BANGKOK • As Bangkok prepares to host climate-change talks, the sprawling city of more than 10 million is itself under siege from the environment, with dire forecasts warning it could be partially submerged in just over a decade.

A preparatory meeting begins tomorrow in Thailand's capital for the next United Nations climate conference, a crunch summit in Poland at the end of the year 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 1.5m above sea level, is projected to be one of the world's hardest-hit urban areas, alongside fellow South-east Asian behemoths Jakarta and Manila.

"Nearly 40 per cent" 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 1cm to 2cm a year and there is a risk of massive flooding in the near future", said Mr Tara Buakamsri of Greenpeace.

Seas in the nearby Gulf of Thailand are rising by 4mm a year, just above the global average.

The city "is already largely under sea level", said Mr 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 exceeded 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.

Making things worse, the canals that used to traverse the city have now been replaced by intricate road networks, said Mr Suppakorn Chinvanno, a climate expert at Chulalongkorn University in Bangkok.

"They had contributed to a natural drainage system," he said, adding that the water pathways earned the city the nickname "Venice of the East".

Shrimp farms and other aquacultural development - sometimes replacing mangrove forests that protected against storm surges - have also caused significant erosion to the coastline nearest the capital.

This means Bangkok could be penned in by flooding from the sea in the south and monsoon floods from the north, said Mr Chinvanno, adding: "Specialists anticipate more intense storms in this region in the years to come."

Bangkok's Department of Drainage and Sewage director Narong Raungsri admitted that the city's "weaknesses" stem from its small tunnels and the hyper-development of neighbourhoods. "Our system can only handle so much - we need to enlarge it."

Today, the government is scrambling to mitigate the effects of climate change, constructing a municipal canal network of up to 2,600km with pumping stations and eight underground tunnels to evacuate water if disaster strikes.

Last year, Chulalongkorn University also built a 4.4ha park in central Bangkok specially designed to drain several million litres of rain and redirect it so surrounding neighbourhoods are not flooded.

But these ad hoc fixes may not be enough.

"We need a clear policy of land management," said Greenpeace's Mr Buakamsri, adding that the need for more green spaces is outweighed by developers' interests.

"The high price of land in Bangkok makes economic interests a priority."

AGENCE FRANCE-PRESSE