At least 88 new hydropower dams are planned between 2010 and 2030 in the lower Mekong River basin in Southeast Asia as a source of electricity with lower greenhouse gas emissions. Dams result in declines in fish populations that will need to be replaced with other sources of protein for food security. We make the first assessment of emissions should beef production substitute for lost fish in Cambodia and Laos. We assessed two sources of emissions. Replacing lost fish with beef would require as much as 12 million hectares of new pasture. Forest clearing for pastures in Cambodia and Lao PDR would initially emit between 0.859 and 3.015 giga‐tonnes of carbon dioxide equivalents (Gt CO₂‐eq.). Methane emissions from additional cattle would add at least 0.0013 Gt CO₂‐eq./year to Cambodia's total greenhouse gas emissions, equivalent to a 20% increase. In Laos at least 0.0005 Gt CO₂‐eq./year would be released, a 4–12% increase in annual emissions. We demonstrate that activities displaced by hydropower developments could significantly increase emissions. It shows how enclosure of commons at local scales impacts upon other common pool resources at different scales, raising questions for sustainable and equitable transboundary governance.

中文翻译：

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湄公河流域下游用牛肉代替鱼蛋白的温室气体影响

计划在2010年至2030年之间，在东南亚湄公河流域的下游建造至少88座新的水电大坝，以减少温室气体的排放。大坝导致鱼类种群减少，为确保粮食安全，将需要用其他蛋白质来源替代鱼类。如果柬埔寨和老挝的牛肉生产能替代失去的鱼类，我们将对排放进行首次评估。我们评估了两种排放源。用牛肉代替丢失的鱼将需要多达1200万公顷的新牧场。柬埔寨和老挝的牧场的森林砍伐最初会排放0.859至3.015吉吨的二氧化碳当量（Gt CO ₂当量）。其他牛的甲烷排放量将增加至少0.0013 Gt CO ₂每年等于柬埔寨的温室气体总排放量，相当于增加了20％。在老挝，每年至少释放0.0005 Gt CO ₂当量/年，年排放量增加4–12％。我们证明，因水电发展而流离失所的活动可能会大大增加排放量。它显示了地方规模的公共场所封闭如何对不同规模的其他公共资源池产生影响，从而引发了对可持续和公平的跨界治理的质疑。