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  people in flood

Water resources and
water risks

Without water, nothing grows. Yet with too much water, all may be lost.

Water is fundamental to all forms of life, with a key role in public health, agriculture, municipal services, industry, hydropower, inland navigation and environmental protection.

For example, about 70 per cent of all freshwater withdrawals are used in agriculture, especially for irrigated food production. For many countries, water offers cheap and renewable energy in the form of hydroelectric power.

Water is necessary for hygiene and good health, but it can also carry pollutants, diseases and disease vectors; each year millions of people get sick with waterborne diseases.

An important target for Millennium Development Goal 7 is to halve, by 2015, the proportion of the population without access to sustainable safe drinking water and basic sanitation. The world is on track to meet this goal, though much remains to be done in some regions.

Globally, water scarcity remains a major problem, affecting one in three people. In many places, the situation is worsening, owing to rising populations and growing household and industrial demands. Supplies are increasingly scarce in many areas including arid regions of South America and Africa and inland regions of Asia and Australia, leading to discussion as to whether water may one day become a valuable commodity that is traded like oil.

At the same time, excessive water in the form of flash floods and river plain floods can cause immense economic damage and loss of life. The economic losses of the seven largest-ever recorded floods range from US$ 10 billion to US$ 30 billion.

In our interlinked global economy, the ripple effects are felt everywhere. For instance, the October to November 2011 flooding in Thailand not only damaged the rice crop of the world’s top exporter, it also impacted on the international supply and price of computer hard drives and auto parts.


“Water use has been growing at more than twice the rate of population increase in the last century.”

Kirsty Jenkinson, World Resources Institute



Climate change and water

Water in its different forms – ice, liquid and vapour – plays a key role in the physics of the climate system. It is a critically important element in the global numerical models used for weather prediction and for climate change projection. Basic hydrological cycle observations are essential to climate change adaptation.

We now know that water scarcity and flooding are likely to increase with climate change, because a warmer world will strengthen the atmosphere’s hydrological processes leading to more droughts and more intense episodes of high rainfall.

In its key messages on climate change, UN-Water states:

Adaptation to climate change is mainly about better water management. Adapting to increasing climate variability and change through better water management requires policy shifts and significant investments by (among other basic principles) improving and sharing knowledge and information on climate, water and adaptation measures, and investing in comprehensive and sustainable data collection and monitoring systems.

Industrialized and developing nations alike need hydrological support services. According to one estimate, the United States will need to spend US$ 1.7–2.2 trillion between now and 2050 to keep water systems running and adapt to climate change.

Quality climate data will be particularly important for water management systems for shared basins that span more than one country. There are 263 trans-boundary river and lake basins worldwide. They account for an estimated 60 per cent of global freshwater flow, 40 per cent of the world’s population and affect 75 per cent of all countries. Sound scientific information is vital to decision-making about the allocation of these water supplies and investments in infrastructure.


Drought management

Because of its long-term socio-economic and environmental impact, drought is the most damaging of all natural hazards. Drought can last for a season or stretch for decades and cover areas from the size of a community to entire regions.

The droughts in 2011 in different parts of the world including East Africa, the southern United States and China have reinforced expert views that droughts have become more common over the past two decades. According to a 2011 special report of the Intergovernmental Panel on Climate Change, this trend is expected to increase.

Most countries lack policy development for national and regional management of drought. Likewise, drought early warning information systems, consisting of monitoring, prediction, risk assessment and communication, are inadequate in most regions.

WMO and its partners are promoting a policy shift from the current crisis-driven approaches to disaster-risk reduction policies that include drought preparedness and mitigation to be developed in high level National Drought Policies.



  woman surrounded by flood distruction

The devastating floods in Pakistan in 2010 affected an estimated 20 million people, causing nearly 2 000 fatalities and damaging nearly two million homes as well as general infrastructure. It was estimated that the 2011 floods in the province of Sindh – Pakistan’s breadbasket – would cut GDP growth by 0.5 per cent.

WMO worked with the Pakistan Meteorological Department on an Integrated Flood Management plan to improve protection of life and property against flash floods. As a result, Pakistan has installed a Flash Flood Guidance System to provide early warning.

The system was developed by the Hydrologic Research Center, in the United States of America, through joint collaboration between WMO, United States National Oceanic and Atmospheric Administration, National Weather Service, USAID, and the Pakistan Meteorological Department.



Flood management

In 2011, many countries experienced devastating floods – Australia, Colombia, Indonesia, Japan, Pakistan, Sri Lanka, Thailand and the United States, to name a few.

While they can bring death and destruction, floods can also promote economic development. In many parts of the world, communities rely heavily on agriculture, fisheries and other activities in rivers and flood-prone delta areas.

The Associated Programme on Flood Management led by WMO and the Global Water Partnership promotes an approach that emphasizes flood management to minimize risks and maximize opportunities.

Integrated flood management embraces flood preparedness and prevention strategies, rather than purely emergency response. It involves climate risk management, flood risk assessment, land use regulation, flood insurance, enhanced hydro-meteorological monitoring, flood disaster preparedness, emergency management and recovery. It aims to bridge gaps that exist between the flood research and development community and flood professionals responsible for mitigating the adverse impacts of major floods.


The Andes

  woman surrounded by flood distruction

Snow and ice in the Andes Mountains, above the tropical regions of Bolivia, Peru, Ecuador and Colombia, supply the drinking water for 30 million people. Ice has been dwindling in recent years due to rising temperatures, threatening the region’s water supply. Quito, the capital of Ecuador, and La Paz in Bolivia respectively draw 50 per cent and 30 per cent of their water from the glacial basin.

Since 1970, Andean glaciers have lost 20 per cent of their volume. Because these glaciers are the major regulators of the water supply, a global effort is underway to help the region cope with increased local climate variability and global climate change.

To address the situation, WMO Members contributed to a multidisciplinary project, led by the World Bank and Global Environment Facility. Several WMO Members are monitoring changes in the glaciers with the use of high-resolution satellite images. Improved observation and assessment practices enable better mapping of vulnerable areas and permit the region to develop adaptation strategies. These include the development of alternative water sources, diversification of the energy supply and shifting to alternative crops and advanced irrigation systems.



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