Environment

The environment in which we live provides the foods that we eat and the water that we drink. Without an environment that is benign to human beings we are destined to starve to death. To most of you that read this this may seem an odd, rather obvious statement to make but it is unfortunately very relevant to the times in which we live.
Due to population growth and the associated increase in consumption of the earth's resources, the capacity of earth to feed its human population is rapidly approaching its limit.

Population growth.

Modern human beings have been in existence in their current form for about 200,000 years 1,2. Since a hypothesized population bottleneck around 70,000 years ago the world population has increased, initially to a stable 1,000,000 3 people which then increased with the advent of agriculture. A marked increase in the rate of population growth occurred with the industrial revolution around 1750 when there were 791 million people worldwide. Since then we have experienced exponential growth that which has left us with about 6.9 billion people today.
Future projections of population growth point to a peak at around 9 billion. These projections are based on something called the demographic transition model (DTM), which expects all countries to follow the development path of European countries in the 20th century. The DTM expects an undeveloped country to go through 2 phases. 
1) It lowers its death rate due to improvements in sanitation and food supply. This has happened in most third world countries already, leading to a huge population explosion. In some cases the food is supplied by aid programmes from industrialized nations. It is to be doubted whether the food supply and sanitation improvements will be maintained until the end of this century due to climate change, but that is another story (see below).
2) It is then supposed to lower its birth rate by increased access to contraception, combined with increased status and education of women, and a reduction in incentives for having more children. Such incentives include a fall in the value of child labour, greater welfare provision and increased economic prosperity (GDP/capita), which should lead to a reduced perception for the need to have kids to provide for a parent in old age. While many developing nations are already experiencing declining birth rates it seems increasingly unlikely that they will match the development trajectory in Europe over the past 100 years.
The population forecasts for the middle of the 20th century and beyond therefore, being based on the DTM should be taken with a pinch of salt. Consider the following questions:
1) If birth rates are to drop then increased availability of contraception, freedom and education of women are required. I ask you to think about the two great religions of Islam and Catholicism which are prevalent in much of the developing world. Are we really expecting that the influence of the Pope and Islamic tradition will wane that significantly in this century? 
2) If birth rates are to drop then increased welfare and GDP per capita should increase dramatically. However we are already running out of energy reserves at current levels of consumption. What is the likelihood that most of the developing nations can increase their GDP per capita, given that GDP is very strongly linked to energy use. OK, you could argue that renewable energy sources could be used, but I don't see these technologies being deployed in the 3rd world very fast. For the most part this is because they have not the funds or expertise to deploy them and the governments in the Western world aren't too bothered by this.
A sustainable human population would probably be at pre-industrial levels of about 500 million people. These people would have to live fairly modest lifestyles consuming about 25% of the current resources that a typical British person does. As I see it the population will eventually stabilise, but this will be due to an increase in death rates and not to the developing nations following the DTM.
As individuals we should be campagning for recognition by the authorities that it is socially irresponsible for any woman to have more than 2 children and that this should be reflected in taxation and childcare policies. We should also campaign for the increase in 3rd world development budgets which should be focused not on food, but on renewable energy projects run by local people.

Resource use

One factor that we cannot overlook when considering overpopulation and the overexploitation of the earth's resources is how much each one of us consumes. The earth has a finite amount of fossil fuel energy sources and the area of arable land is limited. In fact already one third of the total possible arable land on earth is used up. The more that is used the greater the impact on the environment and this leads to climate change which leads onto species extinction and ultimately to a reduction in the overall amount of arable land. 
There is at the heart of the debate about resource use, a moral question, which virtually all of us and the politicians who represent us never face. This is the question of who gets what resources. The picture to the left shows juxtaposes the poverty of a shanty town with a few yards away the prosperity of luxury apartments. It seems likely that nothing has improved in the moral health of modern humans during our 200,000 stay on earth. We happily sit by and take holidays abroad, use hot showers and buy consumer items while the billions of poor (including nearly 1 billion undernourished) people around the world live in abject poverty.
While billions of us inhabit the planet there is no doubt that the amount of resource we use should be closer to that of the typical Ethiopian than that of a typical "green" middle class westerner. Unfortunately achieving a more equitable distribution of wealth in the 21st century will be next to impossible.

Climate change

Man made climate change is known and indeed accepted by most people, although a significant number of people still don't accept it. However few people have a good grasp of the science behind it including 100% of the climate sceptics. 
Fundamentally human generated climate change is caused by the release of greenhouse gases such as methane, nitrous oxide, chloroflorocarbons (CFCs) and of course carbon dioxide (CO2). The pre-industrial level of CO2 was 280ppm, and it is now nearly 390ppm. The extra greenhouse gases we have released have already raised the global temperature by 0.6C and are expected to lead to a 2.0C rise if we release no more. Of course we will release a good deal more and the global temperature rise is likely to be at least 4.0C and possibly more.
The effects of this rise in global temperatures will vary between locations. It is thought likely that the North Polar ice will completely disappear in the next decade or so, while central Africa and the Mediterranean countries will experience increasing levels of drought. It is thought that the climate of Britain will become wetter, leading to more rain and possibly snow.
Ultimately these changes are likely to reduce the amount of arable land overall, further reduce the biodiversity on the planet and lead to the displacement of billions of people through famine and drought as well as inundation by rising sea levels.
 
References:
1 Wikipedia
2 The Origin of Humankind c1994 Richard Leakey
3 Wikipedia - no reference

PS I hope to update and improve these references when I get time with better quality journals and books.

Don't miss.... more from Robin.

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