Climate change is causing global sea levels to continue to rise, with a major impact on low-lying island nations.
This situation increases the risk of flooding, coastal erosion and pollution of freshwater resources. Although it is often said that some countries may 'disappear' before 2100, in fact there is no scientific evidence to confirm that this will definitely happen.
However, if sea level rise continues at the current rate, parts of the land in these countries are at risk of being submerged or becoming uninhabitable.
Here are five countries that are often cited as being among the most vulnerable to this threat.
Tuvalu
Tuvalu is a small country in the Pacific Ocean with an average elevation of less than two meters above sea level.
According to NASA estimates, sea levels could rise by up to 72 centimeters by 2100 under a high carbon emissions scenario.
This rise is causing seawater to increasingly enter populated areas and pollute freshwater resources.
Kiribati
Kiribati consists of 33 atolls and small islands that are very close to sea level. The country is facing a growing problem of coastal erosion, while saltwater flooding is affecting residential areas and agriculture.
In the long term, the Kiribati government has also purchased land in Fiji as a measure to deal with possible future population displacement.
Maldives
The Maldives is a world-famous tourist destination, but this archipelago is also one of the most at risk from rising sea levels.
Its average elevation is only about 1.5 meters above sea level, while more than 80 percent of its area is less than one meter above sea level.
If sea levels continue to rise, the risk of flooding and coastal erosion is expected to become more serious.
Marshall Islands
The Marshall Islands is one of the lowest atoll countries in the world. Most of its islands are only about two to three meters above sea level.
In recent decades, major floods have become more frequent, threatening infrastructure, water supplies and the lives of its people.
Nauru
Nauru is the third smallest island country in the world. Its coastal areas are increasingly vulnerable to erosion, while freshwater supplies are also threatened by the intrusion of seawater.
Climate change also adds challenges to the development of countries with very limited land area.
Although these countries face great risks, it does not mean that everything will be lost before 2100.
Experts expect sea levels to continue to rise throughout this century, but the extent of the impact will depend on the rate of climate change and the mitigation efforts undertaken.
Adaptation measures such as building sea walls, coastal restoration and more sustainable development planning can still help protect at-risk areas and reduce the impact on populations in the future.
