I frequently write posts here that are worrying and alarming, so it’s wonderful to be able to share some links and stories that are incredibly heartening and inspiring.
A couple of weeks back, being in London, I attended an Earthwatch-hosted debate at the Royal Geographical Society. The topic was the water crisis, or water crises, that are growing around the world, and the debate invited five people to propose solutions, after which, the audience voted on what they thought was the best one. It was not a format that provided much space for seriousness, but the most impressive and inspiring presentation, was by Simon Maddrell of the NGO Excellent Development, who talked about sand dams (and won the audience vote, which included mine).
I’d never heard of sand dams! I like to think I know about such things, so was simultaneously peeved and delighted to discover this extraordinary story of ecological restoration in Kenya.
A sand dam, it turns out, is a low retaining wall built across a river bed that traps sand and silt in times of flood. The sand and silt, in turn, trap water (up to 60% by volume) which is then accessible to local people, is automatically filtered, begins to restore the water table, and to restore local ecology. People who have had to walk literally days to get water, now have ready access to it again, and rates of intestinal disease decline rapidly. Combined with terracing, tree-planting and the restoration of local vegetation, sand dams can become the centre of whole new micro-climates. In fact, as whole regions start to follow this process, regional climate soon begins to change.
You can view a six-minute video on sand dams and the work of Excellent Development, which has now supported the construction of over 200 sand dams, here on YouTube.
Excellent Development’s echoes the story of the Loess plateau in China, a huge region which has been rendered dry and barren by thousands of years of badly managed subsistence agriculture. A new short film, Hope in a Changing Climate (streamed online), tells this amazing story:
In the Loess Plateau, an area the size of Belgium has been successfully restored over ten years. A barren, brown landscape, denuded and degraded, has been brought back to life; a people entrenched in back-breaking poverty now work, farm, herd and live, in a functioning, green ecosystem where rainfall infiltrates, water is retained and crops are readied for export.
Hope in a Changing Climate not only covers the story in China, but shows how the same techniques have been used to great effect in Rwanda.
The full importance of this kind of restoration is perhaps only emerging now, as we begin to understand how important vegetation forests are to generating the planet’s winds, not least those that pull rain deep into the interiors of continents. In a recent New Scientist article, Fred Pearce writes about an emerging meteorological theory called the biotic pump, postulated by Russian researchers Victor Gorshkov and Anastassia Makarieva of the St Petersburg Nuclear Physics Institute:
The acres upon acres of lush tropical forest in the Amazon and tropical Africa are often referred to as the planet’s lungs. But what if they are also its heart? This is exactly what a couple of meteorologists claim in a controversial new theory that questions our fundamental understanding of what drives the weather. They believe vast forests generate winds that help pump water around the planet.
If correct, the theory would explain how the deep interiors of forested continents get as much rain as the coast, and how most of Australia turned from forest to desert.