This region is among the world's most vulnerable to climate change impacts. Fish harvests, for instance, are already declining due partly to drought in Cambodia's Tonlé Sap Lake, which supplies the country's 15 million people with more than a third of their protein. The Mekong Delta and its rich agricultural lands are also under grave threat from rising sea levels, storm inundation and their vulnerability to extreme weather.
Climate change in the region is a threat multiplier thanks to unsustainable hydroelectric dams, dozens of which are planned along the lower Mekong River and its tributaries. Two of the most controversial - the Xayaburi and Don Sahong dams in Laos - are now under construction, while dozens more are at the planning stage. It's troubling because, while hydropower is promoted as a CO2 emissions-free "green" energy, a wealth of research now indicates that in reality it is anything but green. By blocking fish migrations, the proposed projects would pose a direct threat to food security by reducing the catch from the world's largest freshwater fishery by as much as one third. Rice production could face a similar impact through the blockage of nutrient-rich sediments.
In short, the increased energy security afforded by hydropower comes at far too high a cost in terms of food insecurity, lost livelihoods, ecosystem degradation and increased exposure to the hazards of climate change. Solar and wind power - available and increasingly cheaper - along with reforestation projects, are far better ways for countries to meet their climate commitments.
Making matters worse, recent peer-reviewed research indicates that large hydroelectric dams not only fail to mitigate climate change, they actually help drive it. They do this in two ways: first, by impairing the roles that free-flowing rivers play as sinks that remove an estimated 200 million tonnes of carbon from the atmosphere annually, and second, by being responsible for emissions of methane - a greenhouse gas 34 times more potent than CO2 - from the rotting vegetation trapped under the reservoirs they create. These dams are also causing subsistence of the Mekong Delta and erosion of its coastline, thus making it even more vulnerable to a climate-change-induced rise in sea level and the increase in frequency and power of storms.
The good news is that there is already a mechanism in place to facilitate regional cooperation on sustainable development of the Mekong: the Mekong River Commission (MRC). Its next meeting takes place today in Phnom Penh, where the water ministers of Cambodia, Laos, Thailand and Vietnam have gathered to discuss the challenges that should unite their countries yet in some cases have divided them.
The bad news is that the Mekong Agreement, the landmark treaty that created the Commission, was signed 20 years ago when most governments had yet to even take note of climate change. But two decades on, this groundbreaking example of regional cooperation is showing its age. Strained by procedural and regulatory disputes over the downstream impacts of large dams, the MRC is not ready to meet the challenge posed by loss of its wild fisheries and the sinking and shrinking of its delta, which, combined with the aggravating impacts of climate change, will have profound and irreversible consequences for the region.
While it remains an invaluable tool for regional cooperation, the Mekong Agreement needs to be refurbished for the 21st century. Fortunately a tailor-made solution already exists - one Vietnam recognized in 2014 when it became the first, and so far only, member of the MRC to ratify the UN Convention on the Non-Navigational Uses of International Watercourses (UNWC).
Passed by the UN General Assembly in 1997, the UNWC codifies the basic principles and best practices of international water law and was written specifically to reinforce - not replace - existing river basin accords such as the Mekong Agreement. Nothing in it supplants, nullifies or contradicts any of the latter's provisions.
So what's the value added? First, the UNWC would provide a mechanism and clear guidelines for dispute resolution - the present lack of which is a major weakness of the MRC. Second, it would clarify existing rules and procedures whose vague wording encourages conflicting interpretations that strain relations among the MRC states, especially over consultations about hydroelectric dams and their downstream impacts. Unlike the Mekong Agreement, it also applies the same rules to mainstream and tributary dams - closing a contentious loophole. By aligning the Mekong Agreement with internationally accepted law, the UNWC would not change the rules so much as hold the MRC members to a higher standard of accountability in following them.
Ratification of the UNWC by Laos, Cambodia and Thailand would not automatically guarantee that misguided projects are abandoned. But it would raise the bar and help reduce tensions by obliging all MRC states to more carefully examine the trade-offs involved and give greater consideration to more viable "green" energy alternatives, based on the best criteria available.
At COP 21 in Paris, the world's governments finally resolved to confront climate change. The MRC ministers need to show the same resolve now in addressing climate-related water issues. As they meet in Phnom Penh, they must look beyond narrow national self-interests and see that a river-be-damned strategy is not the way to a prosperous and climate-safe future for the 60 million people of the Mekong.
Marc Goichot advises the World Wildlife Fund on water and energy-security issues in the Greater Mekong region. The opinions expressed are his own.