At a Bangkok seminar on Oct. 7, environmental and public‑health expert Sonthi Kotchawat warned that the city must act now, not wait for each flood to teach a new lesson.

He pointed to the World Meteorological Organization and the Intergovernmental Panel on Climate Change, noting that global temperatures could rise to 1.5 °C above pre‑industrial levels by 2030.

According to Sonthi, the rapid melting of ice and snow in the Arctic, Antarctic, Greenland and major mountain ranges, together with thawing Siberian permafrost, is already driving more extreme weather across Asia.

Bangkok’s own geography makes it especially vulnerable: the capital sits in a low‑lying, basin‑like plain that is sinking about 1 to 2 centimetres each year.

At the same time, sea levels in the Gulf of Thailand are climbing roughly 4 millimetres per year. Projections suggest a rise of 20 to 30 centimetres by 2050, and in a worst‑case scenario up to 75 centimetres.

When land subsidence and rising seas combine, Sonthi said about one‑third of Bangkok could be permanently submerged by 2050, putting 11 to 12 million residents at risk of displacement.

He also highlighted that Southeast Asia is likely to face more erratic monsoons, heavier rainfalls, landslides and flash floods, all of which add pressure to an already sinking city.

To counter the threat, Sonthi proposed a package that mixes high‑tech infrastructure—such as seawalls, tidal barriers, underground flood‑storage facilities and large drainage tunnels—with stricter spatial planning and tighter control of groundwater extraction.