The organization painted a stark picture in its annual global climate report, with Secretary-General Petteri Taalas laying out the numbers.

"It used to be about 2 millimeters per year 20 years ago, but recently, we have seen 4.5 millimeters per year for sea-levels rise which is a record so far."

Atmospheric levels of climate-warming carbon dioxide and methane also surpassed previous records, the report added.

And with last year's global average temperature 1.11 degrees Celsius above the preindustrial average, the world is inching closer to the 1.5 degree threshold.

That's where the effects from warming are expected to become drastic, warns U.N. special adviser Selwin Hart.

"Without much, much, much greater actions and much greater ambition, much greater urgency, we are about to lose the narrow window of opportunity to keep the 1.5 degree goal of the Paris agreement alive."

U.N. chief Antonio Guterres called the report a failure of humanity.

The latest U.N. climate assessment warns humanity must drastically cut greenhouse gas emissions.

With energy prices going up and European countries trying to replace Russia as an energy supplier,

Guterres said the conflict in Ukraine is only making matters worse.

"The war in Ukraine and its immediate effects on energy prices is yet another wake-up call. The only sustainable future is a renewable one. Time is running out."

The WMO report said the ocean warmed significantly faster in the last 20 years.

That trend is not expected to end anytime soon and the organization warned the impacts of that change could take centuries or even millennia to reverse.