The Humpty-Dumpty Problem
The Changes to Come
When a raw egg is dropped and falls to the floor, it cracks open and its contents are spilled. But as we learned from reading fairy tales, "all the king's horses and all the king's men cannot put Humpty-Dumpty together again." The message to be taken from this: changes wrought are not necessarily reversible. The classic irreversible event is extinction, a fact often advertised by the bumper sticker that says, "Extinction is Forever."
Among the most intriguing objects of human (pre-)history are the drawings of extinct animals found in caves in Spain and France. Among these are furry elephants and rhinoceros, and many other large mammals once hunted in Eurasia. Cave bear, hyena and sabertooth tigers coexisted with these giants and died out at roughly the same time. These extensive and rather recent extinctions also occurred in North America, where camels, horses, elephants, giant bears, sloths, and lions thrived not so long ago (their remains can be inspected in Los Angeles, at the Rancho La Brea Park). These extinctions are interesting for at least two reasons: (1) human impact is thought to be largely responsible and (2) the ecology of the present-day steppe landscapes of North America and Eurasia cannot be understood unless we realize that all the big grazing animals are missing. The plants living there now co-evolved with animals that no longer exist.
It is unlikely that the hunters of the late stone age were aware that the comparatively rapid advances in their hunting techniques, together with abrupt climate change, were wiping out their prey at rates unprecedented in human existence. They performed their hunting and fertility magic, and their wise men assured them that the spirits are taking care of renewing the herds they helped to decimate. They lived in an imaginary world, but it worked just fine — their offspring spread throughout Eurasia and throughout the Americas while extinction, hardly noticed, proceeded at a furious pace. Ever since, accelerated extinction has been with us, as people settled over all the world’s regions and fished the world’s oceans.
Climate Change and Extinction
The effect of global warming, it may be safely assumed, will be to accelerate the process of extinction. The reason is that plants (and therefore the animals that depend on the plants) are adapted to a certain range of conditions for their growth and reproduction. For example, a plant in temperate latitudes is genetically programmed so that it “knows” frost will come when the days become shorter. Thus, sometime in fall, a deciduous tree will shut down and shed its leaves, preventing the frost from freezing the sap in the tree and damaging it. However, more opportunistic plants with a higher tolerance for risk, like brush, will not shut down in fall but wait until it gets cold. These plants, in a situation of warming, will win the battle for sunlight which plants commonly wage. The deciduous trees will make room for brush since trees walk but slowly. Although such a local extinction can be reversed in principle, a sufficient number of local extinctions will add up to global extinction.
Climate Change Optimists
Not everyone agrees that there is a problem. On the contrary,
celebrating the arrival of the 6 billionth human, the Wall Street Journal (Oct 1999) opines, in an editorial entitled “The More the Merrier:” “By almost any measure — life expectancy, calorie consumption, education, housing, etc. — the world is better off than it has ever been.” The Wall Street Journal, even more upbeat than usual (perhaps buoyed at the time by a seemingly endless bull market) reminds us that each new baby comes with not only a mouth but a mind. A mind, that is, to be engaged in creating new wealth. An accompanying essay ("Six Billion Reasons to Cheer") assures us that "the gap between the rich and the poor has never been so small" in terms of life expectancy, and that "the fuel of modern economic development is human — rather than natural — resources." Like that of the stone age shamans assuring their people that everything is under control, the world of the writers of those editorials is an imaginary one, based on wishful thinking. Mantras and magic will do nothing to solve the problems that will come with overpopulation and the overuse of resources.