political, institutional and financial conditions, and climate change.
Global population is projected to reach 9.3 billion in 2050 (UNDESA). Population growth leads to increased water demand, reflecting growing needs for drinking water, health and sanitation, as well as for energy, food and other goods and services that require water for their production and delivery.
Urban areas of the world, particularly those in developing countries, are expected to absorb all this population growth, at the same time drawing in some of the rural population. This intense urbanization will increase demand for water supply, sanitation services and electricity for domestic purposes
Water of acceptable quality and in adequate quantity is needed to meet food production demands. At the same time, food production and supply have a negative impact on the sustainability and quality of water resources.
Agriculture is the biggest water user, with irrigation accounting for 70% of global water withdrawals. With increasing demand for food, competition for water is rising. Specialized crops and livestock products often require more water (and in most cases more energy) to produce and lead to higher levels of water pollution.
In the pursuit of food security, technological advancements in the agricultural sector could have significant impacts, both positive and negative, on water demand, supply and quality.
For example, higher temperatures and an increase in the rate of evaporation may affect water supplies directly and potentially increase the water demand for agriculture and energy.
Significant levels of uncertainty exist with respect to climate change projections, and these uncertainties increase greatly when focusing on local scales.
Water resources management is in a difficult transition phase, trying to accommodate large uncertainties associated with climate change while struggling to implement a difficult set of principles and institutional changes.
Consumer demand and increasing standards of living are driving
increased demand for water, most notably by middle income households in developing and emerging economies through their greater demand for food, energy and other goods, the production
of which can require significant quantities of water (IEA).
According to the OECD, in the absence of new policies (i.e. the Baseline Scenario), freshwater availability will be increasingly strained through 2050, with 2.3 billion more people than today (in total more than 40% of the global population) projected to be living in areas subjected to severe water stress, especially in North and South Africa and South and Central Asia.
Global water demand in terms of water withdrawals is projected to increase by some 55% due to growing demands from manufacturing (400%), thermal electricity generation (140%) and domestic use (130%) (OECD).
While data on precipitation – which can be measured with relative ease – are generally available for most countries, river runoff and groundwater levels are generally much more difficult and costly to monitor.
As a result, trends regarding changes in the overall availability of freshwater supplies are difficult to determine in all but a few places in the world. However, it is clear that several countries face
varying degrees of water scarcity, stress or vulnerability.
In the absence of flow regulation by artificial storage infrastructure, the availability of surface water varies from place to place across days, seasons, years and decades as a function of climate variability.
Climate change means past hydrological trends are no longer indicative of future water availability. According to the most recent climate projections from the Intergovernmental Panel on Climate Change (IPCC), dry regions are to a large extent expected to get drier and wet regions are expected to get wetter, and overall variability will increase.
There is mounting evidence that this is indeed happening as a
result of an intensification of the water cycle and it is affecting local regional water supplies, including those available for energy production.
There is clear evidence that groundwater supplies are diminishing, with an estimated 20% of the world’s aquifers being over exploited, some massively so.
Globally, the rate of groundwater abstraction is increasing by 1% to 2% per year (WWAP, 2012), adding to water stress in several areas and compromising the availability of groundwater to serve as
a buffer against local supply shortages.
Water quality is also a key determinant of water availability, although potable water is not required for all purposes. Polluted (or saline) water cannot be used for several crucial purposes such as drinking and hygiene.
However, for other purposes such as agriculture and certain industries, use of slightly polluted water or partially treated waste water can be considered. This provides an opportunity to use reclaimed waste water and storm water, reducing the cost and energy consumption associated with water treatment.
Although there have been some local successes in improving water quality (mainly in developed countries), there are no data to suggest an overall improvement in water quality at the global scale. Deterioration of wetlands worldwide further contributes to reduced potential in ecosystems’ capacity to purify water.
It is estimated that more than 80% of used water worldwide – and up to 90% in developing countries – is neither collected nor treated
(WWAP, 2012), threatening human and environmental health.
Cleantech Grants
Source: United Nations
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