There are 570 coastal cities that could be impacted by rising sea levels by the 2050s, affecting some 800 million people, according to C40 Cities. Cities along the Atlantic coast in the U.S. and various parts of Asia are under the greatest threat. Here's a look at the cities most at risk if sea levels rise significantly.

Miami, Florida, U.S.A.

Credit: BackyardProduction/iStock

Located on the southeastern tip of Florida, this low-lying city will be completely inundated with flood waters if sea levels rise as some predict. With a population of over 2.7 million, the entire Miami-Dade county is only an average of six feet above sea level, making it an easy target for flooding.

The city is trying to address the problem with $500 million worth of infrastructure changes and the installation of pumps and floodgates, according to NPR.

Alexandria, Egypt

Credit: efesenko/iStock

Located on the Mediterranean coast of Egypt, the city of Alexandria is already feeling the effects of climate change. If sea levels continue to rise at the current rate, an estimated 3 million people would be directly affected, and millions more would eventually be displaced, according to The Guardian.

The drastic impact from rising sea levels is worsened by the Nile, the longest river in the world, which empties into the Mediterranean Sea near Alexandria. The low-lying river delta in this area continues to flood, causing the loss of much-needed crops in this heavily populated city, according to NPR. Climate change is also causing hotter temperatures and beach erosion. This is hampering tourism in the area, which is a very important aspect of the city’s economic livelihood, according to NPR. Making matters worse, the average elevation of the area is only 16 feet above sea level.

Osaka, Japan

Credit: pat138241/iStock

This large port city on the Japanese island of Honshu has been aware of the threat of climate change for a while. There has been massive coastal flooding in areas of the city, including its airport. According to The Guardian, an estimated 5 million people will be directly impacted by the rising sea levels, and an additional 6 million could be displaced in the city’s surrounding region.

Like other major coastal cities, Osaka has been updating its infrastructure in an attempt to combat the rising waters. Unfortunately, in a study by the Institute for Global Change Adaptation Science in Japan, it was found that the current designs for these walls may be insufficient against a prospective higher sea level.

Hong Kong, China

Credit: efired/iStock

The fate of this global financial hub depends on how high temperatures rise. A rise of just 2 degrees Celsius puts Hong Kong’s entire population of 7.4 million people at risk, along with many more in the surrounding coastal areas, according to The Guardian. A warm-up of more than 2 degrees could be catastrophic. The average elevation of Hong Kong varies, but it is typically only about 4 feet above sea level, worsening the situation.

Shanghai, China

Credit: chuyu/iStock

All of China’s coastal cities are at risk, according to GBTIMES. Its largest city, Shanghai, with a population of 24.2 million, is unfortunately at the forefront. Scientists have been warning the city for many years that it is already a major flood risk due to its dense population on the low-lying coast and its abundance of rivers, canals and other waterways, according to The New York Times.

According to The Guardian, 17.5 million people will be affected if sea levels rise to the current expectation. At just 13 feet above sea level, the city has been installing massive flood prevention walls in an attempt to prevent future problems. Only time will tell if these efforts help.