The UN Secretary-General António Guterres has called on all countries to declare a climate emergency.
António Guterres was speaking at a virtual summit on the fifth anniversary of the Paris climate agreement,
He criticised rich countries for spending 50% more of their pandemic recovery cash on fossil fuels compared to low-carbon energy.
Over 70 world leaders are due to speak at the meeting organised by the UK, UN and France.
Mr Guterres said that 38 countries had already declared a climate emergency and he called on leaders worldwide to now do the same.
He said the emergency would only end when carbon neutrality was reached. Carbon neutrality means that emissions have been reduced as much as possible and any remaining ones are balanced by removing an equivalent amount from the atmosphere,
On the Covid recovery spending, he said that this is money being borrowed from future generations.
"We cannot use these resources to lock in policies that burden future generations with a mountain of debt on a broken planet," he said.
The secretary general praised those countries who have come to today's meeting with new targets and plans.
A number of big emitters, including Australia, Saudi Arabia, Russia and Mexico, are not taking part, as their climate actions were not deemed ambitious enough.
The UK has announced an end to support for overseas fossil fuel projects, and has today deposited a new climate plan with the UN.
It's the first time that Britain has had to do this, as it was previously covered by the European Union's climate commitments.
Today's virtual gathering is taking place after the pandemic caused the postponement of the annual Conference of the Parties (COP) meeting, which had been due to take place in Glasgow this year. (BBC)