The United Nations on Tuesday rejected a call by a global non-government network to postpone the upcoming COP26 climate summit in Britain on the grounds that a lack of Covid vaccines risked sidelining developing countries.

"For now, no changes are planned, but we understand the concerns,"  UN deputy spokesman Farhan Haq said of the UN Climate Change Conference set to kick off October 31 in Glasgow, Scotland. 

Earlier Tuesday the Climate Action Network, a global collection of more than 1,500 climate NGOs, called on Britain to postpone COP26 amid an increase in Covid-19 cases, unequal global vaccine rollout, and stringent quarantine requirements for dozens of countries seeking to attend the 12-day UN talks.

But the United Nations joined the host government in countering that the climate crisis was too urgent for the meeting to be put off.

"The global scientific community has made clear that climate change is now a global emergency," Haq said.

"Only an urgent and major step up in climate action can keep the goals of the Paris Agreement within reach, and protect the most vulnerable countries and communities from worsening climate impacts."

Haq said UN authorities and offices are working with the British government "to make COP as safe and inclusive as possible, including offering vaccines to all participants and paying for hotel quarantine costs where quarantine is required."

 A global network of more than 1,500 climate NGOs called on Britain to postpone the upcoming COP26 summit, saying Tuesday that a lack of Covid-19 vaccines risked sidelining developing countries.

An increase in Covid cases, unequal global vaccine rollout, and stringent quarantine requirements for more than 60 "red list" nations or territories hoping to attend the 12-day UN talks mean that "a safe, inclusive and just global climate conference is impossible," the Climate Action Network (CAN) said in a statement.

"Our concern is that those countries most deeply affected by the climate crisis and suffering from the lack of support by rich nations in providing vaccines will be left out," said Tasneem Essop, CAN's Executive Director.

"There has always been an inherent power imbalance within the UN climate talks and this is now compounded by the health crisis."

Host government Britain countered that the climate crisis was too urgent for the meeting to be put off.

A recently released UN climate science report shows "why COP26 must go ahead this November to allow world leaders to come together and set out decisive commitments to tackle climate change", COP President Alok Sharma told AFP, noting that the conference -- originally slated for last November -- has already been postponed once.

The northern hemisphere has been battered over the last three months by record-breaking extreme weather made worse by global warming, according to scientists who have developed tools to tease out the impact of climate change.

Deadly heatwaves in parts of North America and Europe; unprecedented flooding across western Europe, China and the United States; uncontrolled wildfires around the Mediterranean basin and in California -- all were made more intense or likely by global warming.

Britain has said it would cover accommodation costs for delegates subject to the quarantines, and has offered to provide fast-track vaccines. 

"We are working tirelessly with all our partners, including the Scottish Government and the UN, to ensure an inclusive, accessible and safe summit in Glasgow," Sharma said.

But delegates who have applied for them have yet to get their jabs, according to the NGO group.

Not fit for purpose

The British government said the vaccinations would start "this week," and that even with a four-week delay between doses there was still enough time to get the job done before COP26 kicks off on October 31. 

Currently, more than 55 percent of Europeans are fully vaccinated, compared to about three percent in Africa.  

Civil society campaigners, who play a crucial watchdog role as registered observers, will also likely face restricted access, CAN warned. 

Developing countries will be deeply affected by decisions taken at the COP on issues ranging from climate finance, international carbon markets, and how to help poor nations cope with severe climate damages already incurred.

"A climate summit without the voices of those most affected by climate change is not fit for purpose," said Mohamed Adow, a longtime observer of the talks and director of the Nairobi-based think tank Power Shift Africa.

"If COP26 goes ahead as currently planned, I fear it is only the rich countries and NGOs from those countries that would be able to attend," he added. 

"This flies in the face of the principles of the UN process and opens the door for a rich nations stitch-up of the talks."

CAN said the call to postpone COP26 should not be construed as a boycott of the climate talks.

"We will continue our work to push political leaders to deliver ambitious national climate targets, fulfil their responsibilities on climate finance, and phase out fossil fuels," it said.