When the dam broke, it brought with it a torrent of water and mud, killing at least 31 people and displacing upwards of 6,000 people across Laos and Cambodia. Reported numbers of those still missing range from “many” to “hundreds.” The flood, by even the secretive Lao government’s conservative estimates, would have been enough to drown Manhattan in 28 feet of water.

This is what the hydropower boom has come to in Laos. And yet, the deaths and destruction so evident following the July 22 collapse are only the most visible consequences of the country’s dam-building efforts and the hydropower boom globally.

Across the developing world, dams continue to forcibly displace and thereby impoverish millions of people, drain national budgets, emit greenhouse gases, and destroy the ecological balance of entire river basins — balances on which millions of people intimately depend. At the same time, climate change — and the droughts and superstorms it exacerbates — is rendering hydroelectricity the most vulnerable source of power on offer.

Backed by recent research, here are five key things that governments, development financiers, and other proponents of development-by-dams seem to consistently forget.

1. Large dams have displaced tens of millions of people, impoverishing many in the process. And the trend is not abating.

In 2015, in a rare but welcome move, the World Bank owned up to its complicity in a concerning trend that frequently falls under the radar: infrastructure projects, often advertised with the primary aim of poverty alleviation, forcibly displace millions of people per year. In more cases than not, the most vulnerable of local populations are the ones who suffer, and neither their governments, nor any other projects proponents, typically compensate them for their losses.

According to Dr. Michael Cernea, one of the world’s leading resettlement experts and former World Bank Senior Adviser for Sociology and Social Policy, large hydropower dams constitute the sector responsible for the most displacement. Drawing on World Bank data in a new book, Cernea estimates that in the period from 2011 to 2020 more than 200 million people will have been forcibly displaced by development projects worldwide.

The magnitude of resettlement required by even a single dam can be massive. Brazil’s Sobradinho Dam ousted 65,000. India’s Narmada Dam project forced out more than 200,000. In 2002, the World Commission on Dams estimated that, throughout history, dams have displaced 40 to 80 million people in total.

From 1990-2010, more than 1,400 World Bank projects triggered the institution’s “Involuntary Resettlement Policy.” Compensation for the displaced, even by the Bank’s standards, was dismal. Fewer than 50 percent of those displaced by these projects had their livelihoods “restored.” At the same time, the World Bank is known to have some of the strongest social-environmental safeguards of any development financier. Development-induced impoverishment numbers associated with other financiers are likely much higher, but such data do not exist.

2. More often than not, large dams run over budget and under-deliver on benefits — severely enough, in some cases, to put entire national economies at risk.

Without even taking into account the economic destruction wrought by forced displacement, and without even considering environmental impacts, large dams are simply not worth their cost.

Analyzing a sample of 245 large dams, the most comprehensive dataset of its kind, Oxford economists found that “the capital sunk into building nearly half of the dams could not be recovered.” Much of this stems from poor cost-benefit forecasting. They uncover “overwhelming evidence that budgets are systematically biased below actual costs of large hydropower dams — excluding inflation, substantial debt servicing, environmental, and social costs.”

Here, again, the burden of a single dam can be enormous: the authors’ model predicts that Pakistan’s under-construction Diamer-Bhasha dam, initially forecast to cost $12.7 billion, will ultimately require $35 billion (both 2008 dollars) — roughly one quarter of the country’s GDP.

There may even be global consequences to such project development. In a subsequent study on China’s international infrastructure boom, the same Oxford team finds that “poorly managed infrastructure investments are a main explanation of surfacing economic and financial problems in China.”

The Oxford researchers add: “Unless China shifts to a lower level of higher-quality infrastructure investments, the country is headed for infrastructure led financial and economic crisis, which is likely also to be a crisis for the international economy.”

3. Large hydropower is not emissions free. It can generate greenhouse gases more than 30 times as potent as carbon dioxide, frequently contributing more to climate change than fossil fuels plants of equivalent generating capacity.

Every time you see a report counting “hydroelectricity” as “renewable” or “zero-emissions,” look up the credentials of its author. Hydropower is not always clean.

Large dams often flood vast vegetated areas. When they do, that vegetation rots underwater, eventually releasing methane, a greenhouse gas 34 times as potent as carbon dioxide. In some cases, large dams can result in even more lifetime greenhouse gas emissions than would equivalent conventional sources.

In a 2016 study, leading reservoir emissions scientist Phillip Fearnside found that emissions from “18 dams that are planned or under construction” in the Brazilian Amazon “would exceed those from electricity generation based on fossil fuels.”

Once more, let’s look at the effects of a single dam. Recent analyses performed using the NGO Conservation Strategy Fund’s HydroCalculator tool — open-source software that performs basic cost-benefit analyses of hydroelectric dams with user input data — estimated that Bolivia’s planned Rositas dam reservoir will produce 70 million tons of CO2-equivalent emissions. That’s more than the state of South Carolina emits in a year. Note that these numbers do not include the emissions resulting from constructing dams – cement and equipment-heavy projects that usually take several years to build.

Unfortunately, some of our leading institutions continue to mistake large dams as “emissions-free,” misleading governments, the public, and the researchers who build the climate change/energy production simulations that guide policy.

The United Nations Economic Commission for Europe calls hydropower a “cost-competitive renewable energy source” which “contributes to decarbonising the energy mix.” In its Sustainable Development Goals Tracker, the popular data visualization site Our World in Data counts hydropower capacity in its renewable energy indicator. Even the International Energy Agency is still calling hydropower “renewable.”

Meanwhile, a recent Washington State University study finds that methane emissions are currently not included in global greenhouse gas inventories.

4. Large dams can destroy the ecological balances of entire river basins, and, with them, the livelihoods of millions of people.

One need not look further than Laos, and the Mekong Basin in which it sits, as a case in point.

In the summer of 2016, a journalist colleague, Austin Meyer, and I traveled the length of the Lower Mekong River — from nearby the site of the Xe-Pian Xe-Namnoy collapse in Laos to Cambodia, the Vietnam Delta, and the South China Sea. We found and illustrated how large dams on the Mekong mainstream and its tributaries are impacting communities throughout the region — each severely, but in a diverse variety of ways.

While hydropower will transform the greater part of Southeast Asia, the roots of the problem lie in Laos: a 2010 study suggests that, taken together, the Mekong mainstream dams Laos plans to build, along with two others proposed by Cambodia, could wipe out roughly 40 percent of the wider Mekong Basin’s commercial fish catch, valued at more than $500 million annually.

In the villages floating on Cambodia’s Ton Le Sap lake, fishing conditions — once the backbone of sustenance and economic activity — have deteriorated such that young people are now regularly making the dangerous and illegal journey to construction jobs in Thailand.

In the “rice bowl” region of Vietnam, once-lime-green paddy fields are turning yellow, evaporating annual incomes, as dams hasten erosion (allowing salty sea water to intrude upstream), and impede the flow of nutrients on which farmers rely.

Where it enters the South China Sea, the Mekong River spills nearly 200 tons of nutrient-rich sediment into the ocean every minute, creating some of the most productive fishing grounds in the world. There, fishermen carry on, largely unaware of the difficulties to come. Regional scientists predict that, by blocking this flow of nutrients, dams will ultimately mean the end of the Mekong Plume as it is known today.

Given the degree to which “development” institutions continue to promote large hydropower projects, one may find it difficult to believe that there is a huge literature on this topic. For more, read about the Kariba dam’s impoverishment of 57,000 indigenous people, and about how Brazil’s Belo Monte dam has turned an Amazonian village into one of the poorest and most violent cities in Brazil.

5. As climate change renders weather patterns more unpredictable, large dams will become increasingly susceptible to catastrophic failure, and less reliable forms of energy production.

If this list of impacts is not enough, it is going to get worse. As climate change continues to show itself in fuller color, storms like the ones that helped lead the Xe-Pian Xe-Namnoy dam to fail will become much more frequent. In other places, water inputs, without which hydroelectric dams cannot produce energy, will become unreliable at best.

This is already happening. In 2015, less than a year’s worth of sub-normal rainfall caused the Hoover Dam’s electricity generation capacity to shrink by half. In 2016, droughts caused Lake Kariba, the largest man-made reservoir in the world, to dry up, leading to blackouts in both Zambia and Zimbabwe. A report by the environmental NGO International Rivers argued that, given its reliance on hydropower in the age of climate change, southern Africa is “moving toward the edge of ecological precipice.”

Global electricity demand is rapidly rising at the same time that climate change is rendering storms worse and predictable rainfall a thing of the past. These are toxic investment conditions for infrastructure that relies on constant water inputs – and that can kill when storms hit.

International organizations must come to terms

Despite these lessons — learned over and over again, only with greater consequences each time — it seems clear: the global hydropower boom will not end as a result of individual national governments recognizing and acting on their hydropower amnesia.

The Lao government has temporarily suspended all of its new hydropower projects while it carries out safety inspections of existing dams. Yet there is little to no talk of cancellation, and more than 3,500 hydropower dams are planned or under construction worldwide. As of last year, more than 420 hydroelectric dams were currently under discussion in South America, many of which will go straight on top of tropical rainforests and indigenous communities while blocking major arteries of the Amazon. Hydropower development in Africa is faster now than in any previous decade. The political expediency of erecting such grandiose infrastructure, and the profit it can entail, appears stronger than ever.

The destructive hydropower boom will only end when international entities such as the UN, and the financiers that make such projects possible, begin to talk about large hydropower dams as they too often turn out to be: sources of mass eviction and impoverishment, macroeconomic liabilities, climate change enablers, poison for river basins and the communities that depend on them – and vulnerable to the climate future they have already helped lock in.

CITATIONS

• Ansar, A., Flyvbjerg, B., Budzier, A., & Lunn, D. (2014). Should we build more large dams? The actual costs of hydropower megaproject development. Energy Policy, 69, 43-56. doi:10.1016/j.enpol.2013.10.069

• Ansar, A., Flyvbjerg, B., Budzier, A., & Lunn, D. (2016). Does infrastructure investment lead to economic growth or economic fragility? Evidence from China. Oxford Review of Economic Policy, 32(3), 360-390. doi:10.1093/oxrep/grw022

• Cernea, M. M., & Maldonado, J. K. (Eds.). (2018). Challenging the Prevailing Paradigm of Displacement and Resettlement: Risks, Impoverishment, Legacies, Solutions. Routledge.

• Deemer, B. R., Harrison, J. A., Li, S., Beaulieu, J. J., DelSontro, T., Barros, N., … & Vonk, J. A. (2016). Greenhouse gas emissions from reservoir water surfaces: a new global synthesis. BioScience, 66(11), 949-964. doi:10.1093/biosci/biw117

• Fearnside, P. M. (2016). Greenhouse gas emissions from Brazil’s Amazonian hydroelectric dams. Environmental Research Letters, 11(1).

• Gallagher, K. P., & Yuan, F. (2017). Standardizing Sustainable Development: A Comparison of Development Banks in the Americas. The Journal of Environment & Development, 26(3), 243-271. doi:10.1177/1070496517720711

Gus Greenstein is a PhD student in Stanford University’s Emmett Interdisciplinary Program in Environment and Resources. He has been researching and writing about the social, environmental, and economic impacts of large dams since 2012. Follow him on Twitter: @GusGreenstein.

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