5. Tuvalu, Pacific Ocean

The nation of Tuvalu, which lies between Australia and Hawaii, is a mere 4.88 meters above sea level. This island country is vulnerable to flooding and erosion, which are expected to increase as sea levels rise. The salty sea water would bring irreparable damage to local crops. Tuvaluss coral reefs are also under threat.

Tuvalu, Pacific Ocean [huanqiu.com]