New Greenhouse Effect: Global Cooling?

As shorthand for the insulating effect of certain gases in the atmosphere, "greenhouse" has become somewhat of a dirty word among environmentalists. But according to a study published in the current Journal of Geophysical Research and noted in this week's New Scientist, greenhouses, or hothouse farms, can mask "warming signals." Apparently part of southeastern Spain has so many greenhouses with sunlight-reflecting white roofs that the average local temperature has dropped by an average of 0.54 degrees Fahrenheit per decade since 1983, despite rising temperatures in the rest of the country.

About how many greenhouses are we talking? More than 26,000 hectares, or about 100 square miles, of them. You don't have to be a horticulturalist, however, to save energy and money -- and potentially help slow climate change -- with a reflective roof. According to the LA Times, roofs account for 25 percent of total surface area in most cities, and pavement accounts for around 35 percent. If 100 major cities covered that space with reflective materials, such as those used on the Spanish greenhouses, it could offset as much as 44 metric gigatons of heat-trapping gases. As Joe Biden would say, let me repeat that: 44 metric gigatons. "That is more than all the countries on Earth emit in a single year," the Times explained in a report on new climate change research last month. "And, with global climate negotiators focused on limiting a rapid increase in emissions, installing cool roofs and pavements would offset more than 10 years of emissions growth, even without slashing industrial pollution."

Even the 1,000 square feet of a typical American home's rooftop can make a difference. To determine what kind of roof will deliver the biggest savings on your energy bill, the Cool Roof Rating Council  recommends considering slope, climate, and state rebate programs. Information on those factors and more can be found at coolroofs.org.

Share your tips: What energy-saving home improvements have you made?

Read more about science, climate change, and saving energy:
4 Ways to Green Your Gadgets
Americans' Small Changes Mean More For the Planet
Escalators Saving Power
Aloha, Solar
Carbon and Cents

For more practical tips, visit The Green Life.

Comments

[KillTheMessenger]

44 gigatons. Impressive. That's about two year's worth of global CO2 production. That is indeed more than the annual production. It's twice the annual production. If we did it today, we could hope to hold global warming back until 2010. Then it would continue just as before.

Sounds like a solution. sarcasm off.

Except that one wonders how many gigatons of white paint it would take to paint that much area? And how much CO2 would be produced to make the white paint...

:-)

[LintLass]

Considering roofs and the like have to be maintained, anyway, ...and cooler roofs save on the energy expenditure of air conditioning: this kind of notion could be almost a freebie. And there's nothing to say that this is a one-time benefit: the article claims it could potentially offset ten years of effects, ...that's certainly time we could use, though, obviously, it couldn't happen all at once.

Could be an easy source of 'green job,' too. .

[KillTheMessenger]

Ask a painter how much painting your roof will cost. And then try to convince your local authorities that they should paint the road white, with black stripes. And, oh, ask them how they will keep it white... all the time. Daily road wash?

And once you are done with all of this and you know what it will cost, come back and tell me in my face that it was all "a freebie".

[realpolitic]

This article will undoubtedly soon bring out all the crazed climate change deniers who will take a brake from singing the praises of Sarah Palin.

[Michale32086]

You mean those who deny Human Caused Global Warming(Yet The Planet Is Cooling)???

Let me ask you something.

Al Gore has said that the time for talking is done. The question is settled. It's time for action.

And then goes out and raises $300 million dollars...

And what does Al Gore spend it on??

An AD Campaign... More talking....

I honestly and truly cannot believe that people are STILL be con'ed by the likes of Al Gore and Richard Branson who are only making themselves richer...

Michale.....

[realpolitic]

It is interesting that southern Spain has seen declines in temperature, but Spain is also at risk of encroaching desertification from climate change.

"Spain has finally implemented its first Programme of National Action against Desertification which recognises that 37% of the country is at a very high, high or medium risk from desertification, and is in danger of becoming "eroded forever". This risk is also termed Sahelisation, after the North African region, and with coming climate change is set to worsen.

Since 2001 there has been a huge loss in fertile soil due to erosion totalling 17 tonnes per hectare per year: 67 millon tonnes of soil, much of which gets caught up in reservoirs, and representing an increase of 8% since 2001. The problem has been seriously heightened by intensive agriculture and the spread of urbanisation and infrastructures. "

http://www.iberianature.com/spainblog/2008/09/37-of-spain-at-risk-from-desertification/

[KillTheMessenger]

"It is interesting that southern Spain has seen declines in temperature, but Spain is also at risk of encroaching desertification from climate change."

That's not even what she claims. She only claims that "parts of Southeastern Spain" have seen LOCAL cooling. Which is not surprising. It's not particularly helpful, either. If we are talking about a 100 square mile area covered with green houses, that's a ten by ten mile square. If the effect spreads out to ten times that area, it would be a 30 mile sized area. How big is that? It's small. The Great Salt lake in Utah has an area of 1800 square miles, twice of what we are talking about here.

But let's paint the Great Salt Lake black, though, using 40 percent efficient solar cells (yes, we know how to make those). The Great Salk Lake receives approx. 150W/m^2 on average in solar radiation. So our solar cells would produce roughly 60W/m^2 in electricity. Multiply by 4600km^2 makes over 270GW of average electricity output. Total US energy consumption is something on the order of 3000GW, so one Great Salt Lake size solar facility can, in theory, produce close to ten percent of the US energy demand. Given the fact that we can safely discount that demand by a factor of two for all our waste, actually five such facilities would suffice to reduce our GHG production to levels required to stop global warming.

[realpolitic]

I did not say she claims that, rather I claim that. The author of the article says that "parts" of southern Spain are seeing a slight decrease in temperatures. Yes, I agree that it is local and then say that much of Spain is, in fact, seeing a process of desertification which has resulted from erosion, spread of urbanization, and climate change.

I have seen the Great Salt Lake. I found it very eerie for some reason. It is a very harsh environment there.

[Semaj51]

Good plan with a few exceptions...

Solar cells have a very serious limitation, the requirement of direct sunlight. On the average, solar cells have peak production times of approximately eight hours per day. Take also into account with weather effects (rain, clouds, etc) and the geographic location (great in high dry environments, lousy in northen climates and along coasts), solar cell power (while great for the environment and pretty cheap) requires additional power sources to maintain 24/7 electricity distribution.

If we truely want us to change to more carbon-free energy environment, than the only choices we effectively have for the next few decades are solar, wind, dams, and nuclear.