A Pacific Islander is attempting to claim asylum in New Zealand on grounds that climate change is threatening his country.
Ioane Teitiota told New Zealand's High Court that parts of his homeland, Kiribati, were already swamped by rising sea levels.
He is attempting to appeal against an immigration department decision to refuse him asylum.
The high court has reserved a decision on his appeal.
"There's no future for us when we go back to Kiribati," Mr Teitiota told the tribunal.
He said that his family, including his three New Zealand-born children, would suffer harm if forced to return to Kiribati.
Most of the atolls that make up Kiribati are very low-lying and at risk from rising sea levels.
Mr Teitiota has lived in New Zealand since 2007, although his work visa recently expired.
His lawyer said that Mr Teitiota was being "persecuted passively by the circumstances in which he's living, which the Kiribati government has no ability to ameliorate".
The immigration department had refused Mr Teitiota asylum earlier this year on the grounds that he did not face persecution or threats to his life if he returned to Kiribati.
"The sad reality is that the environmental degradation caused by both slow and sudden-onset natural disasters is one which is faced by the Kiribati population generally," the Immigration and Protection Tribunal wrote in June.
It added that the Kiribati government was taking steps to tackle the risks posed by climate change.
Last year, the Kiribati government approved a plan to buy land from Fiji in case rising sea levels forced it to relocate its citizens.
On Wednesday, the Auckland High Court reserved a decision on Mr Teitiota's appeal. A decision is expected in the coming weeks.