Large Dams and Big Flu

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The White Bellied Heron is a critically endangered IUCN red-listed species with only 200 left in the world. Two dam projects proposed in the Himalayan region would wipe out the habitat of about twenty birds, or about 10% of the world’s population. Photo by Tshering Tobgay,

Large hydro dams. They may not be the first thing that comes to mind when we are fighting a global pandemic. But as scientists seek to uncover Covid-19’s origins, a clearly emerging message is that protecting biodiversity and the spaces in which it thrives is critical to inhibiting the spread of deadly zoonotic diseases. As destructive infrastructure projects – such as mega dams  flood, deforest, fragment and deprive biodiversity hotspots of their natural state, humans become exposed to an array of harmful organisms that we typically have little contact with. And with that exposure, the potential to transform into regional and global disasters increases.

Rob Wallace, evolutionary biologist and author of Big Farms Make Big Flu warns that as humans increase deforestation and encroachment, and biodiversity is lost, the conditions for a rapid expansion and spread of new disease from a local infection to a worldwide pandemic becomes far greater. He notes that both Ebola and Zika viruses resulted from well-known ecological processes that link the loss of biodiversity and habitat fragmentation to outbreaks of pathogens.

In our work with dam-affected communities, International Rivers has found that riverine and indigenous communities have a vitally important role in biodiversity protection through safeguarding natural resources and biodiversity hotspots from encroachment while maintaining sustainable fishing, farming, and hunting practices. This role is threatened when communities are displaced from their lands, often to nutrient-deprived areas, to make way for large dams and other infrastructure projects, or when their resource-based livelihoods are eroded through the environmentally destructive impacts of these projects. As dams inundate highly-fertile river systems and the most diverse forests and wetland ecosystems in the world, communities who depend on those systems also lose their ability to support themselves sustainably.

The current pandemic has also brought into focus the startling increase in the wildlife trade, which results in the further stripping of forests in the surrounding watershed areas. As resource extraction and infrastructure prompt an influx of rural populations into cities and towns, the economic pressures that come from living in urban and peri urban environments triggers even greater pressure for wildlife through clearcutting forests and increasing demand for wildlife as food and traditional medicines. Those who seek to industrialize food and traditional medicines from wildlife not only force the demise of rare species, but also creates a cocktail of domesticated animals (pigs, cattle, chickens) and exotic species (bats, civet cats, pangolins) within the human food chain as an experiment of intensively farmed and caged contagions.

As some of the world’s most resilient farmland along riverbeds is lost to reservoirs and manmade droughts (such as the one unfolding in the Mekong region), food security is increasing in local areas. This pushes states and corporations to intensify agribusinesses linked to global food and supply chains. Industrial agriculture complexes also risk becoming purveyors of an array of zoonotic diseases that easily spread to humans through food systems. These are often linked to bats and pigs or other livestock, including H1N1 and MERS with camels, or lesser known outbreaks like the Nipah virus in Malaysia when bats moved from jungles to mango plantations causing a deadly outbreak in industrialized piggeries and leading to the transmission to humans. We also see more cases of virus outbreaks among workers in the food processing facilities that often caters to destructive farming practices, including about a dozen facilities for meat processing across the USA and Canada, and packing facilities for fruit and vegetables.

Large hydro dam developments are submerging hundreds of thousands of hectares of the planet’s key biodiversity hotspots. These projects both flood and deprive forests of water and destroy livelihoods that depend on seasonal river flows and life-supporting nutrients. As more dams are built, fisherfolk and farmers cannot rely on the seasonality of water flows. Upstream nutrient flows stop. Water releases must be negotiated with a dam’s engineering team, sometimes across national borders. The natural ecosystems destroyed by dams also act as our barrier against dangerous pathogens which may be harmless in their natural state, but when biodiversity is destroyed, exposure and spread to humans is far more likely to take place with disastrous consequences. As stated in a July 2012 article published by the New York Times

“…emerging diseases have quadrupled in the last half-century, experts say, largely because of increasing human encroachment into habitat, especially in disease “hot spots” around the globe, mostly in tropical regions… The key to forecasting and preventing the next pandemic, is understanding what they call the ‘protective effects’ of nature intact. In the Amazon, for example, one study showed an increase in deforestation by some 4 percent increased the incidence of malaria by nearly 50 percent, because mosquitoes, which transmit the disease, thrive in the right mix of sunlight and water in recently deforested areas. Developing the forest in the wrong way can be like opening Pandora’s box.”

Unfortunately, China has the designation of having the greatest number of large dams in the world with over 23,000, followed by the US being the second most dammed country with some 9,200, followed by India, Japan, and Brazil. Southeast Asia is also fast becoming a hydro-epicenter, with Laos in the lower Mekong basin, for example, aiming to become the ‘Battery of Asia’ through the extensive development of its hydropower capacity. Meanwhile, plans to construct new dams in some of the world’s most remote and sensitive biodiversity hotspots continue unabated. The Koukoutamba Dam in Guinea would threaten the last stronghold of the critically endangered western chimpanzee. The Batang Toru Dam in Sumatra threatens the extinction of the rarest and most critically endangered great ape, the Tapanuli orangutan. Dam construction in these previously inaccessible locations not only risks potential human exposure to new pathogens, there is increasing concern that these endangered ape species will be exposed to Covid-19, to which they are particularly vulnerable.

Big dams are inextricably linked to the destruction of habitats and biodiversity. Building more of them means increasing threats to food security and eroding natural barriers against dangerous pathogens. Energy planners and dam developers must elevate their consideration of the risks and unanticipated impacts of biodiversity loss whenever they consider large hydro projects. However, the International Hydropower Association is calling for Covid-19 recovery stimulus to prioritize dam construction without mentioning how they would protect biodiversity.

The industry cannot cloak its impacts on the environment and livelihoods while it seeks “financial measures such as tax incentives… to ensure that economically viable and shovel-ready projects can commence” in the midst of a pandemic. The industry, its financiers, and host governments must do far more to protect biodiversity and peoples’ livelihoods before the shovels dig humanity into a deeper crisis.