Death by Numbers: The Dangers of Exponential Growth

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

Dr. Bartlett, now nearing ninety years old, is still eagerto inform others about the least discussed major issue that mankind faces:overpopulation.  While politicians movetheir mouths on topics from unemployment to global warming, not since Nixon hasa leading politician uttered the word overpopulation.  Telling society that we are our own worstproblem is not a popular thing to do; it is, on the other hand, a veryresponsible thing to do.  Overpopulation exacerbatesboth global warming as well as unemployment, not to mention poverty, at thelocal and global level.

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

Imagine a city with a population of one millioncitizens.  Which of the following sounds like it will result in a biggerpopulation 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 anabsolute quantity, and a large one at that, but it represents linear growth.  Add 40,000 times 50 to the current populationof one million, and you have a population of 3,000,000 people fifty years downthe road.  The first option soundsharmless, but the exponential growth causes that measly 1.03 factor to beplaced to the fiftieth power, so that the population of initially 1,000,000becomes (1,000,000*(1.03)50) 4,383,906.

Add an additional fifty years of continued growth at theseemingly small value of three percent, and the once manageable population ofone million will have exploded to nearly twentymillion.  In a finite space, with finiteresources, it is clear that growth of any kind cannot continueindefinitely.  Growth is, by definition,unsustainable.  So, whether by choice ornot, there will come a time where the number of humans will plateau, and eventuallydecline, as it will have overshot its sustainable “equilibrium” value.

The most alarming part about Dr. Bartlett’s lecture comestowards the beginning, when he compiles a list of all the things that result inpopulation growth, including good public health, peace, law and order, andclean air.  Then, he lists what we can doif 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 thatit takes to curb the population graph downwards voluntarily.  The unfortunate reality is that these thingsare already happening and will increase in frequency as a direct consequence ofour population.

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

We live in a time of unsustainability, and the gap betweenthe developed nations and the developing ones is a clear reflection ofthat.  With today’s level of technology,and taking into consideration the present level of resources on our planet, asustainable number of individuals on our planet would be just two billion (witha growth rate of 0%).  That is roughly howmany people at one time can enjoy the quality of life that those who live in developednations experience.  We have surpassedthat number by a factor of 3.5.  Putbluntly, 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 oneoffspring per person (two per couple). Some see the enforcement of this as a non-democratic notion, and theyare right.  But, if a pure democracyresults in exponential growth, then it is a flawed system that must beaddressed.  Say what you will about China’sthirty-year-old mandate of one child per couple, but their thriving economytoday is nothing to sneeze at.

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

Beyond that, we, as a race, must brace ourselves for whatwill 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 havealready been severely impacted by overpopulation.  By the time developed nations are really hit hard by the tsunami of oursheer numbers, they will no longer be in a position to help those who are worseoff.

It is awfully depressing to face the reality ofoverpopulation.  Nobody wants to see theproliferation of disease and famine. With some issues, we can identify the culprits that are responsible, andpoint a finger at them.  However,exponential growth turns out to be a faceless and gradual killer.  I want to believe that the near term futurefor humanity is less bleak, but as Dr. Bartlett correctly points out, “You can’tdebate over arithmetic.”


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