We are clever, resilient and adaptable?perhaps a little too adaptable
- The world population is growing by approximately 74 million people per year
- Population growth is not evenly distributed across the globe
- Scientists are yet to conclusively determine the human ‘carrying capacity’ of Earth
- Population is only one of many factors influencing the environment
- We have consumed more resources in the last 50 years than the whole of humanity before us
- The 20 th century saw the biggest increase in the world’s population in human history
Our growing population
We humans are remarkable creatures. From our humble beginnings in small pockets of Africa, we have evolved over millennia to colonise almost every corner of our planet.
In 2015 the world population is more than 7.3 billion people. That’s more than seven billion three hundred million bodies that need to be fed, clothed, kept warm and ideally, nurtured and educated. More than 7.3 billion individuals who, while busy consuming resources, are also producing vast quantities of waste, and our numbers continue to grow. The United Nations estimates that the world population will reach 9.2 billion by 2050.
For most of our existence the human population has grown very slowly, kept in check by disease, climate fluctuations and other social factors. It took until 1804 for us to reach 1 billion people. Since then, continuing improvements in nutrition, medicine and technology have seen our population increase rapidly.
- consumption of resources such as land, food, water, air, fossil fuels and minerals
- waste products as a result of consumption such as air and water pollutants, toxic materials and greenhouse gases
More than just numbers
Many people worry that unchecked population growth will eventually cause an environmental catastrophe. This is an understandable fear, and a quick look at the circumstantial evidence certainly shows that as our population has increased, the health of our environment has decreased. The impact of so many people on the planet has resulted in some scientists coining a new term to describe our time-the Anthropocene epoch. Unlike previous geological epochs, where various geological and climate processes defined the time periods, the proposed Anthropecene period is named for the dominant influence humans and their activities are having on the environment. In essence, humans are a new global geophysical force.
We humans have spread across every continent and created huge changes to landscapes, ecosystems, atmosphere-everything. Image source: Richard Schneider / Flickr.
However, while population size is part of the problem, the issue is bigger and more complex than just counting bodies.
There are many factors at play. Essentially, it is what is happening within those populations-their distribution (density, migration patterns and urbanisation), their composition (age, sex and income levels) and, most importantly, their consumption patterns-that are of equal, if not more importance, than just numbers.
The IPAT equation, first devised in the 1970s, is a way of determining environmental degradation based on a multiple of factors. At its simplest, it describes how human impact on the environment (I) is a result of a multiplicative contribution of population (P), affluence (A) and technology (T).
Environmental impact (I) can be considered in terms of resource depletion and waste accumulation; population (P) refers to the size of the human population; affluence (A) refers to the levels of consumption by that population; and technology (T) refers to the processes used to obtain resources and transform them into useful goods and wastes.
As well as bringing the link between population and environment to a wider audience, the IPAT equation encouraged people to see that environmental problems are caused by multiple factors that when combined produced a compounding effect. More significantly, it showed that the assumption of a simple multiplicative relationship among the main factors generally does not hold-doubling the population, for example, does not necessarily lead to a doubling of environmental impact. The reverse is also true-a reduction of the technology factor by 50 per cent would not necessarily lead to a reduction in environmental impact by the same margin.