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The Second International Conference on Climate and Water
Espoo, Finland, 17-20 August 1998
Contents
Appendixes:
Preface
The objectives of the Second International Conference on Climate
and Water were to review the developments since the Conference Climate
and Water 1989, in particular as regards to the following topics:
The Conference was attended by over 300 specialists representing about
70 countries. From the presentations 176 were published in the
Proceedings; on three volumes, 1676 pages.
The main conclusions and recommendations are summarized in this
report by Prof. James Dooge (Past-President of ICSU) and Dr Esko
Kuusisto (rapporteur for UNESCO/IHP-projects on global and climate
change) from the presentations at the Conference and the material
prepared by the topic rapporteurs.
The report also records the texts of the speaches at the opening by
the Finnish Minister of Agriculture and Forestry, Mr Kalevi Hemilä,
the Secretary-General of WMO, Prof. Godwin Obasi, the Director-General
of DGXII, EC, Prof. Jorma Routti and the Assistant Director-General of
UNESCO, Dr Gisbert Glaser.
The Conference was organized by the Helsinki University of
Technology in cooperation with the four governmental
(WMO, UNESCO, EC and IAEA) and fourteen other
organizations. During the conference days there was close
cooperation with the Finnish Meteorological Institute and the Weather
Service Finland Ltd.
All the contributions are greatly appreciated.
On behalf of the Organizing Committee
Risto Lemmelä
Huhtatie 12 Tel. +358 9 275 38 35 04300 Tuusula +358 40 556 34 95 Finland Fax +358 9 451 38 27 /wr/caw2 rlemmela@ahti.hut.fi
CLIMATE AND WATER - A 1998 PERSPECTIVE
James C.I. Dooge (Ireland) and Esko Kuusisto (Finland)
with the collaboration of Arthur Askew (WMO), Sten Bergström
(Sweden), Mike Bonnell (UNESCO), Don Burn (Canada), W.M. Edmunds
(United Kingdom), R.A. Feddes (Netherlands), Alan Hall (Australia),
Zbigniew Kundzewicz (Poland), Hans-Jürgen Liebscher (Germany), Harry
Lins (USA), Maria-Carmen Llasat (Spain), Omar Lucero (Argentina), Paul
Pilon (Canada), Lars Roald (Norway), Nils Roar Saelthun (Norway),
Bruno Schädlaer (Switzerland), Igor Shiklomanov (Russia),
W.G. Strupczevski (Poland), R. Vaikmäe (Estonia), Olli Varis (Finland)
and Charles Vorosmarty (USA)
Executive summary
The Second International Conference on Climate and Water was held
in Espoo, Finland on 17-20 August 1998. The papers presented were
preprinted in 3 volumes (1676 pages in all). The objective of the
Conference was to review developments in the study of the impact of
climate variation and change on hydrology and water resources since
the Conference on Climate and Water in Helsinki, Finland, 11-15
Sept. 1989. The purpose of this present report is to summarise the
main conclusions and recommendations of the conference as an input to
the current debate at national and international levels on the
implications for science and for society of climate variation and
climate change.
For convenience, the main recommendations arising from the papers
presented and the discussions held at the conference are grouped in
this executive summary in four categories appropriate to the
particular interests of the reader: (1) research priorities, (2)
research management, (3) project design and management, and (4) policy
formulation. The considerations underlining these recommendations are
described briefly in the body of this report and in more detail in the
published proceedings, in which they are grouped according to the
Conference topics under which they arise. It will be noted that the
theme of the need for improved communication between diverse groups
recurs in the above recommendations. This is a true reflection of the
emphasis on this point throughout the Conference.
In regard to research priorities, the following two recommendations
arise from the papers and the discussion on them:
In regard to research management, the following recommendations are
made:
In regard to project design and management, the following points were
emphasised:
The following recommendations were suggested in the general area of
policy formulation:
The analysis of the present situation and the background to the
above recommendations as presented at the Conference is summarised in
the body of this report under three main headings of (a) data networks
and trend analysis, (b) modelling of climate and water and (c) impacts
and policy responses. The account is of necessity a condensation of
the material in the pre-published papers which amounted to almost 1700
pages.
Introduction
The first Conference on Climate and Water was held in Helsinki,
Finland, from 11-15 September 1989. The aim of that Conference was to
bring together experts involved in the study of climatic variability
and change and of their impact on hydrology and water resources. Since
then, research on climate change and its impacts has been
intensified. The Second Conference was convened in Espoo, Finland,
from 17-20 August 1998 to review the developments related to climate
and water resources since 1989.
The main purpose of this review is to contribute to the continuing
debate at national and international level on the major impacts of
climate variability and change and the options for an appropriate
response based on sound hydrological principles. The papers presented
to the Conference were edited by Risto Lemmelä and Nea Helenius and
pre-published in 3 volumes. They occupied 1676 pages and were grouped
into three main topics: (1) uncertainties of climate change - a
hydrological perspective, (2) impact of climate variability and
change, (3) beneficial impacts and losses for water resources and
water management as a result of climate change. These main topics were
further divided into 9 sub-topics. The following discussion covers all
of these sub-themes but is grouped according to three general areas of
responsibilities: (a) data acquisition and trend analysis, (b)
modelling of climate and water, (c) impact and policy response,
including education and training. A list of the Conference papers is
given in Appendix A. Speeches were made at the Opening Ceremony by
Kalevi Hemilä (Minister for Agriculture and Forestry of Finland),
G.O.P. Obasi (Secetary General of WMO), Jorma Routti (Director General
of DG XII, EC), and Gisbert Glasert (Assistant Director-General of
UNESCO). These speeches are reproduced in Appendix B.
This summary report is being circulated to the participants of the
Conference and through the channels of the cooperating organisations
to a wide range of national experts. In this way it can help to
promote further discussion of these important topics and assist those
responsible for policy decisions to base their decision on the basis
of current understanding in hydrology and water resources. The report
will also be submitted through appropriate channels to the governing
bodies of the sponsoring organisations - World Meteorological
Organisation (WMO), United Nations Educational, Scientific and
Cultural Organisation (UNESCO), European Commission (EC), and
International Association of Hydrological Sciences (IAHS). Its
recommendations will be available to the Fifth Joint WMO/UNESCO
International Conference on Hydrology (Geneva, February 1999), to the
World Conference on Science for the Twenty-first Century (Budapest,
June 1999), and to the Twentysecond General Assembly of the
International Union of Geodesy and Geophysics (IUGG) (Birmingham, July
1999). The most immediate use of the results of the Conference will
be in the restructuring of the World Climate Programme on Water which
is a joint venture of WMO and UNESCO for co-ordinating all
water-related activities under the World Climate Programme. Another
direct use anticipated is as an input to the forthcoming Third
Assessment of the Intergovernmental Panel on Climate Change and
consequently to the high-level negotiations associated with the UN
Framework Convention on Climate Change.
Data networks and trend analysis
A critical situation exists in relation to data for all
stakeholders concerned with water and water resources. Good sets of
reliable data are essential for extending our understanding of
hydrologic processes, for the detection of significant trends in the
relevant variables, for the verification of a wide number of models
involving water behaviour or use, for the evaluation of the impacts of
both variation and change in the hydrologic variables on ecosystems
and on socio-economic systems, and for the clear formulation of the
alternative scenarios to be considered in key policy decisions. It is
not surprising therefore that the question of data sets and their
interpretation arose in a number of presentations and discussions at
the Conference.
Several authors and speakers expressed their concern about the
dramatic reduction in monitoring services in many countries where
basic climatic and hydrological data programmes no longer receive the
same financial support as previously. The comment was also made that
regional and continental scale studies are often hampered by failure
to process, retain and exchange basic data. Inter-governmental and
specialised international agencies should do all in their power to
remedy this situation. It was stressed in many of the papers and
discussions at this Conference that historical records are invaluable
in providing a basis for the evaluation of natural variability and the
consequences of climate change. This applies to both long-term data
sets and to shorter records covering anomalous periods.
It was clearly stated that the decline in ground observations
cannot be compensated for by the greater availability of
remote-sensing techniques. The accuracy of weather satellites is not
high enough for hydrological purposes while the higher resolution of
the more expensive earth resources satellites is offset by their
longer return periods. Reliable conversion of radiation data at the
land surface to hydrologic information is still difficult in many
instances. However, satellite data have proved useful in the
disaggregation of precipitation predicted by GCMs in order to couple
the atmospheric models with high resolution hydrologic models and also
in the estimation of heat fluxes at land surfaces for use in
evaporation studies.
Analysis of extremes and trends
In the period 1990-96 there were five flood disasters in different
parts of the world, during which at least a thousand people lost their
lives: Bangladesh, in April 1991 (140,000 killed); China, in July 1991
(3,074 killed); China, in June-August 1996 (2,700 killed); Pakistan,
in October 1992 (1,500 killed); China, in May-June 1994 (1,410
killed). In the same years, there were 21 floods with materials
losses exceeding one billion USD. The five biggest losses were as
follows: China, in June-August 1996 (26.5 billion); USA, in
June-August 1993 (16 billion); North Korea, in July-August 1995 (15
billion); Italy, in November 1994 (12.5 billion); China, in July 1991
(7.5 billion). (WMO Bulletin 1998 No 2). During the Conference week,
devastating floods in China were climbing towards the top of both of
these statistics (at least 3000 victims, 20 billion USD damage).
Smaller headlines were telling us that a critical water shortage
prevails in Jordan, Lebanon, Cyprus and other countries in the Eastern
Mediterranean region.
Extreme hydrological events have always been with us. In the
Conference both historical events and recent extremes were
analysed. The effect of the coincidence of several factors in
producing extreme floods was described for a number of cases.
Flooding is often the consequence of critical and unfortunate timing
of several flood-generating factors such as delayed snowmelt in
combination with thick snow cover and early summer rains, or heavy
rainfall in combination with high antecedent moisture conditions.
About 15 papers were presented dealing with the analysis of trends
in a number of hydrologic variables. The areas covered included
catchments in the Balkans, the Baltic countries, Canada Colombia,
Estonia, Finland, Greece, Hungary, Italy, Mexico, Nigeria, Poland,
Russia, Scotland and Spain. The hydrologic variables included
precipitation (both rain and snow), evaporation, runoff and lake
levels. In different localities positive or negative trends were
detected for the same or similar variables thus indicating the need
for large scale data networks. Many of the papers applied classical
techniques to their data sets but some developed extended techniques
designed to incorporate non-stationarity into statistical hydrologic
analysis.
The Conference had relatively few papers related to lakes, either
their hydrological or ecological aspects. This was surprising and
somewhat alarming - not only because the Conference was held in a
country of 188 000 lakes, but also due to the fact that lake chemistry
and ecology should be studied as an integrated part of a system
including the upstream watercourse and land area. Two papers explored
physical and biological data from an extensive lake survey in northern
Finland and neighbouring parts of Norway, 98 lakes in total. The main
conclusions of these papers are that, inter alia, catchment vegetation
is a very important explanatory variable for the chemical state of
lake water, and that different taxa of diatoms are temperature
specific to the extent that they can be used as summer temperature
indicators. These organisms can also be identified in lake sediments.
Another paper discussed the potential of using the levels of closed
lakes as climate indicators. It also acknowledged the limits of this
approach, as the lake can get dry or overflow. One paper demonstrated
the potential of a simple lake model to simulate temperature
variations and ice cover duration in a large and morphologically
complex Finnish lake.
The following recommendation is primarily addressed to hydrologists:
Large scale experiments have and are being carried out at a range
of scales including the local scale to measure the energy and surface
water balance and carbon balance of different land use
characteristics: (a) the basin scale from 10 to 100s of km2 focusing
on runoff and runoff chemistry; (b) the mesoscale of 100 x 100 km grid
to address parameterization problems, aggregation and the interaction
of vegetation and the ecosystem distribution; and (c) large-scale
continental experiments the size of the Amazon and Mississippi basins,
which address the issue of coupling soil, water, vegetation and the
atmosphere linked to numerical mesoscale models and large-scale land
use change.
The following recommendation is primarily addressed to research
managers:
Finally, the following recommendation is addressed to both
hydrologists and research managers:
The individual papers dealing with these questions are to be found
largely under sub-topics 2a, 2c, 2d, 2e (see Appendix A).
Increased efforts should be
made in the establishment and maintenance of data networks and the
development of reliable methods of trend analysis and their
application to suitable data sets including historical data.
Continued support should be
given to large scale land surface experiments in order to provide
verification data for hydrologic models. and climate models used for
predicting the effects of climate variations and change.
Advanced planning is needed
to ensure the availability of accommodation on programmes of remote
sensing for instruments of significance in hydrologic data
accumulation and hydrologic research.
Modelling of climate and water
In theory, the modelling of the hydrologic consequences of climate
change is a simple sequence: (a) define, calibrate and validate a
model of the hydrological system using current climate data; (b)
define climate change scenarios and perturb the original climate data
accordingly; (c) run the hydrological model under current and future
conditions; and (d) compare variables of interest. In reality, this
procedure might not lead to useful results. The uncertainties of
climate scenarios and GCM-outputs are large. The ability of GCMs
models to reproduce the present situation on a regional or catchment
scale is low, and for the future the local predictions differ not only
in quantity but sometimes also in sign. The coarse spatial resolution
of GCMs makes the outputs at the catchment scale problematic.
The uncertainties of the hydrological model predictions are also
large. The main assumption in such models is that the set of
hydrological model parameters is the same today and in the future
under different climate scenarios, which might be far from the truth.
For example, at high CO2 content of air, stomata of the plants
contract to take in carbon dioxide, hence transpiration decreases,
implying that water use efficiency increases. This essential factor
is still often neglected in the models. Instead of the mechanical
running of climate change scenarios through hydrological models, more
effort should be given to determining the magnitude of the uncertainty
of the hydrological response to change. These efforts may yield
bigger dividends than a number of single scenario impact studies
conducted throughout the world, which may in the future prove to have
been ill conceived. But without doubt, we can also benefit from the
routine scenario studies. We have for example learned that a marginal
shift in climate can lead to dramatic alterations in the hydrological
regime. This can be the case in catchments with low precipitation and
low runoff coefficient, or in catchments where significant phase
shifts between rain and snow can occur.
Natural climate variability and associated hydrological response
may not be well represented by current GCM-hydrological modelling
efforts. Use of historical records of anomalous periods may prove
valuable in understanding the potential hydrological consequences of
climate change and the natural variability within the climate system.
The climate and water modelling community have been drawn together
by the need to better represent the energy forcing in hydrological
models and runoff in GCMs. Use of the experience of hydrological
models to evaluate what the climate models are doing is proving
beneficial. For example, comparisons of the outputs of a daily water
balance model applied to the Baltic Sea basin were compared to
ten-year climate model simulations of two European GCMs. These helped
pinpoint systematic or compensating errors in the land
parameterization schemes in these models, particularly the need to
adequately represent the seasonal variability of precipitation.
Another fundamental barrier to progress in studies of climate-water
interface is the mismatch of scales used in both areas. Spatial and
temporal scales used in the atmospheric studies considerably differ
from those of hydrology, where the basic unit, the catchment, itself
embraces already quite a considerable range of scales. In order to
match these discrepant scales it is necessary to upscale description
of hydrological processes and to downscale climatic variables.
Despite considerably progress achieved to date, much further effort in
needed to improve further the predictions and make them credible and
practically useful.
The difficulty in direct use of GCM scenarios in hydrological
studies due to scale mismatch may become alleviated by different
techniques of downscaling. One of the promising options is nesting of
higher-resolution regional climate models into a GCM. Sub-grid
parameterization should capture intra-cell variability, with adequate
representation of sensitive components such as lateral flow in
addition to vertical water movement, and snow in the mountains.
Temporal downscaling and disaggregation (capturing daily and diurnal
variability of precipitation) are urgently needed for making
inferences on extreme values. Regional climate models are quite good
in simulation of some variables, yet extreme precipitation cannot be
adequately simulated. Request to atmospheric scientists is that in
addition to reducing uncertainty they should try to quantify
uncertainties.
Scale studies are not yet capable of reconstruction of details of
magnitude, location and timing of extreme events in re-analysis. Yet,
they lead to useful regional results, greenhouse effect may cause
increased winter precipitation (and flood danger), earlier snowmelt
and, possibly, increased summer droughts. As higher annual
precipitation total may fall in a smaller number of days and frequency
of intensive floods may consequently grow.
Models should be sensitive to climate in a reasonable way, thus
they cannot be oversimplified. Models used nowadays range from
empirical formulae and regressions through conceptual lumped models
and water balance descriptions to process-based approaches. Yet,
temporal resolution of many models is insufficient for peak flow in
large rivers. Are models appropriate? It seems that the
representation of evapotranspiration is notoriously difficult to
validate as is the validation of macro-scale models, based on runoff
data.
There is a strong feedback between land surface processes and
weather and climate; the influence of soil wetness is a key issue in
GCMs. Soil moisture is the primary forcing factor over land in summer
in temperate climates. Changes in land use produce changes in
vegetation, which in turn alters the partition of energy and
evapotranspiration through seasonal growth and carbon cycles.
Consequent changes in soil moisture profiles and thus runoff need to
be modelled together with the soil chemistry. While atmospheric models
are based on SVAT models at the grid scale, lateral water flow must
also be adequately modelled to link climate and water. The two-way
coupling of land use processes and NWP (Numerical Weather Prediction)
models requires the aggregation of the processes in NWP and the
disaggregation of the meteorological forcing in the land surface and
hydrological models. Acceptable aggregation rules exist for
vegetation, but the aggregation of soil characteristics is more
difficult. Aggregated soil characteristics at the grid scale can
adequately model average evaporation flux, but fail in defining the
average drainage below the root zone and in handling lateral flow.
The problem of parameterisation of evapotranspiration in
hydrological modelling was identified as a key issue by the
Conference. This includes direct effects of increased temperatures,
but also indirect effects of land use changes, changing vegetation and
feedback from increasing concentrations of CO2 in the atmosphere.
Evapotranspiration can be modelled using GIS data over complex land
use and terrain, taking into account shadow effects if necessary.
Evapotranspiration is most sensitive to relative humidity and is
therefore highly dependent on the spatial rainfall distribution.
Hydrologists are in urgent need of climate simulations focusing on
extreme precipitation and on other flood-generating factors. The lack
of these simulations is a major factor preventing an efficient use of
hydrological models in flood risk assessment in the changing climate.
Methods to quantify uncertainties of all relevant climatological
factors should also be developed. A particularly vulnerable issue
related to extremes is the monsoon rains. They bring rainfall to an
area which includes 60 per cent of world's population and 80 per cent
of rural dwellers. The climate models have their weakest performance
within this zone. The advance in the knowledge of El Niño is a
positive sign but more work is needed.
In June 1998, there was a program at Finnish television, where
people could ask questions related to El Niño. A farmer from a remote
village wanted to know, what role El Niño plays in the occurrence of
night-time frosts in Finland in late summer, particularly harmful
events for farmers. The experts doubted any connection. Two months
later a workshop on "Lake Ice and Climate" was arranged at the
International Limnology Society (SIL) Conference. One of the
findings, based on long ice formation and break-up series from all
over the Northern Hemisphere, was that the lakes in Finland have clear
El Niño signals; when this anomaly on the other side of the Earth is
strong, Finnish lakes freeze later and have their break-up later than
during other winters. (Proceedings of the SIL Conference, August
1998, Dublin). The North Atlantic Oscillation Index (NAOI) was found
to have some connections to Norwegian runoff, precipitation and
temperature series.
As to El Niño/Southern Oscillation (or ENSO), the focus was in the
Southern Hemisphere, although teleconnections were also discussed
e.g. between the ecosystem of Lake Baikal and the Southern
Oscillation. The utilisation of ENSO in the prediction of
precipitation was analysed for Argentina, Colombia, Ethiopia and
India. Despite its accepted importance, the ENSO-related variables
indicated only modest ability for seasonally precipitation forecasts
in these countries. In semi-arid region in Argentina, ENSO produced
identifiable signals only in four months of the year. As to India,
the findings indicated that the effect of El Niño is more severe
during periods, when monsoon rainfall is below normal. An above
normal period seems to have started around 1990; thus the authors
speculate that India may be more vulnerable to floods than droughts
during the next decade or two. The river flows in Australia and in
Southern Africa were rather clearly linked to ENSO cycles. In
Australia, the serial correlation of runoff and ENSO can be used to
forecast runoff several months ahead. Researchers and water
authorities are beginning to assess the benefits and risks of using
these forecasts.
Individual components of the cycle
All the components of cryosphere - glaciers, sea ice, lake ice,
permafrost, snow cover - were dealt with in the Conference, although
only in a handful of papers with the exception that snow played a
considerable role in many flood-related presentations. Among the
extreme views put forward was the prediction that a "catastrophic"
warming of 5 degrees centigrade would lead to the disappearance of the
Novaya Zemlya ice sheet (7,300 km3) within 130 years, with a
consequent sea level rise of two centimetres. With predicted warming
in northern Europe, the Baltic ice season was estimated to shorten by
one month by the year 2050. The amount of snowfall and magnitude of
oceanic heat flux played a major role in the ice conditions on the
Okhotsk Sea. Due to higher air temperatures, the snow cover over large
areas over the northern Eurasia disappears nowadays earlier than a few
decades ago, in spite of increased winter precipitation. In the Swiss
Alps, a considerable reduction in snow water equivalents and
consequently in the profitability of skiing resorts will be expected.
As to lake ice impurities, it was indicated an ecological risk in
spring with a very low pH and enrichment of pollutants in the surface
water layer.
The conference did not have a special focus on groundwater issues,
but they were dealt with in some papers. In Estonia, a considerable
increase of groundwater formation is expected as a consequence of
climate change. This would be very beneficial, because the
productivity and reliability of shallow wells could be significantly
improved. In the Netherlands, increasing groundwater table together
with expected land subsidence would have serious consequences.
What is really happening to water during its underground paths?
True physical mechanisms of runoff generation are today much better
understood than two decades ago, but more experimental investigations
are still needed. Besides, the increased knowledge of runoff
formation is not necessarily reflected in hydrological modelling.
This is a particular problem, when the results should be valid also in
chemical and biological applications, but it can also lead to
misinterpretations in relation to GCMs.
In the session on paleoclimatology, two papers discussed
paleogroundwater. The EU-supported project PALAEAUX has been focused
on the origin of palaeowaters in Europe, their present distribution at
a continental scale, their importance both as archives of former
climatic and environmental conditions, as well as their potential in
certain areas as valuable sources of good quality drinking water.
This project is a good example of efficient integration of different
study methods including isotope measurements, geochemical analyses,
borehole geophysical logging as well as geochemical and hydraulic
modelling. Preliminary results were presented of a case study within
the PALAEAUX project. The groundwater in the Estonian
Cambrian-Vendian aquifer contains a unique isotope record indicating
its glacial origin. The whole complex of isotope and geochemical
methods, including noble gas analysis has been used to interpret the
formation mechanisms of these waters. Subglacial drainage of
meltwater from the Scandinavian Ice Sheet to the aquifer seems here to
be the most realistic explanation of paleogroundwater formation.
Local human impact on the quality of water in this aquifer through
intense exploitation was demonstrated. Recommendations for
sustainable use of paleogroundwater as a high quality non-renewable
resource were made.
The Conference noted the various findings described above and
recommend to hydrologists and to research managers as follows:
The papers relevant to the issues discussed in this meeting are to
be found mostly under the sub-topics 1a, 1b, and 2a (see Appendix A).
High priority should be
given in modelling studies to further research on the scaling problem
(both upscaling and disaggregation), to improved methods of modelling
extreme events, and the integration into model studies of factors such
as biological effects and land use effects.
Impacts and policy responses
The papers and posters on the evaluation of impacts covered a large
band of different climates from semiarid regions in Africa up to
wetland regions in northern climatic zones. Research was mainly
focused on the influence of climate change on water resource
management and on agriculture. Some authors used combined
hydrological and socio-economical and other authors ecological and
agricultural model approaches. A number of them discussed their
hydrological findings in view of some potential impacts in their
respective countries.
It is expected that climate change will effect aquatic ecosystems.
Especially in higher latitudes, changes in regional climate patterns
are likely to have significant negative effects on aquatic flora and
fauna. These areas have large wetlands which are very susceptible to
climate fluctuations and which are habitat for a large number of birds
and other species. Northward migration of permafrost would
dramatically alter regional hydrology and cause massive terrain
slumping. Possible water level changes would affect inland
navigation, threaten fisheries and impact the ecological stability of
the lakes. Improved regional climate models with sufficient spatial
resolution are required that can be coupled with hydrologic models for
better quantitative prediction of ecosystem effects. The rate and
degree of change are unprecedented and prediction on how ecosystems
will respond cannot easily be extrapolated from present understanding.
Only with improved understanding can the questions be addressed
whether needed or desired favourable aspects will persist without
intervention and how dynamically changing aquatic ecosystems should be
managed and what actions and financing are required. Another problem,
which has not been taken enough into consideration, is the influence
of possible water level changes on the ecosystem in the areas with
shallow water table. To understand possible impacts of climate and
environmental change, more quantitative data are needed.
From a few studies on the influence of possible impacts of climate
changes on the aquatic system of rivers it can be seen that the water
quality and the biodiversity may be affected. Studies in some areas
show on one side an increase of water temperature together with
increased levels of ammonium-and ammonia-nitrogen, on the other side a
decrease of dissolved oxygen especially in dry and warm seasons. This
will increase water pollution in rivers. In those countries in which
much was done to reduce water pollution additional measures have to be
undertaken to keep the water quality at present level. There are
still high deficits in river water quality modelling. Not all
chemical and biological processes in the aquatic zone can be modelled
and it is at present not easy to couple river water quality models
with terrestrial ecosystem models. Especially the modelling of the
interference between the aquatic and the terrestrial phase is
essentially an unsolved problem. Many efforts are necessary in this
regard. To solve this problem an interdisciplinary cooperation
between hydrologists, water chemists, biologists and ecologists is
necessary. Interdisciplinary international programs including special
workshops are badly needed.
At present there is also an obvious imbalance between different
climatic zones as to the number and quality of investigations, which
have been undertaken to study the impacts of climate change on the
ecosystems. Relevant studies in all geographical regions are
necessary. The common finding at the Conference was that in almost
all investigated regions the already existing or expected problems
will increase. Expected higher temperatures and less precipitation
will lead to increased water demand for domestic water supply and
irrigation water in regions, which are already suffering from
droughts. Some authors state that the effect of climate change is an
additional increase of water demand beyond the increase which is
expected due to population growth and economic development. In a
number of other countries, the latter two factors are considered far
more important than the consequences of climate change. In some
regions, runoff increases due to snowmelt and higher temperatures
combined with increased precipitation and changes in snowmelt may lead
to severe flooding. The same mechanism can enhance groundwater
recharge, which may raise the groundwater table and shrink the aerated
zone. This affects agriculture and may even lead to extension of
wetland areas. In coastal zones the expected sea level rise may be a
reason for an increased salt concentration in the groundwater. This
affects drinking water quality and may damage agricultural production.
There are also regions where no major effects on hydrology and hence
on water resources are expected - compared with the natural variations
of the past decades. This is especially the case in regions with
present high availability of water.
All authors on these topics concluded that measures should be taken
in strengthening water resources management, in improving water
legislation, in enforcing economic use of water and generally
increasing the sustainability of water management. Many also raised
the point of uncertainty at the regional scale. Some papers described
how different GCMs led to contradictory results. A further critical
element is the unknown amount of water, which is "unavailable" due to
pollution, and the uncertainty in the projections of socio-economic
development.
In the northern latitudes and mountainous catchments, changes in
the magnitude and timing of spring runoff can lead to a need to alter
operating rules and target storage levels. There could also be
requirement to alter the reservoir operating guidelines to reflect a
shift in the balance between flood storage and water conservation,
particularly during the spring runoff period. Reductions in the low
flow regime could have a negative impact on the reliability of a
reservoir system for providing water supply. In the future, the
planning of reservoir systems must consider that the hydrological
regime may not be constant throughout the design life of a reservoir.
This implies fundamental changes in the way that reservoir inflows and
demands are modelled in the process of determining an appropriate
reservoir capacity and also in the identification of reservoir
operation policies. It is clear that there is a need for a paradigm
shift in both reservoir operation and planning. The Conference also
pointed out the diversity of large drainage basin characteristics and
hence potential response to climate change and variability. However,
it is readily apparent that there exists a general lack of scientific
harmonisation across this body of work as a whole, making an objective
assessment of their collective value to the policy-making community
difficult at best.
The implications of climate change for water resources management
were discussed in the Conference, but only few examples could be given
where the possibility of future climate change impacts had already
influenced management praxis. The interest is strong, but there is
still hesitation about how to quantify climate change impacts and on
how to assimilate the increasing uncertainty that has emanated. It
was consequently concluded that it is necessary to find ways to
account for global warming and its effects in water resources
management praxis. Several papers explicitly considered the issues of
water engineering (e.g. river diversion, irrigation, impoundment and
hydropower) either as a factor influencing the water balance of large
basins or from the viewpoint of vulnerability to climate change. The
increasing recognition of the role of water engineering works in
defining the hydrology of drainage basins will require a concerted
effort to link the engineering and hydrological communities. An
economic dimension to this question is also apparent and policy-makers
are urged to foster the appropriate multi-disciplinary understanding
of the issues.
There are many competing demands on high-level policymakers,
especially politicians with short-term agendas. Their attention is
likely to be focused on public welfare, economic stability and foreign
policy. They are certainly not interested in the hydrological cycle.
For them, water is a resource or a source of potential disasters, as
in floods and droughts. There are also likely to be barriers to the
implementation of policies considered desirable by the scientific
community. These may result from established institutional
structures, systems of taxation and land tenure, for example. While
it is reasonable to ask decision-makers to explain their policies and
their basis for developing new policies, it is not reasonable to
expect them to come all the way to meet the scientists in all topics.
It is necessary to offer good arguments for the importance of climate
change and its impact on water resources. In this, it is necessary to
work with and through relevant ministries and other institutions that
advise the policy makers. There will still remain the problem of
enforcing any policy that is announced.
Studies on the current state of the environment can illustrate why
we face a problem and the nature of that problem. Analyses based on
our knowledge of natural sciences and risk assessment can lead to
conclusions as to whether the problem is serious, and the social and
economic disciplines can offer options for ameliorating the problem.
Unfortunately, the natural sciences currently offer advice and
information on mean values, when the decision-maker would be more
concerned with extremes; or on the more likely state, when the concern
is for certain thresholds; or on an equilibrium future state, when the
rate of changes is the controlling factor; or on the magnitude of a
change, when the need is to handle a risk. One policy option in the
face of the lack of data on uncertainty in prediction is to take no
action. But this may lead to the need for major investment at a later
date. It can be argued that at least some investment should be made
now, such as data collection and research, so as to reduce the risk of
major costs later. The problem is - do we have enough information as
yet to be sure that these initial investments will be effective?
One major problem, and a long-standing one, is needed to explain
uncertainty to the public and policymakers. This includes uncertainty
in further climate and the inadequacy of our knowledge on that future.
This leads to an appeal for government policy to support continued
research, data collection and access to existing data. Often the
greatest concern is to match long-term climate variability with
expected population and economic growth, climate change being of much
less concern. Once again this raises the need for better data and a
greater understanding of climatic and hydrological extremes. The
changes of these extremes will be the most critical feature of any
change in climate.
The scientific community must also explain its case to the local
community, who are not familiar with the contents of international
professional journals. This is the public affected by climate impacts
and the voting public who can influence politicians and their senior
advisers. One problem here is that science is not so well respected
now as it was and it will be necessary to present clear explanations
and convincing arguments. The best science and wisest policies are of
no use if the public oppose or ignore them. It would be wise to work
at the local community level to explain the current scientific
understanding and seek local advice as to what studies might be
undertaken to answer local concerns at local and regional level, what
are most critical specific rates of change or critical levels to which
the community is vulnerable. The risk of surpassing these
site-specific levels is what concerns the community, not the results
of global scenario studies.
The round table on Education and Training dealt with a wide range
of topics. As in other sessions at the Conference there was emphasis
on the need to take account of the social sciences as well as the
natural sciences (both physical and biological) and to impart
knowledge based on both theory and practice. It was stressed that a
key problem was to find the best system which would combine modern
learning techniques with local circumstances and traditional values.
The point was made that the concept of technology transfer had been
damaged in the past in developing countries due to the interference of
political and commercial interests. The discussion covered both
general sessions in schools to promote awareness at an early stage and
more specialised instruction in higher education based on best modern
practices. It was suggested that UNESCO and WMO could play a role in
the preparation of pilot courses for the Internet. It was emphasised
that all projects in water education required: (a) careful planning
based on a realistic evaluation of costs and potential benefits; (b)
implementation based on local circumstances and available resources;
and (c) regular updating based on feed-back and rigorous assessment.
Recommendations on impacts and responses
A number of recommendations arise from the discussions summarised above.
It should be recognised by all concerned that climate variation and
change is an important factor in water resource management along with
other key factors such as population growth, changes in land use, and
economic development.
Dialogue is necessary between hydrologists on the one hand and the
planners and managers of water projects on the other hand and this
dialogue will be most useful if focused on the basis an actual
problems arising in practice.
There is a growing need for the study of conflict resolution in
relation to water in view of the ever-increasing pressure on water
resources.
National water planning and legislation should always be based on
the most up-to-date information available and should be adequately
implemented in all sectors of society.
All such administrative action should take due account of local
culture and customs and of the level of economic development.
Governments and administrators should involve all stakeholders at
an early stage of water resource development.
Special attention should be paid to making known to school-children
the basic facts about water and its use.
Research scientists
dealing with climate and water should recognise the importance of
communication between natural scientists of different disciplines
(both physical and biological), between natural scientists and social
scientists, between scientists and policy makers, and between
scientists and the general public. Research managers should make
provision in the planning of research programmes for the communication
of the results of research in appropriate form to policy makers and to
the general public.
| Lemmelä, Risto | (Chair), Academy of Finland, National Committee for the IHP |
| Askew, Arthur | WMO Secretariat |
| Balabanis, Panagiotis | EC |
| Bonell, Mike | UNESCO Secretariat |
| Feddes, Reinder | UNESCO IHP-V (theme 1) and ICASVR of IAHS |
| Froehlich, Klaus | IAEA |
| Grabs, Wolfgang | GRDC |
| Halliday, Robert | IAI |
| Kundzewicz, Zbigniew | ICWRS of IAHS |
| Liebscher, Hans | Bundesanstalt für Gewässerkunde, Germany |
| Nobilis, Franz | ICSW of IAHS and WMO Regional Association |
| VI-Europe | |
| Pilon, Paul | WMO/CHy - Expert |
| Spreafico, Manfred | CHR |
| Van der Beken, Andre | ETNET. Environment-Water |
with the Nordic Contact Group
| Bergström, Sten | Sweden |
| Sælthun, Nils Roar | Norway |
| Snorrason, Arni | Iceland |
| Thomsen, Richard | Denmark |
