The TRUE Costs of Damming Our Rivers | Earth Explained!

Summary

This video delves into the environmental impact of hydropower, highlighting how dams, often seen as a green solution, disrupt ecosystems and wildlife. While hydropower provides 22% of the world's electricity, it has significant negative effects on river ecosystems, from fish migration challenges to greenhouse gas emissions. With many of the world's last free-flowing rivers already dammed, the video emphasizes the need for smarter, more sustainable energy strategies and the importance of balancing energy needs with ecosystem conservation. It also showcases efforts to remove outdated dams and rehabilitate affected habitats.

Takeaways

• 😀 Hydropower is often seen as a green energy solution, but it significantly harms the environment by disrupting river ecosystems and wildlife habitats.
• 🌍 There are currently around 60,000 large dams worldwide, with 3,700 more planned or under construction, including many in protected areas.
• 💧 Dams block the natural flow of rivers, preventing fish migration and causing habitat destruction, which affects biodiversity.
• 🐟 Fish ladders, designed to help fish migrate past dams, are often ineffective due to poor design or being unsuitable for different species.
• 🌱 Dams emit greenhouse gases, such as carbon dioxide and methane, when organic matter in reservoirs decomposes, especially in warmer climates.
• ⚠️ Despite being considered renewable, hydropower contributes to greenhouse gas emissions, with some dams being more carbon-intensive than coal plants.
• 📉 Freshwater species have declined by 83% since 1970 due to the negative impacts of dams on ecosystems and fish populations.
• 🔋 A broader strategy for energy is needed, involving a mix of solar, wind, and storage technologies alongside hydropower.
• 🔧 Upgrading and retrofitting existing dams instead of building new ones, along with optimizing fish passage systems, could reduce environmental harm.
• 🌊 Some regions, like the Elwha River in Washington state, have seen ecological recovery after the removal of outdated dams, with fish populations increasing.
• 🌍 Collaboration between environmental groups and the hydropower industry is underway to reduce the environmental damage caused by dams and remove older, unnecessary ones.

Q & A

What is the main environmental concern with hydropower?

The main environmental concern with hydropower is that it disrupts free-flowing rivers, which are crucial for wildlife, ecosystems, and water quality. Dams obstruct fish migration, degrade habitats, and emit greenhouse gases from decaying organic matter in reservoirs.

Why are free-flowing rivers important for ecosystems?

Free-flowing rivers are essential because they support wildlife, including migratory fish species, maintain natural sediment movement, refresh groundwater, and deliver nutrients to surrounding habitats. They are integral for ecological balance and biodiversity.

How many dams are currently in operation worldwide, and how many more are planned?

There are about 60,000 large dams worldwide, with 3,700 more planned or under construction, including over 500 in protected areas.

How does hydropower impact fish populations?

Hydropower impacts fish populations by blocking migration routes, preventing fish from reaching spawning grounds. This leads to drastically reduced fish populations. Fish ladders are commonly used to address this, but they often do not work well, especially for certain species.

What are fish ladders, and do they work effectively?

Fish ladders are stepped pools that help fish migrate past dams. However, they are not always effective, as they may be too steep or small to support large migrations, and they don't work for all species, such as eels, which cannot jump.

How do dams contribute to greenhouse gas emissions?

Dams contribute to greenhouse gas emissions through the decomposition of organic material, like dead plants and trees, submerged by reservoirs. This process releases carbon dioxide and methane, two major greenhouse gases, into the atmosphere.

What percentage of global greenhouse gas emissions come from reservoirs in dams?

Reservoirs in dams account for 1.3% of the total annual global greenhouse gas emissions caused by human activities.

Why is hydropower considered 'dirty' despite being renewable?

Hydropower is considered 'dirty' because, while it is renewable, it disrupts ecosystems, emits greenhouse gases from decaying organic matter, and leads to the destruction of habitats and farmland due to damming rivers.

What is being done to reduce the environmental impact of dams in the U.S.?

In the U.S., there has been an agreement between environmental groups and the hydropower industry to reduce the environmental harm caused by dams. This includes removing outdated dams, retrofitting existing ones, and improving fish passage systems.

What is the potential future for dam removal in the U.S.?

It is expected that between 4,000 and 36,000 dams may be removed in the U.S. by 2050, as more dams are taken down to restore free-flowing rivers, which can lead to recovery in fish populations and improved ecosystems.