The idea behind controlling waterways through dams isn’t new. The oldest dam in the world, the Kallanai Dam, began operation on the Kaveri River in Tamil Nadu, India in the 2nd century, and it’s still in use today.
Ancient engineers who built these dams did so to control the floodplains and irrigate land for agriculture and also began using them to generate power for milling. Today, we see dams as a source of clean, renewable energy that can wean nations off of a reliance on fossil fuels from far-flung countries and even generate new revenue for nations with the right resources. Switching to renewable energy elsewhere can also offset the footprint produced by air travel, which in many cases has no viable clean alternative.
However, even hydropower has hidden costs that leave it open to criticism and even present danger for both people and species living in around dammed areas. What is the danger of dams? As it turns out, it could be everything.
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Dam Reservoirs Emit Gases More Powerful than CO2
Energy production comes from three major sources: fossil fuels, nuclear energy, and renewable energy. The issues surrounding the use of fossils fuels are well known: they are finite resources with an elastic price that wreak havoc on the planet.
As an alternative to fossil fuels, hydropower is still vastly superior in terms of reliability and affordability. However, it’s not perfect – and worse, it may even be damaging to any climate change reversal efforts. Research from Washington State University found that while the dams generate power, the reservoirs are problematic because they produce more methane per unit area than one might think.
The figures don’t sound catastrophic. Measurements of the reservoir methane bubbles suggested a methane release rate around 25 percent higher than expected. However, the problem lies in that methane is 30 times more potent than carbon dioxide, which means a little goes a long way. Plus, when you consider the rate at which nations build hydropower dams and the size of these new dams and reservoirs (such as the Belo Monte Dam in Brazil), it’s possible to see how a little methane can snowball into a big problem.
Dams Are Bad for Ecology
Not just any dam can become a viable source of hydropower. Often, builders rely on huge dams that can not only power vast regions but produce enough energy to store and then sell at a profit. However, as dams grow, they become more detrimental to the fragile ecosystems around them.
Large-scale dams result in a change in both the speed of the flow and the temperature of the river water, which contributes to the extinction of many aquatic species as well as a huge loss of the surrounding habitats (forests, wetlands, and farmlands). For example, dams in the Pacific Northwest are threatening over 13 species of salmon (a keystone species), which in turn threatens the rest of the local fauna fed by those fish.
These impacts on ecosystems are bad enough, but they also often modify the landscape to the extent that people living in the area need to make difficult choices about whether to stay or leave. In many cases, those people are also poor and marginalized members of the nation, which makes the decision even more complicated. Turkey’s Ilısu dam project at Hasankeyf threatens to submerge a 12,000-year-old village and force at least the 3,000 residents of the closest area out of their homes and villages.
Dams Don’t Help Emerging Economies Either
There was a belief in the early 20th century that suggested large dams were the ticket to prosperity in developing countries. Countries in South America, the Middle East, and Africa built huge dams with dreams turning their power into riches.
Research from Oxford found that out of the 245 large dams built in the years since 1934, all had an average cost overrun of 90 percent. In Brazil, the Itaipu dam (one of the seven wonders of the modern world) cost 240 percent more than projected and damaged the country’s finances for three years.
The problem is that these projects are still underway. Countries are sinking huge amounts of capital to produce electricity, but dams like Itapiu will never pay back the costs needed to build it – and these are only financial and don’t consider the ecological price described above.
What’s Next for Clean Energy if Not Dams?
As it turns out, dams are a better idea on paper than they are in practice. The mega-dams built around the world are particularly destructive for the environment and typically fail to bring about enough economic change to justify them. So what is to be done if dams aren’t the way forward?
Individuals and businesses can make themselves more aware of their carbon footprint with the recognition that all energy sources have some impact on the environment. But we should also remember that alternatives to hydropower do exist: we still have solar, wind, and biomass. Other types of hydropower are also still available that don’t rely on damming or impact the river’s flow.
In other words, there’s more work to do in relation to reversing climate change that doesn’t involve damming. It can be – we just need to change our mindsets.