“[the environment is] groaning under the mountain of wastes dumped onto it daily, and from overuse and misuse, with seemingly little care for the future consequences and future generations. In truth it is attitude and behaviour problems that lie at the heart of the crisis.”

UNDP HDR 2006

Water is an essential part of any ecosystem and reduced water quantity and quality both have serious negative impacts on ecosystems. It is not certain what the precise impact of climate change will have on water resources, although it is acknowledged that there is an increased pressure on water resources. It is generally agreed that many tropical and sub-tropical regions will probably get lower and more erratic rainfall and extreme weather conditions such as flooding, droughts, mudslides, typhoons and cyclones as currently being experienced in various parts of the world. Once again, it is the poor who are the most affected by such impacts – they live in marginal areas, those afflicted by floods, pollution and scarce water supplies as well as the loss of valuable natural sources of food. Where water and sanitation services are poorly managed, the effects of climate change will impact much more negatively. Unless water resources are protected and shared equitably, poor and marginalised communities will suffer the most.

The main source of the world’s food supply is agriculture – crops, livestock, aquaculture and forestry. It is estimated that, where unmanaged, earth systems can feed around 500 million people, so in a current population of more than 6 billion people, systematic agriculture is a necessary evil. To feed a person, per day on the average calorie requirement of 2,800 calories requires an average of 1,000 cubic metres (m3) of water. Agriculture is the mainstay of many rural economies at the local level – where the majority of agriculture is rainfed and irrigated land accounts for about one fifth of the total arable area in developing countries. It is estimated that by 2030, some 60 percent of all land with irrigation potential will be in use. Of the ninety-three developing countries surveyed by the FAO, ten are already using 40 percent of their renewable freshwater for irrigation. By 2030, South Asia will have reached this 40 percent level, and Near East/North Africa will be using about 58 percent. However, for sub-Saharan Africa, Latin America and East Asia, irrigation water demand will be below the critical threshold although at local level serious problems may arise.