The Center for American Progress reports
According to a new French law approved [March 19], rooftops on new buildings in commercial zones across France must either be partially covered in plants or solar panels.
Green roofs, which cover rooftop space with a layer of grasses, shrubs, flowers, and other forms of flora, offer a number of benefits. They create an insulating effect, reducing the amount of energy needed to heat or cool a building depending on the season. They increase local access to green space, which often comes at a premium in urban environments. They retain rainwater, thus decreasing runoff and any related drainage issues. They provide a space for urban wildlife, such as birds, to congregate and even nest, and they reduce air pollution by acting as natural filters.
Green rooftops also significantly reduce the urban "heat island" effect in which urban areas are noticeably warmer than their surroundings. The heat island effect can cause large cities to get 1.8°F to 5.4°F warmer than surrounding areas in the day, and 22°F warmer at night, according to the EPA. This effect happens when buildings, roads, and other developments replace formerly open land and greenery, causing surfaces to become moist and impermeable, and to warm up.
[...]the law was scaled back from initial proposals [made] by environmental groups [who asked that green roofs] cover the entire rooftop surface of all new buildings. The compromise gave businesses a choice to install solar panels instead or to only cover part of the roof in foliage.
Related Stories
The Center for American Progress reports
On [April 8], L.A. mayor Eric Garcetti released an ambitious plan that puts environmental, economic, and equality issues front and center in helping determine the trajectory of the city, which plans to add another half-million residents by 2035.
[...]A few of the plan's highlights include: becoming "the first big city in the nation to achieve zero waste" by 2025, fully divesting from coal-powered electricity by 2025, reducing greenhouse gas emissions by 80 percent below 1990 levels by 2050, having zero smog days by 2025, and making it so that 50 percent of all trips taken by city residents are by bike, foot, or public transportation by 2035. The plan also makes commitments to reduce energy use in all buildings by 30 percent by 2035.
[...]The plan calls for a reduction of the urban heat island effect differential--the difference between the temperature of the city and the surrounding area--by 1.7°F by 2025 and 3°F by 2035.
[...]20 percent of L.A. is covered in rooftops and 40 percent in pavement of some form. Changing the reflective capacity of these areas and adding more greenspace will play a big role in reducing the heat island effect. [Executive director of the L.A.-based Climate Resolve and a former commissioner at the L.A. Department of Water and Power, Jonathan Parfrey] and other city officials have already been pushing for these changes. In December 2013, the Los Angeles City Council unanimously passed a building code update requiring all new and refurbished homes to have cool roofs--which use sunlight-reflecting materials--making L.A. the first major city to require such a measure.
[...]The city's new sustainability plans calls for 10,000 of these cool roofs to be in place by 2017.
The full plan spans 108 pages, covering everything from reducing potable water use by 10 percent in city parks to ensuring that 50 percent of the city's light-duty vehicle purchases are electric vehicles by 2025. With the drought in full swing and no reason to believe that prayers for rain will bring lasting results, the city is hoping to reduce overall municipal water use by 25 percent by 2025 and 30 percent by 2030.
(Score: 4, Insightful) by Anonymous Coward on Sunday March 22 2015, @09:15PM
contrary to popular belief, some nanny state laws save u money
y the free market dindu it? because it is slow to pursue long term gains
(Score: 4, Insightful) by Grishnakh on Sunday March 22 2015, @10:46PM
Yep. Another big problem is that people using a building frequently aren't the people who own a building; this is especially true with commercial real estate (which is the subject of TFA). Businesses almost never buy buildings; they lease/rent them.* Landlords sure as hell aren't going to spend any more on a commercial building than they have to, and putting plants or solar panels on the roof isn't going to significantly affect the rent prices, so they don't do it as that has a large capital cost.
*In the old days, big companies used to buy their buildings because it's cheaper in the long term and they could be reasonably sure they'd still be there in 10-30 years. These days, big companies (in the US) are all selling their buildings, and then either moving someplace and leasing, or leasing the same building back from the new landlord, because this gives them a bunch of cash which looks good on the balance sheet and lets the CEO give himself a big bonus. The only other place you'll see a company owning its building is some small family-owned business where they care more about long-term profitability than short-term gains, but this isn't that common except for really successful small businesses where they don't foresee growing much and really care more about long-term stability more than anything else. Small businesses usually don't have the cash for a down-payment on a piece of commercial property, and if they do (from outside funding/VC), they have dreams of growing big, which means if they're successful they'll be too big for that location in a few years so buying wouldn't make sense.
(Score: 4, Interesting) by Adamsjas on Monday March 23 2015, @12:24AM
But bringing the rant back to the story at hand, the green rooftop can actually be a huge problem to maintain. In rainy weather the increased weight can be an engineering disaster if these rain gardens are mandated upon structures that were not designed for that from the ground up. Roots will tear your roofing to pieces.
In dry periods you could see them completely dry out, and become a fire hazard.
Its easy to mandate something, and walk away feeling like you accomplished something, but unless the rules cover maintenance of the soil covered roof, it will be another one of those things that slum lords will simply abandon.
At least they had the sense not to mandate retrofitting gardens on existing rooftops.
Most scientists say as much could be done by just painting the roofs white.
(Score: 5, Informative) by Grishnakh on Monday March 23 2015, @03:02AM
But bringing the rant back to the story at hand, the green rooftop can actually be a huge problem to maintain. In rainy weather the increased weight can be an engineering disaster if these rain gardens are mandated upon structures that were not designed for that from the ground up. Roots will tear your roofing to pieces. (Emphasis mine)
Did you not even read the summary line? This decree is for roofs on new commercial buildings. What kind of idiot would design a building, knowing this decree is in place, and not bother to design it for a green roof, and then install a green roof?
Its easy to mandate something, and walk away feeling like you accomplished something, but unless the rules cover maintenance of the soil covered roof, it will be another one of those things that slum lords will simply abandon.
Oh please. Buildings almost everywhere are required to have roofs of some kind now. In some cheap-ass commercial building here in the US, it's frequently just metal. As bad as our regulation is here, if that roof leaks, the landlord is still liable. He doesn't get a free pass just because it's a green roof. If he opts for a green roof, he'll be required to maintain it, just like any other commercial property. It's like this for anything on a commercial property: if it comes with HVAC, the landlord has to maintain it. If it has plumbing, the landlord has to maintain it. Same thing for roofs. If he doesn't like green roofs, he can opt for solar.
(Score: 2, Interesting) by canopic jug on Monday March 23 2015, @05:15AM
Further, if I understand correctly, sod roofs last 50 years whereas old tarpaper roofs only less than 15. If that number is correct, then that is a big savings. They also insulate much, much better. The sod roofs do need the occasional visit from a goat, though, to much down the vegetation especially seedlings.
Money is not free speech. Elections should not be auctions.
(Score: 3, Interesting) by TheLink on Monday March 23 2015, @08:00AM
With this method you can both have solar panels AND store a lot more rainwater than the plants+soil alone (thus be better at reducing the amount of flooding due to urban runoff).
The stored water could be used in many ways.
So hopefully they add this option too.
(Score: 1) by xorsyst on Monday March 23 2015, @03:16PM
Most scientists say as much could be done by just painting the roofs white.
How does painting my roof white keep my house warm in winter? I live in a part of the world without a need for A/C, and the green rooftop might improve things, but painting my roof won't do jack apart from make my Victorian house look weird.
Also, how do I install plants on a slope?
(Score: 2) by tathra on Monday March 23 2015, @07:50PM
you think there's no plants growing on hills and mountains?
(Score: 3, Interesting) by TheRaven on Monday March 23 2015, @11:02AM
These days, big companies (in the US) are all selling their buildings, and then either moving someplace and leasing, or leasing the same building back from the new landlord, because this gives them a bunch of cash which looks good on the balance sheet and lets the CEO give himself a big bonus
It's often more subtle than this. You sell a building to a subsidiary and then rent it back. The subsidiary charges rent that only just covers the cost of operating the building, so posts no profit. Depending on how you structure the arrangement, you can end up with more liquidity and a lower tax burden than if you own them yourself.
sudo mod me up
(Score: 4, Funny) by isostatic on Sunday March 22 2015, @11:08PM
But, but, Invisible Hand! [youtube.com]
(Score: 2) by Nerdfest on Sunday March 22 2015, @11:12PM
I seem to recall that there are places in Canada that introduced these laws years ago.
(Score: 2, Interesting) by wisnoskij on Monday March 23 2015, @12:23AM
The cost/benefit definitely is not here. It is a not insignificant cost to build the building to carry thousands of more pounds. And the insulation capacity of dirt and grass is basically zero, I don't know where they are even coming from with that point. And unless they want it to look like complete shit they will need to hire gardeners to maintain it. And it is on the roof in commercial locations, so 99% of it will be hidden from view anyways. If it were residential it would have a far bigger effect on people's view, and they could use them as gardening space.
(Score: 4, Informative) by Immerman on Monday March 23 2015, @02:12AM
Well, dirt has very poor insulation properties in a steady-state situation, but what is does have is a *lot* of thermal mass. And thanks to the 24-hour thermal cycle that can translate to a pretty decent effective insulation - that's part of the reason adobe construction is so popular in parts of the world: the nightly cold-front will only penetrate part-way through the wall before the sun comes up and the coldest part of the wall begins to warm again.
Of course, put even a couple inches of "real" insulation outside of all that thermal mass to slow the heat transfer and then you're *really* talking. My landlord just did that to the north wall of the adobe house I'm living in and my heating bill is now half what is was last winter - I've never lived in a place so cheap and easy to keep warm. And with a green roof you've got plants creating dead(ish) airspace above (and within) the dirt, so I imagine there would be a similar effect
(Score: 3, Informative) by wantkitteh on Monday March 23 2015, @09:55AM
From a paper published by Strathclyde University Department of Engineering, The Thermal and Rainwater Runoff Performance of an Extensive Green Roof System [strath.ac.uk] by Niall Carroll, bottom of page 39:
A chart in the paper just under this quote appears to suggest a 15% decrease in overall energy use for a yearly cycle - it seems natural for folks today to immediately question how warm a building will be in winter, but in designing buildings for the future, it seems foolish not to consider how hot they'll be in summer.... I want to say "taking future climate change into account" but I don't want to deal with the inevitable arguments that always accompany the use of those three words on so little sleep.
(Score: 2) by frojack on Monday March 23 2015, @03:53AM
It is a not insignificant cost to build the building to carry thousands of more pounds.
On the other hand it takes no building changes to paint roofs white [thinkprogress.org].
Concordia University estimated that painting one percent of the world’s urban surfaces white (rooftops and pavement) could reduce CO2 emissions by 130 gigatons over the next 50-100 years. In 2011, global CO2 emissions from fossil fuel combustion reached 31.5 gigatons. ... painting 5% of the world’s rooftops white per year by 2030 could save enough emissions to equal the world’s carbon output in 2010.
And you can do it on old buildings or new ones.
No, you are mistaken. I've always had this sig.
(Score: 2) by FatPhil on Monday March 23 2015, @12:43PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 3, Interesting) by VLM on Sunday March 22 2015, @09:21PM
Google has failed me.
I recall a story out of CA about hipster green types installing fake solar panels on their roofs facing the road. Because its cheap and looks very green and looks matter.
The only thing I can find from Google about CA and fake panels is a historic building where the city demanded some fakes be installed to avoid a "missing tooth" appearance due to a non-full grid being installed. Which doesn't sound all that ridiculous.
Anyway the point seems obvious, install a bunch of fake panels with some 9V batteries installed, demonstrate a nice 18V of voltage coming from each panel on a sunny day (with the panels on the roof and the wiring in the basement) then haul away the demonstration inverter and the panels when you're done.
Of course big brother being big brother they could demand interconnection papers from the local utility, or demand energy bills be submitted with each prop tax.
The main advantage of a green roof, of course, is increasing revenue for roofers. That is going to leak and make a black mold mess.
(Score: 3, Insightful) by lentilla on Sunday March 22 2015, @09:44PM
Fake solar panels. That is brilliant! Talk about one-upping the Joneses.
(Score: 2, Funny) by Anonymous Coward on Sunday March 22 2015, @11:33PM
Yeah, but my fake panels are fake charging my fake electric car.
(Score: 0) by Anonymous Coward on Monday March 23 2015, @03:47AM
> Anyway the point seems obvious, install a bunch of fake panels
Because the because the building code inspector is totally going to not ever think someone would do that!
(Score: 4, Insightful) by mojo chan on Monday March 23 2015, @01:27PM
Much of the cost of a solar PV system is the installation. Getting the panels on the roof, putting the wiring in, connecting the inverter to the main junction box. All that would have to be done to pass even a basic inspection. Might as well just install real panels for maybe 30% extra cost and recover your outlay by generating electricity over a few years.
const int one = 65536; (Silvermoon, Texture.cs)
(Score: 5, Interesting) by c0lo on Sunday March 22 2015, @09:47PM
1.8°F=1°C
5.4°F=3°C
(please spare me of "intended audience" type of arguments)
Did you know France is at origin of the metric system and the system spread due to Napoleon [wikipedia.org]?
The fact that it remained in use even after Napoleon was defeated should tell something...
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 0, Troll) by sjames on Sunday March 22 2015, @10:08PM
Did you know that the EPA (where those figures came from) is in the U.S.? And that Napoleon never conquered here?
OH, and Soylentnews is located in the U.S.?
Still, it doesn't hurt to translate to C degrees.
(Score: -1, Flamebait) by Anonymous Coward on Sunday March 22 2015, @10:31PM
Napoleon did too conquer the U.S., he put Oobama in charge there.
(Score: 1, Insightful) by Anonymous Coward on Sunday March 22 2015, @10:45PM
OH, and Soylentnews is located in the U.S.?
And there I thought that this site was aimed at users, rather than webservers.
Still, it doesn't hurt to translate to C degrees.
ucvt_F2C1f(1.8f)?
Better than C++ degrees, I guess:
std::unit_converter<std::fahrenheit, std::celsius, 1.8f>::value
(Score: 1, Informative) by Anonymous Coward on Sunday March 22 2015, @10:54PM
Just for information, because I have noted that others have also implied that this is a US site (it is, of course, legally established in the US), the editorial policy here is that if the original source of a submission is written in, say, en-GB, then whatever locale units are used in the in source story should stay with it. However we do try to provide conversions where we can - I don't know why this story was missed in this respect. Likewise for en-US, which is the case in point for this story. Furthermore, the spelling rules of the submission source apply throughout the life of the story. We would try not to jump back and forth between the two. The only requirement for submissions is that they are written in a recognised version of English - we don't much care which one as long as we can identify and select the appropriate dictionary.
So simply stating that SN is based in the US is actually irrelevant: it shouldn't affect the story content. A short while back the only regularly active editors for a period of several weeks were both Brits. Many of the SN team live outside the US. SN doesn't really 'have' a nationality - it only needs a community. We don't care who or where they are - as long as they can communicate in something close to the language of TFS and TFA.
janrinok
(Score: 2, Funny) by sjames on Sunday March 22 2015, @11:04PM
Mostly I'm just tired of nit-pickers claiming they have some sort of higher or better authority. It was extra funny considering that the figures did come from the U.S. EPA. and that the report was from The Center for American Progress.
(Score: 2) by janrinok on Monday March 23 2015, @07:14PM
[nostyle RIP 06 May 2025]
(Score: 2) by sjames on Monday March 23 2015, @07:55PM
It's all good. I didn't take it for criticism.
(Score: 0) by Anonymous Coward on Sunday March 22 2015, @11:20PM
(Score: 4, Informative) by aristarchus on Sunday March 22 2015, @11:30PM
Napoleon sold the US to itself, don't you know. The Louisiana Purchase? Yes, Oklahoma and Colorado used to be French Territory! See, the metric system is not a great concern for those who have no idea of their own history.
(Score: 2) by sjames on Sunday March 22 2015, @11:43PM
Not exactly conquering, now is it? Also not exactly populated. Yes, I'm sure the count of people there was not zero, but once you subtract the natives who were very unlikely to care what system of measures the French used, damn close.
(Score: 2) by hubie on Monday March 23 2015, @12:00AM
I'm not quite sure how specific knowledge of the Louisiana Purchase has to do with the usefulness of the metric system, but I digress. I am surprised, given the number of complaints, how much trouble some people have with units conversion, particularly the Fahrenheit scale and to a lesser extent feet and yards. It really surprises me because quite a few people claim this place to be a site with a technical slant. Personally I became quite proficient with unit conversion in primary school (middle school at the latest), but that was a long time ago. I suppose it is not emphasized so much these days because to some it apparently renders some of these stories quite unintelligible.
(Score: 0) by Anonymous Coward on Monday March 23 2015, @12:28AM
C or F does not really matter day to day for MOST people. The 'its scientific' is just mental masturbation of 'look how smart I is'.
What do MOST people use the temperature for? Do I need a coat or a swimsuit. That is it. In that case, any scale, as long as it is consistent is fine. For something where you want to properly interchange data and understand how it relates to other things C is alright, K is better.
I'm not quite sure how specific knowledge of the Louisiana Purchase if you ignore the fact that the US revolution was a major assist from the french and they couldnt help in 1812 because Napoleon was busy in a war at the time and thus the sale of land. https://en.wikipedia.org/wiki/Metric_system#International_adoption [wikipedia.org] If he had not sold off the land to pay for his own wars it may be very different now. It is more of an interesting aside and does not vote on the usefulness one way or the other.
(Score: 2) by c0lo on Monday March 23 2015, @01:06AM
Case at hand, please enlighten me how this applies to the differences in temperature mentioned by TFS, especially the one at night?
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Monday March 23 2015, @04:51AM
C or F does not really matter day to day for MOST people. The 'its scientific' is just mental masturbation of 'look how smart I is'.
Oh, look at Nigel! Expressing tempurature in Kelvin, he is! What a poser! (Wait, what is "C or F", anyway? Cold or Frigid? Calvin or Hobbes? No, that doesn't work. Castigate or Flagellate! There we go! There must be Fifty Degrees of it, or Shades. Oh, no. Not again.
(Score: 2) by c0lo on Monday March 23 2015, @01:01AM
Not being exposed to imperials until rather recently (far more recent than my childhood), I need to break the reading to search for the conversion formulae between the units.
You see, they say the mind is the second thing to go... I can't remember what was the first, though (grin)
Besides, after a certain age, one starts to fall into an engineering way of doing things: if you aren't using a certain knowledge frequently, let it stay in a book rather than in your mind
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by isostatic on Monday March 23 2015, @07:54AM
It seems clear the original measurements were in centigrade (or kelvin), given the precision on an inaccurate range.
It's a symptom of a population that don't grasp significant figures. The given figures appear to be claiming accuracy to 1 part in 40, which is clearly nonsense.
It's akin to saying something is traveling at 161km/h, rather than "that shot through at 100mph!"
(Score: 2) by sjames on Monday March 23 2015, @10:09AM
You should take that up with the EPA, where the figures were quoted from.
And actually, there is nothing at all amazing about measurements to the tenth of a degree, and far less in measurements to the nearest 2 tenths.
Either way, the condescending clap-trap about Napoleon was the real problem.
(Score: 1) by albert on Monday March 23 2015, @05:22PM
Significant figures are idiotic. Let's work through an example. I'll pick something extreme to really drive home the point.
We have a measurement of 1. It could be plus-or-minus about 50%. For example, it could be really 0.5 or 1.4999 but we only have 1 significant figure.
We now multiply by an exact conversion factor. Examples of exact conversion factors include the 2.54 cm per inch, the 5/9 and 32 in temperature conversion, and so on. Our exact conversion factor in this example just happens to be 9.
After unit conversion, we have a measurement of 9. We still have one significant figure, just as when we started. Our measurement is now plus-or-minus about 5%. For example, it could really be 8.5 or 9.4999 now. Oh look, our measurement quality is now ten times as good!
The more you look, the more horrifying significant figures are. There are numerous troubles of this nature. It is common to have cases like the above, and also common to have cases where data is needlessly thrown away. The only reasonable thing to do is report enough figures to be clearly in excess of those considered "significant" by the silly rules. Proper description of significance is too complicated for nearly all situations. It involves reporting statistical distributions. Screw that.
(Score: 0, Informative) by Anonymous Coward on Sunday March 22 2015, @11:24PM
intended audience
Wrong meme this time.
Correct meme: tunnel vision.
My monospaced font (Monofonto) wasn't showing the degrees symbol at all in the dialog box.
Relieved to have gotten that to work when I previewed the page and everything was OK when the text was displayed using a proportional font, I overlooked the i18n thing.
I've done conversions in previous submissions, so I am aware that that is useful.
Just got flustered and distracted this time.
-- gewg_
(Score: 1) by Roo_Boy on Monday March 23 2015, @02:21PM
Er, you forgot the 32 degree offset...
(F - 32) / 1.8 = C
Gives : -16.7c
--- The S.I. prototype "Average Punter" is kept in a tube of inert gas in Geneva.
(Score: 2) by c0lo on Monday March 23 2015, @04:37PM
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 1) by wisnoskij on Monday March 23 2015, @12:16AM
OK, so contractors will be buying $2 flower pots and placing them on all new roofs I guess.
(Score: 3, Informative) by gringer on Monday March 23 2015, @12:56AM
On the roof, you'll need a few potted watermelons as well. Flowers aren't particularly useful without a bit of defense.
Ask me about Sequencing DNA [youtube.com]
(Score: 0) by Anonymous Coward on Monday March 23 2015, @12:55AM
Maybe its easier with plants to fool "heat signature sensors" for important business buildings when the bombs start falling.
Thats smart.
(Score: 2) by VortexCortex on Monday March 23 2015, @09:12AM
So, Hobbits were way ahead of their time?
(Score: 2) by wantkitteh on Monday March 23 2015, @10:37AM
Putin is terrified of Hobbits. True story.
(Score: 4, Interesting) by splodus on Monday March 23 2015, @02:09AM
I wanted to read exactly what has been mandated - what proportion of the roof? What is a 'commercial zone'? How many panels are sufficient? What sort of plants? Must the panels be grid-tied?
I haven't got a lot of time right now, so a quick search - a dozen 'news' sites all have the same story, word for word (even the Guardian, and Al Jazeera!).
Does anyone know of a news site that actually reports the news? Rather than just reprinting press releases?
(Score: 2) by isostatic on Monday March 23 2015, @06:06AM
What a laugh. News organisations don't have time to do research, certainly not in the case of soft news like this. But then people won't pay for news, so what do you expect? SN has enough problems paying for A couple of servers, and it's just an aggregation site. Want to pay $500 for someone to look into this story more closely, vote with your wallet.
(Score: 1) by splodus on Monday March 23 2015, @07:58AM
I see.
So all we can expect from The Guardian Worldwide [theguardian.com] or even lobby groups like ThinkProgress [thinkprogress.org] is to regurgitate press releases, with no further research, or analysis, or critical comment?
Do you think that setting the bar this low will lead to better reporting from journalists? Do you think people want to pay to read verbatim press releases? Do you think rephrasing a story from another news source without adding anything new represents value for money?
Because frankly, I do not :)
(Score: 5, Informative) by Anonymous Coward on Monday March 23 2015, @09:00AM
There is nothing about it in the news here in France (what with the terrorist attack in Tunis, the elections, our own “patriot act”, etc.).
I digged a little.
In fact, it’s not “a law” yet. It’s an amendment that has been adopted by the Assemblée nationale. I found: http://www.assemblee-nationale.fr/14/cri/2014-2015/20150186.asp [assemblee-nationale.fr] (proceedings of the Assemblé nationale for March 19th 2015). You can see (if you read French) that the amendment number 987, sub-amendment 1569, regarding vegetal roofs, has been adopted.
The text of the amended amendment: http://www.assemblee-nationale.fr/14/amendements/2064/AN/987.asp [assemblee-nationale.fr]
This is a part of a ginormous law about biodiversity (http://www.assemblee-nationale.fr/14/dossiers/biodiversite.asp). The discussion is far from being finished. The law has yet to pass through the Sénat. And you have to wait for the Décrets d’application (Application decrees) before knowing about numbers, costs, and the like.
In other words: nothing.
(Score: 1) by splodus on Monday March 23 2015, @09:15AM
Thank you! That's really useful :)
(wouldn't it have been nice if even one of the journos reprinting this story had bothered to check, as you have done. It used to be that fact-checking was part of a journalist's job!)