As the world swaps theories on global warming, Five Disasters Waiting To Happen looks at how some of the world's leading cities are dealing with the practical reality of climate change.
London's flood defences are getting older.
FIVE DISASTERS WAITING TO HAPPEN
Tuesday, 6 June 2006
2100 BST, BBC Two
Since 1982, the Thames Barrier has protected the city from the threat of flooding, but it was only designed to last until 2030 and close once every two or three years. Nearly 25 years later, the barrier now closes five or six times a year and according to Environment Agency predictions, by 2050 the barrier will be closed on almost every tide if the problem is not addressed.
There are 26 underground stations, 400 schools, 16 hospitals, an airport and £80bn worth of property in London's flood risk area, so large scale flooding would be disastrous.
Run by the Environment Agency, Thames Estuary 2100 project is looking at alternative solutions to the flooding problem by moving away from flood defence toward risk management creating salt marshes from reclaimed agricultural land, encouraging developers to use stilts for buildings, and incorporating flood early warning systems.
Over a six week period in July and August 2003, more than 11,400 - mainly elderly people - died in France from heat exhaustion, dehydration and hyperthermia.
Hospitals were overwhelmed as more casualties of the heat were brought in and the government were criticised for responding too slowly.
Heat-waves of similar intensity are expected every seven years by 2050, so what can be done to make sure such a disaster does not happen again?
One solution is government grants to have air-conditioning installed in care homes. But many critics say that this is a short-term solution, as the increase in demand for electricity also increases carbon emissions, creating a vicious circle.
In Paris the local authorities are encouraging architects to design new types of buildings such as architect Edouard Francois's "Flower Tower" which uses a covering of bamboo to act as "natural" air-conditioning. In older buildings residents are encouraged to grow gardens on their roofs and balconies to provide a shield from the sun.
Shanghai is the fastest growing city on Earth. It has a population of 18 million and is only 4m above sea level. Eighteen typhoons hit the area last year and sea levels are predicted to rise by 20cm within the next century.
An estimated 250,000 people move to Shanghai every year in search of work (and to get away from the risk of flooding in rural areas), placing extra demands on energy consumption. China relies heavily on coa- fired power stations, but these emissions increase temperatures and, in turn, warmer seas increase the risk of typhoons.
The government is tackling the problem by raising flood defences and building sluices and barriers. But it has also embarked on a huge programme to construct even more coal-fired power stations.
On the 26 July 2005, in the world's most densely populated city of Mumbai, nearly 1m of rain fell in one day.
The badly polluted Mithi river could not cope with the influx of water and 1,000 people died in the resulting floods.
The city used to be surrounded by mangroves, which acted as a natural drain, but in the last 50 years, 90% (45,000 acres) of the land has been destroyed to make space for Mumbai's ever increasing population. And the water has nowhere to go.
In an attempt to solve the problem the Mithi River Development Authority is draining the river, but with 300 families arriving in Mumbai every day in search of work, the pressure on the land and increasing urbanisation will continue.
In 1989 the UN identified Tuvalu in the South Pacific as one of a number of islands likely to be swallowed by the sea in the 21st Century. The islands's 12,000 residents are subsequently facing the very real prospect of having to abandon their homes.
The highest point of the island is only 3m above sea-level and the lower lying areas regularly suffer from flooding at high tide. The salt deposits from the floods are destroying the agricultural land and the island is slowly being eroded.
Those residents that can afford to are already fleeing to other islands, but with an average GDP of only £1,100, what will happen to those who are too poor to leave?
Producer: Eamon Hardy
Executive Producer: Karen O'Connor
Five Disasters Waiting to Happen is part of the BBC's Climate Chaos season. For more information about other programmes, please click on the link below