Human Population Growth is Our Biggest Environmental Problem

Julie Smith, 4/1/26

This is a summary of Chapter 4, The Elephant in the Room, in the book, “2050: What’s it Gonna Be?”.  You can download the full chapter, as well as other chapters.  References are here.

Uncontrolled human population growth is at the bottom of every environmental issue that we have.  Since 1970, the year of the first earth day 50 years ago, human population has more than doubled.  Every time we add another human to the planet, our carbon emissions increase by 5.26 metric tonnes per year (as of 2020).  For every 1% increase in global population, our numbers increase by 80 million and global emissions increase by more than 400 million metric tonnes.  Does that sound like a lot?  It is. 

In the U.S., we’ve managed to rein in our population growth rate a bit in the past 50 years, from 1.3% in 1970 to 0.5% in 2024.  And, 0.5% might seem really low, but it means we added 2 million people in a single year, which is a lot.  That works out to an average of 40,000 people added to each state each year.  People that have to be accommodated with shelter, food and water, along with enough energy to fuel it all. 

Globally, we need to get to an annual reduction of about 1%/year by 2050 to have any chance at all of getting in balance with our precious planet.  In 2023 global population increased by slightly less than 1%, or 75 million.  As we continue to increase our population, we displace and reduce yet more wildlife, take over yet more land, and continue to increase CO₂ output and reduce CO₂ absorption sinks from forests and other wild lands, as we require yet more food, water, general consumption of goods, and increased construction to provide homes, schools, utilities, factories, stores and roads to handle the extra demands of the additional population.

The reality that we must face is that we live on a planet with finite resources.  After all, even in this day and age, there’s still plenty of open space around, and we are able to feed and house everybody.  Right?  Actually, sorry, but nope.  Not true.  Problem is, we’re actually not able to feed everybody.  At this time about 10% of people on this planet face acute food insecurity, which works out to 864 million people, including 36 million children under 5 years of age.¹⁰   Also, we’re experiencing more and more problems with water scarcity, which is an obvious problem, since we need that not only for basic survival, but also to grow our food and provide our electricity.

As for land, there might seem to be lots and lots of land around, but the sad truth is, that endless as it seems, we humans have already taken far more land than we should from the other life on this planet, basically driving wildlife to the brink of extinction, taking out 73% of wildlife in just the past 50 years.¹¹  If we keep it up, and grow our population to 10 billion, like the UN predicts, we’ll drive our wildlife down pretty much to zero, as shown in the graph below. 

Human population growth is driving wildlife to extinction. Human population must be reduced to avoid complete extinction of wildlife before 2050.

In the American West, there are far too many people for the limited water available, by a long shot.  When we have cities fighting over water needed for human consumption with farmers who grow our food, that’s when you know it’s bad.

We’ve also pretty much overfished the ocean.  Even worse, the massive quantities of CO₂ that we’re spewing into the atmosphere is also dissolving in the ocean, making it more acidic, which weakens and dissolves the shells of shellfish.  So far, we’ve driven at least 2270 terrestrial and aquatic species to extinction or nearly to extinction, meaning they’ll probably be mostly gone in the next human generation.¹²  This is 1,000 to 10,000 times the natural extinction rate for the past several million years.

At this point, global humanity is consuming a quantity of natural resources that is equivalent to 1.7 Earths every year.  This means that humanity is using natural resources 1.7 times faster than the planet’s biocapacity can regenerate.  Even worse, if we all lived like Americans we would be consuming 5.1 Earths per year.  We’re continuing to decimate wildlife as we keep taking yet more land to satisfy our ever-growing population for food, fossil fuels, logging, mining, and all our other collective demands.

Uncontrolled human population growth is overrunning planet Earth and decimating wildlife. Our buildings, roads, factories, farms and overfishing of our oceans are driving wildlife to the fringes of the planet, Our plastic garbage in the oceans is filling fish with plastic and killing them.