Subscription Center
From space Earth is simply a pale blue dot. It's blue because of all the water on its surface. In fact, a little more than 70 percent of the Earth's surface is covered by water, most of it ocean. But how much water is there, really?
This image, produced by the U.S. Geological Survey (USGS), shows all of Earth's water in three little orbs. The big one, over the western U.S., is all the water in the world—everything from the salty oceans to the water found deep underground. It looks small compared with the size of Earth, but that sphere's volume is 1.38 billion cubic kilometers and it is about 1,385 kilometers in diameter. The smaller floating sphere in the middle at 272.8 kilometers in diameter represents a subset of that bigger sphere, showing freshwater in the ground, lakes, swamps and rivers. It doesn't include permanent ice- and snowpacks locked in the polar ice caps—which is where much of the world's freshwater is held; humans, unfortunately, do not have access to this supply. The tiny speck next to it represents and even smaller subset of all the water– just the freshwater in lakes and rivers. It, too, seems tiny by comparison with the big orb, but it is 56.2 kilometers in diameter.
To figure out how big these bubbles would be, the USGS looked at estimates for how much water was in everything from the oceans to swamps. Of course, it's impossible to measure exactly how much water fills the oceans, let alone how much is trapped deep underground. But taking the best estimates available, the USGS artists computed the size of each sphere and placed them on top of the planet.
So where is all that water? Perhaps surprisingly, although oceans, seas and bays cover 70 percent of the world, they contain about 96 percent of its water—all of it salty. The next biggest category is ice caps, glaciers and permanent snow at the poles and peaks, but that only makes up about 1.74 percent of the world's water. Groundwater, both fresh and salty, is the next highest contributor to the blue orbs, making up an estimated 1.69 percent of the world's water. In fact, there is much more freshwater in the ground than there is on the surface in lakes and rivers.
Humans consume vast quantities of both surface and groundwater every day. In 2005 we used 1.24 trillion liters of surface water and 312.7 billion liters of groundwater daily. So while those orbs might seem surprisingly small, they're sustaining the whole human population.
—Rose Eveleth
See what we're tweeting about
JenLucPiquant "The most beautiful inventor in the world" by @hillaryjohnson https://t.co/wHyrTuGH03 JenLucPiquant Via @nprnews: Let's Get Creative And Redefine The Meaning Of Religion http://t.co/wSVZ56Xhx0 JenLucPiquant Via @nprnews: 'Nanogardens' Sprout Up On The Surface Of A Penny http://t.co/uKp4xq8wK6
Deadline: Jun 30 2013
Reward: $1,000,000 USD
This is a Reduction-to-Practice Challenge that requires written documentation and&
Deadline: Aug 31 2013
Reward: $100,000 USD
The Geoffrey Beene Foundation Alzheimer’s Initiative (GBFAI) is launching the 2013 Geoffrey Beene Global NeuroDiscovery Challenge whose
Powered By: 
YES! Send me a free issue of Scientific American with no obligation to continue the subscription. If I like it, I will be billed for the one-year subscription.
12 Comments
Add CommentIncredibly powerful graphic data, (even if it does represent an approximation).
Reply | Report Abuse | Link to thisDesalination isn't that hard. I'll worry about something else. `~- Nehmo
Reply | Report Abuse | Link to this"In the last 150 years, prospectors and energy companies have drilled as many as 12 million holes across the United States in search of oil and gas. Many of those holes were plugged after they dried up. But hundreds of thousands were simply abandoned and forgotten, often leaving no records of their existence."
Reply | Report Abuse | Link to this"The most recent effort to count the nation's unplugged wells was a survey published in 2008 by the Interstate Oil and Gas Compact Commission, a multistate agency made up of regulators and industry representatives. It found that states had located nearly 60,000 wells that needed to be plugged -- and estimated that as many as a million more may be out there. In Pennsylvania alone, regulators estimate that 184,000 wells were drilled before records were kept. Many of those wells were plugged with stumps, rocks or nothing at all."
http://www.huffingtonpost.com/2011/04/04/abandoned-oil-gas-wells-water_n_844662.html
You won't read about these statistics in Fox News, but the reality is each and every one is a potential time bomb that could contaminate our ground water. Oil company engineers don't really know how long their 'safe' plugs will last or how many are not 'safely' plugged.
Water is the real life blood of all life on earth. This article only demonstrates how precious it really is.
When the population reaches 10 billion and desalination plants are the only source of potable water guess how much it'll cost... As much as people can pay!!
Reply | Report Abuse | Link to thisI've noticed it's been a lot wetter here in Kansas for some reason...
Reply | Report Abuse | Link to thisTrue, and guess who will be selling it? If you guessed the oil companies, you are on the right track. They will also be selling recycled waste water and their sub corporations that bottle it will will sell it under the name of a food giant. You can't market Exxon water to easily (except maybe to republicans) but the average consumer will by anything made by Nestles or Kraft even if it's made from recycled sewage.
Reply | Report Abuse | Link to thisMy father was in the navy back in the late 70s and he told me how cheap it was to desalinate water even back then. Considering that and how it tends to rain quite a bit here... um, you know... on most of this entire planet, I've never bought the whole "We're running out of fresh water!!!" scare tactic.
Reply | Report Abuse | Link to thisI'd guess that, wherever you live, you, like me, used more water in your showers than this month's rainfall.
Reply | Report Abuse | Link to thisNot all water requirements can be met by rainfall - including the desert Southwest, Australia, Japan and the Middle East.
Please see http://en.wikipedia.org/wiki/Water_desalination
"Large-scale desalination typically uses large amounts of energy and specialized, expensive infrastructure, making it more expensive than fresh water from conventional sources such as rivers or groundwater."
"Desalination is particularly relevant to countries like Australia which traditionally have relied on collecting rainfall behind dams to provide their drinking water supplies."
Under "Cogeneration" wiki goes on to state:
"...the majority of current and planned cogeneration desalination plants use either fossil fuels or nuclear power as their source of energy. Most plants are located in the Middle East or North Africa, which use their petroleum resources to offset limited water resources."
Japan had eight nuclear plants powering connected desalination plants, but I understand they've been shut down.
The Navy's nuclear powered aircraft carriers and submarines desalinate seawater. This may be why your father though it was so cheap.
The construction of desalination facilities with sufficient capacity to supply water for billions of people would require investments of extraordinary amounts of capital - amounts generally available only to oil producers today. Regardless of the net cost of production, such capital intensive ventures almost always demand high rates of return on investment. As I said, when the availability of water is limited the price will be whatever people will pay. Check back with Los Angeles and other desert cities in a few years...
Back in 2009 the oil industry was using 2.2 billion gallons of fresh water a day in its fracking processes. Over 90% of this severely contaminated water is stored in specially drilled deep-earth wells below underground aquifers because it is the cheapest way to remove and contain the spoiled water. Oil and gas extraction by fracking has been growing 45% per year since 2009; 2.2 billion gallons per day in 2009 turns into 1.164 trillion gallons of spoiled fresh water in 2010, and 2.447 trillion gallons in 2011 ad infinitum. All of which for practical purposes is gone forever. I wonder if this is the wisest use of our nations fresh water?
Reply | Report Abuse | Link to thisIn Moby Dick, Herman Melville made the observation that the biblical flood is still with us: most of the earth is still covered in water.
Reply | Report Abuse | Link to thisBut just as whales were viewed as an inexhaustible resource in his day, is fresh water really inexhaustible?
Living in a rural area outside Brisbane, Queensland, Australia, I value every drop that falls from the sky, the only water I get to drink is from rain water captured in four tanks giving me 20,000 gallons, and over the twelve years I have lived here I have had to purchase water a few times, at a cost of $120/ 2,000 gallons, but fortunately not for a number of years now.
Reply | Report Abuse | Link to thisEvery drop of water that has ever been on earth is still here, and no matter what you think about drinking treated effluent I have bad news for you, unless you, like me rely on rain water or a well, if you live in any town or city that is down stream of a river system from another town or city, you already drink someone else’s pee and treated crap! Every small town flushes their effluent out into the river system which runs down into the same dam that major cities get their water from. So no matter how much you want to kick up a stink about using effluent for recycling and drinking water you are already drinking it. Besides which, every drop of water, every drink you take of soda you have has already been peed out by someone else in the past.
Carrying on about fracking and claiming the water ‘All of which for practical purposes is gone forever’ just shows you have no knowledge of how the worlds aquatic system works.
Awesome. It is so beautiful (and disturbing - I naively thought the amount of water would be much more in comparison with the earth size!) it has been my desktop image for quite a while. I also incorporated it in my lecture of data visualization, as a good example of what Edward R. Tufte would call "Graphic Excellence".
Reply | Report Abuse | Link to this