By Lori Pottinger
The ongoing COP17 climate meeting in Durban, South Africa is themed “saving tomorrow today.” Yet a global dam boom being promoted by dam proponents — including dozens of megadams proposed for Africa’s major rivers — could make a mockery of this vision, by endangering rivers and the ecosystems we all depend on. While we clearly need to reduce our greenhouse gas emissions, a climate-smart energy path doesn’t sacrifice one important natural resource to save another. We need healthy rivers just as urgently as we do a healthy atmosphere.
A new 3-D Google Earth video illustrates three key reasons that large dams are the wrong response to climate change:
- River flows are increasingly unpredictable. Large dams have always been based on the assumption that future stream-flow patterns will mirror those of the past, but this is no longer true. Climate change has begun to significantly and unpredictably change precipitation patterns. More frequent droughts will make many hydropower projects uneconomic. More extreme rainfall will increase the risk of dam failures and catastrophic flood releases.
- Healthy rivers are critical for supporting life on Earth. Big dams make it harder for people and ecosystems downstream of dams to adapt to climate change by reducing water quality and quantity, drying up forests and wetlands, flooding productive land, and destroying fisheries.
- Dam reservoirs emit greenhouse gases. In the tropics, dam reservoirs are a globally significant source of one of the most potent gases, methane. Meanwhile, free-flowing rivers play a crucial role in helping trap carbon.
The Google Earth tour visualizes what we call “hydrodependency” in Africa, where new dams are being built without any analysis of how climate change could affect their economic viability or their safety. Africa cannot afford dried-up reservoirs or dam collapses on top of the already high costs of adapting to a changing climate.
The tour also takes you on a fly-through of the “Roof of the World,” the Himalaya mountain range, where the climate is changing faster than anywhere else. These mountains’ mighty glaciers are the source of many major Asian rivers, and they are melting fast — yet hundreds of dams are planned here.
Dams in glacier-fed river basins are likely to be subject to much higher flows at first. Heavier storms and more frequent floods will jeopardize their safety. So many dams are planned for Himalayan rivers that one dam burst could result in a domino effect of dam failures. This will be followed by drought, as the glaciers dry up. Neither is conducive to a large dam boom.
Finally, the tour takes you to the mighty Amazon, where a contentious dam boom pits indigenous people against a development-hungry government and the Brazilian dam industry. Here, you’ll sink beneath the depths of one of the world’s dirtiest reservoirs, to learn how big dams (especially in the tropics) can be significant sources of greenhouse gases.
There are better solutions. Climate change poses huge challenges and there are no quick fixes. But we cannot sacrifice the planet’s arteries to save its lungs. There are better solutions to solving energy poverty and water management that don’t involve damming the world’s rivers.
For instance, instead of building dirty dams, Brazil could produce half the energy it consumes today by investing in energy efficiency, solar systems, wind turbines, and retrofitting old dams.
In Africa, developing decentralized renewables such as solar, wind and geothermal is a better and faster way to end energy poverty for the millions of Africans who live far away from the grid, and avoids the risk of more failed investments.
Instead of damming the major Himalayan rivers and putting millions of people at risk of dam failures, engineering a more efficient grid in India could save a quarter of the country’s electricity. Decentralized solar and wind systems are a more realistic way to bring electricity to remote mountain communities.
A global dam boom poses huge risks to the natural support systems that we all depend on, and will make it harder for all life on Earth to adapt to a warming world. Instead of damming more of the world’s rivers, it is both possible and practical to develop climate-safe energy and water supply systems that improve lives, share the development wealth, and help us weather the coming storm.
From Huffington Post