We human inhabitants of planet earth have a problem that we would rather not face or discuss. That problem is our astonishing rate of population growth. The human population of our world was estimated to be about 1,000 million in 1800. By 1900 our numbers had increased by 65% to 1,650 million. By 2000 it had increased to 5,973 million – roughly six times as many as in 1800. At expected rates of growth, we will be close to 9,000 million souls by 2050.

So far, we have been reasonably successful in adapting the way we live to accommodate more people. When there was conflict over rights to graze animals wherever we wanted, we invented the idea of private property rights so that we would know who had the right to use which land. When our cities reached a size which allowed vermin to transmit disease, we suffered the plague. Eventually we learned that by getting garbage and sewage out of the city, we could avoid the plague and many other health problems. Later on we learned how to share water with rules that regulate how much one person can take from a stream or well so that there will be water left for others to use. When rules were ineffective or inconvenient, warfare has sometimes been an alternative. Biblical history says that the tribes of Israel slaughtered the inhabitants of the land that they wanted and took it as a place to live. In a similar situation, Americans of European ancestry killed off the Native American population and forced the survivors to relocate to reservations. The competition for land and resources has sometimes been brutal but humans have thrived as a species through whatever means seemed necessary at the time.

Modern health care, agribusiness and industrial scale animal production have succeeded in extending our lives, feeding our burgeoning population and avoiding famine. They enabled the record-breaking population growth of the 20^th and 21^st centuries but added dangerous chemicals to our food and environment in the process. We ignore warnings about poor air quality and fish that are unsafe to eat. In some places (Beijing for example) the air is often unsafe to breathe and hard to see through. Global warming is creating sea level rise which will make some coastal population centers uninhabitable in the next century. New York, Miami, and New Orleans are endangered along with many coastal cities around the world. Mountain gorillas, tigers and elephants are among those who will not survive in the wild if we continue taking their land for human habitation. There are predictions that future wars are more likely to be fought over scarce clean water than oil.

While US states sue each other for allowing their businesses to create pollution which crosses into other states, advocates of economic development and job growth are winning legislative debates to allow hydraulic fracturing for natural gas and expanded use of coal without holding the energy companies responsible for correcting environmental damage that they cause. 21^st century children born around the world will want modern, high tech lives requiring more jobs and more energy.

There is no one with the power or authority to restrict population growth. That is up to individuals. By all appearances, decisions about consumption of energy and other resources will be much the same. I don’t know who first said that, “When everyone is responsible, no one is responsible.” but that sentence sums up the situation in which we find ourselves. Individuals will decide to create more children and the population will continue to grow.

The idea of collective action to control population may seem as repugnant today as restrictions on water use seemed when they were first suggested. China’s “one child per family” law has been withdrawn. Ideas, such as higher taxes on anyone with more than two children or life-long tax reduction to anyone who undergoes voluntary sterilization are generally dismissed as “extremist” and no “moderate” alternatives are offered. Some of our religions (fundamentalist Islam and traditional Mormonism) teach procreation as a responsibility. The largest Christian denomination (Catholicism) teaches that artificial birth control is morally wrong. They fight against including birth control in foreign aid to poor nations with high birth rates and against including it in health care plans. They are so effective that one of our major political parties (Republican) backs those positions. The prospects for meaningful collective action seem dim.

With improving technology, we can probably continue growing our population for a few more generations before some science-fiction sounding combination of disease, famine and war imposes population control on a hotter planet with less land and bigger oceans. In the meantime we might do well to explore this lesson in humility. Modern humans as a species have existed for about 200,000 years. Dinosaurs lasted over 160,000,000 years. Now all of them are gone. There is little question that the Earth and life will survive. There is less certainty about humanity. No individual needs population control but humanity does. When everyone is responsible, no one is responsible. That leaves considerable doubt as to whether we can last as long as the dinosaurs did. Will humans be victims of our own success or will we evolve enough and care enough to leave a healthy planet for our descendants? We are all responsible.