BALTEX Phase II 2003 – 2012. Science Framework and ...

30
BALTEX Phase II Science Framework and Implementation Strategy
substances, and other management issues relevant for the environment. Future projections and
scenarios should address also the unavoidable uncertainties embedded in the driving global and
regional scenarios due to the inherent uncertainties in the climate system science and the evolution of
climate system forcing on both the regional and global scales.
2.3. Involvement of Stakeholders
The stakeholders with interest in this major objective of BALTEX Phase II are i) the public at large, ii)
national authorities with responsibility for e.g. infrastructure and the environment, iii) international
agencies and organizations including the European Environment Agency (EEA) and the
Intergovernmental Panel on Climate Change (IPCC), and iv) actors involved in policy-making,
enterprises, and corporate institutions that need to factor changing climate into long-term planning
decisions.
On the one hand, stakeholders require reliable and useful knowledge about past climate change,
present variability and the occurrence of extreme and rare events 3 . Also, stakeholders increasingly
need detailed, consistent and useful descriptions of possible and plausible future climate variability
and change. Of special concern are the identification of robust changes and the separation of these
from more uncertain ones. Another major goal should be a simplification of the issues, such as ruling
out those facets of climate change that are not significant for a particular stakeholder.
On the other hand, research needs knowledge from stakeholders. Plausible and possible perspectives
for changes of land use, river regulations, regional emissions of aerosols, and other regional or local
agents influencing the regional and local climate are required for comprehensive future projections
and scenarios. Stakeholders should also be encouraged to provide scenarios of other anthropogenic
factors (e.g., release of harmful substances), which will influence the BALTEX region (e.g.,
ecosystem functioning) in conjunction or in addition to climate forcing and change. This latter aspect
is especially important in the context of extensions of BALTEX data and modelling studies beyond the
physical climate system.
2.4. Potential Activities
2.4.1. Reconstruction History of Climate in the past 200 Years as well as Detailed Reanalysis
of “Weather” of the past 40 Years
Regional re-analysis as well as other reconstructions are needed in studies of climate variability and
change. One focus will be on the past 200 years which allows for studies on natural climate variability,
the action of natural forcing factors, and extremes, see below. Another focus will be on the past 40
years, where the increasing range of novel observations and measurement campaigns allows for
increasingly more physical and targeted basic and applied process studies, and model evaluation. The
availability of global re-analyses such as ERA-40 and NCEP (National Centres for Environmental
Prediction) products give a particular rational for the past 40 years. The focus on the past few decades
will also contribute to better understanding of the physical background of the processes which
determine the water and energy cycle in the Baltic Sea basin, as described in more detail in Chapter
1.4.1. In this context, BALTEX Phase II is in line with the World Climate Research
Programme/Coordinated Observation and Prediction of the Earth System (WCRP/COPES) strategy
which suggests using the 1979-2009 period to develop reference climate data sets and advanced
forecasting techniques (see also Chapter 10).
The variables considered are foremost the conventional geophysical ones describing the atmosphere,
hydrology, the ocean and sea ice. For much of the period, available data allow the reconstruction of
state variables. In the second half of the 20 th Century, possibilities to address process-level
3 Here, we refer not only to extreme events that occurred and have caused major consequences, but also to the
likelihood of the occurrence of events being normal but at the same time rare.