Global sea levels are rising and the world’s land ice is disappearing. Sea levels have risen 6 to 8 inches in the past 100 years, and Antarctica has been losing more than 100 cubic kilometers of ice per year since 2002, according to NASA satellite data.
By the year 2100, the Intergovernmental Panel on Climate Change estimates that sea levels will rise as much as 20 inches.
While rising sea levels ultimately influence the entire planet, they pose the greatest threat to the islands currently residing at sea level.
Here are some of the islands — many of them small nations — likely to face this crisis first.
Like many other atolls throughout the Pacific Ocean, this one is very low-lying and its main constituent, the coral, needs to be covered in water most of the time.
Land is created by the ocean when some vegetation, such as a coconut palm or mangrove shoots, take hold in the much shallower parts of the reef. One tree leads to a slight buildup of coral sand around its base.
This leads to more trees (palms) and the size of the individual islets on the reef grow.
Over the long period the islands progress from the seaward edge of the atoll towards the lagoon as the sand is blown and washed towards the calmer shore.
It is easy to determine the direction of the prevailing winds by observing the position and condition of the islets on the reef.
Palms or trees that become exposed in storms usually die by losing their grip in the little sand left at the end of the storm season. Sometimes whole islets get washed away.
People live on the larger island or islands formed around the atoll and trek back and forth to the smaller ones by walking the reef at low tide or by small canoes.
Much of the taro is grown away from the inhabited island. It is often very vulnerable to salt-water inundation, but by being away from the living area is protected from human-waste contamination.