As of mid-2016, 7.4 billion people lived on planet earth—double the population of only 46 years before (1970). Let that sink in for a moment. Twice as many people live on our planet now than lived on Earth in 1970. Considering it took us 199,954 years to get to 3.5 billion—modern humans have been around about 200,000 years—that’s pretty mind boggling.
7.4 billion is a lot of people for our small planet and raises the big question of how many people Earth will support. Determining the answer is complicated since so many variables must be considered–the most sophisticated estimates use dynamic systems modeling in an attempt to account for relationships between resources, emerging technologies, changing climate, etc. Not surprisingly, the people who have taken a stab at identifying a number, have reached wildly different conclusions, declaring earth’s maximum capacity to be anywhere from two billion to over a trillion people. So who is right? Out of 65 studies reviewed by the United Nations Environment Program, 52% put maximum sustainability in the range of eight to 16 billion people.[ii] So either we’ve about reached the limit or we likely will within the next fifty years.
Unless we–as in everyone in existence–work together to make fast and drastic changes, the world is headed for tragedies beyond any humanity has experienced, which is saying something.
One of the most outspoken and respected scientists writing about sustainability, Harvard professor and sociobiologist Edward O. Wilson gives a detailed analysis of population versus resources in his book The Future of Life. Speaking of population limits, Wilson says, “There are two ways to stop short of the wall. Either the industrialized populations move down the food chain to a more vegetarian diet, or the agricultural yield of productive land worldwide is increased by more than 50 percent.” Neither option can be accomplished easily or painlessly.
Having enough food for everyone will be one of the biggest sustainability challenges. Even today, the Food and Agriculture Organization of the United Nations reports in “The State of Food Insecurity in the World 2015” that 793 million people are undernourished. Asia and Africa have the greatest number of undernourished people; meanwhile, they also contain the countries with the fastest growing populations. And food is only one of many resources required to sustain a growing population.
Meanwhile, some population activists say the world currently has an unsustainable population. They argue that if everyone on the planet consumed resources at the rate Western Europeans and Americans consume them, there would be a shortage of resources today. They say we are currently using more resources than are being replaced, and it is only a matter of years before the Earth can no longer support basic needs.
Global Footprint Network (GFN) has developed calculations to compare the annual rate at which resources are replenished to the annual rate at which they are consumed. Their conclusion is that “approximately every eight months, we demand more renewable resources and C02 sequestration than what the planet can provide for an entire year.”[iii] To put things in monetary terms, we citizens of Earth are living on credit for at least four months out of the year, and that deficit is growing and costing us in myriad ways: deforestation, carbon build up in the atmosphere, animal and plant extinctions, loss of land, and declining fresh water stores. The ripple effect is astounding and deadly serious.
To drive home the gravity of the situation, GFN has created a footprint calculator individuals can use to determine how much of the planet’s resources would be consumed each year if everyone consumed resources at the rate they consume. I discovered it would take five planet earths to provide the resources my family uses to every person on earth, and my family is relatively conservative compared to a lot of people I know. Want to see how you stack up? The calculator is available at: http://www.footprintnetwork.org/en/index.php/GFN/page/calculators/
Rapid population growth means it is urgent that each of us consider how we can live a more sustainable life and take steps to do so.
We can take small comfort in the fact that the United Nations predicts slower growth over the coming years thanks to a declining birthrate and other factors, projecting a population of 9.7 billion by 2030 and 11.2 billion by 2050.[i] But as people in countries like China and India increasingly consume in ways similar to Europeans and Americans, even small population increases put our planet and the lives on it in danger.
[i] http://www.un.org/en/development/desa/news/population/2015-report.html
[ii] http://na.unep.net/geas/archive/pdfs/geas_jun_12_carrying_capacity.pdf
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