If it becomes clear that the planet cannot support all of us as resources begin to be in short supply, we may imagine some of the diverse responses of people and governments. For many people, hardship brings out our noblest altruistic nature. For others, there will be food fights and resource wars. Me, my and mine. Governments have already offered us hints about the lengths to which they are willing to go to "preserve order" in a crisis.
Healthy, caring and progressive human minds do better not to think about such things, as their contemplation can make us feel helpless and drag us into depression. Joanna Macy has devoted her career to helping us keep our sanity as we advocate for peace and environmental sanity.
Latency
Chemists call it "latency". Physicists say "hysteresis". Ecologists speak of "delayed functional response". The meaning is that systems have an inertia that keeps them looking the same for awhile, even after everything, everything has changed. You can slowly raise the temperature of a glass of water until it's 10o above boiling, and it looks like a calm liquid, not a bubble in sight. But then touch it or disturb it or drop in a grain of sand and the water explodes. (People have been scalded taking a superheated cup of coffee out of the microwave.)
And so may it be with species extinctions. The producer species have not been keeping pace with consumption for quite some time, but the consumer species goes on, apparently thriving, continuing to increase in number, though they may notice it is a little more difficult than usual to forage the evening meal. By the time the predators realize that something is awry, the game is played out and long past over. There's no road home.
The reason can be explained in terms of exponential mathematics: a depleted prey population grows very slowly, even as the predator population is at maximum demand. Or intuition tells us the same thing: when food becomes scarce, the predators step up their hunt effort and do their best to maintain their quality of life (and their fertility) until food becomes so scarce that it is too late. The prey species, if not extinct, is at such a low level that it will take a long time to recover, long enough for most of the predators to starve. The earth's ocean ecologies have already been transformed beyond recognition by industrial-scale fishing methods.
In 1944, the US Coast Guard introduced 29 reindeer on the island of St Matthew off Alaska. There had been no large mammals on the island before, and no natural predators. It was an experiment to see if a hunting preserve could be established. The reindeer population grew steadily at about 30% per year, first surpassing the number the island could support sustainably in about 1958. That was about 2,000 animals. But by 1963, inertia carried the population over 6,000. The next winter was rather harsh, not extraordinary, but enough to devastate the over-extended population. When wildlife wardens landed on the island the following spring, 42 reindeer remained alive [read more].
The Sixth Extinction
Between the advent of multicellular life and the current era, there have been five major extinction events, in which between 30% and 80% of all extant species vanished on a timescale shorter than can be resolved in archaeological records. These were spread over 500 million years. We are now in the midst of the Sixth Extinction, sometimes called the Anthropocene Extinction, and it is estimated that there is already sufficient inertia in the process to insure that a substantial fraction all extant species will perish in ensuing decades, no matter what conservation efforts are undertaken, and no matter what future direction is taken by human civilization.
In 2002, world leaders represented at the Convention on Biological Diversity committed to a program targeting a significant decline in the rate of species extinction by 2010. It was assumed at the time that conservation measures at the fringe of the mainstream economy would be adequate to achieve this end. But by 2010, it was clear that this program had failed dramatically, and that the loss of biodiversity is essentially linked to the core character of human economy.
I have explained in previous blog posts my belief that ecosystems are highly co-evolved for stability. Large-scale. complex ecosystems have the property of being highly interdependent, and redundant, which creates a resistance to small disruptions. The same structure also creates a vulnerability to large disruptions. There is a "domino effect": Once a threshold of loss is exceeded, the entire system becomes vulnerable to collapse. It is theorized that most of the species lost in the previous five extinctions succumbed to this sort of "collateral damage".
Other existential threats
Ecosystem collapse is not the only way in which human civilization might inadvertently engineer its own demise. Microbial epidemics are made more probable by overuse and abuse of antibiotics. There is an indirect threat from diseases or insect infestations that could devastate agricultural productivity. Our increasing dependence on monoculture, not to mention genetically modified clones, greatly increases vulnerability
There are biological weapons laboratories that are intentionally breeding bacteria for virulence and facility of transmission, and any one of these could escape into the human environment by accident, or could be released by a crazed individual, or by a nefarious conspiracy.
The Global Economy relies on a complex, integrated and multiply-redundant system, feeding humanity's necessities, and also pandering to our appetite for luxuries. It's all very efficient while it works, but if the global system of trade and transportation of goods should ever collapse, we no longer know how to take care of ourselves with local resources.
Nuclear holocaust is the quickest and most terrifying threat to life on earth, and for most people, is the first such that comes to mind. Even after having pulled back from the escalating competitiono of the Cold War, the United States and Russia still retain arsenals of nuclear-tipped missiles sufficient to destroy the world many times over.
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