Water and Global Change (WATCH) (completed)

About the project

The project brings together European hydrological, water resources and climate communities to analyse, quantify and predict the components of the current and future global water cycles and related water resources states, evaluate their uncertainties and clarify the overall vulnerability of global water resources related to the main societal and economic sectors. The WATCH project analyses and describes the current global water cycle, especially causal chains leading to observable changes in extremes (droughts and floods), and evaluates how the global water cycle and its extremes respond to future drivers of global change (including greenhouse gas release and land cover change).

UiO researchers primarily contribute to Work Block 4 (WB4) “Hydrological Extremes” through the assessment of the spatial and temporal characteristics of drought and large-scale flood under current and future climate. At the regional scale, the European Water Archive (EWA) with observed daily river flow from more than 600 stations, has been used to investigate i) changes and trends in mean monthly and low flows across Europe, ii) spatial patterns of inter-annual variability of high and low flows and iii) how well spatial and temporal drought patterns are simulated by a Regional Climate Model (RCM). Recently, a multi-model analysis of droughts has been initiated to evaluate the ability of large-scale models (Land-surface hydrological models and Global Hydrological models) to simulate hydrological extremes (using the same WATCH forcing data).

Objectives

• To integrate modelling of the water cycle into global and regional climate models
• To better quantify possible changes in the water cycle due to human influences and climate change in the period 2000-2100 - esp. floods and droughts
• To assess impacts of the changes on agriculture, industry, energy, drinking water supplies and the environment
• To analyse and describe the current global water cycle
• To evaluate how the global water cycle and its extremes respond to future drivers of global change
• To evaluate feedbacks in the coupled system as they affect the global water cycle
• To develop a modelling and data framework to assess the future vulnerability of water as a resource.
• On this basis, WATCH aims at providing policy makers with a consistent and clear assessment of flows, floods and droughts for present and future scenarios.

Background

The Global Water Cycle is an integral part of the Earth System. It plays a central role in global atmospheric circulations, controlling the global energy cycle (through latent heat) as well as the carbon, nutrient and sediment cycles. Globally, the supply of fresh water far exceeds human requirements. However, by the end of the 21st century, these requirements begin to approach the total available water. Of course, regionally, the water demand – for agriculture, and domestic and industrial use – already exceeds supply (more).

WorkBlocks

The work is divided into seven WorkBlocks (WBs), focusing on:

• WB1: the 20th century global water cycle using a combination of models and data;
• WB2: estimating population, land use and water requirements for the 20th and 21st centuries for use in the other Work Blocks;
• WB3: projections for the 21st century global water cycle, including a full uncertainty analysis;
• WB4: the impact of global change on hydrological extremes, including spatial and temporal patterns of droughts and large-scale floods.
• WB5: feedbacks between the land surface and climate system;
• WB6: assessments of the past and future states of water resources and vulnerability;
• WB7: the management of WATCH and providing training and dissemination activities about the research within WATCH to scientists and stakeholders.

  Financing

WATCH is an Integrated Project (IP) funded under the European Union 6th Framework Program (FP6).