Countries must dramatically and urgently increase efforts to adapt to climate change as it lands “blow after blow upon humanity”, the UN has warned.

Ahead of Cop27 international climate talks in Sharm El-Sheikh, Egypt, the UN said the estimated costs of coping with climate impacts are five to 10 times greater than the finance going to developing countries to help them adapt.

The money needed to help the developing world adapt is set to increase to as much as £300 billion a year by the end of the decade, a UN report said.

UN secretary-general Antonio Guterres called for a “global surge in adaptation investment to save millions of lives from climate carnage”.

Climate risks are rising, with a multi-year drought in the Horn of Africa, unprecedented flooding in Pakistan and record heatwaves across the northern hemisphere all hitting at 1.1C of warming above pre-industrial temperatures.

The UN Environment Programme (UNEP) warned last week that based on countries’ plans to tackle climate-warming emissions, there was currently no credible pathway in place to limit temperature rises to 1.5C, the threshold beyond which the worst impacts of global warming are expected.

Instead, the world was on track for 2.4C-2.6C of warming and climate catastrophe.

Now the UNEP is warning that climate risks will intensify with each tenth of a degree Celsius, and efforts to adapt to the worsening situation must take centre stage along with efforts to halt global warming.

But global efforts to plan for, finance and implement adaptation measures – from alert schemes to deal with heatwaves to increasing greenery in cities, flood defences, and planting climate-resilient crops – are not keeping pace with what is needed, it said.

And even ambitious investments in adapting to climate change will not fully prevent its impacts so the loss and damage to poorer countries, who have done least to cause the crisis but are now on the front line, must be addressed, it added.

The UNEP’s adaptation gap report finds that most countries have some plans, strategies or laws in place for adapting to climate change, but finance is not following and the shortfall continues to widen.

International finance flows to developing countries for adapting to climate change reached 29 billion US dollars (£26 billion), an increase of 4% from 2019.

But significant acceleration is needed to meet the pledge made at the Cop26 climate summit in Glasgow last year to double finance from 2019 levels by 2025, the UNEP said.

Estimated annual funding needed for adapting to climate change is 160-340 billion US dollars by 2030 (£142 billion-£300 billion) and 315-565 billion dollars (£280 billion-£502 billion) by 2050, the report said.

The study also said there were enhanced benefits to linking planning, finance and implementing actions to both adapt to climate change and mitigate the crisis by cutting emissions, for example “nature-based solutions” such as restoring mangroves to soak up carbon and protect against coastal flooding.

Inger Andersen, executive director of the UNEP, said: “Climate change is landing blow after blow upon humanity, as we saw throughout 2022: most viscerally in the floods that put much of Pakistan under water.

“The world must urgently reduce greenhouse gas emissions to limit the impacts of climate change.

“But we must also urgently increase efforts to adapt to the impacts that are already here and those to come.

“Nations need to back the strong words in the Glasgow Climate Pact with strong action to increase adaptation investments and outcomes, starting at Cop27.”

Mr Guterres said: “Today’s UNEP adaptation gap report makes clear that the world is failing to protect people from the here-and-now impacts of the climate crisis.

“Those on the front lines of the climate crisis are at the back of the line for support.

“The world is falling far short both in stopping the growth of greenhouse gas emissions and starting desperately-needed efforts to plan, finance and implement adaptation in light of growing risks.”

He said developed countries at Cop27 must present a credible road map to how they will deliver the promised doubling of adaptation support, as well as action to unblock investment and universal early warning systems for extreme weather.

Mr Guterres said there was a need to recognise that “in many places, it is too late for adaptation”, and that Cop27 must provide a road map to closing the finance gap for addressing loss and damage caused by climate change.