Despite a projected average shortfall of 40% in water supply, globally, by 2030, water scarcity could be "sustainably and affordably" mitigated, the 2030 Water Resources Group highlighted in a report on Monday.
The report, ‘Charting our Water Future: Economic frameworks to inform decision-making', points out that, based on average economic growth scenarios with no efficiency gains, global water requirements would grow to 6 900 billion cubic meters by 2030, compared with the current 4 500 billion cubic meters.
This amounted to an average 40% increase above the current, accessible, reliable water supply.
However, one-third of the world's population, mostly those in developing countries, could face a water deficit of up to 50%.
The authors of the report noted that economic growth and development were drivers of the water resource challenge, with agriculture currently accounting for about 71%, or 3 100 billion cubic meters, of global water withdrawals.
This would increase to 4 500 billion cubic meters of water by 2030, indicating that the water challenge was closely tied to food provision and trade, the research group stated.
It added that centers of agricultural demand included India, where water withdrawals would rise 1 195 billion cubic meters by 2030, sub-Saharan Africa at 820-billion cubic meters and China at 420 billion cubic meters.
Further, industrial water withdrawals, which accounted for about 16% of the current global water demand, would grow to about 22% by 2030, mainly driven by growth in China, where industrial demand would climb to about 265 billion cubic meters.
The Asian nation already consumed about 40% of the world's industrial water withdrawals.
Domestic water use, meanwhile, would climb to 14% of total water consumption, compared with the current 12%, but this growth would vary in different basins, especially in emerging nations, the authors stated.
While the 2030 Water Resources Group was confident that the demand and supply gap would be closed, it noted that the question remained how this would be done.
A 1% a year efficiency improvement has been seen in both the water use of the agricultural and industrial sectors had been recorded between 1990 and 2004.
If this level was sustained in each of these sectors up to 2030, only 20% of the water supply shortfall could be met, the researcher said.
Similarly, a business-as-usual supply build-out, assuming constraints in water infrastructure rather than in the raw water resource, would also only close 20% of the shortfall, the group noted.
"If these ‘business-as-usual' trends are insufficient to close the water gap, the result in many cases could be that fossil reserves are depleted, water reserved for environmental needs is drained, or, more simply, some of the demand will go unmet, so that the associated economic or social benefits will simply not occur," it added.
This could be further exacerbated by the impacts of global climate change on local water availability.
A business-as-usual approach to the water scarcity challenges was no longer an option for most countries, with the financial implications of water scarcity becoming clearer.
The 2030 Water Resources Group said that there was reason to believe that water would be an important investment theme for public, multilateral and private financial institutions in the coming decades.
"Although affordable solutions are in principle available to close the projected water supply-demand gaps for most countries and regions, institutional barriers, lack of awareness, and misaligned incentives may stand in the way of implementation, across both the private and public sectors," the group noted.
Overcoming these barriers would require persistent action and, in many cases, an integrated agenda of water sector transformation, it added.
The focus for most countries has, historically, been investment in additional supply, in many cases through energy-intensive methods, such as desalination, which was often "vastly" more expensive than traditional surface water supply infrastructure.
This was, however, also more expensive than efficiency measures.
The researchers pointed out that solutions did not necessarily have to be "prohibitively" expensive.
If a balanced portfolio of demand- and supply-side measures was adopted in each country, the projected water requirements in 2030 could be met at an estimated cost of $19-billion a year for these countries.
At a global level, the cost would amount to between $50-billion and $60-billion.
However, if only traditional supply-side measures were implemented, an additional capital expenditure of up to $200-billion a year would be required, globally, to close shortfall in water.
The group noted that this was four times more expensive than the balanced approach and more than double what was currently being spent on water resource provision.
Meanwhile, the researchers highlighted that while the need for additional water is global, both the challenges and the solutions differ across geographies, given the drastic variations from basin to basin.
In South Africa, agricultural demand for water would account for about 47% of total use by 2030, while household and industrial demand would account for about 53%.
The most cost-effective solutions for South Africa would, thus, include some agricultural measures, but also a range of industrial efficiency measures, for example, in the mining sector, as well as common household measures, such as improved plumbing fixtures, the report stated.
South Africa was expected to face a 2,7 billion cubic meters gap on a base cash scenario.
For a country like, India, however, where water demand is mainly driven by growth in the agricultural sector, the most cost-effective solutions would be dominated by agricultural measures for both irrigated and rain-fed crop production, which could, collectively, close the estimated 80% water shortfall by 2030.
The 2030 Water Resources Group was formed in 2008 to contribute new insights to the critical issue of water scarcity.