Overviews :
|
Overviews : |
The aim of the BIOCLIM project has been to provide a scientific basis and practical methodology for assessing the potential impacts of long-term climate change on biosphere characteristics in the context of radiological performance assessments (PA) of radioactive waste repositories in deep geological formations. The project brought together twelve different European organisations plus associated sub-contractors with responsibilities for either the safe disposal of radioactive waste or the development of climate models. Through this scientific and technical collaboration, climate models that can simulate future climate changes in Europe over very long timescales have been developed. The climate modelling results have been linked to an understanding of the pattern of biosphere changes for selected European regions in order to address the issue of how to represent future biosphere systems in long term radiological performance assessments.
The project has the following objectives :
The final outcome is an enhancement of the state-of-the-art treatment of biosphere system change over long periods of time through use of a number of innovative climate modelling approaches and the application of the climate model outputs in PAs.
The project has been initiated on the basis of the requirements of European waste management agencies to assess the feasibility and safety of radioactive waste repositories in geological formations, with regard to possible long-term impacts due to climate change. In addition to climate, the associated biosphere system may be subject to major change. Predictions over one million years cannot be considered as very reliable, however possible future evolution scenarios can be proposed, based on the past history of the climate system. Collaboration within the project by participants with different types of expertise will provide a robust scientific basis and practical results to demonstrate how climate and related environmental changes can be represented in radiological performance assessments (PAs).
The project was designed to advance the state-of-the-art of biosphere modelling for use in in radiological assessments through five work packages (WP).
WP 1 – Consolidation of
the needs of the waste management agencies
The aim of WP1 was to summarise information on the issues that have to be addressed
by the waste management agencies represented in the consortium when considering
climate change impacts on repository safety, and the current methods used to
represent environmental change in repository safety assessments. This was achieved
in two reports (BIOCLIM, 2001a; BIOCLIM, 2002).
WP 2 – Hierarchical strategy
for climate modelling
WP2 has used a hierarchy of three types of climate model to derive the climatic
changes for selected discrete time periods of interest to radioactive waste
management (i.e. selected time slices during glacial and interglacial periods).
These three types of model comprise an Earth-system Model of Intermediate Complexity
(EMIC), a General Circulation Model (GCM) and a regional climate model. The
outputs from these models consist of climate and vegetation cover scenarios
for selected time periods in the future. Statistical downscaling approaches
have been developed and evaluated to enable climate model output for large areas
to be downscaled to more appropriate scales for the regions of interest. A report
has been produced that summarises the different long-term climate simulations
that have been undertaken using an EMIC and the recommendations for the six
time slices to be studied using the GCM and regional climate models (BIOCLIM,
2001b). Simulations with these models have also been reported (BIOCLIM, 2003a).
WP 3 – Integrated strategy
for climate modelling
WP3 has involved the development and application of an integrated, dynamic climate
model, representing all [Is this true – were all mechanisms included?]
the mechanisms important for long-term climatic variations such as atmospheric
forcing, ice sheet development and ocean changes. The time-dependent results
from this model have been interpreted in terms of regional climate using a rule-based
downscaling approach (BIOCLIM, 2003d). A second integrated, dynamic climate
model that is structurally very different from the first has also been developed
and applied. Results from these two models have been compared to determine whether
the use of different climate models for the same future forcing of climate by
variations in insolation and atmospheric greenhouse-gas concentrations gives
rise to substantially different patterns of long-term climate change (BIOCLIM,
2003c).
WP 4 – Biosphere system
description
The output from the climate models developed and applied in WP2 and WP3 has
been interpreted in WP4 in terms of model requirements for the post-closure
radiological performance assessment of deep geological repositories for radioactive
wastes, in order to develop a methodology to demonstrate how biosphere systems
can be represented in the long-term. The work undertaken in WP4 is described
in this report.
WP 5 – Final seminar
The objective of WP5 is to disseminate information on the methodologies and
results obtained in BIOCLIM to the international scientific/technical and waste
management community. As each deliverable is finalised, it is made publicly
available on the project web site.
