By Sonya Angelica Diehn
Dams are often touted as environmentally friendly. Although they do represent a renewable source of energy, a closer look reveals that they are far from green. DW lays out the biggest environmental problems of mega-dams.
1. Dams Alter Ecosystems
Water is life — and since dams block water, that impacts life downstream, both for ecosystems and people. In the case of the Grand Ethiopian Renaissance Dam (GERD), which is being built in Ethiopia and is set to be Africa's largest source of hydroelectric power, Egypt is concerned it will receive less water for things like agriculture.
Downstream ecosystems rely not only on water, but also on sediment, both of which are held back by big dams. As solid materials build up in a manmade reservoir, downstream land becomes less fertile and riverbeds can become deeper or even erode away. Emilio Moran, a professor of geography and environment at Michigan State University in the US, described sediment loss of 30 to 40% as a result of large dams.
"Rivers carry sediment that feeds the fish, it feeds the entire vegetation along the river. So, when you stop sediment flowing freely down the streams, you have a dead river."
And ecosystems may have adapted to natural flooding, which dams take away.
Mega-dams also often have a large footprint on land upstream. Aside from displacing human communities, flooding to create a reservoir also kills plants, and leaves animals to drown or find new homes. Reservoirs can also further fragment valuable habitat and cut off migratory corridors.
2. Dams Reduce Biodiversity and Cause Extinction
Aquatic species, particularly fish, are vulnerable to the impacts of dams. Moran says the Itaipu Dam, which was constructed on the border between Paraguay and Brazil in the 1970s and 1980s, resulted in a 70 percent loss of biodiversity.
"On the Tucuruí Dam that was built in the 80s in the Amazon," he added, "there was a 60% drop in productivity of fish."
Many fish species rely on the ability to move about freely in a river, be it to seek food or return to where they were born. Migratory species are badly affected by the presence of dams. In 2016, the International Union for the Conservation of Nature (IUCN) reported a 99% drop in catches of sturgeon and paddlefish — both of which are migratory — over a period of three decades. Overfishing and river alteration were cited as major threats to the species' survival.
A 2018 study predicted that fish stocks on Asia's Mekong River could drop by 40% as a result of dam projects – with consequences not only for biodiversity, but for the people whose lives and livelihoods depend on those fish.
The stakes for biodiversity are particularly high for animals threatened with extinction. And not only for aquatic species. The Tapanuli orangutan — the Earth's rarest ape, with only 500 individuals left — could finally be pushed to the brink if a planned hydroelectric project in Sumatra, Indonesia, is completed. Dams can literally snuff out species.
3. Dams Contribute to Climate Change (and Are Affected by It)
As reservoirs fill, upstream forests are flooded, eliminating their function as carbon sinks. As the drowned vegetation decomposes, decaying plants in manmade reservoirs release methane, a powerful greenhouse gas. That makes reservoirs sources of emissions — particularly those in tropical forests, where there is dense growth. It's estimated that greenhouse gas emissions from dams amount to about a billion tons annually, making it a significant global source.
And as the climate changes, more frequent and prolonged drought means dams will capture less water, resulting in lower electricity production. Countries dependent on hydropower will be especially vulnerable as temperatures keep rising.
Moran described a vicious circle, for example in Brazil, which gets 60 to 70% of its energy from hydropower: "If you wipe out half the rainforest, there will a loss of half the rainfall. And then there won't be enough water to provide the amount of power from those dams," he explained.
4. Dams Reduce Water Quality
Manmade reservoirs trap fertilizers that run into the water from surrounding land. In addition, in some developing countries, sewage flows directly into the reservoirs. This kind of pollution can result in algae blooms that suck the oxygen out of the water, making it acidic and potentially harmful to people and animals.
Still water in large manmade lakes is warm at the top and cold at the bottom, which can also affect water quality. While warm water promotes the growth of harmful algae, the cold water that is often released through turbines from the bottom of a reservoir may contain damagingly high mineral concentrations.
In some cases, water in manmade reservoirs is of such bad quality that it is not even fit to drink.
5. Dams Waste Water
Since more surface area of the water gets exposed to the sun, reservoirs result in much more evaporation than the natural flow of the river before that dam existed. It's estimated at least 7% of the total amount of freshwater needed for human activities evaporates from the world's reservoirs every year.
This effect is made worse in hot regions, Moran pointed out. "Certainly if you had a reservoir in a tropical area with high temperatures, there is going to be a lot of evaporation," he said. And big reservoirs "are, of course, evaporating constantly."
Reservoirs are also a haven for invasive plant species, and weed-covered reservoir banks can lead to evapotranspiration — or the transfer of water from the land to the atmosphere through evaporation from soil and transpiration from plants. Such evapotranspiration amounts to six times more than the evaporation from the water's surface. And there is even evidence that dams increase water use and promote water waste by creating a false sense of water security.
In the face of dwindling global freshwater resources, some question whether dams should be reconsidered.
So What Are the Alternatives?
The evidence is damning. But if mega-dams have so many harmful environmental effects, what are the alternatives? Although some green groups point to small hydropower as being more ecologically sound, Moran is skeptical. "A dam is a dam - it's blocking the fish, it's blocking the sediment."
He pointed to the need to consider not just how to maximize energy production, but also maintain ecological productivity. One option he cited is the use of in-stream turbines.
And many environment advocates agree that other renewable energies such as solar and wind can provide clean electricity at a far lower environmental cost.
Reposted with permission from Deutsche Welle.
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This Earth Month, Starbucks is experimenting with a circular economy.
From March 30 to May 31st, customers at five Seattle Starbucks will be able to order their drink in a reusable cup that they can then deposit themselves at a contactless kiosk or have picked up for them by area recycling service Ridwell.
"Promoting reusability is an important part of Starbucks goal to reduce waste by 50% by 2030," Starbucks Chief Sustainability Officer Michael Kobori said in the program announcement. "We understand the interdependency of human and planetary health, and we believe it is our responsibility to reduce single-use cup waste. We will lead the transition to a circular economy."
Borrow A Cup
Lauren Pinney / Edelman / Starbucks
The Borrow A Cup pilot works like this.
Step 1: Customers will order their drink in a reusable cup and pay a refundable $1 deposit.
Step 2: When they are done, customers will return the cups to a contactless kiosk in the store's lobby or drive-thru. They can then scan the Starbucks App for a $1 credit and 10 Bonus Stars.
Step 3: The cups will be collected and professionally cleaned by GO Box and returned to circulation within 48 hours.
Starbucks said each reusable cup would prevent as many as 30 disposable cups from being wasted.
The new pilot is not the first time the company has experimented with ways to reuse cups, a Starbucks spokesperson told EcoWatch in an email. The company has offered a discount for customers bringing their own containers since the 1980s and has long sold its own reusable thermoses and mugs at its stores. However, the idea of offering cups that can be returned to the store later is rather new. In 2019, it launched a month-long reusable cup trial at London's Gatwick airport and another test in the Bay Area. To prepare for the current trial, it ran single-store tests in the Seattle area during the fall and winter of 2020 and 2021.
"Those tests were intended to explore operations and logistics for our partners, and used our standard reusable traveler cup, usually available at the cash register," Starbucks explained. "This pilot will explore the scalability of the concept and equipment."
Starbucks did not say exactly how, when, or where the project would be expanded if it succeeds.
"We are optimistic about this program and we look forward to customer feedback as we explore scalable options to reduce single-use cup waste," the company spokesperson said.
Lauren Pinney / Edelman / Starbucks
One unique feature of the Seattle pilot is the partnership with Ridwell. Ridwell is an innovative Seattle-area company that grew out of a father and his six-year-old son's search for a place to safely dispose of batteries, according to the company website. Once they found their answer, they offered to take their neighbor's batteries, too.
The company's mission ignited from this initial spark. Ridwell picks up hard to reuse or recycle items from Seattle homes and finds a way to keep them out of landfills. This made partnering with Starbucks a natural fit. During the trial, the company will pick up the reusable cups from customers' homes.
"Our mission is to make it easy to waste less – just as easy (and hopefully more delightful!) than throwing things away. Offering our members the ability to return their reusable Starbucks cups without leaving their homes or needing to remember to bring them back to the store is a fantastic example of simplifying potential friction in reuse and circular programs at scale," a Ridwell spokesperson told EcoWatch in an email.
Ridwell said it would like to engage in more partnerships like this if the Starbucks trial succeeds.
"We are excited about expanding partnerships that enable a more earth-friendly way for our members to consume the things they enjoy (like a coffee!)," the spokesperson said.
A Tale of Two Markets
Lauren Pinney / Edelman / Starbucks
Environmental campaigners said that the Starbucks pilot is a step in the right direction.
"Greenpeace supports the model that Starbucks is exploring, through which customers essentially rent a reusable container for a deposit that is returned to them when they bring the container back," Greenpeace USA Oceans Campaign Director John Hocevar told EcoWatch in an email. "That container is then washed and cleaned and reused many times, as with other dishes in restaurants we frequent. Not only can this model help our environment and health, it can create new jobs and save businesses money in the long run."
However, Greenpeace argued that Starbucks could be moving faster with implementing this model across the U.S., something that seems to be supported by Starbucks' actions abroad.
The day before Starbucks announced the Seattle pilot, it also said that it would phase out all single-use cups from its South Korea stores by 2025. This will begin with a launch of reusable cups in certain stores in the city of Jeju this summer that will then expand to additional locations over the next four years.
"If Starbucks can eliminate all single-use cups in South Korea by 2025 and shift entirely to reuse, it can do more than implement a trial program here with a goal of reducing waste by 50% by 2030," Hocevar said. "Starbucks' goal should be to eliminate all of its disposable coffee cups as quickly as possible and scale up these reusable programs across all of its markets."
Starbucks, for its part, said that local conditions determined how quickly it could roll out new ideas in different places.
"In some cases, market level conditions allow us to move quickly than others, which in turn allows us to share those learnings in other markets," the company said.
But Greenpeace noted there is another key difference between the U.S. and South Korea. The latter passed a law in 2018 banning disposable cups at sit-down restaurants, and the Environment Minister further revised rules in February to cut down on plastic and other disposable items.
"It definitely appears as though South Korea's recent actions against single-use plastics, particularly for dine-in options, has influenced Starbucks to act with greater urgency there," Hocevar told EcoWatch. "This is part of the reason we need to pass the Break Free From Plastic Pollution Act [in the U.S.] and develop a global plastics treaty to move toward reuse urgently."
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As California enters its second consecutive dry year and braces for what could be another devastating wildfire season, Gov. Gavin Newsom declared a drought emergency on Wednesday, in just two counties. The declaration targets Mendocino and Sonoma counties, known for their wineries and grape growing, and where conditions are desperately dry.
Standing in the dry bottom of Lake Mendocino, Newsom said, "Oftentimes we overstate the word historic, but this is indeed an historic moment, certainly historic for this particular lake, Mendocino," according to AP News. The lake is at about 40 percent of its normal capacity. Lake Sonoma, another local reservoir, is only about 62 percent full.
Here in Lake Mendocino, we should be 40 ft. underwater but it’s dry. This is climate change. Today, we declared a… https://t.co/ISsasLAihB— Office of the Governor of California (@Office of the Governor of California)1619034124.0
According to the California Department of Water Resources, this is the state's fourth-driest year on record, especially in the northern parts of the state. At the beginning of the month, state officials announced that snow accumulation in the Sierra Nevada mountains and the Cascades was about 40 percent below average levels, The Guardian reported.
Newsom's declaration has already faced criticism from state officials and farmers in the Central Valley, who say the governor's approach isn't sufficient to address the drought that impacts almost all parts of the state.
"(T)he Central Valley can't afford to be overlooked," state Sen. Andreas Borgeas (R-Fresno) said in a statement, according to The Mercury News. "We need a statewide emergency declaration immediately in order to deliver more water to farmers and growers in the Valley."
To others, the governor's regional approach "sounds like a good idea," Jay Lund, director of the Center for Watershed Sciences and a professor of civil and environmental engineering at UC Davis, told The Mercury News, who added that the governor should not declare a widespread drought too early, to avoid "crying wolf."
Currently, California is in a similar situation to what it experienced six years ago when former Gov. Jerry Brown declared a water emergency. But state officials say today's current drought will be unlike anything seen before, requiring innovative measures, according to CalMatters.
Although the governor has yet to declare a state-wide emergency, officials have been warning Californians of the drought. In March, the California's State Water Resources Control Board, for example, "sent early warnings to 40,000 water rights holders urging them to start conserving," AP News reported.
"If you're in a different part of the state, you probably need to know that this will one day happen to you," Karla Nemeth, director of the California Department of Water Resources, said of the drought declaration, according to AP News.
In early April, a group of state legislators sent a letter to Newsom urging him to declare a drought emergency, CalMatters reported. "This is the slowest, most foreseeable train wreck imaginable," said Sen. Borgeas, who helped write the letter.
Newsom's reluctance to declare a state-wide emergency may have something to do with his looming recall campaign, set for later this year, according to political strategist Dan Schnur, The Mercury News reported.
"It's hard to think of another explanation about why he'd be tiptoeing around such a critically important issue," Schnur told The Mercury News. "He's clearly very sensitive about pushing voters too hard on water usage in the aftermath of the pandemic restrictions."
Regardless of whether the declaration covers their county, some local water districts are already taking matters into their own hands. In Marin County, for example, adjacent to Sonoma, water officials voted Tuesday to require residents to reduce water use by measures such as not washing vehicles at home or filling backyard pools, AP News reported.
As the state continues to battle the COVID-19 pandemic and a sluggish economy, scarce resources and the threat of another wildfire season will only ignite further tensions. Acknowledging that water is a "politically fractious issue" in the state, Gov. Newsom urged people not to resort to "old binaries" like urban vs. rural, The Mercury News reported.
"This is California," he said. "We are Californians."
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Much of the conversation surrounding the ecological benefits of tropical rainforests focuses on South America's Amazon. However, the forests of Central Africa are just as important. While the Amazon is the largest contiguous rainforest in the world, Central Africa's rainforests are the world's second largest, Nature reported. They store more carbon per hectare than the Amazon and host a higher concentration of large trees than any other continent.
They are also under threat. A new study published in Nature on Wednesday maps the different forest types present in Central Africa and pinpoints which are most vulnerable to the climate crisis and human activity.
"Africa is forecasted to experience large and rapid climate change and population growth during the twenty-first century, which threatens the world's second largest rainforest," the study authors wrote. "Protecting and sustainably managing these African forests requires an increased understanding of their compositional heterogeneity, the environmental drivers of forest composition and their vulnerability to ongoing changes."
To accomplish this goal, a France-based research team examined data concerning six million trees from more than 180,000 field plots in Cameroon, Gabon, the Central African Republic, Republic of the Congo and the Democratic Republic of the Congo, AFP reported.
The team mapped the forests based on where different plants thrived.
"The forest area of Central Africa is far from being a homogeneous green carpet. It is home to a wide variety of forests with different characteristics, including their own particular carbon storage capacity," Maxime Réjou-Méchain, study lead author and French National Research Institute for Sustainable Development (IRD) ecologist, said in an IRD press release. "This diversity can be explained by the different types of climate (humidity, temperature, evapotranspiration rate, amount of rainfall) and soils, as well as by the history of the African flora and the degree of human activity that has disturbed the forests for thousands of years, such as shifting agriculture."
The researchers identified 10 types of forest, according to Nature. These include Atlantic coastal evergreens in Gabon and semi-deciduous forests at the northern edge of the Central African study area. The researchers then compared their map with projections for how the region's climate is likely to change by 2085.
Because the various forest types have evolved over time to thrive in different climate niches, the rise in global temperatures might mean that some trees will be less able to adapt to a changing climate.
"[T]he forest margins in the north and south of the region, the Atlantic forests and most of those in the Democratic Republic of Congo, which is home to more than half of Central Africa's forests, are among the most vulnerable," Professor Bonaventure Sonké, study coauthor and University of Yaoundé 1 botanist, told IRD.
However, the research also presents a guide to conserving the particular biodiversity of these forests.
"These results must now be used and applied to develop land use plans that preserve forest characteristics while maintaining connections between protected zones through sustainably managed timber production forests," Sylvie Gourlet-Fleury, study coauthor and CIRAD forest ecologist, said in the press release.
While human activity threatens the forests, they are also key resources for the people who live in and near them.
"[R]ainforests in Central Africa and the ecosystem services they provide are intertwined with people's livelihoods and food security," Marion Pfeifer from Newcastle University's School of Natural and Environmental Sciences and Deo Shirima from Tanzania's Sokoine University of Agriculture wrote in Nature. "Developing sustainable management plans that recognize the diversity of the ways in which people interact with and depend on these forests will be a huge challenge. It will require concerted cross-disciplinary and cross-sectoral efforts that move beyond national boundaries."
The Race to Save the World is releasing on Virtual Cinema this Earth Day. Instead of focusing on paralyzing facts and numbers this inspiring feature takes a unique approach by following passionate activists, ages 15-72, who are in the trenches fighting for a livable future. These brave climate warriors put their lives on the line to push for change, regardless of the personal cost.
Emmy award-winning filmmaker Joe Gantz brings an urgent and intimate portrait of the protests, arrests, courtroom drama and family turmoil these activists endure as they single-mindedly focus their attention on the goal of creating a more sustainable world for future generations. "The Race To Save The World" is an inspiring and energizing call-to-action to quit waiting on the sidelines and make our voices heard.
Watch the exclusive Earth Day preview above.
For more on "The Race to Save the World" read Olivia Rosane's article "3 New Films to Watch This Earth Week."
Where to Entire Film Watch: Virtual Cinema
Forty leaders from the world's top greenhouse gas-polluting nations where hosted by the Biden administration on Thursday for an all-virtual summit to discuss the global climate emergency and the pathways — including individual emission reduction goals — that governments must take to stave off the worst impacts of global warming and runaway destruction of the planet's natural systems.
Just ahead of the gathering, President Joe Biden announced new U.S. commitments to meeting the goals set forth in the 2015 Paris climate agreement and said that the nation will now aim to reduce annual carbon output by 52% compared to 2005 levels.
"Our clean energy plan will create millions of good-paying union jobs, ensure our economic competitiveness, and improve the health and security of communities across America," Biden said in a declaration released ahead of the summit. "By making those investments and putting millions of Americans to work, the United States will be able to cut our greenhouse gas emissions in half by 2030."
While the most ambitious target ever set forth by an American president — and a total reversal from the destructive policies of his predecessor Donald J. Trump — climate scientists and advocacy groups have been outspoken to say that even Biden's stated goals are simply "not enough" to meet U.S. obligations or keep the world from less than 1.5ºC of warming this century.
Watch the summit above.
Reposted with permission from Common Dreams.