Governments began work on Monday on a rule book to implement the 2015 Paris Agreement to limit global warming, with the United Nations urging stronger action after a string of record-smashing monthly temperatures.
NASA said at the weekend that last month was the warmest April in statistics dating back to the 19th century, the seventh month in a row to break temperature records.
The meeting of government experts is the first since 195 nations reached a deal in Paris in December to limit climate change by shifting from fossil fuels to green energies by 2100. It will begin to work out the detail of the plan.
"The Paris Agreement represents the foundations ... Now we have to raise the walls, the roof of a common home," French Environment Minister Segolene Royal told a news conference.