Death by Numbers: The Dangers of Exponential Growth

Physicist Dr. Albert Bartlett believes that man’s greatest shortcoming may be his inability to understand the exponential function.  A long time member of the faculty at the University of Colorado at Boulder (since 1950), Bartlett has given his famous lecture, “Arithmetic, Population, and Energy,” 1,600 times over the past fifty years.  Add to that millions of hits on YouTube, and it may be the most viewed lecture of all time. 

Dr. Bartlett, now nearing ninety years old, is still eager to inform others about the least discussed major issue that mankind faces: overpopulation.  While politicians move their mouths on topics from unemployment to global warming, not since Nixon has a leading politician uttered the word overpopulation.  Telling society that we are our own worst problem is not a popular thing to do; it is, on the other hand, a very responsible thing to do.  Overpopulation exacerbates both global warming as well as unemployment, not to mention poverty, at the local and global level.

Economists typically examine the health of a given economy based on its population growth.  Nations like Japan consider themselves to be in a depression if their population growth is any less than 3%.  To the ear, a population growth of three percent per year does not sound like a problem, but that’s because it is a relative term, a factor of 1.03.

Imagine a city with a population of one million citizens.  Which of the following sounds like it will result in a bigger population fifty years down the road?

1.  Three percent growth every year.

2.  Increase of 40,000 people each year

The second option sounds like more, because it is an absolute quantity, and a large one at that, but it represents linear growth.  Add 40,000 times 50 to the current population of one million, and you have a population of 3,000,000 people fifty years down the road.  The first option sounds harmless, but the exponential growth causes that measly 1.03 factor to be placed to the fiftieth power, so that the population of initially 1,000,000 becomes (1,000,000*(1.03)⁵⁰) 4,383,906.

Add an additional fifty years of continued growth at the seemingly small value of three percent, and the once manageable population of one million will have exploded to nearly twenty million.  In a finite space, with finite resources, it is clear that growth of any kind cannot continue indefinitely.  Growth is, by definition, unsustainable.  So, whether by choice or not, there will come a time where the number of humans will plateau, and eventually decline, as it will have overshot its sustainable “equilibrium” value.

The most alarming part about Dr. Bartlett’s lecture comes towards the beginning, when he compiles a list of all the things that result in population growth, including good public health, peace, law and order, and clean air.  Then, he lists what we can do if we wish for the population to decrease, such as the spreading of disease, participation in war, and increasing environmental pollution.  We would never dream of doing the things that it takes to curb the population graph downwards voluntarily.  The unfortunate reality is that these things are already happening and will increase in frequency as a direct consequence of our population.

There is a dangerous mindset among many people that science can solve all of our problems.  Although man’s knowledge also grows at an exponential rate, it does not necessarily result in feeding more hungry mouths.  And, although man has devised many ways to produce energy, we cannot provide the power that the near seven billion people alive today desire. 

We live in a time of unsustainability, and the gap between the developed nations and the developing ones is a clear reflection of that.  With today’s level of technology, and taking into consideration the present level of resources on our planet, a sustainable number of individuals on our planet would be just two billion (with a growth rate of 0%).  That is roughly how many people at one time can enjoy the quality of life that those who live in developed nations experience.  We have surpassed that number by a factor of 3.5.  Put bluntly, we are five billion too many at present, and growing.

What can we do?

We could each do our part by having no more than one offspring per person (two per couple).  Some see the enforcement of this as a non-democratic notion, and they are right.  But, if a pure democracy results in exponential growth, then it is a flawed system that must be addressed.  Say what you will about China’s thirty-year-old mandate of one child per couple, but their thriving economy today is nothing to sneeze at.

Other than keeping our reproduction under control, the best we can do is to cope as best that we can with the hand we currently hold.  We must continue to work towards large scale energy production methods that are both economically and environmentally sound.  This is a tall order, but it is the only way to manage the stubborn fire we see spreading before us.

Beyond that, we, as a race, must brace ourselves for what will surely be a tough period in our history.  It is dishonest to write as though we face this as a collective.  Those with a lower standard of living have already been severely impacted by overpopulation.  By the time developed nations are really hit hard by the tsunami of our sheer numbers, they will no longer be in a position to help those who are worse off.

It is awfully depressing to face the reality of overpopulation.  Nobody wants to see the proliferation of disease and famine.  With some issues, we can identify the culprits that are responsible, and point a finger at them.  However, exponential growth turns out to be a faceless and gradual killer.  I want to believe that the near term future for humanity is less bleak, but as Dr. Bartlett correctly points out, “You can’t debate over arithmetic.”