It's unstoppable: future flood-related disasters will be biggerand costlier even if coastal cities take measures to improveinfrastructure, shows a new study by the journal Nature ClimateChange.

The recent report shows that global flood losses may hit $52billion by 2050 from socioeconomic changes alone, with a 15 percentto 20 percent damage increase due to rising sea levels and earth'stectonic activity.

With no risk mitigation strategy, these costs may rise to morethan $1 trillion annually by midcentury; however, improvingstandards of coastal protection and trying to decrease flooding maykeep costs at about $60 billion.

Here is a list of top 10 global portcities that stand to suffer the most from sea level change by 2050,factoring in current GDP and level of disaster-readiness.

10. New Orleans, La.
Average Annualized Loss (AAL): $1.86 billion, 18% increase from2005

The Insurance Information Institute reported that HurricaneKatrina, which struck Louisiana in 2005, generated a record $41.1billion in insurance losses—not including $16.1 billion in claimsinsured by the National Flood Insurance Program and millions morein insured damages to off-shore energy facilities.

9. Ho Chi Minh City, Vietnam
AAL:$1.95 billion, 12% increase from 2005

In a briefing on Asian flood risks, Marsh & McLennan says,"In emerging markets [such as Vietnam], companies often choose totake the risk themselves rather than buying insurance in the firstplace, so the issue isn't necessarily around flood insurance, it'sabout insurance penetration."

8. New York, N.Y.—Newark, N.J.
AAL:$2.06 billion, 5% increase from 2005

Swiss Re estimates that in 2012, Hurricane Sandy, which causedmassive destruction in the U.S. Northeast, caused $35 billion ininsurance losses.

"As illustrated by the recent landfall of Sandy on the EastCoast of the United States, there is a need to prepare at thelocal, national and international level for larger floods and thedisasters that ensue," says Nature Climate Change. 7. Tianjin, China
AAL: $2.27 billion, 26% increase from 2005

Tianjin's manufacturing industry, including an airline assemblyfactory, makes up the majority of the city's economic output. Anydeluge that hits this city nestled between the Hai, Yellow andYangtze rivers would have drastic effects; thus, in May 2012 thecity began a project that would increase Tianjin's drainagecapacity. 

6. Miami, Fla.
AAL: $2.55 billion, 21% increase from 2005

"The U.S. appears particularly vulnerable, with three in ranking[in the top 10 at-risk cities] by relative AAL," states theNature Climate Change report. "On average, however, richcities are better protected than poorer ones, and the ranking interms of absolute flood losses contains more cities from developingcountries."

5. Shenzen, China
AAL: $3.14 billion, 7% increase from 2005

Shenzhen is a major city in South China's Guangdong Province,one of the nation's most flood-prone regions. Marsh & McLennansays a lack of penetration is a major issue in China, although thenational government has increased funding for flood preventionprojects and flood storage basins.

4. Guayaquil, Ecuador
AAL: $3.19 billion, 13% increase from 2005

The largest, most populated city in Ecuador sits on the banks ofthe Guayas River, which is fed by the Pacific Ocean. It is poisedto become one of the nation's poshest areas, but is highly prone toflooding due to its closeness to sea level and taxed sewage system.The city experienced destructive flooding and mudslides due toheavy rain in March 2013. However, Guayaquil has undergone electricand road infrastructure projects in recent years.

3. Kolkata, India
AAL: $3.35 billion,24% increase from 2005

Kolkata, or Calcutta, is a commercial and cultural center withupwards of 4 million residents, which houses India's oldestoperating port.  Kolkata is one of two Indian locations onthe list of top 10 cities at risk of coastal flood damage.According to Towers Watson, the Indian non-life industry is growingfast, registering $176.4 billion of total gross written premiumincome in spring 2012, a nearly 20 percent increase from theprevious year.

2. Mumbai, India
AAL: $6.41 billion,5% increase from 2005

Formerly known as Bombay, Mumbai is the world's fourthmost-populous city, and home to 26 billionaires (more than live inShanghai, Paris or Los Angeles). Located on India's west coast, ithas a deep harbor and rich economy: it is the center of theBollywood movie industry as well as the Reserve Bank of India, theInsurance Institute of India, and the country's major stockexchanges.

1. Guangzhou, China
AAL: $13.2 billion, 11% increase from 2005

Guangzhou, China's third largest city, is the capital of China'sGuangdong province. Home to nearly 13 million people, it is atransportation and trading hub situated on the Pearl River, just 75miles northwest of Hong Kong. It is a "Beta World City", or globaleconomic node, as categorized the Globalization and World ResearchNetwork.