Even "dry" parts of Venice are now regularly flooded

However, should the waters of the world continue to rise up and fight the land, the first casualty of the war may well be Venice.

Venice has been battling the Adriatic Sea for over 1,500 years, and many see the massive, and long-delayed, anti-flood project that was finally launched by Prime Minister Silvio Berlusconi in May as the last chance to save the famous and beautiful Italian city.

"A city which is regularly flooded is not a viable city," Anna Summers-Cox of the Venice In Peril Fund told BBC World Service's One Planet programme.

"People in Venice are living in a state of denial."

Battling waves

St Mark's Square in the centre of the city now floods every week, rather than once or twice a year, as it did in Napoleon's time in the city, and it is now possible to buy Wellington boots from ice cream vendors.

Find out how Venice will be protected from rising sea levels In pictures

"It's too humid and you get water coming in."

The people of Venice have been battling the waves since the city was first established as a sanctuary during the collapse of the Roman Empire in the 5th Century.

"If you dig down below any old building, you find there's a kind of lasagne of archaeological layers, going right back to the very first stage," Ms Summers-Cox said.

"What happened was that they sank these great pilings of tree trunks into the ground... because they exist in anaerobic conditions, these very ancient pilings are still in very good condition.

"It's an extraordinary engineering feat."

The Venetians were soon able to benefit from the key advantage of the city's situation.

Being surrounded by water meant easy access to the sea at a crucial point along the Mediterranean.

The sinking city Covered with water for 200 days every year - compared with only seven 100 years ago Over 50 high tides between 1993 and 2002 - compared with just five in the 10 years between 1923 and 1932 Sank 20 cm between the 1950s and 1980s

But the city's leaders never forgot their debt to the sea - or to the lagoon on which the city is actually built, protected by a long strip of land, the Lido, from the Adriatic.

"The Venetian Republic relied on its isolation, on the water surrounding it as a means of self-defence," said Marco Mirani of Padua University.

"The Republic in ancient times always took good care of the lagoon."

There was even a special department of the city-state's government entirely dedicated to researching ways of flood prevention as far back as the 1300s.

"The Magistry Of The Waters was an incredibly important part of government," Ms Summers-Cox confirmed.

"They had enormous accumulative empirical knowledge of the lagoon, and they understood how one activity in the lagoon could have a knock-on effect.

Venice is regarded as one of the world's most beautiful cities

This river plan was a huge, and successful, engineering feat. But it also created unnatural changes in the lagoon.

"The lagoon was destined to silt up because of the rivers flowing into it," Mr Mirani said.

"This was changed by the Venetians in the 16th Century. That changed the course of the evolution of the lagoon forever - it shaped the lagoon as we see it now."

Forgotten knowledge

But the changes the 16th Century Venetians made were done after careful study and learning from the effects the city had had on its environment.

The lower levels of many of Venice's buildings are uninhabitable

"This is a case where people in the past acted with great empirical knowledge, whereas people in the 20th Century have acted quite brutally in cutting great channels through the lagoon and cementing up the edges," Ms Summers-Cox said.

"They have forgotten what a delicate and organic creature it is."

The in-depth knowledge of the 16th Century was drowned out by the confidence of technological prowess.

By the 1950s a deep-water channel was being dug along the edge of the lagoon to allow oil tankers to dock at a new refinery.

That - together with over-extraction of groundwater by industry - tipped the delicate balance and Venice began sinking rapidly.

"When you pump out groundwater, what happens is that the soil compacts and the area sinks," Mr Mirani explained.

By the time the city's government had realised the effect that groundwater pumping was having, Venice had sunk 20 centimetres in just over two decades.

The lagoon is the source of Venice's success

"The city is stable, the subsoil is no longer subsiding," Ms Summers-Cox confirmed.

"But the trouble is that the whole of the north-east of Italy is very slowly tipping downwards, so that there is a tendency for the city to go down a few centimetres a century."

In the 1970s concrete was the solution - pavements were raised and sea walls strengthened.

This had the knock-on effect of damaging the lagoon still further.

"The attention is often on the city of Venice, but the city is inside a lagoon, and preserving the city means also preserving the environment around it," Mr Mirani said.

"We want to understand what the impact on the environment will be.