Ocean temperatures reached a record high last year, extreme weather events are exacerbating world hunger, and the world is not on track to meet emissions reduction targets, a new report says.
The latest state of the climate report by the World Meteorological Organisation said the effects of climate change were accelerating to dangerous levels, and were being felt in the Pacific.
The report, with contributions from dozens of scientists, UN agencies and national weather authorities including Fiji, Australia and New Zealand, also said greenhouse gas emissions had risen to unprecedented levels.
It showed sea levels were on the rise, and the water was warmer and increasingly acidic, which threatened to destabilise whole ecosystems.
And there were no signs the warming trend, which began at the start of this century, will ease.
The UN body's report comes ahead of a summit in September that's been billed as a last-chance opportunity for leaders to tackle climate change.