Climate Data and Model Integration

Changes in air temperature every 3000 years from the Last Glacial Maximum 21,000 years
before present to the pre-industrial (present before CO₂ emissions increased) period circa
1900 simulated by a global model of the atmosphere and oceans. The maps show the
differences between the indicated times in the past and the pre-industrial period. Blue colors
are colder than the pre-industrial and yellow and red colors are warmer. Geologic data were
used to prescribe the size and area of the continental ice sheets and ice core data were used
to prescribe atmospheric CO2, methane and nitrous oxide. The ice sheets and their melting
through time are clearly evident by the very cold temperature differences over North America
and Europe. Warmer temperatures are the result of changes in the solar radiation inputs
associated with prescribed known changes in the orbit of the Earth around the Sun.
Source: S. Hostetler, USGS, CLU R&D and J. Alder, Oregon State University.

Climate models based on physical data are continually improving their ability to simulate current and past climates enabling them to predict future climate changes. Because climate changes during the last few decades of instrumental modeling are modest compared to those of the geologic past, it is important to determine whether the models can simulate climate conditions much different from today. To do so, model performance is evaluated using paleoclimate data from much warmer and colder climates, preserved in the geologic record. These models operate over both global and regional scales and help visualize the possible outcomes of different climate change scenarios and their impacts on biome distribution and sea level, and other factors. Other modeling efforts integrate hydrologic, habitat sustainability, and other models to develop predictive tools to aid resource managers and policy makers.

Projects in the Research and Development Program utilize diverse data sets to further our understanding of global change. These data sets range spatially from local to global , and temporally from the present to millions of years in the past. Projects use observations gleaned from satellite images, ecological research, and the geologic record and a variety of models to understand climate and surface processes such as changes in sea level, glacier dynamics, the hydrologic cycle, and ecosystem dynamics. Many models have been tested and verified with observed data, but new and existing models need to be evaluated, particularly if they are to be applied to the future. Evaluating models with observed and geologic data is a key component of the R&D program.