Sleepwalking To Extinction

The nations of the world have been meeting in Bonn trying to map out a strategy for dealing with climate change. But we face another crisis -- which, in itself, is related to climate change. William Rees writes:

Biodiversity loss may turn out to be the sleeper issue of the century. It is caused by many individual but interacting factors — habitat loss, climate change, intensive pesticide use and various forms of industrial pollution, for example, suppress both insect and bird populations. But the overall driver is what an ecologist might call the “competitive displacement” of non-human life by the inexorable growth of the human enterprise. 

On a finite planet where millions of species share the same space and depend on the same finite products of photosynthesis, the continuous expansion of one species necessarily drives the contraction and extinction of others. (Politicians take note — there is always a conflict between human population/economic expansion and “protection of the environment.”)

We are the dominant species -- and we have been crowding out all the others:

Competitive displacement has been going on for a long time. Scientists estimate that at the dawn of agriculture 10,000 years ago, H. sapiens comprised less than one per cent of the total weight of mammals on the planet. (There were probably only two to four million people on Earth at the time.) Since then, humans have grown to represent 35 per cent of a much larger total biomass; toss in domestic pets and livestock, and human domination of the world’s mammalian biomass rises to 98.5 per cent! 

One needs look no further to explain why wildlife populations globally have plunged by nearly 60 per cent in the past half century. Wild tigers have been driven from 93 per cent of their historic range and are down to fewer than 4,000 individuals globally; the population of African elephants has imploded by as much as 95 per cent to only 500,000 today; poaching drove black rhino numbers from an already much reduced 70,000 in 1960 to only 2,500 individuals in the early 1990s. (With intense conservation effort, they have since rebounded to about 5,000). And those who still think Canada is still a mostly pristine and under-populated wilderness should think again — half the wildlife species regularly monitored in this country are in decline, with an average population drop of 83 per cent since 1970. Did I mention that B.C.’s southern resident killer whale population is down to only 76 animals? That’s in part because human fishers have displaced the orcas from their favoured food, Chinook salmon, even as we simultaneously displace the salmon from their spawning streams through hydro dams, pollution and urbanization.

We have adopted the mantra of exponential growth. It has become our measure of success. But consider:

The past two centuries of exponential growth greatly have accelerated the pace of change. It took all of human history — let’s say 200,000 years — for our population to reach one billion in the early 1800s, but only 200 years, 1/1000th as much time, to hit today’s 7.6 billion! Meanwhile, material demand on the planet has ballooned even more — global GDP has increased by over 100-fold since 1800; average per capita incomes by a factor of 13. (rising to 25-fold in the richest countries). Consumption has exploded accordingly — half the fossil fuels and many other resources ever used by humans have been consumed in just the past 40 years. 

All of this is unsustainable. But we continue to follow the same old patterns -- sleepwalking to extinction.

Image:  USA Today