Every $1 invested in tackling climate change and air pollution together can generate approximately $15 in economic benefits, according to a landmark report released on 7 September by the UN Environment Programme (UNEP) and the Climate and Clean Air Coalition (CCAC). The report, titled Hidden Assets: The Economic and Health Case for Climate and Clean Air Action, is the first comprehensive global economic assessment of integrated climate and clean-air action, and was published on the International Day of Clean Air for Blue Skies.

Why Integration Outperforms Separate Action

The $15 return per dollar invested is significantly higher than what is achieved when climate change and air pollution are addressed independently, the report found. Even when non-market welfare benefits — such as the monetary value of lives saved and improved health outcomes — are excluded, the measures still return around $4 for every $1 invested.

The report notes that in 2022, explicit fossil fuel subsidies consumed 2.18% of global GDP, while global healthcare expenditure stood at 9.3% of GDP in 2023. Every year of delayed action, according to the assessment, would forgo more than $1.5 trillion annually — equivalent to 0.5% of global GDP — in combined market and non-market benefits.

The Human Cost of Air Pollution

In 2025, exposure to human-caused outdoor air pollution — specifically PM2.5 and ozone — was linked to an estimated 6.4 million premature deaths worldwide. Household air pollution was associated with a further 2 million premature deaths, including approximately 300,000 children.

The same year, outdoor air pollution contributed to 5.5 million new cases of childhood asthma, 2 million new cases of dementia, and millions of additional cases of heart attack, pulmonary disease, diabetes, stroke, and lung cancer. Unlike earlier assessments, this report factors in the economic drag of air pollution-related illness, including pressure on health services and losses to productivity and well-being.

What the Report Recommends

The assessment examines a package of 25 measures spanning six sectors: energy and fossil fuel systems, industry, transport, agriculture and food systems, residential cooking and heating, and waste management. The measures target both long-term decarbonisation and super pollutants such as methane, black carbon, and hydrofluorocarbons (HFCs).

Specific interventions include renewable power and energy efficiency upgrades, expanding clean cooking and heating solutions, tighter vehicle emission standards, electric vehicles, low-sulphur shipping fuels, ending routine gas venting and flaring, improved livestock and manure management, more efficient fertiliser use, and phasing down HFCs. By 2050, full implementation of these measures could cumulatively prevent 144 million air pollution-related premature deaths — including 96 million from ambient air pollution alone — and hundreds of millions of cases of chronic disease.

What Leaders Said

Inger Andersen, Executive Director of UNEP, said the report upends a long-held assumption about the economics of environmental action. 'For too long, we have treated climate action as a cost to be managed and air pollution as the unfortunate outcome of development. This report shows the opposite: Clean air is a key driver of development, health, food and energy security, and climate stability — an asset we must invest in,' she said.

Andersen added that proven solutions already exist, but what is lacking is 'decisive leadership from governments, financial institutions, and businesses to deliver them with the speed and coordination this crisis demands.'

Elliott Harris, independent co-chair of the Assessment, highlighted the structural reason why capital has not flowed into integrated action. 'A benefit-cost ratio of 15 to 1 would attract capital instantly in almost any other sector. The only reason it hasn't on integrated climate and clean air action yet is that the returns are split across health systems, productivity and avoided climate damage rather than landing on a single balance sheet,' he said. Harris warned that finance ministries and investors who keep climate and air quality in separate budget lines are 'leaving trillions on the table.'

What Comes Next

The report is expected to inform upcoming multilateral climate and environment negotiations, where integrated financing frameworks are increasingly on the agenda. Analysts say the $15-to-$1 return ratio could strengthen the case for blended finance instruments that pool health, climate, and productivity dividends into a single investable vehicle — though translating the assessment's findings into binding policy commitments remains the central challenge.