Comments on the state of knowledge about climatic and geological processes and extra-terrestrial events

The Workshop on Transitional Processes has provided a good review of the range of possible climatic, geological and extra-terrestrial factors that could influence the integrity of a depository for radioactive waste buried in crystalline rock of the southern Canadian Shield. The discussion uncovered many areas where more knowledge is needed. Information about likely timing and periodicity of future events is poor, partly because all current experience is in a period that appears to be anomalously active, geologically and climatically. Attempts to model or simulate future conditions will be severely hampered by the difficulties of combining deterministic and stochastic happenings that may have linked or synergistic consequences. The workshop demonstrated also that the geosciences have a contribution to make to this important problem. There is justification for proceeding with the formulation of a comprehensive conceptual model of transitional processes that might affect the integrity of a buried vault over the next one million years