Monday, 13 March 2006

Gaia in Africa

I have always liked the concept of Gaia Theory. It is relatively simple, and does explain a lot of what we observe in the natural world. And while snoozing on a train back from London last week, I was wondering how the impact of human populations could be explained using Gaia Theory. This in turn led me to think about the problems of Africa, and the way aid agencies were using goats, cows and other livestock to solve the problems of poverty and human suffering.

So I gathered some very simple statistics. The human populations of Africa, the cattle population and the goat populations. I got om to the FAO website and garnered data for 1961 and compared it with 2000. Pretty scary stuff. The human population leapt from 284 million to over 795 million, and similar increases occurred in all the livestock figures, viz cattle jumped from 122 million to 224 million, sheep and goats from 229 million to 451 million, camels doubled from 8 million to nearly 16 million, buffaloes from 1.5 million to 3.3 million and there were similar increases in all other livestock such as geese, chickens and ducks.

Gaia Theory assumes that the total biomass is more or less constant, and the increase in human and related livestock biomass has increased, and will therefore incur an equivalent loss from the ecosystem, probably of wildlife. The human biomass alone (assuming an average weight of 50kgs per person), will have increased by about 26 million tonnes. In the same period the biomass of cattle has risen by som 20 million tonnes, sheep and goats by 6 million tonnes. Taking these figures alone, it is an increase in mammalian biomass of at least 52 million tonnes. This represents nearly 9 million elephants -- or over a billion antelopes.

Now there's some food for thought. And we are still encouraging more livestock in Africa, and the human population is, to use a hackneyed phrase, a time bomb of which the fuse has been lit. Without the aid agencies putting more effort into controlling female fertility, wars, famine and disease are the only certainty for much of Africa. But a quick search of websites for information on what the big aid charities are doing to control female fertility, or subjects such as "population growth" reveal very few mentions at all. Worrying.

1 comment:

  1. "Controlling female fertility" sounds as if you are putting the onus of population control on women, which may make you unpopular. Perhaps you should use the definition of fertility as the ratio of livebirths to total population, e.g.per 1000 per year.

    I wonder if some of the compensatory decrease in biomass is seen in the loss of antarctic krill and the serious reduction in some penguin species. But the ups and downs of antarctic populations are not straightforward. The devastation of fish populations around the world could be added to your equation