Burning fossil fuels isn’t the only way to pour carbon into the atmosphere. In this TED talk, Zimbabwean ecologist Allan Savory explains how desertification – the process of land turning into desert – is an equal if not greater threat to humanity. Across some two thirds of the Earth’s surface, plants are disappearing and soil is degrading. Not only is this causing carbon to leak out of the Earth and into the air, it leaves us with less land for farming and grazing livestock. Desertification contributes to climate change, famine, poverty, social unrest and even outright war.
You may have been told that desertification is caused by large animal populations – especially herds of livestock – overgrazing the land. This is a dangerous half-truth, as Mr Savory learned to his anguish when, in the 1950s, he recommended an elephant cull to stop desertification in part of Africa. The problems worsened, and after years of determined work Mr Savory deduced that large herds of grazing animals were – correctly handled – the solution, not the problem.
Naturally occurring herds are pressured to stay mobile by predators, and because they contaminate grassland with their own droppings, they never linger in one area long enough to overgraze it. Further, they trample grass as they move, flattening it down so that rainwater is retained and the sun’s heat reflected. They’re an integral part of natural processes that enable grass to store moisture and nutrients in arid areas at risk of desertification. Human attempts to influence these processes – such as through controlled fires – have previously been crude, and usually done more harm than good.
However, by adapting planning techniques to account for nature’s complexity, Mr Savory developed his methods of “holistic management”, which aim to replicate these processes through planned herding of livestock. He discusses several encouraging test cases across the world in which he and his colleagues have shared these methods with local farmers; his photographs show that some remarkable turnarounds are achievable, and that it’s even within our power to rescue land that has almost totally desertified. These techniques are low-cost and seem to be very effective. They are already being practised on over 15 million hectares of land across five continents – the possibilities for world hunger, climate change, threatened wildlife and developing economies are tremendously hopeful.
But Mr Savory saves his most astonishing claim for last: climate scientists have calculated that, if we spread these techniques further and employ them on half the world’s grasslands, we can take enough carbon out of our atmosphere to restore our climate to its pre-industrial state.
The full twenty-minute talk goes into much more detail about the causes of desertification, how it contributes to climate change and why holistic management is our best and probably only hope at undoing it. It’s well worth listening to, if only to be cheered by the argument that this is one climate problem we may be able to solve.
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