The population problem
The baking summer temperatures of February 2009 have southern Australians thinking about climate change and their limited water supplies. As high temperatures led to grid collapse and massive blackouts followed by disastrous fires, they also had the opportunity to think about how dependent their lives are on technology and the resources that keep technology ticking. For me, a biologist interested in politics, the summer of 2008-2009 has been quite interesting for another, related reason; the more open discussion of the effect of population growth on our ability to mitigate climate change. As Kevin Rudd explained last December about emission reduction targets:
The EU's 20 per cent target announced over the weekend is equal to a 24 per cent reduction in emissions for each European from 1990 to 2020. Our 5 per cent unconditional target is equal to a 27 per cent reduction in carbon pollution for each Australian from 2000 to 2020 - and a 34 per cent reduction for each Australian from 1990.
This is because Europe's population is not projected to grow between 1990 and 2020. By contrast, Australia's population is projected to grow by 45 per cent. If the Europeans were to adopt the same per capita effort as Australia is proposing, their cuts would be around 30 per cent by 2020.
So it seems that Australians will be required to make larger sacrifices in their energy use so that population growth can continue and we can, ultimately, achieve a lesser total reduction than the Europeans in any case. Part of me wants to believe that Rudd’s comment might be the first subtle move in a campaign to relieve us of the illusion that economic and population growth can continue for ever. However, the far more likely explanation is that the political leadership (of both major parties) believes so blindly in the benefits of population growth that they regard Rudd’s excuse for our failure to make larger cuts in CO2 emissions as acceptable and noble.
I do not know of any topic that evokes more heated, passionate, and opinionated argument than population. For a biologist the matter appears simple. There are numerous examples of species expanding their populations until they exceed their energy resources (i.e. food supply), after which starvation kicks in and the population crashes. Humans are clearly animals and if we do not get sufficient food then we starve too. But most of the scientifically under-educated population seems to think that humans are in some way exceptional, that we are too clever to starve. Either our technology or our ability to respond to crises, or both, will save us if food ever becomes limiting. I wish this were true but history - and a cold, objective look at the numbers involved - shows that this idea is just a comforting illusion.
For most of history the threatening shadow of hunger has been humanity’s constant companion. The oil driven “green revolution” of the 1960s and 1970s boosted food production at a time when it seemed our population might soon exceed its food resources (as predicted by the original dismal economist, Thomas Malthus).
The food price hikes and riots of 2008 led some commentators to declare that we need another green revolution but nobody can really say how this will be accomplished. Gene technology is sometimes cited as the saviour to come but this ignores the fact that most of the genetic gains in crop productivity in the last 40 years have been possible because we have been using stupendous volumes of oil energy to perform more and more tasks for the plants that they would otherwise have to spend energy doing for themselves. (For an excellent illustration of this see Folke Günther’sarticle “Making western agriculture more sustainable”).
By some estimates we use 10 times as much energy from oil to grow our food as is provided to us by the food itself. (Additional energy is then used in transport and distribution, processing, packaging, the driving involved in collecting it from the supermarket and then cooking it.)
What more can we do for our pampered plants? And how will we be able to keep them pampered in any case now that oil production seems to be set for rapid decline and phosphate fertiliser may disappear even faster?
Currently, the world’s population increases by 76 million people a year - the equivalent of almost four Australias. However, world food production (as illustrated by grain production) may have peaked in 2007-8 and grain per person peaked back in 1986. In fact, widespread drought may reduce world food production by more than 20 per cent in 2009. Water for agriculture is becoming increasingly scarce, unpredictable weather patterns resulting from climate change are decreasing agricultural production, fertilisers have been rapidly increasing in price as their raw materials become scarce, and our farmers are collapsing into financial crisis as volatile agricultural markets play havoc with their income. The world’s stocks of grain in reserve have now fallen close to critically low levels and are on a downward trend.
These problems have been exacerbated (until recently at least) by the trend to higher per capita consumption of meat in Asia as the region becomes (or, rather, became) wealthier. Eating meat is far less food-energy efficient since many grams of grain must be fed to any animal to return each gram of meat which then finds its way into a human mouth. Only the most optimistic fantasist could imagine that we could turn around these worldwide trends in time to increase food production to match the UN’s often-quoted estimate of a 40 per cent increase in world population by 2050. A realistic estimate based on projections of energy and other resources must see a crash in agricultural production before 2020 and declining population numbers before long thereafter.
When one appreciates how rapidly trends are moving compared to the time that would be required to educate the world’s population and turn the situation around (if that was even still possible) then it is, perhaps, understandable that the topic of population growth is avoided, especially at the international level. There is also an arrogant and misplaced assumption on the part of industrial nations that hunger, if it does become a problem, will only affect “developing” nations. That assumption is almost certainly false for a number of reasons. As cited above, industrial agriculture is heavily energy and fertiliser dependent. However, almost all of the industrial nations have severely depleted their domestic sources of energy in the process of building their economies during the 20th century. Almost without exception, they are now very dependent on importation of large volumes of energy - often from great distances. As energy resources decline, “resource nationalism” becomes more prevalent and energy markets become more chaotic, we will see increasing energy shortages in industrial nations and this will affect agriculture.
While European populations now appear to have stabilised, the populations of nations such as Australia and the United States are still growing rapidly. Australia's grew by more than 330,000 people last year - equal to a city the size of Canberra - while the US population recently passed 300 million and grows by 2.8 million per year.
In 2008, population growth and the drought led Australia’s most densely populated state, Victoria, to become briefly a net food importer for the first time. In other words, Victoria will soon no longer be able to feed itself and will be looking to the wider world to supply it with food - when almost everyone else will be doing the same thing. The Victorian population is currently growing by 1.5 per cent a year. At that rate it would double within 50 years but its food production then would almost certainly be less than today.
As Melbourne’s population grows it sends out pipelines like invasive roots to suck water out of what used to be distant river systems - but those river systems, such as the Goulburn River, are already being used to grow the food that Melbourne needs. (The Victorian government would do well to remember “Stein’s Law” that “If something cannot go on forever, it will stop”.)
Population growth lies at the core of all questions of “sustainability”. It is growth of the human population and the increasing resources that it requires that drives the destruction of habitats, the increasing levels of pollution (especially CO2), and the accelerating depletion of finite resources. It is impossible to stop exacerbating these problems if we do not stop population growth.
Efficiency gains in resource use can slow the damage for a while but we need to remember that efficiency gains are subject to what economists call “diminishing returns”. That means that the first 10 per cent of efficiency gain may be easy but the next 10 per cent will be harder, and there is a limit beyond which one cannot become more efficient. So while the efficiency gains decrease with time, the exponential nature of growth means that the increase in the number of individuals accelerates with time.
In case you thought that was bad enough, efficiency gains can actually make a population less resource secure, not more. To understand this you need to realise that what limits the survival of a population is not a range of resources but the most limiting single essential resource (Leibig’s law of the minimum). To be resilient a population must have significant reserve capacity in its essential resources so that, if any essential resource should become restricted, the population still has enough of that resource to survive. Efficiency gains can increase resilience by increasing the reserve capacity of essential resources - but only if the population does not grow! If the population is allowed to expand on the back of efficiency gains in resource use, this decreases reserve capacity and resilience. The population will then be far more vulnerable to shortage shocks in its resource base; it will be in greater danger of collapse.
For now, I am still a member of the Green Party in Australia. When I first took up the topic of population growth on a South Australian Greens Party internet forum I was labelled an “eco-fascist” among other pleasantries. My concerns were not ignored. Instead, they generated violent antipathy! However, for every outspoken objector there seems to be a number of quieter but supportive people to whom the role of population in questions of environment was obvious. This was revealed by the attitudes of audiences attending debates on the topic.
Nevertheless, while there may be broad but covert support for limiting population within the Greens, the Party’s leadership appears to be very concerned about alienating their growing support among the general public. (This is a pity because it was the willingness of the Greens to fearlessly take the rational but less popular line on important issues that initially attracted me to them.) This was revealed to me in the lead-up to the Party’s policy review of 2006 when those drafting the revised policies had decided unilaterally to drop the population policy by simply not presenting a revised policy because they saw it as too contentious.
Fortunately, a strongly worded letter drafted by the South Australian Greens helped to see the policy retained.It is a pity however, that one must struggle so hard just to keep treading water on such an important issue. The current population policy is vague and sounds almost apologetic. It regards consumption as more important than population and wishes to avoid all talk of actually limiting numbers. Typical lines from the policy are:
2. Our environmental impact is not determined by population numbers alone, but by the way that people live.
7. An Australian population policy must consider the geographical distribution of human settlements rather than just concentrate upon population size at the national level.
There is a constant struggle within the Greens between those who believe environmental issues must have primacy and those who regard social issues as paramount. If this struggle cannot be resolved in a manner that recognises population growth as the key driver of our environmental difficulties then maybe Australia will need an alternative political organisation - an “Environment Party” perhaps?
In my next article on population I will look at some of the misconceptions and outright deceptions in the population debate.
What do you think? Leave a comment below.
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