Human-induced climate change undoubtedly represents a significant threat to environments and people throughout the world, including the Mekong River Basin in mainland Southeast Asia. For example, rising sea levels pose a serious threat to the Mekong Delta in Vietnam.
It is also well-known, however, that the construction of hydropower dams on the mainstream Mekong River and its tributaries is causing a number of serious negative environmental and social impacts.
What's worse: climate change or dams?
Recently, a journalist asked me whether I thought climate change or hydropower dams had more of a negative impact on the Mekong River Basin. The question surprised me, considering research I had recently done along the mainstream Mekong River in Stung Treng Province, northeastern Cambodia in June 2022.
During that research, which involved assessing almost 100 years of Mekong River hydrological data, and conducting interviews with local fishers and field observations, it became clear that over the last 15 years or more, dry season water-levels just below the Khone Falls – on the border between Laos and Cambodia – have increased between one and 1.5 meters during the low-water and driest part of the year, between February and April. Climate change is certainly unlikely to cause this sort of change in the foreseeable future.
As a result, various specially adapted and seasonally inundated forest tree species found in the riverbed have been dying in large quantities. These trees and bushes are adapted to being underwater for many months each year. During the height of the dry season, however, water levels usually decline significantly, revealing the roots of these trees and allowing them to survive. This also provides opportunities for new seedlings to become established, with their roots wrapped around rocks in the river’s bed. In recent dry seasons, however, water levels have not declined to the extent that they did in the past, leaving these flooded forests underwater year round, disrupting their life cycles, and causing them to die.
The loss of these flooded forests has widespread environmental and social impacts, including negative effects on a wide range of fish, bird and other species of aquatic animals that rely on these forests for food and habitat.
Dams affect flora and fauna
The cause of the dramatic increase in dry-season water flows in the Mekong is undoubtedly the construction of large hydropower dams, including on the mainstream river in China, but also on Mekong tributaries in Thailand and especially in Laos. These dams, which have large reservoirs, are capable of collecting large amounts of water during the rainy monsoon season, and releasing that water to produce energy during the dry season.
Thus, large hydropower dams in the Mekong River Basin have many serious negative impacts on the river. First, the dams threaten Mekong River Basin freshwater fisheries, the most important freshwater fisheries in the world, ones which support the dietary requirements and generate income for tens of millions of people. Second, the dams threaten the rich aquatic biodiversity of the Mekong River Basin.
Human-induced climate change is also causing environmental changes in the Mekong River Basin, which in the long-term can be expected to result in serious negative impacts. However, compared to the dramatic changes in the Basin that have been caused by large hydropower dam development in recent years, these changes are relatively modest.
Over a longer period of time, though, it can be expected that impacts will increase. Nonetheless, there is no reason to believe that climate change will ever lead to such dramatic hydrological changes that dams have so far caused in the Mekong River Basin. Moreover, if more dams are built, things could get worse. Therefore, returning to the question that the journalist asked me, there is no doubt that hydropower dams have a much more serious environmental impact when it comes to the Mekong River compared to human-induced climate change.
Profitable 'renewable' energies
Ironically, however, global concerns about human-induced climate change have given the large hydropower dam industry a new lease on life, by allowing dam developers and their government and private sector advocates to define energy produced by large dams as “green” or “renewable” energy. This opens the door for international financing, including from European banks, to support some of the most destructive hydropower dams in the Mekong River Basin. To make matters worse, the Clean Development Mechanism of the Kyoto Protocol has even helped facilitate the construction of new large and destructive hydropower dams in various parts of the world, including in the Mekong River Basin, in the name of solving the climate crisis. Various NGOs, led by International Rivers, have tried to raise awareness about this important issue, but without receiving enough attention.
The future of large dam construction looked bleak in the early 2000s, after the World Commission on Dams (WCD) released its final report, sponsored by the World Bank and International Union for Conservation of Nature, which widely condemned hydropower dam development around the world as socially and environmentally problematic, and also economically unattractive for a number of reasons. International donors and financial institutions dared not provide financing. But then concerns about human-induced climate change – ones that are well justified – suddenly made it possible for the industry to gain more political backing and financing, leading the industry to grow dramatically.
This is despite the fact that in recent years, technological advances have dramatically decreased the cost of solar, wind, geothermal and other renewable energy sources, which should make hydropower energy that much less attractive, since there are more cheap renewable energy alternatives than ever before.
Real solutions are needed
Nevertheless, the 2010s saw an unprecedented increase in hydropower dam construction in the Mekong River Basin. Financing from China has played an important role in this hydropower development boom, but so has financing from various parts of the world, justified by the promise that hydropower dam development is “environmentally friendly”. Fishers in northeastern Cambodia, who have been watching the seasonally flooded forest there die, would certainly disagree.
Human-induced climate change is undoubtedly a critical problem that requires our attention. But reducing greenhouse gas emissions in ways that have even more serious environmental and social impacts is not the appropriate way to combat climate change. We need real green solutions, not fake green solutions such as large hydropower dams.
Guest commentary by Ian Baird.
Ian Baird is professor of Geography at the University of Wisconsin-Madison, where he is also the coordinator for the Hmong Studies Consortium. His interests include dams in the Mekong River Basin and their impacts on fish and fisheries, land tenure issues in Southeast Asia, and the global Indigenous peoples movement. He has extensive experience living and working in Laos, Thailand and Cambodia. His most recent book is titled "Rise of the Brao: Ethnic Minorities in northeastern Cambodia during Vietnamese Occupation" (University of Wisconsin Press, 2020).
