The world is "losing the race" against climate change, United Nations chief Antonio Guterres has warned during a speech at the elite Davos forum, demanding bolder action from governments to arrest catastrophic warming.

A World Economic Forum (WEF) survey ahead of the Davos meeting found climate change was the leading concern for forum participants from around the world, noting, in particular, the growing frequency of extreme weather events.

"Climate change is the defining issue of our time. We are losing the race," said Guterres. "It is absolutely central to reverse this trend."

Following a UN summit in Poland last month, which was designed to advance the Paris climate accord, Guterres said he was "not hopeful" that nations would find the necessary resolve.

But he stressed: "We need political will and we need governments who understand this is the most important priority of our times."

The Paris accord has been shaken by the withdrawal of the United States under President Donald Trump and by threats to do the same by Brazil's new far-right leader, Jair Bolsonaro.

The UN secretary-general said the commitments made in Paris were already "not enough".

"If what we agreed in Paris would be materialised, the temperature would rise more than 3C," he said.

"We need countries to make stronger commitments," Guterres said, calling for more measures to mitigate against climate change and adapt to it, along with financial aid for poorer countries.

'Suicide pact'

Many companies have touted their moves towards creating a greener economy, such as Patrick Pouyanne, CEO of French energy giant Total, who told the AFP news agency that "natural gas and renewables" are the best way forward.

But activists say companies are not doing nearly enough.

One vocal voice in Davos this week has been Swedish 16-year-old Greta Thunberg, who has inspired a wave of climate protests by schoolchildren around the world after delivering a fiery speech at the UN climate summit last month.

"They [companies] have known exactly what priceless values they have been sacrificing to continue making unimaginable amounts of money," she told AFP in an interview.



Former US secretary of state John Kerry, who signed the Paris accord for Washington in 2016, said 38 out of the 50 US states were implementing their own climate policies despite Trump's withdrawal and vocal scepticism on climate change.