The future population of Australia is a hot topic because we are running out of water. The media interviews people who know nothing about Australia and publish suggestions of 100 million people. Unfortunately they do not look outside their inner city apartments.
In the cities
Sydney is the Australian city with the largest population. Sydney is stealing water form country areas and is using a huge desalination plant but still cannot supply enough water. Sydney people live under water restrictions that make it almost impossible to grow food in Sydney and impossible to maintain an environment that lets you avoid air conditioning. The water shortage forces people to use more electricity and to import food. We cannot import all the food from our nearest country areas because they did not have enough water before Sydney started stealing their water and they have less now.
Melbourne is the next biggest city and is stealing water from the food growing areas around Melbourne. That area used to be an exporter of food but is now an importer. Melbourne also has a desalination plant.
The other big cities in Australia are all struggling to find water in good years and not many years are good in Australia when it comes to rain. In any one year there is drought in and around most of Australia.
Most cities in Australia cannot increase their population without stealing water from somewhere else and most of those somewhere elses are already short of water.
Near the cities
You used to be able to live in the hills around the major cities but now water restrictions are forcing people out of their near city homes. You used to be able to collect rainwater most of the year and depend on tap water the rest of the year. Rainwater is disappearing because the cities are stripping out the trees that keep down the air temperature. Replacing trees with buildings increases temperatures by 3 degrees centigrade and in hot Australia, that is enough to make rain not fall and enough to make rain evaporate off the ground before it can soak into the ground. The people living near the cities lose their rain despite keeping their own trees because the hot cities dry out huge surrounding areas.
The water shortage is so severe that collecting rainwater off your land is now almost illegal. If rain runs down from unused land onto your land, you cannot collect it in your dam and have to let it run further down the hill even if it will be wasted and dumped in the sea as storm water. How can you set up a dam to collect some raindrops but not others?
The dams that used to supply people in areas near the city are now redirecting most of their water to the cities, leaving too little for the remaining population. You now have to depend entirely on your own dams and are often restricted from building adequate dams.
New South Wales is the Australian state with the largest population. As a comparison, NSW is bigger than Texas but not as big as Alaska, larger than Pakistan but not as big as Egypt. In a good year 40 percent of NSW is in drought. Often it is 80 percent. When a dry spell is not declared an official drought, there is not necessarily enough rain to produce food. Only a small area of Australia has enough water to product food and of that area, a huge portion can only produce a crop every second or third year. An area is not officially in drought until it drops below the level where it produces an occasional crop.
If you average 40 percent and 80 percent, you get 60 percent as dry as a desert and only 40 percent is liveable. Now severely reduce the liveable area based on a big percentage producing crops only once every three years. You are soon down to 30 percent viable for humans.
Allow for all the farmers with a 1000 hectares of land who can crop only 100 or 50 or 10 hectares because the other 900+ hectares are purely to collect the occasional rain into dams to irrigate the crop over the dry season. You are now looking at less than 20 percent of NSW as viable for human habitation. We have not yet removed the huge areas of rock or the national parks that were left untouched by farmers because they do not receive enough rain to run cattle or produce anything edible.
Now take out the salt affected areas and the huge areas allocated for major cities.
NSW is soon down to 10 percent farming land and most of that is out of action for 10 to 20 years at a time due to major droughts. The one at the start of last century is the longest (20 years), hottest, and driest on record. The one at the start of this century was almost as devastating. There were lots of little ones in between.
Western Australia, WA, is the size of the Sudan (the largest country in Africa). The population of Sudan is 41 million and the population of WA is 2.5 million. Look at satellite pictures. Half of Sudan is green. WA has only a small green patch at the south west corner and an occasional green fringe along the northern edge. You can instantly see why WA has a smaller population.
There is a television show named Insight that said they would discuss a possible population limit for Australia. The first person to speak on the show said Australia should take refugees from Afghanistan. The people in Afghanistan use more water than Australians. Afghanistan uses more water per head of population than Australia. If we were to transfer a large number of people from Afghanistan to Australia, they would die of thirst.
Some of the ignorant self centred people on the show suggested Australia could take 100 million people because Australia has such a large area of land but none were suggesting sending refugees to live in the Sahara desert. The main portion of Australia is a desert similar in size to the Sahara. The huge dry area in Australia is not classified as desert because the occasional aboriginal lives there. There is not enough water to grow crops. There is not enough water for the aboriginals and, before European settlement, the aboriginals had to roam over hundreds of kilometres to feed their families. Those ignorant people where talking about numbers of people per square kilometre instead of square kilometres per person.
Today there are many tiny settlements supplied with water from an underground source called the Great Artesian Basin but that source is already used beyond capacity and is drying up.
None of these limitations were mentioned on Insight.
There is one desalination plant in Australia run from wind power when the wind is blowing and from coal power the rest of the time. The other plants are run from the electricity grid using coal, petroleum gas, or diesel as the energy source. There are lots of desalination plants under construction or planned for our current population. Based on the fact that we already use less water per head than most of the countries sending us immigrants and that fact that we cannot now exist without artificial sources of water, an increase from our current 22 million to 100 million would force 78 million people to live on manufactured water.
When NSW decided to manufacture water, Sydney was expanding by about 0.4 million people and the desalination plant was designed to handle more. The plant at full capacity was the equivalent of running an extra 250,000 cars on our roads. If we used a really generous estimate and said the plant could handle a million people, then adding 78 million people to our population would require 78 more desalination plants and be the equivalent of dumping 20 million cars on our roads.
You can make your own estimates of the energy consumption of 20 million cars. Just remember that in Australia our cars travel huge distances and an estimate based on travel in a European country should be multiplied by ten.
18 percent of Australia is classified officially as desert. Most of the rest is semi-arid. Try telling ignorant people that semi-arid is not viable and should be classified as desert. People look at the rainfall in semi-arid areas and say it is liveable. What absolute rubbish. There are some semi-arid areas where you get rain at the same time each year and can produce a quick crop of grass for some sheep. Most of Australia's semi-arid is desert for years at a time then wet for a while then desert for many more years. There are huge areas where there is one bit of rain every ten years. There are huge areas that never have rain and survive only on irregular floods in rivers.
The Nile in Egypt floods every year and irrigates a huge area, supporting a huge population. Australia has the Murray Darling system that does the same but it is not every year. Floods might be two years apart or ten years apart. What do you live on for the other nine years? The Murray Darling system starts as rain in the northern part of Australia then flows south. There is not a lot of water at the start of the flow and most of the water evaporates along the way.
Once every ten or twenty years there is a flood of water into Lake Eyre in the centre of Australia. Lake Eyre is so salty you cannot drink the water. You cannot use the water on crops or feed it to stock. The water is saltier than the ocean. The area around the lake is not classified as desert. How can we estimate a viable population when an area like that is counted as not desert.
Imagine trying to farm the Dead Sea or the Great Salt Lake in USA. One sixth of Australia drains into Lake Eyre and there is still only enough water to fill it occasionally. The smaller southern section has some water in it every few years. The larger northern section receives a decent water flow only once every ten or twenty years. The whole lake fills only once or twice per century. If you were to use Lake Eyre as an inland source of water for a desalination plant, you would have to warn prospective residents that they can drink water only once every three years and if the population grows to more than a few thousand people, they can drink water only every ten years.
If you like to drink water or to use water to grow food then Australia is not a good long term destination. Our current population of 22 million is 2 million more than we can supply with our current natural water supply. Every four people over 20 million requires desalination plant guzzling the same amount of fuel as a car. A population over 20 million is not sustainable for Australia until someone invents an entirely new energy supply.