At least 19.3 million people worldwide were driven from their homes by natural disasters last year — 90 percent of which were related to weather events, according to the Geneva-based Internal Displacement Monitoring Center.
The study, by the nonprofit research and news organization Climate Central, looked at global population data and sea rise projections.
The U.S. Department of Defense has called climate change "an urgent and growing threat to our national security, contributing to increased natural disasters, refugee flows, and conflicts over basic resources such as food and water," according to a report this year.
Yet climate change does not make one a refugee, a designation for people forced to leave their home countries because of war, persecution or other violence.
Someone seeking refuge from environmental disaster cannot apply for refugee status, lacks protection under the U.N. High Convention for Refugees and can be sent back to their countries of origin without question at any time.
Carlon Zedkaia doubts his 11-year-old daughter will be able to remain in their home in the Marshall Islands, a cluster of coral atolls near the equator in the Pacific that was flooded this year by an extreme high tide.
New Zealand deported a man back to the tiny South Pacific island nation of Kiribati earlier this year after its Supreme Court dismissed his appeal — the world's first — for asylum as a climate refugee.
Some in vulnerable countries fear they could face the same hostile reception that Syrian war refugees have received from some countries.
"What's happening now in Europe with all these refugees will be a small thing compared to what will happen when climate change takes effect," Marshall Islands President Christopher Loeak told The Associated Press in his nation's capital of Majuro.
"The U.N. protocol on refugees has to be revised, and responsibility for climate change migrants has to be taken by the developed countries, who are responsible for climate emissions," said Rezaul Karim Chowdhury, head of a Bangladeshi organization that aims to help people affected by climate change called COAST.
In October, poor and developing nations known as the Group of 77 & China submitted a proposal for the Paris talks to deliver a plan for climate migrants — an effort started in 1991 when the island nation of Vanuatu suggested a global insurance scheme to compensate climate-induced losses.
The European Union remains undecided on whether to include a provision on migration in the Paris treaty, though European Commission President Jean-Claude Juncker said in his Sept. 9 state of the union address that "Climate refugees will become a new challenge — if we do not act swiftly."
