UNEP’s Adaptation Gap Report 2025 warns of deepening crisis as Jamaica reels from Hurricane Melissa

The United Nations Environment Programme’s (UNEP) Adaptation Gap Report 2025: Running on Empty (AGR) was launched on a day when the Caribbean island of Jamaica lies devastated by the impact of Hurricane Melissa. Melissa is one of the strongest hurricanes ever to make landfall in the North Atlantic Ocean, and the most powerful to strike Jamaica, on October 28, 2025.

The AGR brings little comfort to countries such as Jamaica that are extremely vulnerable to the impacts of global warming and consequent climate change, one of which is the rapid intensification of monster storms like Hurricane Melissa.

The report stated that developing countries will need between $310-365 billion annually by 2035 to adapt to the rapid-onset changes already under way, such as more frequent extreme rainfall events, intensifying tropical cyclones, flash floods and landslides, and heatwaves. They also face slow-onset changes such as long-term droughts, sea-level rise, and melting glaciers and ice sheets.

The figure of $310 billion comes from modelled costs. When estimates are extrapolated from Nationally Determined Contributions and National Adaptation Plans, adaptation needs rise to $365 billion. “These numbers are based on 2023 values and not adjusted for inflation,” the report noted.

The report highlighted that international public adaptation finance flows fell to a worrying $26 billion in 2023, down from $28 billion in 2022. This generates an adaptation finance gap in the range of $284-339 billion. Adaptation finance needs are 12-14 times the current adaptation finance flows to developing countries; the previous estimate was $194-366 billion per year until 2030.

“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,” said António Guterres, secretary general of the United Nations. 

If current trends in public finance for adaptation persist, the Glasgow Climate Pact goal of doubling adaptation finance from 2019 levels by 2025 to $40 billion will not be achieved, the report warned. The New Collective Quantified Goal for climate finance, agreed at the 29th Conference of Parties (COP29) to the United Nations Framework Convention on Climate Change (UNFCCC) in Baku, Azerbaijan, calls for developed countries to provide developing nations with $300 billion annually for climate action by 2035. However, this will still be insufficient to close the adaptation finance gap, the report states.

It cited two main reasons: “First, if the past decade’s inflation rate is extended to 2035, the estimated adaptation finance needed by developing countries goes from $310-365 billion per year in 2023 prices to $440-520 billion per year. Second, the $300 billion target is for both mitigation and adaptation, meaning that adaptation would receive a lower share,” UNEP explained in a press release accompanying the report.

The Baku to Belém Roadmap, also decided at COP29, may make a difference, “but care must be taken not to increase the vulnerabilities of developing nations,” according to the release. “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,” it added. 

Adaptation planning and implementation are on the rise, the report notes. Around 172 countries have at least one national adaptation policy, plan or strategy, though 36 of these are outdated and have not been revised in at least a decade, the AGR stated.

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

The report also called for actions to close the adaptation finance gap, including containing adaptation finance needs through stronger mitigation measures to limit the worst impacts of warming. Countries should also avoid maladaptation — actions that consume financial resources but undermine communities’ ability to adapt. It urges nations to “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 can play a role in closing the gap, its potential contribution is limited to around $50 billion per year, up from the current $5 billion, according to the report. “Reaching $50 billion would require targeted policy action and blended finance solutions, with concessionary public finance used to de-risk and scale-up private investment,” said the UNEP press release. 

“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,” said Inger Anderson, executive director of UNEP.