Freshwater availability varies globally due to its uneven distribution and factors like population growth, climate change, and development levels that impact supply and demand. Aquifers underground store freshwater, but some are being drained faster than replenished. While three percent of water is fresh, most is locked in ice or far from population centers.

1. How does freshwater
vary globally?

3. 1. Distribution of fresh water
• What is the link in all these images?
LO: How does freshwater vary globally?

4. What are aquifers?
LO: How does freshwater vary globally?

5. What are aquifers?
• Aquifers are underground stores of fresh water.
They can hold millions of litres of water but take a
long time to be filled.
• Sometimes they are being drained by humans
faster than they are being replenished naturally by
rainfall.
LO: How does freshwater vary globally?

6. 1. Distribution of fresh water
• With 70% of the earth covered in sea, often it is
nicknamed The Blue Planet
LO: How does freshwater vary globally?

7. 1. Distribution of freshwater
• 97 % of all water is too salty for us to drink.
• That means 3% is left as freshwater. Two thirds of
this is stored in ice and difficult to get to. Which
leaves one percent left for us to use.
LO: How does freshwater vary globally?

8. 2. How does freshwater availability
vary globally, nationally and locally?
• Major rainfall is away from major centres of
population so there is a problem of getting water to
where people need it.
• Therefore the availability of freshwater varies
hugely globally, nationally and locally too.
LO: How does freshwater vary globally?

9. Locally – Ross and Cromarty
(North Scotland)
LO: How does freshwater vary globally?

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14. 3. Why do some parts of the world
have a water surplus or deficit?
• Surplus = Too much water
• Defect = Lack of water
• Factors influencing this are:
1. Levels of precipitation in area.
2. Level of evaporation in area.
There could be an average volume of rain but a lot is
evaporated quickly.
3. Level of transpiration
There could be a lot of plants using soil moisture and releasing
it back to the atmosphere through their leaves (transpiration)
4. Levels of evapotranspiration
A combination of both evaporation and transpiration.
LO: How does freshwater vary globally?

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16. 4. How and why has the supply and demand
for water changed in the past 50 years?
• Turn to your neighbour and tell them all the things
you use each day that involves water?
LO: How does freshwater vary globally?

17. 4. How and why has the supply and demand
for water changed in the past 50 years?
• Turn to your neighbour and tell them all the things you use each day that involves water?
• Did you get these?
LO: How does freshwater vary globally?

18. 4. How and why has the supply and demand for
water changed in the past 50 years?
LO: How does freshwater vary globally?

19. Research time!
Copy out the table below and complete it in your books.
Population Growth Climate Change Level of development
of a country
What has
happened?
• The worlds
population is now
over …….
• ………………………
• ……………..
• ……………..
• ……………..
• ……………..
How does this
impact water
supply and / or
demand?
• Every person ‘eats’
3496 litres of water
a day in the UK.
• ………………………..
• ……………..
• ……………..
• ……………..
• ……………..
LO: How does freshwater vary globally?

20. Practice question

21. 1. Using the map describe the distribution of the
global supply of water (4 Marks)

22. Describe and explain the changes to global
fresh water availability over time (6 marks)

23. 4. How and why has the supply and demand
for water changed in the past 50 years?
But did you think about these things?
Have a look at this
LO: How does freshwater vary globally?

24. 4. How and why has the supply and demand
for water changed in the past 50 years?
• Virtual Water = The freshwater used to produce
something. E.g. It takes 15 400 litres of water to
make a kg of beef.
LO: How does freshwater vary globally?

25. 4. How and why has the supply and demand
for water changed in the past 50 years?
• There are three main areas which have impacted supply and
demand over the last 50 years;
1. Population Growth.
More people means more demand for water. The worlds
population has grown exponentially (rapidly) over the past 50
years. This is true for ‘virtual water’.
2. Climate Change.
Precipitation is becoming unreliable in some areas of the
world, e.g. overall it may be lower each year or it may come in
more intense showers.
3. Development.
The more developed a country is the more water it will use.
This is true of ‘virtual water’ too.
LO: How does freshwater vary globally?

26. Plenary
• Summarise the lesson in 5 words to your
neighbour.
LO: How does freshwater vary globally?