June 11th, 2025
| As summer begins here in the Northern Hemisphere, staying cool is on everyone’s mind. And with cities around the world getting warmer each year, specialized paints that keep buildings cool have become a hot topic. These paints generally reduce temperatures using radiative cooling, which works by reflecting sunlight to radiate heat into the air. But this is most effective in dry climates, on clear days, and on the roof—leaving people in humid, rainy, and dense urban environments to feel the heat during the dog days of summer. Now, researchers have designed a new paint that effectively cools buildings in humid environments and works when placed on the sides of buildings.
The cement-based paint goes beyond radiative cooling because it also harnesses the power of evaporation to reduce heat. The team used barium sulfate nanoparticles to make the calcium silicate hydrate structure of cement more porous without affecting its strength. This porosity lets the paint capture more water vapor, which can then evaporate and, much like sweat evaporating from skin, effectively cool the painted surface. To see how their creation measured up, the researchers painted three small, concrete houses; one with their new paint, one with a radiative cooling paint, and one with a regular white paint. The results were far more exciting than watching paint dry: The new material kept that house more than 4.5°C cooler than the other two structures. Next, they tested it on concrete houses with air conditioning and electricity meters; the house with the new paint used 30 to 40% less energy to stay comfortable than the one with radiative cooling paint. Plus, the paint is durable, weather- and mold-resistant, relatively inexpensive to produce, and easy to apply, the researchers note—so overall, “an innovative passive cooling solution with practical viability for global decarbonization.” |
'Black Swans' are highly improbable events that come as a surprise, have major disruptive effects, and that are often rationalized after the fact as if they had been predictable to begin with. In our rapidly warming world, such events are occurring ever more frequently and include wildfires, floods, extreme heat, and drought.
'Green Shoots' is a term used to describe signs of economic recovery or positive data during a downturn. It references a period of growth and recovery, when plants start to show signs of health and life, and, therefore, has been employed as a metaphor for a recovering economy.
It is my hope that Black Swans / Green Shoots will help readers understand both climate-activated risk and opportunity so that you may invest in, advise, or lead organizations in the context of increasing pressures of global urbanization, resource scarcity, and perils relating to climate change. I believe that the tools of business and finance can help individuals, businesses, and global society make informed choices about who and what to protect, and I hope that this blog provides some insight into the policy and private sector tools used to assess investments in resilient reinforcement, response, or recovery.