Climate change is a grave threat to global peace and security, Boris Johnson has warned ahead of a United Nations Security Council session on the issue.

The Prime Minister, who is chairing the session on Tuesday, said a warming planet is driving insecurity, “from the communities uprooted by extreme weather and hunger, to warlords capitalising on the scramble for resources”.

He called for action to help vulnerable countries adapt to climate change and cutting global emissions to “net zero” – which requires huge cuts to greenhouse gases and any remaining pollution to be offset through measures such as planting trees – to protect prosperity and security.

The UN Security Council (UNSC) session on climate and security will hear from Sir David Attenborough, who will say that if the world acts to bring down emissions with “sufficient vigour” it may avoid runaway climate change.

Unlike many issues the Council deals with, this is one we know exactly how to address

The UN’s Cop26 climate summit being hosted by the UK in November in Glasgow could be the last opportunity to make the necessary step-change, the naturalist and broadcaster will warn the 15-member council in a video message.

The UNSC session is the first leader-level discussion it has held on climate, and is the first time it has been chaired by a British prime minister in nearly 30 years.

It comes as countries increasingly face the effects of rising temperatures and extreme weather, which is forcing populations to move and creating competition over increasingly scarce resources.

Of the 20 countries ranked most vulnerable to rising global temperatures, 12 are already in conflict, officials said.

Ahead of the session, which will also hear live from UN secretary-general Antonio Guterres and Sudanese climate activist Nisreen Elsaim, Mr Johnson said: “The UNSC is tasked with confronting the gravest threats to global peace and security, and that’s exactly what climate change represents.”

But he said: “Unlike many issues the Council deals with, this is one we know exactly how to address.

“By helping vulnerable countries adapt to climate change and cutting global emissions to net zero, we will protect not only the bountiful biodiversity of our planet, but its prosperity and security.”

If we bring emissions down with sufficient vigour we may yet avoid the tipping points that will make runaway climate change unstoppable

Sir David said: “If we bring emissions down with sufficient vigour we may yet avoid the tipping points that will make runaway climate change unstoppable.

“In November this year, at Cop26 in Glasgow, we may have our last opportunity to make the necessary step-change.

“If we objectively view climate change and the loss of nature as worldwide security threats – as indeed they are – then we may yet act proportionately and in time.”

Responding to the meeting, Christian Aid’s climate policy lead, Dr Kat Kramer, said: “Millions of the world’s poorest people are already living with the impacts of climate change, which is forcing displacement, devastating livelihoods and putting pressure on communities who are competing over resources such as land and water.

“In some countries these impacts become the drivers of local conflicts which can be instrumentalised by leaders and escalate into violence and war.”

She said investment in efforts to adapt to the effects of climate change can build peace and social cohesion, and it is vital that international leaders get funding directly to local groups, particularly women and youth.