
By Tim Radford
What's considered by some to be clean energy could devastate the Amazon, according to new research. A massive increase in hydropower from a series of planned Amazon dams could harm the world's most important rainforest all the way from the slopes of the Andes to the Atlantic Ocean.
Altogether, 428 dams are being built or are under consideration along the network of rivers that drain—and nourish—6 million square kilometers of forest spanning nine countries. Of these, around 140 are already finished or under construction.
The Amazon is home to four of the world's 10 largest rivers. Of the 34 largest tropical rivers, 20 are in the Amazon region, and these rivers are the source of one fifth of the planet's fresh water.
That same flow delivers the nutrient-rich sediments to habitats downstream to support the teeming life of the region, including the canopy that shelters its shrubs, plants, insects, reptiles, amphibians, mammals and birds.
Widespread Benefits
Those rivers exchange sediments and nourish a mosaic of wetlands, said Edgardo Latrubesse, a geographer at the University of Texas at Austin, who led a collaboration from 10 universities to assess the potential environmental damage, and report in the journal Nature.
"People say: 'Oh another dam, another river.' It's not. It's the Amazon," Prof. Latrubesse said. "We have to put the risks on the table and change the way people are looking at the problem. We are massively destroying our natural resources, and time urges us to find some rational alternatives for preservation and sustainable development."
Dams conserve water, deliver irrigation in the dry season, reduce the threat of flooding and of course provide energy for hydropower. On the other hand, they impose an environmental cost: Sediments vital downstream are trapped upriver and the floods they might prevent are an integral part of the forest's long-term stability.
So dams come at a price not normally measured in economic cost-benefit analyses, but they can change a river system and damage an economy all the same.
The researchers first devised what they called a Dam Environmental Vulnerability Index, assessing the vulnerability to land use change, erosion, run-off pollution, trapped sediment and other changes to river systems, to test the real value of the 140 dams already happening and the ones still under consideration.
Many of the dams are in areas that yield heavy loads of sediment: the Andean Cordillera, for instance, provides more than 90 percent of the silt to the entire river system. The Marañon and Ucayali rivers are or will be home to 104 and 47 dams respectively.
Up to 80 percent of the area upstream of the lowest-planned dam will be vulnerable: dams will change river dynamics, to alter the pattern of creation of oxbow lakes and floodplain sediment storage, putting thousands of species at risk.
The Madeira River drains waters rich in sediments from Bolivia and Peru and has the most diverse fish population. Two huge dams have already led to a 20 percent fall in sediment concentration in the Madeira, and 25 dams are planned further upstream.
Indivisible
"The Amazon is the most important river basin on the planet. It's a microcosm of our issues of today involving environment, energy and health of the planet," said Victor Baker, a hydrologist at the University of Arizona, and one of the authors.
"The river and its individual pieces cannot be separated out. That an individual dam assessment can be separated from the rest of the system isn't scientifically valid."
And collectively, the authors close their study with a warning: "Citizens of the Amazon Basin countries will ultimately have to decide whether hydropower generation is worth the price of causing profound damage to the most diverse and productive river system in the world.
"If those decisions are made within the context of a comprehensive understanding of the fluvial system as a whole, the many benefits the rivers provide to humans and the environment could be retained."
Reposted with permission from our media associate Climate News Network.
- Redwoods are the world's tallest trees.
- Now scientists have discovered they are even bigger than we thought.
- Using laser technology they map the 80-meter giants.
- Trees are a key plank in the fight against climate change.
They are among the largest trees in the world, descendants of forests where dinosaurs roamed.
Pixabay / Simi Luft
<p><span>Until recently, measuring these trees meant scaling their 80 meter high trunks with a tape measure. Now, a team of scientists from University College London and the University of Maryland uses advanced laser scanning, to create 3D maps and calculate the total mass.</span></p><p>The results are striking: suggesting the trees <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">may be as much as 30% larger than earlier measurements suggested.</a> Part of that could be due to the additional trunks the Redwoods can grow as they age, <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">a process known as reiteration</a>.</p>New 3D measurements of large redwood trees for biomass and structure. Nature / UCL
<p>Measuring the trees more accurately is important because carbon capture will probably play a key role in the battle against climate change. Forest <a href="https://www.wri.org/blog/2020/09/carbon-sequestration-natural-forest-regrowth" target="_blank">growth could absorb billions of tons</a> of carbon dioxide from the atmosphere each year.</p><p>"The importance of big trees is widely-recognised in terms of carbon storage, demographics and impact on their surrounding ecosystems," the authors wrote<a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank"> in the journal Nature</a>. "Unfortunately the importance of big trees is in direct proportion to the difficulty of measuring them."</p><p>Redwoods are so long lived because of their ability to <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">cope with climate change, resist disease and even survive fire damage</a>, the scientists say. Almost a fifth of their volume may be bark, which helps protect them.</p>Carbon Capture Champions
<p><span>Earlier research by scientists at Humboldt University and the University of Washington found that </span><a href="https://www.sciencedirect.com/science/article/pii/S0378112716302584" target="_blank" rel="noopener noreferrer">Redwood forests store almost 2,600 tonnes of carbon per hectare</a><span>, their bark alone containing more carbon than any other neighboring species.</span></p><p>While the importance of trees in fighting climate change is widely accepted, not all species enjoy the same protection as California's coastal Redwoods. In 2019 the world lost the equivalent of <a href="https://www.worldwildlife.org/threats/deforestation-and-forest-degradation" target="_blank" rel="noopener noreferrer">30 soccer fields of forest cover every minute</a>, due to agricultural expansion, logging and fires, according to The Worldwide Fund for Nature (WWF).</p>Pixabay
<p>Although <a href="https://c402277.ssl.cf1.rackcdn.com/publications/1420/files/original/Deforestation_fronts_-_drivers_and_responses_in_a_changing_world_-_full_report_%281%29.pdf?1610810475" target="_blank" rel="noopener noreferrer">the rate of loss is reported to have slowed in recent years</a>, reforesting the world to help stem climate change is a massive task.</p><p><span>That's why the World Economic Forum launched the Trillion Trees Challenge (</span><a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a><span>) and is engaging organizations and individuals across the globe through its </span><a href="https://uplink.weforum.org/uplink/s/uplink-issue/a002o00000vOf09AAC/trillion-trees" target="_blank" rel="noopener noreferrer">Uplink innovation crowdsourcing platform</a><span> to support the project.</span></p><p>That's backed up by research led by ETH Zurich/Crowther Lab showing there's potential to restore tree coverage across 2.2 billion acres of degraded land.</p><p>"Forests are critical to the health of the planet," according to <a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a>. "They sequester carbon, regulate global temperatures and freshwater flows, recharge groundwater, anchor fertile soil and act as flood barriers."</p><p><em data-redactor-tag="em" data-verified="redactor">Reposted with permission from the </em><span><em data-redactor-tag="em" data-verified="redactor"><a href="https://www.weforum.org/agenda/2021/03/redwoods-store-more-co2-and-are-more-enormous-than-we-thought/" target="_blank">World Economic Forum</a>.</em></span></p>EcoWatch Daily Newsletter
- Offshore Wind Power Is Ready to Boom. Here's What That Means for ... ›
- American Skyscrapers Kill an Estimated 600 Million Migratory Birds ... ›
Trending
Kentucky is coping with historic flooding after a weekend of record-breaking rainfall, enduring water rescues, evacuations and emergency declarations.
<div id="0f31c" class="rm-shortcode" data-rm-shortcode-id="4290ab3e7ec4e142f8bce774bab39f03"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1366307788155219969" data-partner="rebelmouse"><div style="margin:1em 0">Just got back from my office... downtown Beattyville Kentucky is not a pretty sight. @KySportsRadio… https://t.co/6nXwyMKtRb</div> — Tom Jones (@Tom Jones)<a href="https://twitter.com/8atticus/statuses/1366307788155219969">1614588136.0</a></blockquote></div>
<div class="rm-shortcode" data-rm-shortcode-id="b41a2da6bf23cc19a5f38c2dc6c5f9fc"><div class="fb-post" data-href="https://www.facebook.com/dekalbtnfire/photos/a.924258171004562/3713119618785056/"></div></div>
Spring is coming. And soon, tree swallows will start building nests. But as the climate changes, the birds are nesting earlier in the spring.
- Spring Is Arriving Earlier Across the U.S. - EcoWatch ›
- Climate Change Leading to Fatal Bird Conflicts - EcoWatch ›
- The Unsettling Reason Why We're Seeing More Snowy Owls ... ›
Citigroup will strive to reach net-zero greenhouse gas pollution across its lending portfolio by 2050 and in its own operations by 2030, the investment group announced Monday.
- 20 Attorneys General Launch Climate Fraud Investigation of Exxon ... ›
- Exxon Plans to Increase Its Climate Pollution - EcoWatch ›
- Exxon to Slash 14,000 Jobs Worldwide as Oil Demand Drops ... ›