Environmental Stressors

"Industry gets away with too much. A lot of damage is taking place just outside the borders of our territory. Western science has had its voice heard long enough. We need to be putting First Nations people as the primary contributors and owners of the data."

Hydropower has become the world’s leading renewable source for electricity generation, supplying 72% of all renewable electricity by 2020. Reaching 1,064 GW of installed capacity in 2016, hydropower generated 16.9% of the world’s electricity from all sources. Almost all of this power is produced by more than 45,000 large dams built in over 160 countries. Of these, China is the world’s largest producer (163.1 million tonnes of oil-equivalent or mtoe), followed by Brazil (89.6 mtoe), Canada (82.9 mtoe), and the US (58.8 mtoe). The number of these mega dams continues to grow; some 35 GW of new hydropower capacity was commissioned in 2019, thereby increasing total global capacity by 3.6%. At least 3,700 major dams are currently planned or under construction, most of these in Asia, which will further increase the current global hydroelectricity capacity by 73 % to about 1,700 GW.

Proponents argue that benefits arising from hydropower projects are substantial and that consumers and business benefit from this inexpensive power. They also argue that dams are environmentally friendly as a renewable resource that takes advantage of water flows that would otherwise be wasted. Hydropower is thus presented as a low-carbon, even “clean” and “green”, energy source that can displace more carbon-intensive sources such as coal and natural gas. Over the last 20 years, exports of hydropower by Manitoba are reported to have displaced 170 million T of greenhouse gas emissions in the US. Globally, hydropower prevents the emission of about 3 GT CO2 per year or about 9% of global annual CO2 emissions from coal-fired power plants.

The claimed potential for dams to mitigate climate change has contributed to a renewed global interest in hydropower. Most dams in North America and Europe were built from 1920-1980, at which point construction slowed; indeed, dam removal has become the norm in these regions. This is, in part, because of aging infrastructure, the extreme costs of replacement and growing concerns about their environmental and social impacts. Although such concerns once led to the withdrawal of support by international policy institutes and funding agencies, hydropower and large dam development have recently made a global comeback. Amidst rising awareness about climate change, hydro is presented as a key solution when transitioning towards the new ‘green economy’ and has re-established its dominance as the world’s main renewable energy source, Critics argue such claims amount to greenwashing.

To learn more about the Hydropower visit Wa Ni Ska Tan.

Despite the above claims, hydro projects generally have dramatic and adverse impacts on both environments and nearby communities. Recent research indicates that reservoirs are actually significant sources of carbon emissions, sometimes more than the coal-fired plants they are designed to replace. They often result in the flooding of large expanses of natural habitat, especially in undulating landscapes. The Three Gorges Project in China, the world’s largest dam (22,500 MW), has a reservoir area of 1,084 km2 and the second largest in Brazil and Paraguay (14,000 MW) flooded 1,350 km2. The Robert Bourassa Dam in Quebec flooded 11,300 km2 whereas the WAC Bennett Dam in BC and the Grand Rapids Dam in Manitoba submerged 1,650 km2 and 1,157 km2 of upland habitat, respectively. As flooding occurs, microbially released methylmercury is released and accumulates in invertebrates and zooplankton, which is further concentrated at higher trophic levels. Mercury levels can be extremely high in predatory fish such as pike and walleye and for muskrat, ducks, and moose and gull eggs.

Flooding erodes shorelines, resulting in the collapse of permafrost and riparian forests in northern climates. Cumulative impacts of flooding cause declines in the productivity and biodiversity of downstream deltas as well as estuarine and coastal areas. Rare or endangered species that are especially vulnerable to these changes include lake sturgeon and woodland caribou in northern Manitoba and salmon in the Pacific Northwest. Indeed, hydro dams are increasingly being built in the world’s most biodiverse river basins, including the Amazon, Congo and Mekong, which will have enormous implications for biodiversity including one-third of the world’s fish species.

The implications of these dams for the health and wellbeing of impacted communities is often drastic. In the most extreme cases, entire communities are forcibly relocated which has extraordinarily adverse impacts on traditional economies and culture. Post-impoundment mercury levels in fish are soon high enough that they are no longer safe to consume, much less to export, thus undermining community confidence in traditional foods and in turn contributing to increases in diabetes, obesity, and heart disease. Impacts including declines in traditional harvesting and in health and wellbeing are widespread, and visible in communities across Canada and the Global South.

Yet, research on hydropower, especially as it relates to the environment and wellbeing, still largely excludes impacted communities and does little to address the individual much less cumulative impacts of projects on environments and communities. Moreover, there is an even greater dearth of hydro-related and other environmental and health research that focus on strength-based solutions to impacts.

To learn more about the impacts of hydro dams visit Wa Ni Ska Tan and Hydro Impacts.