Look where global warming hysteria is taking us now. Increasing heating costs in higher latitudes and increasing the glare from road surfaces so it’s too dangerous to drive in daylight hours… When are we going to stop this crap?
Imagine a world where the rooftops and pavements of every urban area are resurfaced to increase the reflection of the Sun’s light rays. Well, this is exactly what a group of Canadian researchers have done in an attempt to measure the potential effects against global warming.
In a study published today, 13 April, in IOP Publishing’s journal Environmental Research Letters, researchers from Concordia University created this scenario to see what effect a global increase in surface reflectance would have on global temperature and our own carbon dioxide (CO2) emissions.
They estimate that increasing the reflectance – commonly known as albedo – of every urban area by 0.1 will give a CO2 offset between 130 and 150 billion tonnes. This is equivalent to taking every car in the world off the road for 50 years, assuming a single car gives off around 4 tonnes of carbon dioxide a year.
This could also provide huge financial gains: CO2 is currently traded at $25 a tonne meaning savings could be in the range of $3300 and $3800 billion dollars. Albedo is measured on a scale ranging from 0 for a non-reflecting, perfectly black surface to 1 for a perfectly white surface. The albedo of all roofs can be increased, on average, by 0.25 and all paved surfaces can be increased by about 0.15. The researchers believe this will increase a city’s overall albedo by about 0.10.
Researchers have long proposed that changing the albedo of a surface could be an effective way of reducing CO2 emissions. A change could effectively cool buildings that would usually retain heat and therefore reduce the use of air-conditioning systems; it could also improve outdoor air quality and offset the warming that the world is currently experiencing.
In this new study, the researchers showed that increasing the albedo of a 1m2 surface by 0.01 would have the same effect on global temperature, over the next 80 years, as decreasing emissions by around 7kg of CO2.
The researchers used a dataset of all global urban areas, called the Global Rural and Urban Mapping Project (GRUMP), to give a realistic estimate of the effects of a global albedo change. In addition to the very large carbon dioxide offset, the researchers calculated a potential decrease in temperature of about 0.07°C
Completely changing the surfaces of all the world’s roofs and pavements seems like a mammoth task; however, the researchers believe that it is possible if promoted in the right ways.
“Typically roofs are resurfaced (or changed) about every 20-30 years; paved surfaces are resurfaced about every ten years. When roofs or paved surfaces are installed, they can be changed to materials with high solar reflectance, typically at no incremental cost,” the researchers write.
Lead author Professor Hashem Akbari said: “It is all based on planning, codes and policies. If we really put the nuts and bolts in place, we can get close to 100 per cent of urban areas increasing the albedo of surfaces.”
Fast facts:
- Over 50% of the world’s population currently lives in urban areas. This is expected to increase to 70% by 2040.
- Pavements and roofs comprise over 60% of urban surfaces (25% roof and 35% pavement).
- According to the GRUMP model, the combined size of global urban areas is around 2 million km2.
###From Friday 13 April, this paper can be downloaded from http://iopscience.iop.org/1748-9326/7/2/024004/article
ummmm…….”promoted in the right ways” means subsidies/taxes/rules/penalties……etc?
Reflecting heat energy off of a roof in the tropics might be a good thing. However, in view of the long winters in Canada, it would seem beneficial to absorb as much heat energy from the roof as possible.
One month after putting a white steel roof on my house my average monthly electric bill was down almost $20.00.
We have long summers in Florida.
An average of one month is just that, one month. A single data point is meaningless. I live in Florida too and my monthly bill varies by more then $20 without any change to my roof.
Aside from that, the whole concept seems futile. Urban areas make up but a tiny portion of the Earth (something like 3% of land area), and the surfaces they are considering are only a fraction of that (probably less than half), for a total of less than 0.4% of the surface of the earth, only half of which is lit by the sun at any given time. A minimal change in albedo would not even be measurable. Also, except for newly paved roads, most asphalt surfaces are already a fairly light shade of gray; its thermal properties are likely the major factors in heat retention. Finally, CO2 is not a pollutant anyway, so why waste resources.
than
SLP, I have heard numerous anecdotal accounts confirming Ralph’s experience. Replacing a roof, especially a black tar roof, with a white colored roof significantly reduces heat and it is a good idea in tropical climates. However, this is for energy consumption purposes. Yeah, the idea about doing it to cool the planet is nonsense.
Just because idiots announce ideas for nonsensical reasons doesn’t mean that it’s a bad idea entirely.
Good insulation is a better investment. Shiny roofs must be kept clean to maintain that reflectivity, especially here where the humidity leads to fairly rapid mildew accumulation. And, metal gets very hot regarless of color; it is impossible to touch in the heat of the day whereas typical composite shingles are less so. That being said, I still hope to replace mine with copper some day, for aesthetics rather than any thought of energy savings.