United Nations chief Ban Ki-moon called Tuesday for the "elimination of fossil fuel subsidies" to accelerate the transition to clean energy for the sake of the planet.

Countries and businesses must do more to curtail global warming caused by fossil fuel emissions, he said in Marrakesh, which is hosting the annual UN climate conference.

"We have no right to gamble with the fate of future generations or imperil the survival of other species that share our planet."

Ban said planet-warming greenhouse-gas emissions must peak by 2020 and decline rapidly thereafter for the world to meet the UN goal of limiting average global warming to under two degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels.

Current country pledges to curb emissions "will not get us out of us the danger zone," he warned.

Last year was the warmest on record, the UN secretary-general noted, adding that 2016 "is virtually certain to be even hotter."

"Today more than 150 million people live on land that could be submerged or suffer chronic flooding within this century, possibly causing massive waves of migration and instability," Ban said.

The choices we make today could have "catastrophic climate impacts" for thousands of years to come.

"This is an enormous responsibility and an enormous opportunity to do what is right for our future," said Ban, attending his last Conference of Parties (COP) of the UN's climate body before his term ends.

"I strongly urge all countries to increase the mitigation ambition of their national climate plans by 2018," he said.

"The private sector must also do much more, and I call for the elimination of fossil fuel subsidies to accelerate the transition to clean energy."