special Report on Emissions Scenarios (SRES)**

By 2100 the world will have changed in ways that are hard to imagine - as hard as it would have been at the end of the 19th century to imagine the changes of the 100 years since. Each IPCC storyline assumes a distinctly different direction for future developments, such that the four storylines differ in increasingly irreversible ways. Together they describe divergent futures that encompass a significant portion of the underlying uncertainties in the main driving forces. They cover a wide range of key "future" characteristics such as population growth, economic development, and technological change. For this reason, their plausibility or feasibility should not be considered solely on the basis of an extrapolation of current economic, technological, and social trends.

* The A1 storyline and scenario family describes a future world of very rapid economic growth, low population growth, and the rapid introduction of new and more efficient technologies. Major underlying themes are convergence among regions, capacity building and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income.

* The A2 storyline and scenario family describes a very heterogeneous world. The underlying theme is self-reliance and preservation of local identities. Fertility patterns across regions converge very slowly, which results in high population growth. Economic development is primarily regionally oriented and per capita economic growth and technological change are more fragmented and slower than in other storylines.

* The B1 storyline and scenario family describes a convergent world with the same low population growth as in the A1 storyline, but with rapid changes in economic structures toward a service and information economy, with reductions in material intensity, and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, but without additional climate initiatives.

** From the IPCC Special Report on Emissions Scenarios

 

Demographic, social, economic and technological profiles of the SRES scenarios:

Source: http://www.grida.no/climate/ipcc/emission/091.htm

Schematic illustration of the SRES scenarios:***

The four scenario "families" are illustrated, very simplistically, as branches of a two-dimensional tree. The two dimensions indicate the relative orientation of the different scenario storylines toward economic or environmental concerns and global and regional scenario development patterns, respectively. There is no implication that these two are mutually exclusive or incompatible. In reality, the four scenarios share a space of a much higher dimensionality given the numerous driving forces and other assumptions needed to define any given scenario in a particular modeling approach. The schematic diagram illustrates that the scenarios build on the main driving forces of GHG emissions.

*** From the IPCC Special Report on Emissions Scenarios

Atmospheric Carbon Dioxide Concentrations Projected by the SRES Scenarios:

More information on the SRES scenarios can be obtained from:

http://www.grida.no/climate/ipcc/emission/index.htm

http://sedac.ciesin.columbia.edu/ddc/sres/

Data Providers:

The National Center for Atmospheric Research
Boulder, Colorado

Website for Community Climate System Model, version 3 (CCSM3):
http://www.ccsm.ucar.edu

Latest Data Update:

November 8, 2005

Last Doc. Updated:

November 8, 2005

Doc. Updated By:

Annette Schloss

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