• Adaptation finance needs of developing countries estimated at over US$310 billion per year by 2035

• Glasgow Climate Pact goal of doubling international public adaptation finance to approximately US$40 billion by 2025 will not be met on current trends

• Report highlights progress with adaptation planning and implementation, but challenges remain

Nairobi, 29 October 2025 – Amid rising global temperatures and intensifying climate impacts, a yawning gap in adaptation finance for developing countries is putting lives, livelihoods and entire economies at risk, according to the Adaptation Gap Report 2025: Running on Empty from the United Nations Environment Programme (UNEP).

Released to inform negotiations at COP30 in Belém, Brazil, the report finds that while adaptation planning and implementation are improving, adaptation finance needs in developing countries by 2035 are over US$310 billion per year – 12 times as much as current international public adaptation finance flows.

“Climate impacts are accelerating. Yet adaptation finance is not keeping pace, leaving the world’s most vulnerable exposed to rising seas, deadly storms, and searing heat,” UN Secretary-General António Guterres in his message on the report. “Adaptation is not a cost – it is a lifeline. Closing the adaptation gap is how we protect lives, deliver climate justice, and build a safer, more sustainable world.  Let us not waste another moment.”

“Every person on this planet is living with the impacts of climate change: wildfires, heatwaves, desertification, floods, rising costs and more,” said Inger Andersen, Executive Director of UNEP. “As action to cut greenhouse gas emissions continues to lag, these impacts will only get worse, harming more people and causing significant economic damage.

“We need a global push to increase adaptation finance – from both public and private sources – without adding to the debt burdens of vulnerable nations. Even amid tight budgets and competing priorities, the reality is simple: if we do not invest in adaptation now, we will face escalating costs every year.”

A worrying gap

The figure of US$310 billion needed to finance adaptation in developing countries per year by 2035 is based on modelled costs. When basing estimates on extrapolated needs expressed in Nationally Determined Contributions and National Adaptation Plans, this figure rises to US$365 billion. These numbers are based on 2023 values and not adjusted for inflation.

International public adaptation finance flows to developing countries were US$26 billion in 2023: down from US$28 billion the previous year. This leaves an adaptation finance gap of US$284-339 billion per year – 12 to 14 times as much as current flows. The previous AGR estimate was US$194-366 billion for the year 2030.

If current trends in financing do not turn around quickly, the Glasgow Climate Pact goal of doubling international public adaptation finance from 2019 levels to approximately US$40 billion by 2025 will not be achieved.

Planning and implementation on the rise

Some 172 countries have at least one national adaptation policy, strategy or plan in place; only four countries have not started developing a plan. However, 36 of the 172 countries possess instruments that are outdated or have not been updated in at least a decade. This should be addressed to minimize the possibility of maladaptation.

In the Biennial Transparency Reports – submitted under the Paris Agreement to outline progress in meeting climate pledges – countries reported on over 1,600 implemented adaptation actions, mostly on biodiversity, agriculture, water and infrastructure.

However, few countries are reporting on actual outcomes and impacts, which are needed to assess their effectiveness and adequacy.

Meanwhile, support for new projects under the Adaptation Fund, the Global Environment Facility and the Green Climate Fund grew to nearly US$920 million in 2024. This is an increase of 86 per cent over the five-year moving average of US$494 million between 2019 and 2023. However, this may only be a spike, with emerging financial constraints making the future uncertain.

Public and private finance to step up

The New Collective Quantified Goal for climate finance, agreed at COP29, calls for developed nations to provide at least US$300 billion for climate action in developing countries per year by 2035. This is insufficient to close the finance gap, for two reasons.

First, if the past decade’s inflation rate is extended to 2035, the estimated adaptation finance needed by developing countries goes from US$310-365 billion per year in 2023 prices to US$440-520 billion per year. Second, the US$300 billion target is for both mitigation and adaptation, meaning that adaption would receive a lower share.

The Baku to Belém Roadmap to raise US$1.3 trillion by 2035 could make a huge difference – but care must be taken not to increase the vulnerabilities of developing nations. Grants, and concessional and non-debt-creating instruments, are essential to avoid increasing indebtedness, which would make it harder for vulnerable countries to invest in adaptation.

For the roadmap to work, the international community must contain the adaptation finance gap through mitigation and avoiding maladaptation, increase funding with the help of new providers and instruments, and engage more finance actors in integrating climate resilience into financial decision-making.

While the private sector must do more, the report estimates the realistic potential for private sector investment in national public adaptation priorities at US$50 billion per year. This compares to current private flows of around US$5 billion per year. Reaching US$50 billion would require targeted policy action and blended finance solutions, with concessionary public finance used to de-risk and scale-up private investment.