Across the Globe:
1.  Maldives (could be uninhabitable by 2030)
2. Palau (much of the island is on higher ground but this area is currently largely uninhabitable due to its rocky and inhospitable terrain)
3. Solomon Islands*
4. Micronesia*
5. Fiji**
6. Tuvalu
7. Seychelles (could be uninhabitable by 2030)
8. Kiribati (expected to be uninhabitable by 2050)
9. Cook Islands
10. French Polynesia (expected to lose at least 30% of land mass)
11. Marshall Islands
12. Cape Verde
13. Torres Strait Islands†
14. Carteret Islands
15. Vanuatu
16. Samoa
17. Nauru
18. Esanbe Hanakita Kojima, Japan (disappeared in 2018, uninhabited)

Within the United States:
1. Tangier Island, Virginia (expected to disappear by 2040 to 2065)
2. Sarichef Island, Alaska (expected to disappear by 2035)
3. Key Biscayne, Florida (expected to lose at least 86% of inhabitable land by 2100)
4. St. Helena Island, South Carolina (expected to lose at least 59% of inhabitable land by 2100)
5. James Island, South Carolina (expected to lose at least 68% of inhabitable land by 2100)
6. Tybee Island – Wilmington Island, Georgia (expected to lose at least 70% of inhabitable land by 2100)
7. Middle Keys, Florida
8. St. Pete Beach, Florida
9. Upper Keys, Florida (expected to lose at least 77% of inhabitable land by 2100)
10. Lower Keys, Florida
11. Hilton Head Island, South Carolina (expected to lose at least 58% of inhabitable land by 2100)
12. Key West, Florida
13. Isle de Jean Charles, Louisiana
14. Kivalina, Alaska

Notes:
* represents a country that has already seen more than one of its islands disappear
** has already lost up to 20 meters of shoreline due to loss of mangroves
† represents a country whose residents have become climate change refugees
NB: A few items on this list are classified as barrier islands, rather than true islands.

Sources:
World Bank (1)
World Bank (2)
Public Radio International
Environmental Research Letters
Springer
Statement from Prime Minister of Tuvalu
Seychelles News Agency
United Nations Office for Disaster Risk Reduction
Cook Islands National Infrastructure Investment Plan
Nature Conservation
Nature.com
U.S. Department of the Interior
Pacific Climate Change Science
Spiegel Online
UNICEF
The Guardian
24/7 Wall Street
Independent
Washington Post