Developing countries need $305 billion annually for climate adaptation, a figure that could rise to $420 billion by 2035.
Even tripling international public adaptation finance would meet only 20–29% of funding needs by 2035.
International public adaptation finance reached an estimated $28.2–31.7 billion in 2024, far below requirements.
Limited funding and barriers to accessing finance continue to hamper adaptation efforts in vulnerable countries and communities.
Developing countries need an estimated $305 billion annually to adapt to climate change, but even a tripling of international public adaptation finance could meet only 20-29 per cent of their requirements by 2035, according to a new United Nations report.
The annual requirement could rise to $420 billion by 2035 after accounting for inflation, the United Nations Environment Programme's (UNEP) Adaptation Gap Report 2026 said.
Tripling international public adaptation finance could raise annual flows to $85-120 billion by 2035. Including domestic public finance could take the total to $154-189 billion, still leaving more than half of estimated needs unmet.
The $305 billion estimate draws on national climate commitments and adaptation plans, alongside modelling studies. It largely covers public and mixed activities, excluding most private-sector requirements, which could add another $260 billion annually in the 2030s.
Least developed countries (LDCs) and small island developing states (SIDS) together need an estimated $49-51 billion annually. Low-income countries may need to spend around 4 per cent of their gross domestic product on adaptation.
International public adaptation finance from developed to developing countries stood at $28.2 billion in 2024. Another $3.2 billion in private finance was mobilised through public funding, bringing the total to $31.4 billion.
The Glasgow Climate Pact's commitment to double adaptation finance from 2019 levels by 2025 has not closed the gap. Developed countries' bilateral and multilateral institutions allocated an average of $29 billion annually between 2020 and 2024.
Finance between developing countries rose from $3.9 billion in 2019 to $9.7 billion in 2024, accounting for 25 per cent of adaptation-only flows.
Loans accounted for 55 per cent of finance, or $12.3 billion, while concessional instruments represented 88 per cent of funding to LDCs and 78 per cent to SIDS.
Domestic public finance remains important but uneven. UNEP estimates annual domestic adaptation spending at $50 billion, potentially rising to $69 billion by 2035.
Brazil allocated $993 million in public adaptation finance during 2016-20, with 81 per cent sourced domestically. Bangladesh contributed at least $400 million to its Climate Change Trust Fund between 2010 and 2017-18, including $180 million for adaptation.
The report emphasised improving the quality and accessibility of finance alongside increasing funding.
Of 111 investments examined across 13 funds and facilities, only 15 had a strong climate adaptation rationale. Another 75 treated resilience as a secondary benefit, while 21 had no direct adaptation focus.
Between 2016 and 2023, around 29 per cent of international public adaptation finance referred to local implementation, but just 0.17 per cent explicitly mentioned locally led or community-led action.
Kenya's Financing Locally Led Climate Action programme, launched in 2021, had supported more than 1,775 climate investments across 45 counties by mid-2026, including 1,237 completed projects.
The Least Developed Countries Group has called for 70 per cent of climate finance to reach local communities by 2030.
Gender and social inclusion also remain poorly integrated. Only 26 of 112 costed national climate commitments and adaptation plans included dedicated allocations for these priorities, averaging just 3.8 per cent of identified adaptation finance needs.
UNEP identified 2,339 significant climate-related events between 2020 and 2025, around 70 per cent of which occurred in low- and middle-income countries.
Their consequences extended beyond infrastructure damage and economic losses to include ecological harm, non-economic losses and cascading effects across communities.
The report said data gaps and differences in valuation methods prevented a reliable global estimate of funding needed to address climate-related loss and damage.
It called for new, additional and predictable financial resources, stronger adaptation planning and greater recognition of losses that adaptation alone cannot prevent.