GNV News March 14, 2025

As global warming progresses, various efforts are being made to lower temperatures. One approach is to paint roofs white to reduce indoor temperatures. This measure takes advantage of the fact that white roofs reflect sunlight and prevent excessive heat absorption. A study in Burkina Faso found that painting roofs white lowered temperatures by up to 1.7°C over two years even in homes with corrugated metal roofs, and had positive effects on residents’ health.

It is also known that painting not only roofs but also roads and exterior walls white has an effect of lowering temperatures.

However, new research has found that climate measures that whiten roofs, roads, and exterior walls can raise temperatures in surrounding areas. When white paint is used at the neighborhood scale to increase solar reflectivity, differences in reflectivity with surrounding areas increase convection and change cloud cover. As a result, rainfall decreases in nearby areas and temperatures rise.

These findings indicate that climate change could exacerbate inequality. For example, if high-income areas adopt measures to whiten roofs, roads, and exterior walls, temperatures in neighboring low-income areas could rise, effectively offloading warming onto them.

Learn more about climate change and inequality → “A new ‘apartheid’ created by climate change”

Learn more about inequalities caused by climate change → “A major step on climate change: Bringing it to the ICJ”

Learn more about climate reporting → “The reality of exceeding 1.5°C: Global climate challenges, responses, and Japanese media coverage”

Greece: Cycladic-style houses on Santorini Island (Photo: Orthodox Church Architecture
/ Flickr［CC BY-SA 2.0］）