374 I PART 3 I THE MEKONG EMERGENCY
1. Climate change in the Mekong region, a potential catalyst for socio-ecological imbalances The Mekong region contains the world’s 12th longest river, which flows from the Tibetan Plateau through China, Myanmar, Thailand, Laos, and through the rich Mekong Deltas in Cambodia and Viet Nam. Altogether, it drains a basin area of 810,000 km2 and is home to over 65 million people. The basin plays a crucial role in the livelihoods of millions of people from six countries: Cambodia, China, Laos, Myanmar, Thailand, and Viet Nam. After a troubled history, the region has embraced modern diplomacy to tackle the various interests and potential conflicts associated with using and amending transboundary resources such as water and fish [ Kittikhoun & Staubli, 2018 ]. While resource use and exploitation have contributed to socio-economic progress, the changes have also brought environmental disturbances, and various risks to the life and livelihoods of millions of people. Until today, people in the region have experienced various impacts from environmental changes, which include — but are not limited to – hydrological fluctuation, degradation of water and related resources, pollution from fast developing cities, deforestation, and others [ Stibig et al., 2014; Simpson, 2007; Hirsch, 2016; and Chapters 7 and 9 of this report for the case of the Vietnamese Mekong Delta ]. Climate change adds to these ongoing environmental problems by increasing the region’s fragility. Various studies analyse possible changes in the region linked to climate change
scenarios. There are possibilities of higher temperature, increased precipitation, increased melting of glaciers in the Upper Mekong [ Eastham et al., 2008 ], followed by a temporary increase in runoff, thus changing the seasonal discharge (ibid, Hoang et al., 2016; Chapter 5 of this report for the analysis of the impact of climate change on the hydro-energy supply). Another projection of climate change influence concerns the decline of groundwater recharge in short-medium-, and long-terms [ Shrestha et al., 2016 ]. The most likely impacts of climate change in the region are linked to temperature change (e.g. more severe drought), unexpected climatic events and hydrological alternation. In fact, a high confidence conclusion from the Intergovernmental Panel on climate change (IPCC) states that global warming is likely to reach 1.5°C between 2030 and 2052 if human activities associated with the industrial regime continue to increase at the current rate [ IPCC, 2018 ]. Chapter 1 and 7 of this report confirm these findings in the case of Viet Nam. One meter of sea level rise was supposed to cause the displacement of 7 million inhabitants and flood the homes of more than 14.2 million people in the Vietnamese Mekong Delta [ ADB, 2013 ] even before the elevation of the Delta was recently re-evaluated [ Minderhoud, 2020 ]. This is even more critical in a country like Viet Nam, which is ranked fifth out of 233 countries in terms of direct extreme weather risk (physical climate impact) (see Part 1 of this report for further details on this matter). The changes will either worsen or improve flooding and drought in the region. Negatively, there could be worse flooding events in the rainy season and droughts in the dry season in the basin, with increasing water shortage, and deeper and more uncertain salinization in the downstream Mekong Delta. While changes in hydrological system have
