How much development aid is spent on climate change?

This is a question I’ve had for a while. I care a lot about climate change. I also care a lot about basic health and development programs in the world’s poorest countries — vitamin supplementation, nutrition programs, antiretroviral treatment for HIV, and bed nets treated against malaria.

These two priorities could easily come into conflict. With a fixed aid budget, every dollar spent on climate programs is one less dollar for everything else. And with large cuts to foreign aid in the last few years, that budget is shrinking.

For a long time, I didn’t have good data to see whether this tension was real. But someone recently pointed me to the RioMarkers database, which tags aid projects according to whether they target environmental outcomes under the Rio Conventions (which include biodiversity, climate change mitigation, climate change adaptation, and desertification).1

Using it, we’ve constructed data on the amount of development aid allocated to climate-related projects, and how that compares with aid for other causes.

The headline statistic is that around one-fifth of development aid is now coded as climate-related.2

But the “climate-related” label is not as straightforward as it might seem. Some of these projects look like ones that would have happened regardless of climate change. Untangling how many matters for anyone concerned about where aid is being spent, regardless of whether their focus is on health, development, or climate.

Hannah Ritchie and Pablo Arriagada (2026) - “How much development aid is spent on climate change?” Published online at OurWorldinData.org. Retrieved from: 'https://archive.ourworldindata.org/20261026-063310/how-much-development-aid-is-spent-on-climate-change.html' [Online Resource] (archived on October 26, 2026).