Ecological footprint

The world population is closing in on seven billion, so it may be surprising to learn that our species, Homo sapiens, almost became extinct at one time in the past.

Our species came about shortly before 195,000 years ago, at a time when the African climate was mild and there was plenty of food. At its highest, the population of Homo sapiens at the time consisted of about 10,000 breeding people. This did not include Neanderthals, who lived in Eurasia.

By 195,000 years ago, the planet started a glacial stage known by geologists as the Marine Isotope Stage 6 (MIS6), a stage that would only end about 72,000 years later, or 123,000 years ago. During that time, as the climate grew colder and more arid, and deserts we know of today were probably even larger, most of Africa would have been uninhabitable. During this time, the number of Homo sapiens went from 10,000 people to just hundreds. (Again, this did not include Neanderthals, whose population seems to have remained stable.) This means all people alive today are the descendants of a group which was lucky enough to find a milder part of Africa in which to survive.

It’s therefore ironic that our species eventually came to have such a negative effect on so many other species in the millennia that followed. A TV show called Découverte on Radio-Canada (the French CBC) recently explored the sixth major extinction of Earth’s natural history. Unlike the others which were caused by natural phenomena, this one is caused by human activity.

According to recent research, a certain species of caribou in Quebec avoids anything that smacks of human activity to the point of refusing to even cross logging roads. Imagine what happens when the caribou habitat is affected by clear-cutting.

In various parts of the world, scientists are working to identify new species as quickly as possible in order to better know whether their eventual extinction is caused by human activity. One of the scientists spoke of the homogenization of species around the world. Just like music and news that become the same in all countries, we may one day see only species adapted to human presence, as the others will all be gone.

It’s not that humanity doesn’t follow its conscience. Instead, we must recognise that after only about two hundred thousand years of existence, our species has reached a stage of development that disturbs the natural balance of the entire planet. For years, our species had to constantly struggle against the onslaughts of nature with few defences, little natural strength, and virtually nonexistent technology. Our intelligence, the only special weapon at our disposal, was not always enough.

Over time, we have made remarkable progress and discoveries that have allowed us to overcome diseases that were once deadly, and in many cases, put an end to repeated famines. Mortality rates today are significantly lower than in the 19th century. Today, we no longer die of old age at 40.

These advances occurred in a wink of geologic time, and nature can only compensate partially and slowly. When a natural balance can’t be restored, nature seeks a new equilibrium. However, we have long thumbed our collective nose at nature, always trying to deceive and defeat. Our presence in larger and larger numbers on the planet has already led to negative consequences for biodiversity.

Life has always managed to bounce back after major extinctions. Will it do so again this time?