RICHARD M. FORESTER’S SOLUTION TO THE YUCCA MOUNTAIN, NEVADA, FUTURE CLIMATE CONUNDRUM

Richard M. Forester led the U.S. Geological Survey’s Yucca Mountain Climate Program from 1991 to 2000. Yucca Mountain, in southern Nevada, was the proposed site to dispose of and isolate high-level radioactive waste from the biosphere for tens of thousands of years. Forecasting future climate states, particularly colder and wetter climates with potentially increased infiltration, was important because infiltration can affect the long-term hydrologic integrity of the repository. In addition to informing decision-makers on past climate states, one of Rick’s assignments was to establish a methodology to forecast future climate scenarios for the next 10,000 years. Not only did this methodology require being scientifically sound, it must withstand litigation. Forecasting future climate using computer models was not acceptable because future climate boundary conditions needed to be known with confidence for input to the model and the value of the output from such a model would have limited value in terms of legal defensibility. Rick stated that this methodology was just one methodology that could be used. To reconstruct the nature and magnitude of past climate states in southern Nevada, Rick (1) collected ostracode data and procured new and published records on past climate and hydrology, (2) estimated upper and lower temperature and precipitation bounds for several past climate states based on these records, (3) related these records to synoptic and global circulation patterns, and (4) selected analog (modern) meteorological stations with long records to represent upper and lower climate bounds for each past climate state (~50 years of recorded daily data could then be utilized). Rick used data and ideas from Winograd et al. and compared the relations among the well-dated record of continuously-deposited calcite at Devils Hole, Nevada, calculated orbital parameters, and paleoclimate proxy data to identify past climate patterns. He then used calculated orbital parameters and projected this pattern into the future to establish the magnitude and timing of future climate states. These estimates were used as input to the infiltration model and the total system performance assessment for the Yucca Mountain Site Recommendation. This methodology, which was based on past records, was defensible in court.