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The Myth of Clean Hydro: Dams and Reservoirs Emit Greenhouse Gases and Make Climate Change Worse

“Nothing strengthens authority so much as silence.” — Leonardo da Vinci

by Gary Wockner, June 2021

Over the last several years, I’ve started writing and speaking about an important component of the argument against dams – perhaps the most important of all – that dams and reservoirs make climate change worse. Hundreds of big dams are being constructed across the planet and thousands more are planned, all under the auspices that hydropower dams are “clean energy”. This false, anti-science story is being pushed forward by international governments – including the U.S. – to fast-track dam construction on some of the wildest and most pristine rivers on the planet.

But the science tells a different story.

Over the last ten years, the science has shifted dramatically, indicating that a large percentage of dams and reservoirs – most of which were built for hydropower – are emitting carbon dioxide and methane, and some of those emissions can be very large. In some cases, especially in tropical environments, hydropower dams emit two or three times as much greenhouse gases as coal-fired powerplants producing an equivalent amount of electricity. This new science has created an intense furrow in the river-protection and climate-change movements – for NGOs, governments, banks, and the hydropower industry.

The United States as well as the United Nations has been slow or even recalcitrant to walk-back their support of “clean energy” hydropower even though the science has shifted. Over the same last ten years, the Intergovernmental Panel on Climate Change (IPCC) and its COP 21 negotiations have unfortunately further solidified the concept that hydropower is clean energy and are promoting the construction of more massive dams across the planet. Even worse, the World Bank and other international lenders are trying to ramp up their funding for more dams, all under the guise of “clean energy” and the COP 21 agreement.

Maybe worst of all, the dam-building hydropower industry has turned out to be an extreme political force – they are rabidly greenwashing their environmental damage, outright lying about the greenhouse gas emissions from their electricity production, and working to make sure that not only decision-makers and the public are misinformed but also that anti-dam activist are marginalized, threatened, or worse.

In the text and images below, I first lay out the history of the science about how dams and reservoirs emit greenhouse gases and especially methane. It turns out this science is not new at all, but has been around for at least twenty-five years. Second, I discuss the problems with the current Kyoto Protocol that was enshrined by COP 21, as well as a positive movement forward to change in the Protocol so that it more accurately accounts for greenhouse gas emissions from dams and hydropower. Third, I note three river systems I have visited—the Mekong River, the Maranon River which is headwaters of the Amazon, the Colorado River here in the U.S. – and discuss the implications for greenhouse gas emissions from each. Finally, I discuss how you can combat the “myth of clean hydropower” and fight for the protection of rivers.

The world’s rivers are facing an apocalypse of dams, most of which are being pushed forward under the false premise that hydropower is clean energy, and it could be apocalyptic not just for river health, but for our planet’s climate. To protect rivers, stop dams, and protect the earth’s climate, we need to break the silence. Every person, ever dam-builder, every organization, every media outlet, every government needs to relentlessly be told the truth about how dams and reservoirs emit methane and greenhouse gases and make climate change worse.

They may call us every name in the book, but we will call them out.

History of methane measurement

Twenty-five years ago, a small team of scientists in Brazil started measuring the methane produced at hydropower dams and reservoirs. Led by Dr. Philip Fearnside, these scientists found surprising results, indicating that hydropower dams and reservoirs in tropical countries like Brazil emit high levels of greenhouse gases, especially methane, sometimes more than a coal-fired powerplant. After years of research, in 2008 Dr. Fearnside published an article in Oecologia Australis titled, “Hydroelectric Dams as ‘Methane Factories’: The Role of Reservoirs in Tropical Forest Areas as Sources of Greenhouse Gases”.

Around the same time, other scientists around the world launched new studies that confirmed the Brazilian results.
International studies of dams and their reservoirs multiplied over the last two decades, and for the first time in 2006, the Intergovernmental Panel on Climate Change (IPCC) included calculations for measuring “CH4 [methane] Emissions From Flooded Lands” in national greenhouse gas inventories. Since 2006, study after study has confirmed high levels of methane emissions from many dams and reservoirs. One study in 2016, by the U.S. Environmental Protection Agency, found methane emissions from a reservoir in the Midwestern U.S. to be as high as those measured in Brazilian hydropower plants. The EPA blogged about the study, a blog which is still on their website as of October 2016, titled, “Bubbling Up: Methane from Reservoirs Presents Climate Change Challenge”.

Further in 2016, this science came to a head when an international team of scientists synthesized dozens of studies from around the planet indicating that methane emissions from dams and reservoirs have been widely ignored and dramatically under-estimated. Published in Bioscience, the article was titled, “Greenhouse Gas Emissions from Reservoir Water Surfaces: A New Global Synthesis” and was funded by the U.S. Army Corps of Engineers, Environmental Protection Agency, and National Science Foundation. The study made international news and posited that the IPCC needs to revise its calculations and include dams and reservoirs’ significant emissions in climate change scenarios.

Further yet, a study published in September 2016 by a team of Swiss scientists used previous measurements at dams and reservoirs around the world to create a model to estimate the equivalent carbon emissions from nearly 1,500 hydropower facilities across the planet. The study’s conclusions further rocked the climate change and energy world – one particular estimate indicates that the climate change emissions from Hoover Dam and Lake Mead on the Colorado River near Las Vegas are approximately equal to that of coal-fired powerplants.

The first and most common question asked is: “Why do dams and reservoirs produce climate change emissions like methane?”

The answer is that organic material – vegetation, sediment, algae, and other nutrients from the landscapes – is carried downstream by water, trapped behind dams, and decomposes under a reservoir’s water releasing large amounts of carbon dioxide as well as methane. Called “anaerobic decomposition,” this natural process is dramatically intensified in dam and reservoir systems that are not natural lakes. Conversely, when vegetation decomposes in the presence of air, it is called “aerobic decomposition”, and it only releases smaller amounts of carbon dioxide. So, as a simplified example, if a leaf falls off a tree and lands on the ground, it decomposes and emits carbon dioxide, but if it travels into a reservoir and decomposes under water, it emits carbon dioxide and methane, and the methane is a much more powerful and damaging greenhouse gas.

As depicted in the figure above, the greenhouse gas emissions can percolate directly up through the surface of the reservoir and out through the release mechanisms of the dam including the hydropower turbines.

Dam and reservoir greenhouse gas emissions are often worse where:

  • the dam is bigger and the reservoir is larger, and especially where the surface area of the reservoir is larger;
  • the weather is warmer and wetter, and the water temperature of the reservoir is warmer;
  • the initial flooding of the landscape involves large areas of vegetation;
  • more vegetation and sediment run off into the reservoir;
  • the reservoir’s water level goes up and down on a seasonal or hydropower-ramping cycle causing vegetation to grow on the dry banks of the reservoir, and then become submerged when the reservoir level rises causing that vegetation to drown and decompose;
  • the reservoir is newer and the landscape more recently flooded;
  • the reservoir is near agricultural areas where fertilizer-heavy water and erosion runs off into a reservoir feeding the biological cycle that grows algae and other submerged vegetation;
  • and, where any other type of heavy nutrient load is pouring into a reservoir including that from direct human wastes, stormwater runoff, or wastewater treatment plants.

Another common question is: “Wouldn’t all of the organic material flow into the river and decompose anyway, and so why does the dam and reservoir make it worse?”

The answer is three-fold:

  • When a reservoir floods a landscape and the water level cycles up and down, the vegetation that grows on the banks gets flooded and decomposes on a yearly basis or due to seasonal hydropower ramping, thus dramatically increasing the methane and greenhouse gas emissions.
  • A large reservoir will dramatically increase the amount of leaf-litter and other vegetation that flows into the reservoir because a much larger area of landscape is in contact with the water than the former rivulet of land along a river. In a normal river system, much of the vegetation simply falls to the ground and decomposes releasing carbon dioxide rather than flowing into the reservoir and also releasing methane.
  • Because dams and reservoirs cause dramatically more anaerobic decomposition of organic material, and because methane can be up to eighty times more potent greenhouse gas than carbon dioxide, the construction of dams and reservoirs dramatically increases the greenhouse gas emissions compared to a natural river system. The graph below, created by the NGO International Rivers and published in their 2008 report, “Dirty Hydro”, depicts how greenhouse emissions from tropical dams and reservoirs can be significantly greater than that of coal-fired powerplants:

How bad is it? Several studies have estimated the greenhouse gas emissions from dams and reservoirs, all of which indicate that the emissions are greater than are currently being accounted for by any national or international system by any country. How much greater, is a big question. One 2012 study titled, “Uncertainties of carbon emission from hydroelectric reservoirs”, and published in Natural Hazards journal was summarized in 2014 Climate Central story which stated:

“Those researchers suggest all large reservoirs globally could emit up to 104 teragrams of methane annually. By comparison, NASA estimates that global methane emissions associated with burning fossil fuels totals between 80 and 120 teragrams annually.”

That’s right – it’s a big deal, perhaps as bad as all fossil fuels combined. Further, as I was writing this chapter in October 2017, the European Union and Netherlands Environmental Assessment Agency issued a report indicating that although global carbon dioxide emissions may be flat, far more powerful greenhouses, like methane, “keep creeping up”.

COP 21, the Kyoto Protocol, and the IPCC

Methane emissions from hydropower dams and reservoirs has not gone unnoticed by international scientific audiences, but the politics behind the Intergovernmental Panel on Climate Change (IPCC) and its role in these identifying and reporting these emissions has been a convoluted mess.

The “Kyoto Protocol” was one of the larger and more consequential attempts by the international community to identify and regulate greenhouse gases. The Protocol extended a 1992 United Nations treaty that recognized that global warming was occurring and is caused by human emissions. The Protocol entered into force in 2005, and identified what it called a “Clean Development Mechanism” for generating electricity, and it unfortunately included hydropower as one of those mechanisms.

As the science on hydropower emissions progressed, a 2006 report from the IPCC did begin to include “CH4 [methane] Emissions From Flooded Lands” (Appendix to Chapter 4) in its calculations, but the calculation and reporting of these emissions continues to be seriously diminished or completely ignored. Called the “IPCC Guidelines for National Greenhouse Gas Inventories”, the report describes how countries are supposed to calculate greenhouse gas emissions. But, during the exact same period, there have been very few measurements of these methane emissions at the very same time that large hydropower projects are being built by the hundreds across the planet.

What’s worse is that 2015 IPCC COP21 Paris agreement has further entrenched the problem of not calculating or reporting hydropower’s methane emissions. In the lead-up to COP 21, countries around the world had been sending their “Intended Nationally Determined Contributions” (INDCs) to the United Nations. An INDC is a description of how each country intends to reduce its carbon emissions and is a key component of the COP21 Paris Agreement. The INDC is, in plain terms, where the rubber hits the road.

Before the COP21 agreement, I did a quick survey of the INDCs of some countries and found that hydropower and its emissions had been completely ignored. Here are the five quick, random examples out of the 181 INDCs sent to the UN:

  1. China is in the midst of building dozens of massive hydropower plants per year, including the largest on the planet. In its INDC, China states they intend to: “proactively promote the development of hydro power, on the premise of ecological and environmental protection and inhabitant resettlement.”
  2. India’s INDC uses hydropower to meet its emission reduction target, and states: “With a vast potential of more than 100 GW, a number of policy initiatives and actions are being undertaken to aggressively pursue development of country’s vast hydro potential.”
  3. Japan’s INDC states that it intends to reach its “emissions reduction target” in part by getting to 9% hydropower by 2030. Japan has dozens of currently operating hydropower plants with dozens more in the planning stages.
  4. Canada’s INDC states that it will use “low-impact hydro” as one of its “investments to encourage the generation of electricity from renewable energy…” Canada has dozens of new hydropower dams under construction, and few if any are even remotely considered “low-impact hydro.”
  5. Costa Rica’s INDC boasts: “Costa Rica has a long standing tradition of innovation on hydroelectric generation, in conservation and specially, on matters of climate change.” Costa Rica routinely markets itself as having a nearly carbon-free energy system, with over 80% coming from hydropower – with absolutely none of the methane emissions measured or accounted for in its INDC – and is just finishing construction of the largest hydropower dam in Central America.

What’s even more problematic is that many of the countries around the world that are most aggressively pursuing hydropower don’t even list it in their INDC, but rather state they are using the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Take Indonesia as just one example, which has built and is continuing to build dozens of massive hydropower dams. In their INDC, Indonesia does not mention hydropower and states they will meet emissions reductions and that: “The inventory is based on 2006 IPCC Guideline for National Greenhouse Gas inventories.”

All of this ‘false reporting’ was discussed at length in a seminal article in a 2015 in the scientific journal Environmental Science & Policy by Dr. Philip Fearnside, who, again, was one of the original researchers who discovered hydropower’s methane emissions, has published numerous studies on the topic, and is trying to reform IPCC’s process on hydropower. Fearnside’s sleuthing of the problem of the false reporting has been as rigorous as his science. The article is titled, “Emissions from tropical hydropower and the IPCC”, and meticulously discusses the false reporting, the bad calculations, the reasons for omissions, and the politics surrounding the whole mess. The paper’s abstract states plainly: “The role of hydroelectric dams in emissions inventories and in mitigation has been systematically ignored.”

Near the end of the article, Fearnside also digs into what he calls the “Sociology of science and dam emissions” and says that the large and politically powerful hydropower industry – what I and some people call “Big Hydro” – has actively interfered with the science, has done their own bad studies to undermine the real science, and is squelching the entire IPCC scientific process of calculating and reporting emissions.

Fearnside notes in the article:

“A large proportion of the published work in this field comes directly from researchers connected to hydroelectricity companies, such as Eletrobra´s or Hydro-Que´bec’’

and suggested as a result that:

‘‘a mechanism is needed to remove any taint of interest so that CDM [Clean Development Mechanism] projects and national inventories can earn confidence.”

Fearnside specifically calls out “Hydro-Quebec” which has a strong seat in the IPCC’s committee of deliberators: The Hydro-Quebec expert argues that we don’t have enough knowledge for CH4 diffusive emissions. . ..”

Fearnside concludes with scientifically muted but ominous statement:

“If national inventories submitted by each country do not reflect the true amount of emission because tropical hydroelectric dam emissions have been omitted or understated, then the assigned amounts negotiated under the UNFCCC will be insufficient to contain climate change and the impacts of passing the 2 8C threshold will ensue.”

Like Fearnside, I have deep skepticism about the IPCC’s process and results. Countries that are completely destroying their rivers and our climate with hydropower including Malaysia, Brazil, Guatemala, Russia, and even the United States don’t even list hydropower as a greenhouse gas emission source in their INDC while including hydropower as a clean energy source, all under the auspices of misconstrued or purposely ignored IPCC guidelines.

As I’ve noted, hundreds of large hydropower projects are under construction and thousands are planned. Examples are far too numerous to go through, but as just one example, the Eastern European Balkan countries have recently announced they want to build 2,700 hydropower dams and every single one is being touted as a clean energy alternative to fight climate change.

As the world cartwheels after COP 21, there are many reasons why scientists and advocates have little faith that the negotiations will yield consequential results to fight climate change. The lack of information about the methane emissions from hydropower, the apparent lack of enforcement of the IPCC guidelines, and the ruse of calling hydropower “clean energy” are just more issues in the long list of problems with COP 21.

Even the U.S. government still perpetuates the anti-science myth of clean hydropower, and it occurred way before Trump and center-front in Obama’s U.S. Department of Energy (DOE). A 2014 DOE report titled “New Stream-reach Development Assessment” calls for “new hydropower development across more than three million U.S. rivers and streams.” The report says, These findings demonstrate one of the ways the United States can further diversify its energy portfolio with sustainable and clean domestic power generation.” The report includes map depicting the river devastation proposed across the country, including in my state of Colorado which would be particularly devastated.

Unfortunately, the international banking industry follows closely on the heels of the IPCC and the “Clean Development Mechanism” problem. In many cases, it is the role of the banks and other financial institutions that seal the deal to build massive hydropower projects, again, all under the guise of “clean energy”. A hydropower company will often propose a project to a country, but it’s not until a bank enters the deal – that is often over billion dollars (U.S.) – that a project gets built. International environmental and human rights groups including International Rivers and Bankwatch, try hard to keep track of the banking problem, but it is a never-ending debacle of false advertising about clean energy and political gamesmanship.

Worse yet, the World Bank – mostly led by the United States – still lists, promotes, and funds hydropower as “clean energy” (and lists it right on their website). What’s even worse (which I will discuss in the last section of this chapter), some international NGOs – led by The Nature Conservancy – are promoting hydropower in developing countries. Sickeningly, in the exact same paragraph on the World Bank’s website where it discusses hydropower as clean energy, it includes a quote from The Nature Conservancy’s Giulio Boccaletti who is the “Global Managing Director for Water” of the organization. Further The Nature Conservancy has a whole international program called “Hydropower By Design” where, right on its website, it calls hydropower “low carbon energy”.

The problem is not just with Big Hydro, it’s not just the IPCC, it’s not just the banks, it’s not just the U.S. government, it’s also with lots of environmental groups that don’t follow science and pander to financial and political support gotten from blindly following the status quo.

Three Case Studies Where I have Personal Experience

Mekong River: In April of 2016, I boarded a longboat for a cruise up the Mekong River just upstream of the town of Chiang Khong in northeast Thailand. The air was thick with humidity and smoke coming from Laos on the other side of the river. Laos farmers use slash-and-burn agriculture that’s creating its own set of serious problems, but it was the flow of water in the river that concerned us that day.

The Mekong River is facing an onslaught of dams. Several large hydropower dams have already been built upstream, and over a dozen more have been planned between Chinese territory upstream all the way down through Cambodia where the Mekong River meets the South China Sea. And the Mekong is a perfect breeding ground for the worst type greenhouse gas emissions from dams and reservoirs. The river has a huge sediment load, has lots of vegetation running into it, is very warm, and the landscapes around it are generally flatter which will result in large, shallow reservoirs with a big surface area. The farther downstream the dams are built, the likely worse the greenhouse gas emissions because the heat and humidity creates a soupy breeding ground for CO2 and methane in the reservoir.

Downstream of Chiang Khong, where the climate is the warmest and the Mekong River is warm and filled with vegetation, the countries of Cambodia and Laos are planning several large hydropower dams. And, point-blank in their INDC given to the IPCC for their participation in the COP21 Paris agreement, they both list “hydropower” as a “priority action” to create electricity to “mitigate” their greenhouse gas emissions. In fact, Laos’s INDC is the most egregious, staying:

“In terms of Lao PDR’s large scale electricity generation, the electricity grid draws on renewable resources for almost 100% of its output. Lao PDR also aims at utilising unexploited hydropower resources to export clean electricity to its neighbours. By supplying neighbouring countries such as Cambodia, Viet Nam, Thailand and Singapore with hydroelectricity, Lao PDR is enabling other countries in South East Asia to develop and industrialise in a sustainable manner.”

Damming the Mekong will likely have extreme negative greenhouse gas implications, and the countries along the Mekong are telling the exact opposite story, falsely heralding hydropower as the solution to climate change.

Maranon River: In June of 2016, eighteen of us boarded whitewater rafts and began a 7-day wilderness trip paddling down the Maranon River in Peru, which is the headwaters of the Amazon River. Our trip was the maiden voyage of the “Maranon River Waterkeeper”, a local environmental organization dedicated to protecting the Maranon which is a chapter of the international Waterkeeper Alliance based in New York. Upstream, the Maranon is a cold mountain river, raging with the spring runoff. The Maranon is the largest tributary to the Amazon and drains almost the entire east slope of the Andes, and then turns east into the lowlands and jungles of Peru and into Brazil.

Peru has very ambitious plans to dam the Maranon for hydroelectricity. During our trip, we stopped in one very remote village that is fighting against the dams – the villages had spray-painted anti-dam slogans on their homes and schools, and were openly flouting the hydroelectric corporations.

While the proposed upstream dams on the Maranon would cause considerable environmental damage – as well as damage and displacement of villagers – they may not be large greenhouse gas emitters due to the cold water and the narrow canyons. But downstream, the so-called “jungle dams” would likely be huge greenhouse emitters. It is in the lower jungle regions where Brazil scientists have estimated that the greenhouse gas emissions of hydropower can be significantly worse than coal-fired power plants.

Fortunately, for now, this story has a happier ending. Near the end of the summer in 2016, the Peruvian Minister for the Environment announced that the “lower dams on the Maranon” that are in the jungle had been postponed for at least 5 years. The Minister’s announcement came after a visit from Robert F. Kennedy, Jr., who is President of the Waterkeeper Alliance and had lobbied the Minister – along with the local Maranon River Waterkeeper – to not build the dams on the Maranon.

Colorado River: I like to say that the Colorado River is the genesis of large-scale planetary river destruction. In fact, the construction of Hoover Dam marked the first and biggest hydroelectric dam on earth, and since then the technology has been replicated upstream on the Colorado River as well as across the planet. Hoover Dam is where it all started, this hubristic notion that humans could build these mega-dams to control rivers and generate electricity with no environmental consequences.  I’ve rafted many sections of the Colorado River, and I co-founded the “Save The Colorado” campaign in 2010. I’ve also paddled a kayak just a couple hundred yards downstream of Hoover Dam – the hulking cement monolith towering overhead – through the Black Canyon of the Colorado River. And it is in that Black Canyon where the story gets more problematic.

The Colorado River should be a muddy, red torrent – indeed, that’s what it used to be when the Spanish explorers named it “Colorado”, which means “color red”. But, just below Hoover Dam, the river is an eerie crystal-clear greenish color because all of its sediment is trapped by Hoover Dam and Glen Canyon Dam upstream. That massive sediment load, combined with the huge sprawling reservoir behind Hoover Dam (“Lake” Mead) which bakes in the hot Las Vegas sun, make for a perfect cocktail of greenhouse gas emissions. The reservoir is enormous, about ¼ the size of Rhode Island, and fluctuates in size over the year causing many square miles of its banks to dry up, grow vegetation, and be re-flooded each year. Thus, Hoover Dam and Lake Mead are a high greenhouse gas producing hydropower plant and water storage facility

In fact, in September of 2016, the first scientific article was published which estimated the greenhouse gas emissions of Hoover Dam, and that estimation rocked the climate change world.

The scientific article was published in the international online journal, PLOS ONE, by a team of Swiss scientists, and was titled, “Hydropower’s Biogenic Carbon Footprint”. The article used statistical models and prior research to estimate the greenhouse gas emissions of 1,473 reservoirs across the planet, including Lake Mead behind Hoover Dam. The estimate put Hoover Dam’s emissions roughly equal to that of coal-fired powerplants with the same electricity output. Further, even though these measurements and estimates of methane are Lake Mead are very recent, as far back as 1948 the U.S. Geological Survey examined what they then called “gas pits” in the mud flats of Mead.

It all started on Hoover Dam – this naïve notion that hydropower was “clean energy”, and now it’s all come crashing down at Hoover dam.

Four Things You Can Do To Fight The Myth of Clean Hydro and Protect Rivers

1. Fight The Greenwashing

  • By the Hydropower Industry: Part of the reason that the climate change emissions produced by dams and hydropower are not well known to the public or media is that the hydropower industry has done everything possible to greenwash its image and market the “carbon free,” “clean,” and “renewable” energy myth to compete with fossil fuels. Like the fossil fuel industry, the hydropower industry has also gone on the offensive – scientists, activists, and citizens who have spoken out against new dam construction have faced attacks and even death in countries around the world.The National Hydropower Association in the U.S. is directly implicated in this greenwashing. In 2016, when the team of scientists published the seminal paper in Bioscience titled, “Greenhouse Gas Emissions from Reservoir Water Surfaces: A New Global Synthesis”, the National Hydropower Association responded within hours and issued a scathing statement dismissing the findings before it was even publicly available and without presenting adequate data or science to refute it. Every time the industry spouts false information, we need to respond publicly and loudly.
  • By Elected and Government Officials: Elected officials across the planet routinely spout the “hydro is clean energy” myth, even when they know better. In the U.S, elected officials at all levels including members of Congress, and even more recently President Trump, have touted the myth. The fight around removing the Snake River Dams in the northwest U.S. has recently caused a torrent of greenwashing from elected officials. In my hometown of Fort Collins, CO, the Water Utility director recently wrote a column in our newspaper bragging about the City’s “non-carbon based sources, which includes wind, solar and hydroelectric power, supplied more than 32 percent of the community’s electricity.” I challenged the director on this claim and we are moving to get changes made here in Fort Collins. This is a drop in the bucket compared to the torrent of rhetoric in other countries for government officials at all levels. Every time a decision-maker spouts false information, we need to respond publicly and loudly.
  • By the Big Banks: Oftentimes, big banks are the straw that breaks the camel’s back and pushes through bad mega-dam project. Banks across the planet – in the U.S., China, Europe, and Latin America – see easy money and good profits from financing hydropower protects. As I noted earlier, the World Bank itself as well as the International Monetary Fund still push hydropower as clean energy. Groups including International Rivers and Bankwatch are atively pushing back against the big banks. Every time a bank spouts false information, we need to respond publicly and loudly.
  • By Environmental Groups: Oftentimes I feel like I’m spending half my time fighting the dam builders, and the other half fighting the large, mainstream environmental groups led by their foundation and corporate funders. This is an especially big problem because environmental activists often move back and forth in their career working for different organizations, and the foundation/funder circle is increasingly small and concentrated. As such, most activists simply don’t want to speak out against their colleagues, other organizations, or the foundation and corporate funders. However, it is that silence that may strengthen the authority of the dam-builders and river-destroyers more than anything.

In the text above, I called out The Nature Conservancy because I see them as one of the biggest and most vocal dam supporters in the environmental community. I’ve written articles calling out other groups, as well as foundations and corporate funders. Most notably in the U.S., the Walton Family (WalMart heirs) and their grantees catch my attention for bad behavior. Oftentimes I call out these groups and foundations behind the scenes, as I did recently to the director of the Rockefeller Brothers Fund when he openly called for more dams on Nepal’s pristine rivers, another place I have visited and rafted. Calling out your colleagues and their funders is difficult work – you don’t make a lot of friends and you may limit your career opportunities. Still, every time an environmental group or a “green” foundation spouts false information, we need to try to respond publicly and loudly.

  • When Speaking Out, Be Careful and Be safe: Dr. Philip Fearnside has been one of the most prominent and vocal scientific voices pointing out the myth of clean hydro for over twenty-five years. When he was awarded the international “River Guardian” award from the prominent group, International Rivers, he spoke about he “drew the wrath of the hydropower industry”. Fortunately, Dr. Fearnside has remained safe, but that cannot be said for other dam fighters especially in developing countries. Severe harassment, abuse, people going “missing”, and even murder has occurred, most recently in Honduras with the murder of Berta Caceres, and then afterwards with her daughter surviving an attack. Wherever you are, please be safe. In addition, I think those of us in safe countries – especially here in the U.S. – have an even bigger responsibility to speak out to create space and power for those who cannot. Every time someone spouts false information, we need to respond publicly and loudly.

2. Alternatives to Hydropower: Can Elon Musk Save The World’s Rivers?

Solar power has started to make dramatic inroads into the power grid system. Over the last 25 years, the price of solar power has dropped by at least 90% while the amount of solar power deployed has increased by 90%.

More recently, Tesla and the technology pushed forward by Elon Musk, has continued to advance battery technology to the point where solar electricity can be stored for days or weeks into the future.

As the crisis unfolded in Puerto Rico after Hurricane Maria, both Elon Musk (of Tesla) and Richard Branson (of Virgin Airways) have offered to revolutionize the power grid system on the island and construct a scalable solar-powered microgrid to replace the fossil fuel system that collapsed. If the entire island of Puerto Rico can be used as a testing ground, then villages – or regions – across developing countries are also viable candidates. A dramatic amount of the current and proposed hydropower in developing countries is being promoted to bring electricity to rural and remote households. Solar power may offer a viable solution to the damming and draining of rivers worldwide.

BBC recently reported on another company, BBOX from England, which predicts that “Africa will largely bypass the grid and leapfrog over Europe and North America straight into solar – just as it did in skipping landlines, a rarity in rural Africa, in favour of cell phones”. The off-the-grid technology offered by BBOX and several other companies has brought electricity to hundreds of thousands of households in Africa, with unlimited potential for the future.

As I was writing the first draft of this paper in 2017, the publication Think Progress posted a story titled, “Solar power crushes its own record for cheapest electricity ‘ever, anywhere, by any technology’”. And in the same few days, the Associated Press posted a story titled, “Navajo Solar Plant Breaks New Ground”, which is a large solar plant very near Hoover Dam and Lake Mead.

As river-protection activists, we need to do everything we can to promote and support alternatives to hydropower that offer real solutions to people and households that currently do not have electricity across the planet. New solar and battery power technology may offer that opportunity at a grand scale. As a friend of mine, Buck Ryan who is Snake River Waterkeeper told me in 2016, “we no longer have to destroy rivers and kill endangered fish to keep the lights on.”

3. Support Our Colleagues Who Are Fighting Dams Across The Planet

As I’ve traveled around the world – and even in the U.S. over the past few years – I see individual groups and collections of people fighting dams and protecting rivers often without a greater connection or network with other groups and people around the planet. We need to connect more with, and support, each other and help each other be successful. Keep these two things in mind: 1) If you are currently fighting dams and have any capacity to assist other people, see it as part of your job to offer support to other river-protectors in your region, country, or around the planet. And 2), if you are fighting a dam in our region but don’t have connections to a larger network, begin to reach out and ask for assistance.

Here’s a list of groups you can reach out to:

  • International Rivers, based in Berkeley, CA, is the biggest and most advanced dam-fighting organization in the world. They have several regional support networks, sometimes offer funding, and have many connections to legal, organizing, and advocacy people and tools.
  • Waterkeeper Alliance, based in New York City, is the fastest growing water protection organization in the world and has recently launched a “Free-flowing Rivers Campaign” to create and support more river-protectors across the planet.
  • River Watch, a European organization in the Balkan countries, is trying to protect rivers in that region but has many connections to river-protectors around the world.
  • North American Megadam Resistance, a Canadian organization fighting dams across Canada and especially in Quebec.
  • Bankwatch is the “largest network of grassroots, environmental and human rights groups in central and eastern Europe”, and also works around the globe keeping track of banks that make loans to ill-advised development schemes like mega-dams.
  • Of course, stay in contact with us, Save The World’s Rivers.

There are hundreds of local and regional groups throughout the world – get on google and start searching in your area. Also, be aware that some well-known groups – especially in the U.S. – are not good to connect with because they are co-opted by large foundations and corporations that support new dams in many cases. Do your homework and see where the money is coming from and what motivates it.

Get online – especially on twitter – and share information about your work, your successes, and your problems so that we are connected across the planet. In 2014, I created the twitter hashtag #CORiver for activists to share information and it has become the go-to place for Colorado River information. I suggest using the #TheDamTruth hashtag to start sharing information about fighting dams and protecting rivers internationally. Share information and get more active on social media. Follow two groups on Twitter for the most comprehensive global summary of dam fights: International Rivers and Save The World’s Rivers. Share press releases. Share funding sources. Share new science – especially science about greenhouse gas emissions from dams and reservoirs. Share the names of legal firms who can represent dam fighters. Share stories about bad actors, bad banks, bad projects. Share everything and create an international community so we are connected across the planet, online.

4. Believe in yourself and state the facts:

  • Hydropower is not clean energy.
  • Most dams of any size or consequence make climate change worse by emitting greenhouse gases, sometimes huge amounts of greenhouse gases.
  • Rivers are the arteries of the planet – they carry the oxygen and nutrients throughout the water cycle and the life cycle. Rivers are the Earth’s biodiversity hotspots.
  • Blocking a river with a dam is like blocking an artery in your body.
  • Saving rivers from dams, saves the planet, saves biodiversity, and saves humanity.

Nothing strengthens authority so much as silence, and nothing undermines authority and the status quo on dams as much as massive communication, interaction, and support by dam fighters and river protectors across the planet.

Keep up the fight!


Bibliography of scientific studies: 


Bertassoli, D. J., Sawakuchi, H. O., de Araújo, K. R., de Camargo, M. G. P., Alem, V. A. T., Pereira, T. S., Krusche, A. V., Bastviken, D., Richey, J. E., & Sawakuchi, A. O. (2021). How Green can Amazon Hydropower be? Net Carbon Emission from the Largest Hydropower Plant in Amazonia. Science Advances, 7(26).

Harrison, John, Yves T. Prairie, Sara Mercier‐Blais, Cynthia Soued. (2021) Year‐2020 Global Distribution and Pathways of Reservoir Methane and Carbon Dioxide Emissions According to the Greenhouse Gas from Reservoirs (G‐res) Model. Global Biogeochemical Cycles, doi: 10.1029/2020GB006888

Jane, S.F., Hansen, G.J.A., Kraemer, B.M. et al. (2021) Widespread Deoxygenation of Temperate Lakes. Nature 594, 66–70

Keller, P.S., Marcé, R., Obrador, B. et al. (2021) Global Carbon Budget of Reservoirs is Overturned by the Quantification of Drawdown Areas. Nat. Geosci. Global carbon budget of reservoirs is overturned by the quantification of drawdown areas


Beaulieu, J, et al.; (2020) Methane and Carbon Dioxide Emissions From Reservoirs,  Journal of Geophysical research. Biogeosciences, Vol.125 (12), p.n/a, doi: Methane and carbon dioxide emissions from reservoirs: Controls and Upscaling 

Deemer, Bridget R. et al. (2020), Data from: Greenhouse Gas Emissions from Reservoir Water Surfaces: A New Global Synthesis, Dryad, Dataset,


Almeida, R.M., Shi, Q., Gomes-Selman, J.M. et al. (2019) Reducing Greenhouse Gas Emissions of Amazon Hydropower with Strategic Dam Planning. Nat Commun 10, 4281.

Beaulieu, J.J., DelSontro, T. & Downing, J.A. (2019) Eutrophication will Increase Methane Emissions from Lakes and Impoundments during the 21st Century. Nat Commun 10, 1375.

Hager, PhD, Cecil Green  and Ida Green Professor of Earth Sciences Department of Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology

Documentation of the Carbon Footprint of Hydro Québec’s Hydropower

Marcé, R. et al. (2019) Emissions from Dry Inland Waters are a Blind Spot in the Global Carbon Cycle. Earth Sci. Rev. 188, 240–248. 

Ocko, Ilissa B.  and Steven P. Hamburg, (2019) Climate Impacts of Hydropower: Enormous Differences among Facilities and over Time,  Environmental Science & Technology 2019 53 (23), 14070-14082   DOI: 10.1021/acs.est.9b05083


Chow, M.F.; Bakhrojin, M.A.b.; Haris, H.; Dinesh, (2018), A.A.A. Assessment of Greenhouse Gas (GHG) Emission from Hydropower Reservoirs in Malaysia. Proceedings 2018, 2, 1380.

DelSontro, T., J. Beaulieu, AND J. Downing. (2018), Greenhouse Gas Emissions from Lakes and Impoundments: Upscaling in the Face of Global Change. Limnology and Oceanography Letters. John Wiley & Sons, Inc., Hoboken, NJ, 3(3):64-75.

Kosten, S. et al. (2018). Extreme Drought Boosts CO2 and CH4 Emissions from Reservoir Drawdown Areas. Inland Waters 8, 329–340.

Prairie YT, Alm J, Beaulieu J, et al. (2018). Greenhouse Gas Emissions from Freshwater Reservoirs: What Does the Atmosphere See?. Ecosystems; 21(5):1058-1071.

Räsänen, Timo A. et al. (2018). Greenhouse Gas Emissions of Hydropower in the Mekong River Basin, Environ. Res. Lett. 13 034030

Samiotis G, Pekridis G, Kaklidis N, Trikoilidou E, Taousanidis N, Amanatidou E. (2018). Greenhouse Gas Emissions from two Hydroelectric Reservoirs in Mediterranean Region. Environ Monit Assess. May 26;190(6):363.  doi: 10.1007/s10661-018-6721-4

Song, C. et al., (2018). Cradle-to-Grave Greenhouse Gas Emissions from Dams in the United States of America, 90 Renewable and Sustainable Energy Reviews 5


Maavara, T., R. Lauerwald, P. Regnier, P.Van Cappellen. (2017) Global Perturbation of Organic Carbon Cycling by River DammingNature Communications, 8: 15347 DOI: 10.1038/ncomms15347


Beaulieu, J.J., McManus, M.G. and Nietch, C.T. (2016), Estimates of Reservoir Methane Emissions based on a Spatially Balanced Probabilistic-survey. Limnol. Oceanogr., 61: S27-S40.

Deemer, Bridget R., John A. Harrison, Siyue Li, Jake J. Beaulieu, Tonya DelSontro, Nathan Barros, José F. Bezerra-Neto, Stephen M. Powers, Marco A. dos Santos, J. Arie Vonk, (2016). Greenhouse Gas Emissions from Reservoir Water Surfaces: A New Global Synthesis, BioScience, Volume 66, Issue 11, 1 November 2016, Pages 949–964, “

Fearnside, P.  (2016) Greenhouse Gas Emissions from Brazil’s Amazonian Hydroelectric Dams,  Environ. Res. Lett. 11 011002. doi: 10.1088/1748-9326/11/1/011002

Scherer, Laura & Stephan Pfister, (2016). Hydropower’s Biogenic Carbon Footprint, PLOS ONE, September 14, 2016.


De Faria, Felipe A M, Jaramillo, Paulina, Sawakuchi, Henrique O, Richey, Jeffrey E, & Barros, Nathan (Dec 2015). Estimating Greenhouse Gas Emissions from future Amazonian Hydroelectric Reservoirs. Environmental Research Letters, 10(12), 13.

Fearnside, Philip. 2015. Emissions from Tropical Hydropower and the IPCC. Environmental Science and Policy 50:225-229. doi: 10.1016/j.envsci.2015.03.002

Fedorov, M.P., Elistratov, V.V., Maslikov, V.I. et al. 2015. Reservoir Greenhouse Gas Emissions at Russian HPP. Power Technol Eng 49, 33–39.


Maeck, A., Hofmann, H., and Lorke, A. (2014).  Pumping Methane out of Aquatic Sediments – Ebullition Forcing Mechanisms in an Impounded River, Biogeosciences, 11, 2925–2938,


Hertwich EG.(2013)  Addressing Biogenic Greenhouse Gas Emissions from Hydropower in LCA. Environ Sci Technol. 2013 Sep 3;47(17):9604-11. doi: 10.1021/es401820p

Maeck, Andreas, Tonya DelSontro, Daniel F. McGinnis, Helmut Fischer, Sabine Flury, Mark Schmidt, Peer Fietzek, and Andreas Lorke, (2013) Sediment Trapping by Dams Creates Methane Emission Hot Spots, Environmental Science & Technology 2013 47 (15), 8130-8137
doi: 10.1021/es4003907


Steinhurst, William, et al. (2012). Hydropower Greenhouse Gas Emissions, Synapse Energy Econ.. 12.

Teodoru, Cristian  et al. (2012). The Net Carbon Footprint of a Newly Created Boreal Hydroelectric Reservoir, Global Biogeiochemical Cycles, May 2012, at 1. 

The net carbon footprint of a newly created boreal hydroelectric reservoir

West, W. E. et al. (2012). Effects of Algal and Terrestrial Carbon on Methane Production Rates and Methanogen Community Structure in a Temperate Lake Sediment.Freshwater Biology 57, 949-955.


Barros, N., Cole, J., Tranvik, L. et al. (2011). Carbon Emission from Hydroelectric Reservoirs Linked to Reservoir Age and Latitude. Nature Geosci 4, 593–596.


Gunkel, G. (2009), Hydropower – A Green Energy? Tropical Reservoirs and Greenhouse Gas Emissions. Clean Soil Air Water, 37: 726-734.


Walter, Katey, Laurence Smith, and Stuart Chapin. (2007) Methane bubbling from northern lakes: present and future contributions to the global methane budget.  Phil. Trans. R. Soc. A.3651657–1676.


Intergovernmental Panel on Climate Change (IPCC) (2006), Appendix 3 — CH4 Emissions from Flooded Land: Basis for Future Methodological Development, 


Fearnside, P. (2005)  Do Hydroelectric Dams Mitigate Global Warming? The Case of Brazil’s CuruÁ-una Dam. Mitig Adapt Strat Glob Change 10, 675–691..

Tremblay et al. (2005). Greenhouse Gas Emissions – Fluxes and Processes: Hydroelectric Reservoirs and Natural Environments. Germany: Springer, 2005.


Rosenberg, David M., Patrick McCully and Catherine M. Pringle, (2000). Global-Scale Environmental Effects of Hydrological Alterations: Introduction, BioScience, Volume 50, Issue 9, September 2000, Pages 746–751,[0746:GSEEOH]2.0.CO;2

St. Louis, Vincent L., Carol A. Kelly, Éric Duchemin, John W. M. Rudd, David M. Rosenberg, (2000). Reservoir Surfaces as Sources of Greenhouse Gases to the Atmosphere: A Global Estimate. BioScience, Volume 50, Issue 9, September, Pages 766–775,[0766:RSASOG]2.0.CO;2


Fearnside, P. (1997). Greenhouse-Gas Emissions from Amazonian Hydroelectric Reservoirs: The Example of Brazil’s Tucuruí Dam as Compared to Fossil Fuel Alternatives. Environmental Conservation, 24(1), 64-75. doi:10.1017/S0376892997000118


Fearnside, P. (1995). Hydroelectric Dams in the Brazilian Amazon as Sources of ‘Greenhouse’ Gases. Environmental Conservation, 22(1), 7-19. doi:10.1017/S0376892900034020






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