Environmental footprint and maximum population.

Every living creature has an ‘environmental footprint’, or an impact on the environment in a multitude of different ways. Most of us are aware of concept of a ‘carbon footprint’, and how we can reduce this footprint by changing how energy is produced.  In the end energy is energy no matter how it is produced.  But there are other things we consumer with a more complex footprints.  For example food.  It is important to consider not just ‘how many people can we feed?’, but also ‘what do we desire to eat’.  It is one thing to feed the world grain, but don’t we all want to live at a much higher standard than that?

It turns out that you cannot answer ‘how many people can the Earth support”?, without answering ‘how do you wish them to live?’. 

Some of these ‘footprints’ or impacts are beneficial, but generally there comes a point where the combined impact of the population in an area damages that area.

Consider a paddock with dairy cattle.  The is a number of cattle who can live in the paddock and eat the grass without the grass dying, but if we put in double this number of cattle then before long the grass will start to die.  As area of grass die the pressure on the remaining grass is even greater all the grass will die and the ground will be dirt, after which the cattle will start to die of hunger.

The cattle each have an environmental footprint impacting (amongst other things) the grass in the paddock.  Once the combined impact of the population of cattle in the paddock is to great the environment starts to suffer damage and without intervention the environment will collapse.

Of particular interest of late to us humans has been the ‘carbon’ component of our environmental impact. If I was a cow in that paddock and bare patches started to appear I would be calling for a larger paddock or a feed supplement immediately and trying to go easy on the grass.  I mean better safe than sorry.  It could be just a dry spell and the grass will recover, but with warning signs and cows only having the one paddock taking action even if not certain would seem wise.  Of course we humans are smarter than cows and many of us will take no action until we are 100% certain the warning signs mean we really do have a problem 🙂

However many are taking action.  But even with steps being taken that successfully reduce emissions per person, there are two problems to reducing total ‘carbon’ emissions.  Firstly, the gains from reducing emissions per person are eroded in any country that is still increasing the number of people.  Secondly, over half the global population live in circumstance far less developed than ideal by current standards and currently could only move to developed status by radically increasing their own emissions.

Carbon or CO2 emissions are a special case, and i will cover that in another post.  However it is challenge to reduce environmental footprint without reduction in living standards.  Consuming less energy without increasing efficiency means a lowering of living standard.  Consuming less energy by increasing efficiency at this time typically means paying more for the energy, which leaves less for other things and again lower living standard.

Again, carbon or CO2 environment footprint is a special case because if society was structured correctly, zero CO2 environmental footprint can coexist with any standard of living we desire.  But getting if of CO2 emissions does not mean energy production has no environmental impact.  Humans also do need to eat, to drink, to have waste, to living in houses and engage in all manner of activities that impact the environment and the more each individual can do these things the better their life.

Take food for example.  How many people we can provide with food? Estimates range from not even the current population, since we are not currently managing to product food sustainable,   through estimates that we will be able to feed the current 2050 estimated population all the way through to estimates that we could feed double the projected 2050 population by using hydroponics far more extensively.

The trouble with all these projection is just what do we mean by ‘provide food’?  Do we mean sufficient to keep people alive and in adequate health?  Or do we mean to provide choice and variation and the food people desire to eat?  Lobster if they wish.  Because the two answers are radically different.  Currently we can only sustain a global population under 3 billion if we wish to feed this population in the manner current middle class America can enjoy.

Until very recently, humans were able to hunt and gather.  The first change was farming of some crops.  Then it became almost all plants that we eat are farmed.  It started as a small variety of animals farmed with many still hunted but gradually food from hunting became unsustainable and unthinkable except in rare and exceptional circumstance.  Then came fishing. As recently as 2005 fishing ‘or hunting wild fish’ was n industry twice the size of fish farming.  By 2010, fish farming was almost as large as traditional fishing.  I suggest the days of being able to sustain catching fish on a large scale from the wild without endangering more species are numbered.

But farming still has an environmental impact.  Unlike other animals, the area of environment that supplies our needs is not the area where we live.  It is useful picture that for each person living in a city a ‘nature space’ somewhere is required for the earth to recover from the environmental impact of everything consumed by the person in the city.

It is clear that today the earth is unable to recover from the collective impact of the human population as we are living now.  There are estimates that the planet can sustain around 10 billion people. Together with theses estimates are statements like ‘somewhat less if we do not all become vegetarians’.  Now while many would rejoice at the idea that we will not eat animals, remember that reason we need to vegetarians under such a model is so we are not competing for food.  In other words, we do not eat the animals, but they never get to live at all.   These models consider producing enough food to live, not enough that we all enjoy eating.  Or that other animals are sharing the earth with us!

Now what if everyone has a living standard like the average in the USA today? Or even better?  And we still have pets and farm animals and let even wild animals still exist.  That would multiply the average environmental footprint substantially.   In reality it is very difficult to see how the earth can support over 3 billion people if we all live to the standard of the current USA.

in the end, how many can we feed is a factor of the standard of living desired.  Twice the people or more if we simply provide bread as would be the case if the population enjoys luxury food, shares the planet with other animals and is even allowed to have pets!

This is the big trade off.  More people at a lower footprint per person, or fewer people with the potential of a luxury life for all.  I would suggest the maximum possible at the highest standard of living.  Not the maximum possible at all costs.  If we believed in the maximum possible at all costs then we would insist on every woman having the maximum possible number of children possible.  I suggest that to chase the maximum possible at all costs is crazy, which brings us to a much lower number.


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