Image: Kristiaan/Flickr
More In This Article
-
Overview
Water In, Water Out
-
The Best Science Writing Online 2012
Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...
Read More »
We hear every day about the need to conserve freshwater. That goal seems sensible—although knowing if humankind is making any progress could be impossible without a reliable way to quantify how much water nations use. To find out, engineers Arjen Hoekstra and Mesfin Mekonnen at the University of Twente in the Netherlands calculated the water footprint of the world's countries as well as per capita water consumption in those nations.
Overall, the world is using 9,087 billion cubic meters of water per year. China, India and the U.S. consumed the highest annual totals: 1,207 billion, 1,182 billion and 1,053 billion cubic meters, respectively, followed by Brazil at 482 billion. But the water consumed per person in these and other countries varies considerably, due primarily to higher living standards or widespread waste among consumers. The U.S. had the world's highest per capita water footprint, at 2,842 cubic meters per annum. Meat consumption accounts for 30 percent of the American figure, and sugar consumption is responsible for another 15 percent, Hoekstra says. In India, where few people consume much meat, the individual footprint is only 1,089 cubic meters a year. The global annual average per capita is 1,385 cubic meters.
As you might guess, populous countries use a lot of water to produce their food and products, but inefficient agriculture or dependence on water-intensive foods such as meat can exacerbate demand. Some countries also export significant quantities of water in the form of food and products, complicating their own water balance, as shown in Scientific American's June 2012 Graphic Science column.
Hoekstra and Mekonnen went through exhausting calculations to figure out each nation's water footprint. Basically, they added three quantities: the consumption of rainwater (the so-called green water footprint); the use of ground- and surface water (blue); and the volume of gray water polluted (and therefore depleted). The specific calculations can be found in their online paper as well as its supplemental material.
Rights & Permissions
See what we're tweeting about
12 Comments
Add CommentI just ate a mango from Ecuador...who is tasgged with the per capita usage of water to grow the mango...the produser or consumer?
Reply | Report Abuse | Link to thisCanada uses vast amounts of water and energy to refine metal ores....these metals are then used by 'energy-efficient' Danes...Danes who, if they produced their own metals, would have to divert all of their water and energy to refine these metals themselves.
Per capita usage of water is largely irrelevent in today's economy. Scales of efficiency trump what happens within borders.
In most of the world private consumer household use barely makes a mark on total water consumption. The big users are energy, agriculture, industry.
I refuse to feel guilty about consuming natural resources until the world can effectively control its population growth.
Reply | Report Abuse | Link to this@ jtdwyer -
Reply | Report Abuse | Link to thisI don't think "the world can effectively control its population growth" is a problem right now. Species/animals are dying left and right to make room for more humans. Looks like our world is controlling it's population just fine. Now if you want humans to control human population growth - well just keep over watering your lawn and the World will eventually do that for us too.
ps. I love the Red Herring Fallacy - it's my favorite. (I'm guessing you are a Republican "Conservative"? Since everything is someone elses fault and hence problem...)
jtdwyer: "I refuse to feel guilty about consuming natural resources until the world can effectively control its population growth"
Reply | Report Abuse | Link to thisAgreed. It is 'THE' issue that trumps everything else by several magnitudes.
I'm not sure what you're trying to say, but you're guessing wrong and I am not responsible for the 3.5 billion increase in population since I became of age.
Reply | Report Abuse | Link to thisGood point about the countries that claim high efficiently levels but just foster off the real cost to others.
Reply | Report Abuse | Link to this@jtdwyer:
Reply | Report Abuse | Link to thisThe earth is big enough and has more resources for many more population than what we might think. We need to do something instead of erasing the problem.
This and many other articles about the diminishment of natural resources focus on American per capita usage, as though we should feel guilty or somehow be responsible for causing other nations to go without adequate resources. Nothing could be further from the truth! America is not taking any water away from children in Africa or India or anywhere else - those poor children were brought into a local environment that could not sustain them by their parents!
Reply | Report Abuse | Link to thisI take responsibility for providing for the children that I've brought into this world - not yours or anyone else living anywhere else around the world. I do not appreciate being held up for denigration for letting poor children around the world suffer!
As this article states:
"China, India and the U.S. consumed the highest annual totals: 1,207 billion, 1,182 billion and 1,053 billion cubic meters, respectively, followed by Brazil at 482 billion."
A large percentage of the U.S. water consumption goes directly to agricultural production, at least some of which is sent around the world to feed hungry children. Countries that are producing very little food for their growing populations are not expending much water for that purpose.
The article lauds India, which (for religious reasons) does not use water for the production of beef. India's human population has grown from 370 million in 1950 to 1.2 billion and is projected to reach 1.7 billion in 2050. As I understand, many of those people not only drink out of but urinate and defecate into the Ganges River.
It goes on to point out that:
"The U.S. had the world's highest per capita water footprint, at 2,842 cubic meters per annum."
"The global annual average per capita is 1,385 cubic meters."
If I extrapolate the average times about 7 billion people then I can compare the total annual U.S. water consumption of 1,053 billion cubic meters to that of the rest of the world at 9,695 billion cubic meters.
The U.S. population is ~314 million people. We are not responsible for the births of the other ~6.7 billion people and we are not responsible for caring for however many people the rest of the world chooses to produce.
I hate to see those starving children on TV but, most unfortunately, feeding them will produce more of them in the future. I do not appreciate attempts to make me feel guilty about those poor suffering children around the world that I have no responsibility for because I have no control over them or their parents. Our reason for being is not to determined how many people the planet can hold.
Evidently, people are not that intelligent. Thus no effective measures are being taken either to provide enough water of the slow global warming. The consequence is that most of us are going to die, and it is problematical about the few thousand who would remain alive.
Reply | Report Abuse | Link to thisWe can't 'consume' water we use it and send it down the sewers and drains where it is evaporated into the atmosphere and falls as rain to replenish the rivers and lakes. Our problem then is to keep the human usage rate below the evaporation rate and I am certain we are nowhere near that parity. The evaporation rate must be a million times higher than our usage rate.
Reply | Report Abuse | Link to thisLenedwin is exactly right. This article seems to be setting the stage (e.g., the use of the term "water footprint") for making the case that there should somehow be a reduction, or even global parity, in the per capita use of water. Next thing you know, people will be proposing global limits on water use, establishing a market to trade "water credits," and setting up an international Water Police Force. Fresh water is a fully renewable resource, and (surprise) nations that are blessed with a more abundant natural supply will use more-- and that's perfectly OK.
Reply | Report Abuse | Link to thisI totally agree with you on most points. I am an Indian and I don't feel any pride in that we have very less 'per capita' water consumption. That is just one way of seeing the problem. US and China are roughly three times the size of India and if you look at it that way we actually consume about 1.5 times more water per unit area than US and China. Thus, we consume more than our share of fresh water. And on whose shoulders the should responsibility of over population lie. Ours of course. Telling that we consume less water per capita is just an excuse for neglecting our responsibility and cutting water conservation measures. The region I live in (Haryana, Northern India also known as the Grain Bowl) consumes more ground water than any other part of the country. When I was a kid the ground water level was about 50 feet. Just fast forward 15 years and the present ground water level has dropped 120 feet below surface. Thanks to the urban development and large number of tube wells in use for irrigating paddy fields.
Reply | Report Abuse | Link to thisThus even when we are consuming very less water per capita, the water resources are fast depleting. But this
is the situation when India is still undeveloped. Even if we stop growing at this moment the water will still become scarcer. So what if we picture ourselves as developed. Where will all the water come from when every
person will consume double the amount he consumes now.