The UN's meteorology experts say levels of greenhouse gases in the Earth's atmosphere reached a record high last year.
The World Meteorological Organization added that carbon dioxide, methane and nitrous oxide are now far above pre-industrial levels with no sign of a reversal in sight.
According to the report, CO2 levels reached more than 405 parts per million in 2017 - a 46 percent increase from levels in the atmosphere before the industrial revolution.
WMO chief Petteri Taalas warned that without rapid cuts in greenhouse gases, climate change will have increasingly destructive and irreversible impacts on life on Earth.
He added that the window of opportunity for action is almost closed.
