Future climate analysis -- 10,000 years to 1,000,000 years after present

The purpose of this report is to provide quantified estimates of temperature and precipitation and estimate the timing of climate states in the Yucca Mountain, Nevada, area for the period from 10,000 to 1,000,000 years beyond the present. Primary tasks are limited to: 1) selecting modern analog climate stations for three different magnitude glacial stages; and, 2) determining the timing of future climate states using orbital parameter data and Devils Hole and Owens Lake records. These estimates are intended to be used as input to models of the infiltration process to assess the performance of the natural and engineered systems of a potential underground geologic repository for the storage of radioactive nuclear waste. This report uses the methodology established and the assumptions set forth in USGS 2000a, Sections 5 and 6, which provide predictions of future climate for the next 10,000 years. USGS 2000a (Table 2, p. 66) identified present-day meteorological stations to represent three potential future climate states: modern (interglacial), monsoon, and glacial transition (intermediate) in the Yucca Mountain area. Table 2 of USGS 2000a also includes estimated durations of these climate states. This analysis uses the same approach as USGS 2000a and estimates the duration, magnitude, and timing of climate for the next 1,000,000 years based on the celestial mechanics theory (calculated earth-orbital parameters) and their relation to the Devil\u27s Hole, Nevada, paleoclimatological record and the Owens Lake, California, record (Figure 1-1). This report identifies four potential future climate states (interglacial, monsoon, intermediate, and full glacial) for the next 1,000,000 years and proposes minor changes in climate predictions for the next 10,000 years from those described in USGS 2000a. This report also identifies present-day meteorological stations that represent the four future climate states, describes a process to estimate the timing of future climate states, and provides timing and duration of climate states for the next 1,000,000 years. The timing and duration of climate states (interglacial, monsoon, intermediate, and full glacial) may be used as part of the process to address the peak dose within the period of geologic stability. The level of confidence obtained by this methodology is suitable for its intended use (40 CFR 197.35). Although the Environmental Protection Agency (EPA) in 40 CFR Part 197, Public Health and Environmental Radiation Protection Standards for Yucca Mountain, Nevada, sets a period of 10,000 years for which the U.S. Department of Energy (DOE) must demonstrate compliance with the proposed radiological standard, both the National Academy of Sciences and the EPA have suggested that estimating climate for the next 1,000,000 years would help in design and licensing decisions. Based on the geologic record, climate is likely to be much wetter and/or cooler beyond 10,000 years after present, when a peak dose would be most likely to occur. It should be noted that the EPA states in 40 CFR Part 197 that the Nuclear Regulatory Commission (NRC) is not to use the additional analysis in determining compliance with 40 CFR Part 197