Yes. Bangkok will gradually go underwater but the cause is not climate change. The cause Is development on a natural river delta that changes the characteristic’s of how normal discharge would occur.
its no different to any other river system.
Without any development, the annual flooding would deposit silt, sand and plant matter on the banks gradually raising the land levels. As the get higher, instead of 100’s of small creeks discharging, there would be a few major and vast areas of land would dry out, some only being exposed during higher level floods.
But Bangkok’s development has changed this. Silt build up cannot occur on the hard surfaces and the level of any piece of land remains at the height from the very day any development occurred. The silt is just being discharged into the Gulf.
The flooding is not increasing. It’s just the natural variation to the rain cycle and frequency.
But development is increasing which results in more disturbance to the natural flow paths, more people affected, more media attention and more alarmists demanding action or else.
There is no feasible solution but ti live with the annual cycle. Some years the flooding will be minor and others, extreme.
Bangkok won’t be 70m underwater in 80 years as the extremists will have you believe. It will be exactly the same as it is today with normal climatic frequency variations determining the flood depth.
The attraction to what caused the establishment of the Bangkok area is now the problem as the delta is no longer primarily used for the original purpose which was probably subsistence living, fishing, rice, and the river provided a means to transport goods to and from.