The real challenge of the 21st century is to reduce world population without massive famine, disease or war.

Today let’s go big picture and look at some pressing global problems and my conceptually simple solution to them:

As Nobel Prize laureate Joseph Stiglitz points out, in the U.S. and worldwide, we face an excess of productive capacity that presses wages downward everywhere.  Lower wages means that owners and investors keep more of the wealth created by the economy.  Helped along by artificially low tax rates, this excess of productive capacity redistributes wealth upwards unless there are social constraints to prevent income polarization, as exist in western Europe.  From the Roman Empire to Mughal India, Spain in the 16th century, the Ottoman Empire, various Chinese dynasties to 21st century United States, history teaches us that when incomes polarize, then rapid economic decline soon follows.

Here are the ways to increase the need for labor:

• The market solution, which is preferred by most large industrial concerns and very wealthy people; that means to grow markets, open new markets, create new products for existing markets. 
• The government solution, e.g., raising minimum wages, lowering maximum work times, mandating additional workers to perform government-required work, raising the basic standard of living that society guarantees to all such as education and medical care.  All attempts in this area are routinely met with great resistance by those who like market solutions and the mainstream and rightwing media they own or control through advertising purchases.

Note that in Europe and increasingly in China and Brazil, governments are employing combinations of both these strategies.

But spreading the wealth around in either of these ways pushes against the other major problem facing the U.S. and the world: the impact of humans on the earth, especially the inexorably accelerating spew of additional carbon into the environment.  Give more people relative wealth and they will create more pollution.  In world summits, this problem plays out as rich nations versus poor ones, developed versus nondeveloped, north versus south.  

My conceptually simple solution to both these problems is to shrink the population.  We know for a fact, again from a close reading of history that after a rapid depopulation economic good times soon follow as the cost of labor goes up and more people have money to spend.  The classic example is 14th century Europe after the bubonic plague wiped out about half the population.

Depopulation usually occurs because of some disaster: war, famine, disease.  But why does it have to be that way?

Suppose, for the sake of dreaming, that every person in the world today would have just one child.  Since having a child takes two parents, in about a generation the population would begin to naturally fall and within a century, we would have somewhere between 500 million to one billion people in the entire world.  With a century of investment into recycling, solar, wind, biofuel, smart grid and other technologies, we could very easily support a billion people with a fairly comfortable western middle class lifestyle.

But what of the transition costs, some may ask.  Remember that in most places, people have it drummed into their head that the only good economy is one that is growing.  But what if we know that the economy is going to shrink because there will be fewer people to serve?  It’s such an easy problem to address.  We merely do all the stuff mentioned in the two bullets above: let the market work and let government redistribute wealth and guide social and economic policy.

Now as the population shrinks, labor shortages will grow everywhere, as there will be fewer young people always entering at the bottom rungs of the economic ladder while the upward part of the ladder will always be relatively larger.  The number of people retired and supported by the workforce will also be relatively larger but that impact will be offset by a small population of children to serve.  But we know in advance professions serving the elderly will grow and those serving children will shrink and so can plan.

Additionally, developed nations can readily fill their labor shortages with people from the undeveloped world.  Western Europe has been doing just that as its native populations start to decline, e.g. in Italy and Germany.  It’s too bad that many of the locals and some governments in western Europe are reacting to the newcomers so poorly.  After all, it is this instream of immigrants that can enable the world to make a painless transition to a shrunken human population. 

But the last point I want to make about the transition costs of peaceful negative population growth is that whatever they are, they’re better than war, famine or disease.  

Humans are pushing against the upper limits of the earth’s carrying capacity for the current incarnation of our species, and natural history tells us that this situation typically leads to decline or outright extinction.  We can “rightsize” our species in a peaceful way or we can make a lot of people suffer.  I vote for peace and therefore endorse all efforts to reduce our population.