Human population has an obvious impact on the health of our environment. Generally, more people consume more resources and leave less habitat for other creatures. But the relationship isn’t simply more people = greater impact. The way we live is also an important factor, so even though our population growth is slowing, our environmental impact continues to rise.
Paul Ehrlich wrote in his now-famous 1968 treatise The Population Bomb that human population growth was on a track that could see us quickly outstripping the planet’s resources and leaving our species struggling to survive. Thankfully, that hasn’t happened. Population pressures are still very much a reality and take a tremendous toll on the environment, but at least the human population is expected to start leveling off around mid-century.
However, even though population growth is slowing, we are still expected to end up with at least nine billion people in the world – 50 per cent more than we have today. Achieving any semblance of sustainability, where this vast populace is not steadily degrading the earth’s natural systems that we depend on, will require efficiency and wise use of the planet’s resources. When I was born in 1936, there were only about two billion people. Think about how much simpler our food, energy and pollution issues would be if that was all there were today!
Wealthy, industrialized countries like Canada use a disproportionate amount of resources. For example, Canadians are the highest per capita consumers of energy in the world. And the United States, with less than five per cent of the world’s population, is responsible for one quarter of the world’s greenhouse gas emissions – the culprits behind global warming. (Sadly, this trend is continuing. The average new vehicle sold in North America actually burns more gasoline, and therefore releases more greenhouse gas, than did the average 2002 model.)
But there’s more to our resource consumption patterns than just the imbalance of wealth. A report published in the journal Nature argues that household dynamics also plays an important role. Right now, the worldwide trend is towards smaller households and this does not bode well for the environment. If households are smaller (ie. each dwelling contains fewer people) but population remains the same, then there will have to be more dwellings to house the same number of people. That means more urban sprawl, more land co-opted for buildings and less habitat for wildlife. It also means more stoves and furnaces burning more fossil fuels and wood. It means more electricity needed to run more refrigerators, lights and home appliances – things that used to be shared in larger households. All this leads to less habitat, more pollution and more greenhouse gas emissions.
To make matters worse, the greatest increase in the number of households is taking place in countries with the highest number of biodiversity “hotspots” – areas that contain a disproportionately high number of species. According to the report, if households in these countries had remained the same size as they were in 1980, they would have had 155 million fewer homes by the year 2000. At current rates of growth, there will be an additional 255 million more households in these countries by the year 2015. Four of them – Italy, Portugal, Spain and Greece are actually declining in population, but because of the reduction in household size, the number of homes is still rising fast.
Why are households becoming smaller? According to the report, rising divorce rates, declining prominence of multi-generational families living together and ageing populations are some of the answers. These trends are likely to continue, which means that environmental health, and ultimately human health and welfare will suffer unless we make a concerted effort to become much more efficient and less wasteful in the way we use our limited resources.