Long-term water withdrawals and overuse: the drivers

By Peter Brabeck-Letmathe

27 May 2016 See comments (7)

Table showing global freshwater withdrawals from 1900 - 2030

Growing abstractions of freshwater (particularly for irrigation, public water supplies, industrial processes and cooling of electric power plants) and its resulting overuse are increasingly seen as a major risk to societies and prosperity across the world. This post looks at trends behind this issue with some data. It is also meant to respond to a question I received from one of my readers in February this year concerning longer-term developments and drivers of withdrawals of freshwater for human use.

Let me start with some general data.

  Annual freshwater abstraction globally, in km³ World population, in million World GDP, in billion 2014 USD
1900 600 1,563 2,635
1950 1,400 2,526 7,125
2010 4,500 6,896 73,730
2030 6,900 8,300 181,260

Sources: Shiklomanov for the historic water figures and 2030 Water Resources Group for the forecast data, UN Population Division and World Bank/OECD

Since 1900, average annual freshwater withdrawals globally have grown significantly, from 600 km³ to more than 4,500 km³ in 2010. By 2030, withdrawals are expected to reach about 6,900 km³ per year. And yet, sustainable annual supply is only about 4,200 km³ .

The main drivers behind this increase are the rise in the global population, on the one hand, and economic/technical progress on the other. The latter represents the net result of prosperity-driven higher per capita water withdrawals combined with improved water efficiency as enabled by technical progress.

  Average annual growth in freshwater abstraction, % p.a. Average annual increase in world population; % p.a Change in per capita abstraction, % p.a. (and litres per capita and day)
1900-1950 1.7% 1.0% 0.8% (1,050 - 1,520)
1950-2010 2.0% 1.7% 0.3% (1,520 - 1,790)
2010-2030 2.2% 0.9% 1.2% (1,7920 - 2,280)

Sources: own calculation based on data from Shiklomanov and 2030 WRG Charting our Water Future; UN Population outlook

Population growth, as the table shows, explains about half of the increase in freshwater withdrawals in the periods 1900-1950 and 2010-2030. In the intervening period 1950-2010, a period characterised by particularly high global population growth, demography was actually the dominant driver. In the total period 1900-2010, population growth can be considered to have contributed an additional 2,040 km³ to the initial volume of 600 km³ of freshwater withdrawn per year.

The increase in per-capita water consumption – for all uses, including water abstracted for irrigation, but not including water use in rain-fed agriculture – from 1,050 litres per capita per day to close to 1,800 litres 2010 added another 1860 km³ of total annual withdrawals.

There are several reasons behind the increase in per-capita withdrawals, let me mention two of them.

With a growing population, more land requiring irrigation (i.e. that is not rain-fed) is needed. Indeed, in the period between 1950 and1990, irrigated land increased by an average of 1.5% annually. Looking ahead to 2030, an increase of about 0.6% a year is expected.

A more significant driver is the rise in economic prosperity. The impact of economic prosperity is passed through in several ways: more water is needed to generate energy and more water is needed to provide for diets characterised by an increasing share of meat (calories and proteins from meat require ten times as much water as calories and proteins from plants do). As billions of people in developing and emerging economies continue to climb out of poverty, they consume more meat. Their meat consumption, compared to OECD countries, is still very modest - at 60-70 grams per capita/day - and so are the annual daily intake increases amounting to approximately 1-3 grams. But with the large number of people transitioning out of poverty and moving further up to some prosperity, itself a very positive development, this nonetheless has a significant impact on water balances.

On the positive side, however, we have seen and will continue to see significant improvements in water efficiency.

  Average annual growth in real world GDP, in % Efficiency of water use: Change in water withdrawals per USD of GDP (real at 2014 prices) in litres Improvement in water use efficiency: average annual rate of change in water withdrawals per USD of GDP, in %
1900-1950 2.0% 228 - 196 litres -0.3%
1950-2010 3.0% 196 - 61 litres -1.9%
2010-2030 4.6% 61 - 38 litres -2.3%

(Additional) sources: OECD (pdf, 2Mb) and Citi (for GDP growth rates)

Water use fell from about 230 litres per USD of GDP (at constant 2014 USD) in 1900 to 60 litres in 2010, and a further decrease to less than 40 litres is expected to occur by 2030.

This brings me to the outlook: population growth will continue while high global GDP growth is also probable, despite the recent slowdown in China. Indeed, we are seeing the emergence of new growth engines, such as India or a number of African countries. Moreover, given its much higher share in world GDP today, even growth below 8% in China will keep global economic growth at high levels.

Global water withdrawals, in this scenario, will increase to 6,900 km³ per year, an amount that far exceeds sustainable supply of 4,200 km³ per year. This forecast, which represents the ‘status quo’ scenario drawn up by the 2030 Water Resources Group, also factors in accelerating improvements in water use efficiency – from 1.9% annually in the period 1950-2010 to 2.3% in the period 2010-2030.

As very little can be done to change population growth, and as economic growth is a positive factor, we must find ways to be much more ambitious concerning water efficiency.

If we want to be sustainable about our use of freshwater, the 2030 target will have to be limited to around 25 litres of freshwater withdrawals per USD of world GDP instead of 38 litres as indicated in the status quo scenario. This increases the required annual rate of improvement in water efficiency to close to 5%.

This is already per se quite ambitious, but there is also an additional challenge. Water savings only have an impact if achieved at the right place (where there is actual overuse, not, for instance, in rainy Switzerland), at the right time (not, for instance, during monsoon) and in the right form. I will come back to this in one of my next posts.

As ever, your comments on any points I have made in my post would be most welcome. And I would very much appreciate your ideas whether, or rather how these improvements might be possible.

  1. Ib Jespersgaard - mANAGER @ VIFIN

    30 May 2016 - 10:45 (GMT)

    A way to reduce the high consumption of groundwater resources is of recycle runoff water from rainfall. This can be done both with tax incentives and legislation.

    With such an initiative is the sewage system at the same time relieved.

  2. Peter Brabeck-Letmathe - Chairman @ Nestle

    21 Jun 2016 - 09:12 (GMT)

    Dear Ib, many thanks for the comment.

    A good point, and I agree with it. And, as in other areas, this is something where we can learn from people in the developing world. I made this experience in a meeting with Bunker Roy from the Rajasthan Barefoot College during a discussion that I hosted in Davos more than 10 years ago - http://the-world-around-water.net/main.php?do=page5.



  3. Roger Patrick - President @ Competitive Advantage Consulting Ltd

    01 Jun 2016 - 12:08 (GMT)

    Dear Peter,
    Thanks for highlighting the growing water supply/demand gap. However, there needs to be a distinction drawn between water withdrawals and consumption. The difference is return flow. For example, a standard water industry joke is that the water you drink in London has been through 7 sets of kidneys. Similarly, much of the water that is sent to power generation and other industries is returned to usable water bodies. In agriculture, return flow is a resource available for downstream users, and some recharges to aquifers. Return flow credits are valuable in many jurisdictions for the above reasons.

    Under a "withdrawals" logic, water pumped out of a river and deliberately recharged into an aquifer would be counted as a "demand", but this is not the case - it is merely be transferred from one place to another. It would be interesting to see a total global return flow figure (I don't have it) to be subtracted from withdrawals to get the appropriate matching figure to be compared the available supply (which I note in your OECD reference is qualified by certain factors that reduces the number).

    The main issue that the OECD figures highlight is unsustainable water use in irrigated agriculture. Much domestic and industrial water becomes return flow and is thus available to be used again; likely the proportion of use in agriculture is actually higher that the charts based on withdrawals show.

    Not to say that the supply/demand trend isn't adverse; it is. And of course the problem varies greatly by location as you say.
    As for solutions, please see my article which I will email to you. They include less wastage/spoilage of food and crop breeding, not just water-sector specific actions.

    Best regards


  4. Peter Brabeck-Letmathe - Chairman @ Nestle

    21 Jun 2016 - 09:14 (GMT)

    Dear Roger,

    Many thanks for your comment, once again very thoughtful, and highly relevant.

    You are absolutely right, withdrawals are only a second-best proxy to look at the water accounting. It has one advantage: it can be measured relatively easily.

    Just a few more considerations: In the case of irrigation in agriculture: if done efficiently, the water withdrawn will be evaporated by the plants, i.e., actually consumed. And overall on return flows: in many instances, they are not happening automatically, and not where and how needed. On earlier occasions I tried to develop the idea that water for human use must be available at the right time, in the right form and at the right place. To organise this with return flows and wastewater will be a challenge, but in many instances worthwhile as one way to (re-)increase water availability.



  5. Rabi Mohtar @ 224 Scoates Hall

    06 Jun 2016 - 18:40 (GMT)

    Thanks for the Blog. The projections are intriguing. I would be happy to engage with you in further discussions on this. Do you think the water reuse trends for agriculture and other uses will change the withdrawal data? What role socioeconomic plays in the future projections since these may emerge more so than what we have seen in past century. The water scene for the future may involve broader players (energy, agriculture, domestic, and urban population.

  6. Peter Brabeck-Letmathe - Chairman @ Nestle

    21 Jun 2016 - 09:15 (GMT)

    Dear Rabi,

    Thanks for the comment - good to hear from you.

    You make a good point: indeed, water reuse will have a major impact on water withdrawals, and there are a number of stories showing how this can be done also among the main water users, i.e., agriculture (e.g., Subak irrigation system in Bali, see also my post on ‘wastewater as a resource’, https://www.water-challenge.com/csv/water/water-challenge/posts/wastewater-as-a-resource). The limit, obviously, is evapotranspiration, i.e., the actual water consumption of plants.

    I also agree with you about the need to involve broader players, in the first place around watersheds, i.e., the place where action has to take place, and less in fancy international hotels and symposia. I know and appreciate how much you are part of such relevant, ‘down-to-earth’, or rather watershed-based discussions.

    It would indeed be great if there was an opportunity to continue our exchange!

    Regards, Peter

  7. Amit Shah - Senior President, Corporate Marketing, Strategy & Communications @ YES BANK

    24 Jun 2016 - 15:00 (GMT)

    Dear Mr. Brabeck-Letmathe,

    Thanks for your thought provoking article on freshwater withdrawals. You have very rightly pointed out that due to burgeoning population and rising economic activity, efficient utilization of this vital natural resource is imperative to sustain economic growth as well as livelihood.

    YES BANK through its sustainability practice, has been promoting efficiency in water management. A report titled Water – The Next Sustainability Frontier was released in April, 2016 and is available at https://www.yesbank.in/pdf/water_the_next_sustainability_frontier.pdf. The report deals with water related constraints in India and possible interventions to address them.

    I hope the report would provide you useful insights on water related issues especially in India.

    Amit Shah

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