Earth’s biosphere is amazingly resilient. Nature has worked out a multitude of checks and balances that stabilize the environment and protect it from excesses, including changes in climate, population, and availability of food. If a change occurs, for instance an increase in solar energy reaching the earth, the earth will warm up a bit, plankton in the sea and green plants on land start pulling more carbon dioxide from the atmosphere and replacing it with oxygen, thus reducing the greenhouse effect and cooling the Earth. If the temperature keeps rising, however, the negative feedback loops [represented by the plankton in the ocean and greenery on land] will eventually cease to absorb atmospheric carbon dioxide. The biosphere will no longer be able to compensate for the rising temperatures.
There is a possibility that higher temperatures will change the makeup of the biosphere so that it will reach a stable state, much in the way strange attractors form in a dynamic system. The problem with having a stable state at a significantly higher temperature is that it will probably render the biosphere unfit for human habitation.
Suppose that the average temperature of the Earth rises 10° Fahrenheit from its base level and then stabilizes. The sea will rise until all the ice melts, and then start falling, as it will be evaporating at a higher rate.
Water vapor is a greenhouse gas, an increase of which increases the heat retention of the atmosphere. At some point the oxygen-liberating plankton In the oceans will quit doing their job, so that the CO2 level in the atmosphere rises.
Some plants will survive, but it Is likely that new species will evolve to accommodate to the changed environment. Some of the plants will be nasty. Plants, especially food plants raised in traditional environments, will likely die off or evolve in such a way that they can no longer serve as a principal source of food for humans. Perhaps new plants will evolve as substitutes, but that is uncertain.
The tropics will become uninhabitable. Millions of refugees will migrate in desperation into what are now called the temperate and frigid zones. That will lead to fierce conflict between refugees and natives, especially after the food supply diminishes in the temperate zones. A substantial part of the world’s population will die from either starvation or war.
There is no assurance that a society stressed beyond its limits will not resort to nuclear weapons.
Until recently, I have been optimistic about humanity’s ability to put its environmental house in order, but with the Trump administration and the substantial following that has supported Trump no matter what he says and what he does, I am not quite so optimistic.
We live in apocalyptic times. Societies constellate apocalyptic archetypes but usually emerge from them, transformed into a radically different civilization. During the apocalyptic phase there are upheavals and general disorder. A large part of the human race will be seized by a destructive madness.
The poet Yeats summed it up:
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity.
We are in the middle of apocalyptic times. The difference this time around is that we have the power to end humankind. A narcissistic fool has become the most powerful human being on Earth with his finger on the nuclear button. He is being either served or humored by a legislature that, having taken over the government, has become a wrecking crew, destroying or dismembering public institutions painstakingly built over 200 years by dedicated statesmen working for the common good.
It appears that no branch of the government, legislative, executive or judicial has any long-range plans for the future. Their absence of concern for climate change, nuclear war, pollution and extinction of species will, if it continues, destroy us in the not too distant future. This is a form of madness, especially among the misguided citizens that support the present regime.
The dangers that now confront the entire World can be ameliorated only by concerted action by all the nations of the World. Sadly, the United States has turned out to be the most uncooperative nation of all. If we are lucky, we will emerge from this convulsion before the biosphere has reached the point of no return, that we will have not waged war with nuclear weapons, and that we will have gained a modicum of respect for the Earth, our island home.
But don’t bet on it. Our capacity for self-delusion has no limits.