Five famous cities doomed by climate change

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Sunday, September 27, 2015, 6:57 PM - Whether you believe humans are contributing to it or not, climate change is happening, temperatures are rising and ice caps are melting.

At this point, even if we limit global temperature rise to 2oC, studies suggest sea levels will still rise by several feet.

Our civilization is in many ways a coastal one, so when the seas rise, and stay risen, that'll do a real number on world populations and economies.

Here are five metropolises in climate change's crosshairs.

Bangkok: Thailand's capital isn't just a popular tourist destination. It's very much a working city, home to 15 per cent of Thailand's 65 million people.

It's the centre of a major, growing national economy, that nationwide includes a burgeoning manufacturing sector, and an agricultural sector that employs almost half the population around the country.

And the rising ocean is putting all of it under threat. One expert told AFP in 2011 much of the city, built on swampland, could be underwater in 50 years.

That's to say nothing of the additional flooding that happens during the monsoon season, or storm surge from the occasional typhoon.

More powerful storms are likely in the coming century, and the Atlantic reports the monsoon season may be longer and more intense as well.

Bangkok has already had a taste of what's to come. The city spent a fair bit of coin developing manufacturing on former rice paddies in the Chao Phraya River floodplain, attracting big names like Sony, Honda and Toyota to set up shop. In 2011, massive flooding dealt huge damage to these industries, causing an estimated $45 billion in economic losses.

It won't get much better as sea levels rise, and just this month 14 Thai provinces were experiencing flooding and landslides as Tropical Storm Vamco passed through the region.

Venice: This long-lived tourist paradise has had to fight the sea almost from day one from its precarious perch atop the low-lying islands of the Venetian lagoon.

Once a powerful merchant republic with a wide-reaching Mediterranean trading empire, Venice's star has waned somewhat (The European Centre for Climate Adaptation says the population is down to around 70,000 in the lagoon, mostly due to major decline in industry), but its romance endures.

Unfortunately, it may finally be on its way to losing its fight to stay afloat, or at least have to pay dearly for it.

With sea levels continuing to rise, flooding is becoming more common. Tides of 100 cm or more are expected to happen seven times per year, swamping the lowest-lying areas. It'll be harder to attract tourists when they know flooding is more likely, costing the industry up to 42.9 million euros (C$ 64 million) by 2030. That's not even factoring damage to the clam industry and the city's infrastructure.

But the authorities haven't been sitting there quietly waiting for it to happen. They've poured 5.4 billion euros (C$ 8 billion) into Mose, a series of concrete barriers in the lagoon's inlets that will be raised when the tide is expected to reach above a certain level.

It could be completed as early as next year, according to the Guardian, but some detractors say it may already be obsolete. In 2009, researchers at Venice's Institute of Marine Sciences said the Mose project was based on sea level rise predictions that may have been underestimated.

They recommended looking into alternatives, including pumping seawater into a 700 m deep aquifer to raise the city by up to 30 cm, according to the New Scientist.

Alexandria: This ancient metropolis is situated in the delta of Nile River. It's seen empires rise and fall ever since it was first founded from scratch by Alexander the Great, and has endured for more than two millennia.

Though nowhere near as populous as the capital, Cairo, its importance to the country is far out of proportion to its size. The port handles four fifths of Egypt's international trade, and is home to 40 per cent of the country's industry, not to mention the tourism potential that comes from its prime Mediterranean location.

And then there is the delta itself, which is one of the most fertile parts of the country. But, being a delta, its low-lying terrain makes it especially vulnerable to the rising waters.

Most reports we've seen factor in only a modest sea level rise, but even that could be devastating. A 25 cm increase would put 60 per cent of the city's population underwater (according to the Climate Institute), and a half-metre increase would wipe out 66 per cent of the industry, most of the service sector and about a third of the city's area.

Beyond the city, the rest of the delta, which accounts for 40 per cent of Egypt's agricultural output, would suffer as well. The Canada-based International Development Research Centre says around 60 per cent of the delta would be affected by increased salinity due to sea level rise.

It's a potential economic disaster on top of the country's political woes.

Guangzhou: This Chinese metropolis topped a recent World Bank study as the number one city most at risk of coastal flooding related to climate change.

That's a huge problem. Guangzhou has already struggled with major flooding due to extreme weather and the occasional typhoon blowing in from the Pacific. In 2010, heavy rainfall killed dozens of people and caused $85 million in damages.

That last figure pales in comparison to what is to come. By 2070, the city will be home to some $3.4 trillion worth of what the OECD calls "assets at risk." In 2005, more than two million of its denizens were exposed to coastal flooding, but by 2070, that'll be up to 10.3 million.

Guangzhou is an economic giant among China's economic giants, and both that country and neighbouring India will be hard-hit by sea level rise

On that World Bank-led study, Mumbai is at number four, with $2 trillion in at-risk assets by 2070, and more than 10 million people exposed to coastal flooding effects.

Miami: Guangzhou was at the top of the last World Bank-led study, but Miami occasionally makes it into that spot on similar rankings.

America's beachside Mecca is a haven for sunseekers, but rising sea levels are set to put a serious damper on property values. During spring and autumn tides, the city is already dealing with periodic flooding, and even a 30 cm rise in levels over the next century could prove catastrophic.

That's just regular ocean activity. It gets worse when you factor in storm surge from major tropical storms.

2005's Hurricane Wilma brought more than 200 cm of storm surge to the Miami area, a once-in-76-years event. If sea levels rise 60 cm, that kind of storm surge would be likely to happen once every five years.

The Miami-Dade area of Florida has more people living less than 120 cm above sea level than any other U.S. state except Louisiana, according to the World Resources Institute, accounting for 2.4 million of people whose homes and livelihoods are at risk (according to the Guardian).

At risk: Around $14.7 billion worth of beachfront property, and $21 billion in tourism revenues. Officials in the state are already planning hundreds of millions of dollars worth of climate change adaptation measures, but it remains to be seen how effective they'll be.