Sunday, 25 November 2012

How Will the World’s population die?

Of all the major trends, overshoot will bring , one of the most important is how the global human population will shrink to a sustainable level. this is assured as current population levels well exceed the Earth’s carrying capacity with only renewable resources available. The basic graph looks like this.

For us humans the declining carrying capacity has two parts;

Loss of non-renewables: Fossil fuels belong to this category, anything that requires them to access and ores deep in the ground, the main industrial materials in this category (recycling is a different matter). For agriculture the main loss is the relatively stable climate, other losses include fossil aquifers or deposits of Phosphates and other nutrients. Once this section of carrying capacity is lost it won’t be regenerated over anything but geological timeframes.

Loss of renewables: Soil fertility, fisheries and forests are the most common; this includes elements that can renew themselves over time,normally biological systems. However, once depleted many of these elements stop regenerating, examples  include the collapse of the North Atlantic Cod fishery and the deforestation by the Anasazi of Chaco valley (Collapse by Jared Diamond). Action can be taken to create renewable resources; reforestation, recycling of metals (renewal of stocks), building soil fertility, silviculture etc.

While the ultimate carrying capacity is variable and will fluctuate over time due to climate, ecological and cultural variables (consumption levels), it will be well below current population levels.

The important question now becomes how the world’s human population will decline. On a global scale this is likely to follow a smooth curve down, shown on the graph above, however what we care about for Australia is the local/regional of us and the Asia-Pacific change. Here’s an example of the differences between global (or continental in this case) and local.  2011 was for the US an average year in terms of rainfall over the entire nation, but when each state was looked at separately what was found was that more extremes had happened. Simply put there were more floods and droughts but when the entire nation was analysed they cancelled each other out.

As such there are two ends of the spectrum of population collapse; fast or slow. Dimitri Orlov describes the slow process in his book Reinventing Collapse as a changing in the birth/death ratio so a population exponentially decays (say 2-4%). This is a fairly peaceful and stable way for population to decline, if we have a choice we should aim for this. The fast way includes (and makes other fast collapse more likely) mass migration, plagues, wars, famines or other disasters. These can quickly change population levels and in the process cause great discord and chaos. We should try to avoid these events. The worst action we could take is to maintain current population levels as this just prolongs the collapse.
While the general trend will be decline, areas will experience population growth. The northern coast of Australia will likely see a boom as desperate refugees (climate, war or other) migrate there. This would then be followed by a crash as the lack of agricultural potential causes famines; the graph to the right shows such a process with reindeer. Some areas will keep a stable population; New Zealand is a good candidate for that., while Indonesia (among many others) is set for a dramatic reduction in population.

A note on time frames: if we use 300 years as a benchmark for the the massive population growth which is now going to be reversed, the decline will probably take 200-300 years overall and places will alternate between fast, slow collapse and points of stability (or even growth).

Population changes it will have dramatic effects on our economic, political and military systems. Anticipating and preparing could negate unnecessary misery and ease the many transitions we face

While its a bit late for any drastic changes to the outline, basic preparations could still help. Most of the standard response to overshoot (summed up as a mixture of using less resources and switching to more sustainable production/agriculture modes). Other options include slowing, then stopping, major international food trading while making food importers more self-sufficent, using organic agriculture or massive agricultural research into agriculture in third world countries.

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