A preparatory meeting begins Tuesday in Thailand's capital for the next UN climate conference, a crunch summit in Poland at the end of 2018 to set rules on reducing greenhouse emissions and providing aid to vulnerable countries.
As temperatures rise, abnormal weather patterns -- like more powerful cyclones, erratic rainfall, and intense droughts and floods -- are predicted to worsen over time, adding pressure on governments tasked with bringing the 2015 Paris climate treaty to life.
Bangkok, built on once-marshy land about 1.5 metres (five feet) above sea level, is projected to be one of the world's hardest hit urban areas, alongside fellow Southeast Asian behemoths Jakarta and Manila.
"Nearly 40 percent" of Bangkok will be inundated by as early as 2030 due to extreme rainfall and changes in weather patterns, according to a World Bank report.
Currently, the capital "is sinking one to two centimetres a year and there is a risk of massive flooding in the near future," said Tara Buakamsri of Greenpeace.
Seas in the nearby Gulf of Thailand are rising by four millimetres a year, above the global average.
The city "is already largely under sea level", said Buakamsri.
In 2011, when the monsoon season brought the worst floods in decades, a fifth of the city was under water. The business district was spared thanks to hastily constructed dikes.
But the rest of Thailand was not so fortunate and the death toll passed 500 by the end of the season.
Experts say unchecked urbanisation and eroding shorelines will leave Bangkok and its residents in a critical situation.
With the weight of skyscrapers contributing to the city's gradual descent into water, Bangkok has become a victim of its own frenetic development.