PIK Biennial Report 2000-2001 - Potsdam Institute for Climate ...

Fig. 1: Pressure on water
resources in the future: Changes
in the ratio of total water withdrawal
(including domestic and
industrial sectors as well as irrigation)
over the available water
supply given as river discharge
(measured as surface and shallow
subsurface runoff) with estimates
of population growth and
economic development over the
next 25 years. It shows that most
areas on Earth will have a greater
water demand in the future than
today.
GAIM
Global Analysis, Integration and Modelling, a Task Force within the International
Geosphere-Biosphere Programme (IGBP)
Task Force Chair: Hans Joachim Schellnhuber
PIK Task Force Members: Wolfgang Cramer (Vice Chair),
Martin Claussen.
Postdoc: Hermann Held
GAIM’s Role
GAIM was established within IGBP to "promote the
development of a suite of global biogeochemical Earth
system models." As such, GAIM is charged with constructing
an integrated whole from the various parts of
the Earth system being explored by each of the Core
Projects. This presents two unique challenges. Firstly,
GAIM must be able to identify the most critical links
between subsystems and any gaps in our understanding
within and between parts of the Earth system. This
introduces a "think-tank" character that necessitates a
comprehensive vision of the Earth as a unit, and an integrated
approach to GAIM activities. Secondly, GAIM
must be able to effectively link the efforts and results
produced by the Core Projects as well as interface with
the other Earth System Science Partners (ESSP) WCRP
(World Climate Research Programme), IHDP
(International Human Dimensions Programme on Global
Environmental Change) and DIVERSITAS.
Moving to the Earth system level required expanding the
scope of GAIM's activities beyond the strictly biogeochemical,
and into the physical, on the one hand, and the
socio-economic, on the other. As such, GAIM aims to
act as a "lighthouse" for the broader global change
research community to ensure that it does not overlook
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any key issues that will prove to be important at the system
level.
Analysis
GAIM poses questions and challenges the broader community
to address them in ways that ultimately contribute
to Earth system level investigations (i.e. Hilbertian
Questions, cf box p. 108). The set of issues so defined by
GAIM will need to be addressed by all of IGBP and the
community at large. As such, it is hoped that the products
of GAIM's analysis role will inspire the research
community by extending the scope of its research to
explore challenging questions at the system level that are
not presently investigated.
Integration
GAIM works closely with the IGBP Core projects and
beyond IGBP to promote and conduct research activities
that are broader than the scientific scope of individual
(or pairs of) Core Projects, but require input from
across a wide range of IGBP scientists. It would be
overly ambitious to assert that GAIM, with its limited
number of scientists and resources, can unilaterally tie all
the pieces of global change research together into a unified
whole. We therefore focus on those integrative
activities which can pave the way for others to join in
integrated Earth system analysis.
Modelling
The models that GAIM is charged to develop must be
based on a solid foundation of analysis of the critical