. I'm Jonathan Tomkin from the University of

Illinois. Is there enough water?

The UN estimates that there is a number of countries that use their water stocks,

unsustainably. If you look at this map, you might see if

your country is one of those. So our consumers are responsible?

Is it running the taps at home while we brush our teeth or taking too many showers

that's causing water stress? Domestic use turns out to be only a small

part of total water use. It is true that the water used in the home

is often highly treated, and so, it's a sort of a special case of water.

And so I want you to be aware of this difference.

When I'm talking about water stress, I'm normally talking about, natural water

processes. So, rain, water, or river water, or ground

water. So this isn't like the water that comes

out of a tap necessarily. This water, hasn't been treated, but is

part of a hydrologic cycle. So when I talk about,

Water stress or the amount of water needed to make a product.

I'm usually talking about this water in the natural system.

. Take this cup of coffee.

How much water is used to make it. Well, we need about 250 milliliters.

That's one cup, of treated water. To make the cup of coffee itself.

But there's actually a lot of, water that we can't see.

In this cup. What I'm thinking about here is that to

make the coffee beans that were ground up and brewed to make this cup of coffee, we

had to have irrigation, we had to have precipitation depending on the region.

And this, it turns out that coffee beans have a very large amount of water embedded

in them and I'm gonna to use this term embedded a lot.

So, so it's sort of like a hidden amount of water that was needed in their process.

This is a similar idea when we might talk about embedded energy that you might need

to, for example, make a car or an aluminum can.

The irrigation that you need to make a cup of, of coffee is about 200 liters.

So, we have 200 liters of embedded water in this cup.

So consumers use the water, but we just don't use it at home.

So when we think about our water use, our domestic use, is in fact only a tiny

fraction of the total amount of water that we used.

If you're a tea drinker, by the way, you can rest easy.

Tea only needs about a tenth as much water as coffee does per cup.

As we discussed previously, most water is used for agriculture.

It is difficult to be precise, but here are some estimates people have used for

various embedded water measures for different industrial and agricultural

objects. A kilogram of wheat requires about 1,300

liters of water, while rice requires about three and a half thousand liters of water

per kilogram. Meat tends to require even more because

most animals are fed crops that have been grown specifically as feed.

So a kilogram of hamburger requires about 15,000 liters of water.

That's around 4,000 gallons for two pounds of meat, if you if you are from the United

States. Industrial processes are often even more

water dependent. Microchips are a great example, they need

about 15,000 liters of water per kilogram of microchip.

Or a cotton shirt, of course you have to grow the cotton, is thought to require

around 4,000 liters. Manufacturing a car might require as much

as a half a million liters of water. So, whenever we consume any object, an

industrial object, or an agricultural object, we're actually using up some

embedded water. Now, this water is part of a, can be part

of the natural hydrologic system, so it can be a renewable resource.

But, when we think about water use in the home.

We should think less about the tap, the water coming out of the tap, and things

like the tap itself. Or the apple that we're washing.

All of the things that we consume, in the home.

Not just the flow of water that we can observe.

This embedded water has a special name. It's often called virtual water.

And this concept is important as it explains why we can have some regions that

can use more water than they posses But they still don't starve,

Or indeed, they don't even die of thirst. Right?

We need water to drink as well. So consider this.

Would you rather transport one metric ton of rice or 3,400 metric tons of water.

Clearly, the metric ton of rice is much easier to move.

And so by trading virtual water, we can replace the water needs of the region by

bringing in agricultural and industrial goods that require large amounts of water

production from other regions in the globe that are not water stressed.

This is one way in which nations can cooperate to manage water resources.

If we look around the world, there are some countries that are net water

exporters in a sense. And remember, water is a renewable

resource if it's use sustainably, so, and so, this is not a bad thing it's not like

North America for example is losing water, when it exports water objects, with lots

of, embedded water in them. Such as meat or microchips for that

matter. Canada and Australia are relatively rich

in water. And so they produce lots of agricultural

goods that require lots of water. Like meat, beef, lamb.

Water importing countries can export less water intensive products in return and so

in this way they can reduce the amount of water stress in those regions.

This ideal arrangement is not always followed however.

Consider Yemen. Yemen is water poor and has a rapidly

growing population. Poor policies can prevent sustainable use

of water resources. Yemen is thought to have around 200 cubic

meters per person per year, which is well below what the UN considers a reasonable

level of around 1,000 cubic meters per person per year.

This is a country with many problems. It has many internal conflicts.

There's a lot of poverty and there's a lot of undemocratic and unresponsive

government. These treat for economic and peace into

the Global Peace ranking of 119 and of a 144.

Well the United Nations Development Program Human Development Index is 140 out

of a 192 nations. So you can see this is a country that is

in need of development to raise the standard of living for its citizens.

Yemen's government has policies however, that don't promote sustainable use of

water. For example, diesel power is subsidized.

And diesel, diesel fuel is used in water pumps.

So as a consequence, we see an over-extraction of water from the aquifers

in Yemen. A lot of the water used in Yemen is to

produce QAT, which is a chewable leaf that, creates, slight euphoric feeling.

It's a drug. And as a consequence, much of its prime

farmland and water is used in the production of a non-agricultural, an

agricultural item that's not for food. And so 80% of all food in Yemen is

imported. Because of this overuse of Yemen aquifers,

by, the water tide on Yemen is dropping. If we talk about it in terms of a flux.

If we have, for every one gallon of flux, that is, sustainable flow, four gallons

are removed. So, of course, I could say one liter and

four liters are removed. So, the stock is being depleted much

faster than it can be replaced by the natural hydrologic cycle.

Some wells have been contaminated by sea water because if you lower the water table

by enough, then salt water from outside will be attracted inland.

Remember, just like on the surface, water wants to flow downhill, and under the

surface of the Earth, the downhill is determined by the height of the water.

So if you have contamination from the ocean, then that means your aquifer

becomes salty and so you can no longer use it for drinking or for agriculture.

What's more and in this way Yemen is typical of countries that face future

water stress, there's lots of population growth.

Currently, it's about seven percent per year.

In fact, it's predicted that local water sources will run out by 2017.

This is a very serious problem in the country where half of population lives on

less than $two a day. Most places are not in such a dire

situation, but we will, we can still learn lessons from places that are not managing

water sustainably. I've talked a little bit about water

tables dropping, and overuse of water and also stocks, but as we saw in the Yemen

example, another threat to sustainable water use is pollution.

Water pollution is an issue in many places.

And it, because water can be polluted in many ways.

And if we pollute an aquifer, that might be the equivalent of removing all the

water from the aquifer as far as we're concerned.

If there are heavy metals or, or organic compounds that cause cancer, in a water

resource, then we can no longer use it. Industrial and agricultural processes both

create pollution. Sometimes we can see this locally with

things like sewage overflow. There are lots of examples in the

textbook. We can also see this on a small scale with

industry. For many years of course in the United

States there's been a large dry cleaning business and this wasn't regulated.

It turns out that fluids used in dry cleaning poison local aquifers.

So again if we don't know very much about the natural system we can damage it and

make it unsustainable without being aware. In the state of Illinois, officials

recently identified 415 dry cleaners, where spills of PCE, which is a toxic

solvent, have damaged the local aquifers. For a long time, it wasn't well understood

what PCE would do in the natural environment.

And although I'm not spending very much time of it in this course, another

extremely important issue in terms of human development, is sanitation.

A staggering of large amount of people around the world lack access to clean

water. And this is a human development issue,

which I think in turn, makes it an important sustainability issue.

The United Nations estimates that about 2,500,000,000 people do not have improved

sanitation. And around or 1.1 million people practice

open defecation because they don't have flush toilets or even pit toilets.

So, you can again see how this creates a cycle.

Because we are damaging water resources of the surface by polluting them.

And so, this reduces the, potential for development.

So the demand for water are only set to increase.

More people, more agriculture, more industry means we need more water.

This will particularly be an issue in places with growing populations.

As we saw when we talked about populations in week two, the one place in the world

where this is set to increase the most over this century is Africa.

India is also a place with a large population increase, and they're also a

place that appears to be set for increased water distress.

Here we see in this graph a list of countries and UN judgment on to whether or

not they're under water stress now or if they will be in the future.

As you can see, many places in Africa already are under water stress.

And as I said in the last lecture, note that we don't really see wall-to-walls per

se in these places now, even though these countries are currently under water

stress. That is, they don't have quite enough

water to meet all their needs. But again water is very important for

development. We need clean water to, to improve

sanitation and to reduce disease. We need water for agriculture and

industrial development. So if we don't have enough water, these

countries will find growth in their development much harder.

As we saw in the Yemen example however, there's lots of scope for improvement with

improved policies. When we talk about policies next week, you

might get a sense of how water use can be better managed.

We'll touch on this in the next lecture as well.

Before I move on to the next lecture, I want to leave a final thought.

Is that so far I've been talking about water from a human center point of view.

And one thing I would like to underline is, is that the more we use the water The

more we take it away from natural systems. So it might in some ways be sustainable to

use the flux of water in it's entirety. But in practice we would be robbing the

natural ecosystems. So if we value the natural world at all we

need to minimize the total amount of water that we extract so that there is enough

for the natural systems. For the forests.

For the rivers. And so on.

In the next lecture, we'll talk about another major threat to world ecosystems.

That is, the clearing of land to grow crops.

And this actually comes back to one of the most important issues in twenty-first

century sustainability. Can we grow enough food to feed the extra

billions? .

Produced by OCE, Atlas Digital Media, at the University of Illinois,

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