The Mekong Delta is facing climate change; this situation may happen double impacts. In your opinion, what is the biggest threat that is most impacting?

In the short term, the problem of unsustainable development in the Mekong Delta, including subsidence at an average rate of 18 cm across the plain for 25 years (1991 - 2016) due to excessive use of groundwater. Landslides occurred in the last 25 years since 1992 and the more and more intense.

Currently, more than half the length of the Mekong Delta is landslide. Total landslide of river shoreline, sea shoreline is 891 km. The main cause of the erosion is the lack of fine silt and lack of sand; River water pollution has to deal with many unmanaged wastes from household wastewater, livestock, fisheries, industry, and large amounts of fertilizer pesticides from intensive three-crop agriculture for many years.

Next impact of Mekong Hydropower. At present, the amount of fine silt has fallen by 50% from 160 million tons to 83 million tons. It is forecasted that after 11 dams downstream, smooth silt will be reduced by 50% again and 100% sand and gravel will be blocked. Of the three challenges mentioned above, the impact of hydropower is long-term, serious, and most difficult to overcome because of the lack of silt and sand, the land will be degraded and river bank and seacoast erosion will increase.

However, the most worrying and urgent impact today is the subsidence of the delta because this subsidence speed causes the delta to sink very fast, up to 10 times the sea level rise. If it is not solved soon, the delta will be submerged.