310 I PART 3 I THE MEKONG EMERGENCY
SUMMARY I THE MEKONG EMERGENCY This third part of the report focuses on the complex interlinkages between climate change impacts and local anthropogenic environmental changes in the Mekong region [ Figure 1 ]. According to the 5th IPCC report, studying the effect of climate change on coastal regions cannot be independent of “local drivers of exposure and vulnerability”. Viet Nam’s Mekong Delta (VMD) is the third largest delta on Earth, and currently home to 17 million inhabitants, whose livelihoods depend mainly on agricultural and aquacultural production. The region supplies more than half of Viet Nam’s rice production, 90% of which is exported, and is thus crucial for both national and international food security. However, the VMD is subject to various drivers of change, of which anthropogenic drivers — namely hydropower dams, sand mining and groundwater extractions — pose the greatest threats in this first half of the century. The Delta is already under pressure, which leaves us with a limited window of opportunity for adaptation, since climate change effects will most probably start to dominate the threats in the second half of the century. The VMD has long historical experience of dealing with water- and climate-related factors which can threaten agricultural production and livelihoods. However, the increasing impacts of climate change and anthropogenic activities challenge the sustainability of existing approaches, and call for new adaptation and mitigation measures. Furthermore, the Delta is strongly influenced by the water governance of the whole Mekong basin, or lack thereof. Climate change adds a layer of uncertainty to the already complex water management problems. The current regional structure of governance and management for transboundary resources in the Mekong region is made up of a web of organizations, including different partners inside and outside the region. This scattered institutional architecture still needs to be fully aligned with the mitigation and adaptation objectives of the Paris Agreement, while acknowledging the full scope of local anthropogenic environmental dynamics.
Climate change Temperature and precipitation Over the last four decades (1981–2018), the VMD has experienced significant temperature and precipitation changes: uThe mean annual temperature has increased over the whole Delta, with an average trend of +0.76°C over 38 years. However, the number of hot and very hot days show contrasting trends depending on the weather station. uIn general, rainfall shows an increasing trend over most of the Mekong Delta, but the trend is only statistically significant at a few stations. Trends in rainfall extremes vary greatly between regions.
