Recently the world became home to our 7 billionth human. How should we feel about that? Some consider this a blessing but many consider it a catastrophic marker.
From 1900 to year 2000 the global population increased by 1.84 times to just over 3 billion. From 1960 to 2000, our population doubled; we added 205,000 per day. Since then we have been adding 218,000 per day and now we have we reached 7 billion.
But some still worry that we are in danger of a shrinking population.
That worry is prompted by misinterpreted regional population statistics. Inadequately explained statements that family size, in particular populations, is falling below 2.0 (so-called replacement rate) cause some to believe, erroneously, that the population, for that particular region, is in decline. First, if enough additional people form reproductive family units, family size can fall below 2.0 and the population can still increase due to the increase in the number of reproductive families. Without accounting for the age structure of the population, family size is not informative. Second, in Canada, population increase has two causes, natural births and immigration which strongly supplements birth rate. What must be known, to evaluate population effects, is the rate of increase of the population. Not family size in particular regions.
Historically, the global population has increased in the fashion of a compound interest bank account. Such a rate of increase is commonly called exponential; the population rises in a J-shaped curve without any apparent limit.
But there are limits to a global human population. The FAO estimated that there were 925 million hungry people in 2010, increasing rapidly from a low of 780 million in 1995-97. Every year, FAO says, 15 million children die of starvation. Through the 1990’s more than 100 million children starved. Is that morally acceptable?
There are other kinds of limits to population growth that are reflected in the impacts that the human population has on our planet. These are often summarized by the shorthand that: Environmental Impact is proportional to the product of Human Population X Affluence X Technology (I = PAT). The message is: it is not just the number of people that controls the Impact. It is also how much resources they consume. Resource consumption is influenced by advances in technology that increase the amount and the types of resources used by the human population. Shortened and simplified, the impact on our one and only earth is governed by the size of the human population and how they consume resources.
The North American population, even if smaller, consumes much more and has a more damaging global impact than a much smaller population elsewhere that consumes much less.
The questions are: should we 1) accept the fate of malnutrition and starvation for so many children born into the population, and 2) should we accept the degradation of the earth’s capacity to support future generations of humans and of other organisms? These are the predictable outcomes from increasing the human population along with their consumption of resources and their degradation and elimination of vital natural processes? These are questions of morality and some of the popular answers we hear are immoral.