It's already having a huge impact on the lives of those in the Mekong Delta , the agricultural heartland of the country and home to 20% of the country's population.
If you have been affected by the issues in this series and would like to speak to the BBC, email haveyoursay@bbc. co. uk
Video by Olivia Lace-Evans
The Displaced: Vietnam can be seen at varying times on BBC World News over the weekend of October 26 and 27, 2019.