Paint your roof white to save 1 tonne of CO2
Friday, September 26th, 2008 by Nigel
An aquaintance just sent me an interesting email: “During my Astronomy exams at University, one of the questions was “if the roof of every building was painted white, what impact would it have on the albedo of the Earth”. Over the last few years I’ve mentioned this to a few climate scientists and they’ve looked quizzical but then nodded…
“Now, he says, someone has actually done the work (with some hefty assumptions) and come up with this.”
If that’s a bit baffling, it’s explained more fully in this article here, which says:
if the 100 biggest cities in the world installed white roofs and changed their pavements to more reflective materials - say, concrete instead of asphalt-based material - the global cooling effect… would offset 44 metric gigatons of greenhouse gases, which have been trapping heat in the atmosphere and altering the climate on a potentially dangerous scale…
That is more than all the countries on Earth emit in a single year!
The upshot, my mate says is: “Paint your roof white to save 1 tonne of CO2.”
Should we be selling eco friendly white roof paint?
image thanks to Huang and Taha
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October 2nd, 2008 at 6:48 am
“would offset 44 metric gigatons of greenhouse gases, which have been trapping heat in the atmosphere and altering the climate on a potentially dangerous scale…”–just wow!
Just imagine if all the nations would use white paint on the majority of it’s architectural projects, things would’ve been “cooler” but I guess, the farthest that every major household would do is to replace their bulbs with eco friendly ones.
October 4th, 2008 at 5:53 am
And I just want to add that I will be renovating my house soon and that I will use white paint to cover everything up!
I’m always pleased to see blogs like yours because they share my point of view. If you’d like, you can check out
http://www.alternative-energy-secrets.com for the latest articles involving alternative energy.
October 24th, 2008 at 3:18 pm
What a simple. wonderful Idea! i cant believe this is not in practice! I had the idea of self suff. buildings covered on plants, roof gardens etc with wind turbines… but white paint… that would be so easy to do. makes you think!!!
December 6th, 2008 at 12:29 pm
Great…i love this idea…i will definitely employ white paint as i renovate my house.
December 7th, 2008 at 12:25 pm
Now Let us be frank about the issue of saving the planet.I think we are on a freefall to total destruction. Everyone expect others to slow down on their individual contribution to the greenhouse gases but no one wants to let go their little comforts.
If people can start to be realistic about simple things in life like replacing most of the trees that we have cut down from the Earths surfaces, It is no longer an issue of one tree planting day but the whole year dedicated to planting trees.It mght sound a joke but this is serious stuff. If you come from Africa like me which is basically Sub- saharan terrain you will have witnessed the desertification of our Continent and the the complete elimination of species small and large that once lived there during my life time.
Why? Answer;Greed.
December 15th, 2008 at 5:45 pm
It’s worth noting the environmental impact of producing paint. Most paint is very toxic and harmful to the environment, on top of this there is the carbon impact of producing the paint and transporting it and then carbon footprint of producing and transporting the food that sustains the labour required to paint the rooves, and their subsequent touch ups. Sorry to put a downer on things but the cement industry is one of the worst industries on the planet in terms of greenhouse gas emissions.
April 4th, 2009 at 5:15 am
a quick explanation of why white paint works to cool the planet
1 around 50 percent of sunlight is visible light
2 around 50 percent of sunlight is heat
3 visible light is a frequency of light not absorbed by the atmosphere
4 some heat from the sun is absorbed by the atmosphere directly (greenhouse gasses which makes the atmosphere warmer).
5 heat from the sun also warms the surface of the planet and this heat is then radiated back into the atmosphere again being absorbed by greenhouse gasses.
6 visible light is poorly absorbed by the atmosphere, some of it gets reflected back by the atmosphere.
7 the visible light that doesn’t get reflected back by the atmosphere is either reflected by the surface (eg a snow field) or absorbed by the surface (an asphalt carpark/ road). this absorbed light heats the dark surface. this heat is then radiated into the atmosphere and is absorbed by greenhouses gasses makiig the atmosphere warmer.
8 by painting your roof white and other surface you reflect around 50 percent of the visible energy from the sun, a significant amount of this is reflected back into space without heating the atmosphere.
9 by painting enough roofs you make buildings cooler and cool the atmosphere. air conditionig works easier to cool houses because they are cooler, perhaps you wouldn’t even need air conditioning?
the main to understand is that by reflecting visible frequencies away from the planet we can cool the atmosphere.
April 23rd, 2010 at 5:27 am
Nice post…Thank you for sharing some good things!!
July 21st, 2010 at 2:57 pm
Such a useful blog wow !!!!