International Hydrological Programme

Global changes and water resources

The first theme of IHP is concerned with how climatic and human-induced changes will affect the world’s water resources. Specifically, it concentrates on answering the questions of how, when and where human-induced changes, together with weather and climatic extremes, will influence water resources and the sustainability of the biosphere upon which we depend. However, these questions are extremely difficult to answer without better access to improved assessment and analysis technologies.


Focal areas


Those aims are accomplished through a set of focal areas, which include:

  • global distribution of resources: water supply and water quality
  • global estimation of water withdrawals and consumption
  • integrated assessment of water resources in the context of global land-based activities and climate change

The aims of this theme


The general aims of IHP activities implemented in the framework of the theme 'Global changes and water resources' are:


  • to estimate the variation in time and space of water supply and demand at regional, continental and global scales due to changes in land use, cover and intensity; population growth and water engineering and industrialization
  • to explore the effects of climate-induced forces on water resources
  • to encourage the adoption of emerging technical capabilities to perform broad-scale international, integrated and multifactor water resources assessments
  • to support problem prevention and mitigation efforts with respect to water as a strategic resource

Answering the questions


To answer the questions posed by this theme, it is necessary to expand upon existing assessment and synthesis technologies, as well as develop new ones. To this end, IHP’s first theme focuses on the following two priorities:


Improved assessment


It has been difficult, even with current technology, to accurately assess the state of world water resources in the face of global changes brought on by the greenhouse effect and climatic variability, land cover change, industrialization and population growth, and the control of the natural water cycle through hydraulic engineering.


There is no carefully maintained and clear record of global hydrologic change by which to judge the cumulative impact of human activities on the world’s freshwater and coastal support systems, as their highly site- and region-specific physical and water quality attributes make such an assessment extremely difficult. Furthermore, deterioration in routine monitoring networks in many parts of the world does not currently make an accurate assessment possible.


Better synthesis and analysis


While process-based hydrological research remains successful on a small scale, there is a critical need for synthesis studies of complex drainage basins on continental or global domains. This need has provided the impetus for several major international and national observational and modelling programmes such as the Global Energy and Water Cycle Experiment (GEWEX), the Biospheric Aspects of the Hydrological Cycle project at the International Geosphere-Biosphere Programme (IGBP-BAHC), the Global Climate Observing System (GCOS) and the Global Terrestrial Observing System (GTOS). The initiatives of Hydrology for the Environment, Life and Policy (HELP) and Flow-Regimes from International Experimental and Network Data (FRIEND) help to clarify the inherent scientific issues at the river basin scale, in connection with the legal and water management aspects and impacts.


Several opportunities exist for analysing the global status of the land phase of the hydrological cycle and associated water resources. The emergence of improved models, high-quality biophysical data sets as well as improved access to remote sensing imagery and data assimilation schemes, provide an opportunity to monitor the state of the hydrological cycle over broad domains and in near-real time. In addition, appropriately cast models can be used with this information to improve understanding of the spatial and temporal aspects of global water resources.


EVENTS
12th Biennial ERB Conference: Hydrological Extremes in Small Basins
The 12th edition of the Euromediterranean Network of Experimental and Representative Basins (ERB) Conference was held in Cracow from 18-20 September 2008.
PARTNERSHIPS
World Water Assessment Programme (WWAP)
Established in 2000, WWAP is a United Nations system-wide programme. It seeks to develop the tools and skills needed to achieve a better understanding of the basic processes, management practices and policies that will help to improve the supply and quality of global freshwater resources.

Flow Regimes from International Experimental and Network Data (FRIEND)FRIEND is a cross-cutting programme intended to develop, through the mutual exchange of data, knowledge and techniques at a regional level and a better understanding of hydrological variability and similarity across time and space.

GRAPHIC
The Groundwater Resources Assessment under the Pressures of Humanity and Climate Change (GRAPHIC) project develops methodologies for assessing effects of climate change and human activities on groundwater and applies them in case studies.

Hydrology for the Environment,
Life and Policy (HELP)


HELP is a joint UNESCO and WMO initiative conceived to develop a new approach to integrated catchment management by building a framework for water law and policy experts, water resource managers and water scientists to work together on water-related problems.

International Groundwater Resources Assessment Centre (IGRAC)
IGRAC is dedicated to sharing groundwater information, knowledge and experience in the widest sense, on a worldwide scale and on a non-commercial basis.
PUBLICATIONS
2nd World Water Development Report
'Water, a shared responsibility'



The 2nd report presents a comprehensive picture of freshwater resources around the world as it tracks progress towards the water-related targets of the UN Millennium Development Goals and examines a range of key issues including population growth, increasing urbanization, changing ecosystems, food production, health, industry, energy, risk management, valuing and paying for water and increasing knowledge and capacity.

Groundwater resources
of the world and their use [PDF format – 10 MB]
This monograph represents a multicultural approach to groundwater resources and their use and aims to contribute to a better understanding of the crucial role played by groundwater resources in support of both the ecosystems and mankind.