1 - Introduction

Summary

PROBLEM IDENTIFICATION

The subject of UNESCO's International Hydrological Programme (IHP-IV) project H-2.1, ‘Study of the relationship between climate change (and climate variability) and hydrological regimes affecting water balance components’, is relatively new, but it is of vital importance for society. Climate change and variability will affect the hydrological cycle, which will in turn affect both the distribution and availability of water resources for domestic use, for food production, and industrial activities, as well as for the production of hydropower. Other hydrology-related aspects include flood control, water quality, erosion, sediment transport and deposition, and ecosystem conservation. Most uses of water are economically important, and thus are related to socioeconomic development, as well as to public health and wellbeing and the environment, which themselves are also interrelated. Thus the concerns over the potential impacts of climate change range from the causes to the ultimate and diverse social consequences, which will vary depending on the location and the human responses. This volume addresses mainly the impacts of climate change on hydrological systems, but occasionally some other aspects are also considered.

The social relevance of this study is well illustrated in the tentative statement formulated at a meeting of the Working Group, as follows:

The world's population is increasing at an unprecedented rate, and this will have implications for many areas of human activity. According to the UN Conference on Population and Development, held in Cairo in 1994, the global rate of population increase is now about 1.6%, whereas for the continent of Africa the rate is as high as 2.8%. […]