UN envoy says 80 countries ready to step up on climate

Young activists have held protests worldwide to demand action on climate change. (AFP/Martin BERNETTI)

Under the landmark deal, countries agreed to announce by 2020 new efforts to strengthen their national plans to reduce greenhouse gas emissions in a bid to limit global temperature rise.

UN climate envoy Luis Alfonso de Alba told journalists that "80 is the number of countries (from) which we have already received a signal that they are willing" to enhance their plans.

"But it doesn't mean that they are willing to do that to the scale we need," he added.

The United Nations is pushing for stronger action on climate change in the face of new scientific data showing that current efforts fall well short of the goal of containing global warming.

"We need to step up ambition quite radically. We are not talking about a small incremental approach, but rather a quite drastic increase," said De Alba.

A total of 197 parties have signed the Paris agreement, of which 186 have ratified it.

The United States under Donald Trump decided to pull out of the deal, but the withdrawal will only become effective in 2020.

De Alba was in Washington last week to meet with US officials ahead of a major UN climate summit in New York in September that some hope will be a turning point.

The climate envoy said he held "very positive" meetings with US administration officials, who encouraged the United Nations to push other countries to do more even if the United States is pulling back.

"They agree that a lot more needs to be done," said De Alba of his meetings in Washington. "They are waiting for those countries to do it."

The United States is the world's biggest polluter after China.

At the UN summit, about 20-30 countries will be chosen to be in the spotlight for their ambitious plans.

The UN is pressing governments to commit to a 45 per cent cut in greenhouse gas emissions over the next decade and to become carbon-neutral by 2050.