Kimberly Powell

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If green roofs were mandatory in cities would there be less development and building?

William McDonough knows the benefits that come from designing and implementing green roofs. McDonough has helped design living roofs for big companies such as Nike and Ford Motors. But many companies and homeowners overlook the benefits of green roofs. One benefit of green roofs is that they keep the internal temperature of a building steady throughout the year. The National Research Council of Canada found that having a green roof reduced the daily energy demand for air conditioning in the summer by 75%. Toronto is the first North American city to pass a law mandating green rooftops for all new residential, commercial and industrial developments. Any new construction with floor space of more than 2,000 square meters must devote between 20 and 60 percent of its roof to vegetation. But with green roofs comes an unwanted financial upfront cost. Will developers decide that the benefits outweigh the costs for installing green roofs?

If green roofs were mandatory in cities would there be less development and building?

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    May 23 2012: I agree with Mike Robinson, but wanted to dig a little deeper: I take it from the phrasing of your question that you are afraid that mandatory green roofs would scare off development. To me, that phrasing already concedes that Big Money has a stranglehold on our priorities. That stranglehold is exactly what we need to reverse if green building, or even environmentalism as a whole, are to take hold.

    Of course, there is such a thing as a thoughtful, well-intentioned benevolent developer/corporation (very exceptional); but is further development--even smart/green development--what we really want? To me, that is just an intermediate band-aid, and not nearly sufficient to the task at hand. It was reported recently that most oceanic life is predicted to be extinct by 2049 unless we humans radically change our ways, and soon. We are hitting an environmental wall right now, and only a few people are even aware.

    Given this situation, the whole paradigm of who develops what, how, and why needs to consciously shift to a much more sustainable path. Essentially psychotic corporations need to be put in their place (purely as tools of the people), and governments need to pull their noses out and get with the program!
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      May 23 2012: I find a lot of what you are saying is very poignant and insightful. The one piece that I would like to touch on is the idea that corporations should be tools of the people. I find it fascinating that people are so easily manipulated into letting business have control over their lives. Mass population has and will always have the upper hand if they unite in a cause. Look at any period in history and this proves to be true over and over again (in both good and bad ways) But, corporations are the one entity that seems to have figured out how to manipulate the masses into thinking a certain way. If people would just unite and simply communicate they could use these money magnates as for their own means instead of simply feeding the machine. Development would be a lot easier if the people that were supplying the money knew the only way they could use the building was to build it a certain way. I don't think laws are the answer to the problem, because time has shown us that corporations will find loopholes or worse simply ignore them and get reprimanded later. It is the consumer that decides the fortunes of companies, but people simply have not seemed to figure it out yet...
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        May 23 2012: Yes, I wholeheartedly agree. I think we are getting a bit off topic, but it's good that this discussion has spurred a deeper related discussion. There are probably other conversations on TED related to this very issue of finding a collective consciousness and following it, but I haven't looked yet.

        This issue of laws not being the answer is also very ripe for further discussion. Laws are really only necessary when and where there are moral/ethical/behavioral differences between people. I don't see fundamental differences fading away anytime soon, so there is still a place for law. However, I would say that virtually all the laws we live by are far too complex (and many are mis-directed), thus difficult to enforce. Laws should be very simple, clear, well-directed, and most importantly easy to enforce. Hopefully, as you imply, we'll someday get to a point where laws are essentially superfluous, and we're all keyed in to a fairly unified purpose (e.g. the sustainability of life on Earth).
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    May 22 2012: I watched a ted talk recently about the issue facing us in future, and that is how to feed a possible 9 billion people in the next century (Jonathan Foley, The Other Inconvenient Truth), when so much of the earth's surface is already devoted to agriculture, and being overtaxed. Perhaps there will be a time where we will all have to produce our own food, because the resources of the world will be unable to cope. Green roofs could be the way of the future, especially in terms of growing our own vegetables, and this would also reduce the use of industrial fertilisers, which apparently account for quite a bit of the world’s emissions due to the fact that they have doubled the world’s levels of phosphorus and nitrogen.
  • May 22 2012: I hope it will stimulate innovation but am also hopeful it will lead to less development. Or more accurately I hope it will lead to less greenfield development and more brownfield development (revitalizing already existing developments).

    We may also want to consider living underground or underwater if we are looking for niches to occupy that may be more efficient than square boxes exposed to the elements.
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    Aja B.

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    May 22 2012: This discussion has been selected as today's featured TED Conversation on our Facebook (http://www.facebook.com/TEDConversations) and Twitter (http://twitter.com/tedconversation) feeds. Congrats! :)
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    May 22 2012: The saying raining cats and dogs came from animals falling through sod roofs in ole England. My grandparents in central Kansas built their house almost all underground. The temperature was consistant year around (before air conditioning). In Phoenix one of the high schools is underground elminating the need for extensive air conditioning. This is not a new thought nor is it a bad thought. Ideas come around in a circle. However I am against making it mandatory. If I was building in Toronto I would build my factory in 1,900 foot sections and link them with tunnels and walkways. All the best. Bob
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    Jun 1 2012: Personally, I do not believe that by making green roofs mandatory that it will stop the development of new buildings. The price of the building will just increase due to the price increase in the production.
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    Jun 1 2012: I do think that green roofs are a great idea and would increase the biodiversity of a neighborhood and help with energy efficiency. However, I do wonder about the risks of making this mandatory. I feel that if developers are to continue building at the rate they are going now in order to maintain their business and at the same time to implement green roofs, they might cut corners elsewhere. It is no surprise that construction sites go up as fast as possible because it is what will make them the most money. If you require them to add on green roofs and all of the extra work and special materials that go along with building a green roof, I fear that corners will be cut elsewhere and therefore possible cause a greater risk than the green roofs are worth.
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      Jun 1 2012: Theresa, you make a very valid point. Today, our society is big on being cost efficient. A building company would care more about the initial cost then saving earths biodiversity, simply because it is just not their job. If green roofs were to become mandatory, the developers might indeed cut cost somewhere else in the building process. With that said, do you think that there is any way around this obstacle? Is there a way that green roofs could become mandatory without it effecting the quality of the work?
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      Jun 1 2012: It is true that there would be cuts elsewhere but I don't think that the quality of the work would be affected to a point that it was bad. What kind of work do you mean? Like the building itself? There regulations that must be followed so that it is not a poorly constructed building. Now if it is decoration that would decrease in quality , that is not a big deal. If it a reduction in the quality of work of the service provided, then that affects those in charge directly.
  • May 27 2012: Kimberly, your question is really one of economics, and simple economic reasoning is enough to answer it without going into the details of what green roofs are and how they work (although these details are interesting in their own right, to be sure!).

    The effect of compelling producers to add a new component to each of their products is that the cost of production rises. The result is that the marginal producers -- those whose costs have now been driven higher than the revenues they can obtain from the product -- are driven out of business. We end up with reduced supply and a higher market price, which in turn leads to the marginal buyers -- those who were prepared to pay the original price but not the new, higher one -- investing elsewhere, e.g. in other cities.

    Now, of course people can freely purchase a green-roof building, and they will do so if the savings on air conditioning and the other benefits of such a building outweigh the additional cost -- in short, if the choice is economical. Thus we arrive at the conclusion that if green-roof buildings are economical, a government mandate is irrelevant; and if they are not, it's harmful (reduced production and higher prices).

    This conclusion should really just be common sense: social wealth and well-being can't be increased by ordering the police power to forcibly prevent people from engaging in voluntary exchange.
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    May 24 2012: Mandating green roofs seems like a great idea to spur environmentalism, as well as help people be greener in general. I don't think that developers would have a problem following a new mandate, but I do question what the individual would think. Would purchasing a space or home that has been built with a green roof increase the up front cost, and would individuals still want to shell out the money despite the promise of 75% reduced air conditioning energy demand? For people who don't use air conditioning or heating what is the incentive to purchase a home that has a green roof, especially if it's more expensive than a traditionally built house? If new mandates don't ensure that all newly built spaces require a green roof and therefore an increased purchasing cost I fear that people will tend towards traditionally built spaces and the new spaces would go unoccupied, unless the developer covered the cost of the green roof.
    • May 24 2012: Not only are green roofs great for reducting HVAC costs but they also have implications for global climate change. If new roofs were installed on new private homes, these places would have substantially less carbon emissions than houses without green roofs. The green roofs will be photosynthesizing constantly, making them extremely beneficial. If homeowners are only looking at the short term consequences of green roofs, they might not be as appealing but all the long term benefits are so great, it seems to me like they outweigh any bad things that could arise.
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        May 24 2012: I don't argue that green roofs would be beneficial with regards to global climate change, but I question how many people are willing to pay an extra up front cost for a space with a green roof. Many ways to help the environment are simply options in current society such as being vegetarian or using LED lights rather than incandescent. If the option isn't turned into a requirement I don't believe that everyone will choose something that benefits the environment, especially if there is a larger up front cost. To me the option of buying a home with a green roof is similar to the option of buying an electric car, just because it helps the environment doesn't mean that it will be the choice of every individual, particularly if it is initially more expensive.
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          May 28 2012: I agree, if the savings from heating and air conditioning take many years to match the upfront cost of the home, people will go with the standard home that is much cheaper. I think most people are becoming more aware about the human impact on the environment, but until the cost of green technology becomes affordable to everyone, we will stick with the cheaper option that causes greater environmental harm.
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      May 24 2012: You have to remember that people who would make green roofs wouldn't be just homeowners. You have to think of a renting scenario as well, apartment complex owners, hotel owners, etc. For someone who owns an apartment complex with a green roof, they could charge a bit extra for the green roof and make a bit more profit in the long run, and as a renter that would be justified because you save on heating/cooling costs. There is an incentive for both the building owner and the renter.
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    May 23 2012: I do not think that green roofs would limit building. Building cost are already high and adjusting for a green roof would not add that much cost relative to the cost of the whole building. I personally think green roofs should be mandatory for all new buildings, especially new government buildings. If the government started adopting green policies such as this it would have a positive effect on the industry and the environment. Green roofs are also very beneficial for pollination. If green roof companies created an alliance with pollination biologists and honey producers we could slow the decline of honey bees.
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    May 22 2012: I agree with Mike that I would be happy if something finally slowed the development and expansion of our cities. I also think this is a very innovative idea and am excited to see similar innovations.

    In looking at this question though, we also need to consider that as Kimberly said, buildings can save 75% of energy used in the summer. If businesses took these savings into account it could result in perhaps more new development, and also changing of existing buildings. It would be nice to see something like this required of existing buildings as well, because we shouldn’t be expanding our populations or cities in the first place, but we should be focusing on changing the way we live now, not just in the future.
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    May 22 2012: I think this is a very noble idea and one that will gain momentum over time to help our society live both more within its means and also foster a greater connection with the environment around us. These roofs aid in cooling building, but can also aid in small scale food production as has been seen throughout many cities across the globe that have rooftop gardens. They also can serve as a place for people to relax and meditate, perhaps on a lunch break which can foster a more productive day and a happier workforce.
    Since I'm not an architect I can't give a completely knowledgeable answer but I believe that, with proper government support, these regulations will do little or no harm to the ability to build in a more sustainable manner. In some ways, this may revitalize these urban areas that have fallen into a state of decay and help aid in cooling our cities, making these building more cost effective in the long run and also providing a cleaner aesthetic feel to the city. Obviously this applies only to certain locations as this would probably be ineffective in say an area that has insufficient water to keep the plants moist or a location that freezes, but it is a positive start in the right direction. I think this is the future of architecture and we will only see more and more buildings designed in this manner.
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      May 22 2012: I didn't even think of the green space on the roofs being able to produce food during the proper seasons. Do you feel that if the roofs had to produce food that it would impact if the building grows and by grow i mean possibly start at a new location (add more buildings to the company)?
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    May 22 2012: I like the idea of green a green roof, but I like what McDonough says about the planning of new cities and buildings even better. Mandatory building codes exist all over the world why not implement them in places where the climate allows. I think of places that are cold more often than they are warm and wonder how well the idea would work. Especially since they would require standing water systems that could freeze and impose massive costs to the building owners. To me though the idea that we take advantage of the environment around buildings and design to it should be mandatory. The study of sun, wind and landscapes can mean just as much to a sustainable building that the green roof idea. cheers
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    May 22 2012: I personally think that green roofs are a fantastic idea. I would however have questions about the durability and lasting power of these roofs. Also, how might this roof design system limit architecture in terms of what shapes we can create with buildings? Overall it's a wonderful solution to a long time issue of combing an environmentally conscious design and one that effectively protects us from the elements. As far as making it a mandatory part of building design, I think it would be most effective to implement something like this in large metropolitan regions such as los angeles and new york where air pollution is high and extreme heat pockets in summer can kill residents. Not to mention they are just so visually appealing.
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      May 28 2012: I would agree with you that green roofs could be especially helpful in large cities where pollution levels are high. And as to the durability, green roofs can actually drastically increase the life of roofs. As long as the original roof is properly sealed and waterproofed there are no detriments to roof life span. The organic materials used in living roofs protect buildings from storms, UV radiation, and many other factors that usually age roofs.
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    May 22 2012: I don't think there would be less development, but there would have to be more innovation around design and architechture, to meet the environmental standards as well as the development needs. I lived in Christchurch New Zealand that was partially destroyed last year in a massive earthquake. the new city plan for the central business district which was levelled, is for buildings to include green roofs, and sustainable design as part of the rebuilding process. Included in that are the many earthquake safe provisions and codes that are mandatory in a place like New Zealand (which is split down the middle by the Pacific and Indo-Australian tectonic plates). This disaster has opened the door to a massive jump forward in sustainable and environmentally friendly building. And lets face it, green roofs are also much nicer visually than an ugly concrete rooftop!
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    May 21 2012: I think that if green roofs were mandated, then many different businesses would sprout (pun fully intended) to provide that service, and would need to build, and even if the initial cost went up, people still need buildings. Development and building costs are already fairly high, and green roof initial costs are not that astronomically high that it would be so detrimental that development and building would slow. I feel the benefit outweighs that initial cost, and development would increase to replace the old.
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      May 22 2012: Do you think UO or any other university for that matter would take the initiative to build with green roofs?
      • May 23 2012: The mandatory implementation of green roofs seems like a great idea to me. In addition to the points that many people have made the already high upfront building costs, I really do think that considering the later savings that green roofs can have for building temperature regulation, etc may outweigh or at least equalize the upfront costs. Especially when you consider how long you expect a building to be in existence and how those savings add up over the years.

        As to your question, Kimberly, I do think that a university may be one of the early places to take on this initiative. Not only is a place like UO full of young people who are passionate about making changes towards a more green future, including architecture, but at least at our university there seems to be constant construction and remodeling. This provides many opportunities for new technologies. Additionally students studying architecture are probably at the forefront of learning about these things and can be key assets for new green architecture implementation. This could provide opportunities for the school to save money, be a pioneer on a new green architectural front and allow students gain experience by using their education to provide input into changes in the university.
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        May 24 2012: I think the University of Oregon would be an amazing place to start a green roofs program. We currently have a sustainability initiative and this seems like a logical next step especially with the work that Jessica Green of the biology department is doing in partnership with the architecture school. It would be interesting to find out how many current building could be retrofit for green roofs on campus as well as how to initiate a mandate for all new buildings.
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    May 21 2012: I don't think so, in fact I think it would remain the same. The builders would merely add any extra expenses into the bill while promoting themselves as an Eco-Friendly company. In Florida mandatory hurricane codes do not hamper building, Miami is growing everyday as well as Orlando.

    It would certainly change the landscape for the better though.
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      May 27 2012: I have to agree with Adam and the view he is taking. The assumption that new construction would decrease because of mandatory green roofs is the same as assuming new construction would decrease because different or more stringent earthquake structure regulations are put into place. The alterations of building codes happen relatively frequently and they do not result in noticeable changes in the amount of development.
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    Jun 1 2012: Hi Allison,
    Many people will not vounteer for a prosocial behaviour but when it becomes mandatory they make the best of it and adapt it to their own purposes so that they do not appear to have been maliable to authority figures. Did you ever notice how many people compost now that recycling is required?
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    Jun 1 2012: I do not think green roofs shouldnbecome mandatory, though I could see it being strongly encouraged such as on top of apartment complexes in large cities where you know at least of the tenants would care for the plants and it would give a common space for neighbors to hang out and enjoy the nature scene together since they would not have a backyard. It would also be beneficial on hospital roofs for patients who cannot leave the premises of the building or for those visiting long hours. A fear I have about making green roofs mandatory is that I know many people would not have the time to care for the plants and it would be an eye sore for neighbors. There are already people who do not care for their lawns, shrubs and trees in their front yard and I would imagine it would cause some complaints in a residential neighborhood.
  • Jun 1 2012: Although it will increase the upfront cost of development, it may decrease the cost over time and will definitely decrease the negative environmental impact. To alleviate the upfront cost perhaps a government assistance program could be implemented. Additionally, the costs of adding a green roof to a development project probably would not exclude a large percentage of the market. Green roofs may even inspire a new type of development which is ultra efficient to minimize the extra cost of a green roof.
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    May 31 2012: Buildings will rise regardless of mandatory green roofs. I doubt there will be less development and building, but there may be less diversity in what buildings are being constructed. With the added cost of green roofs either the design of the building will have to suffer and be less creative in an architecture sense or the amount of companies able to build will be smaller allowing for them to experience more growth. If somehow tax dollars were able to help contribute to the expense perhaps that would maintain development of buildings.
    • May 31 2012: If we could use tax dollars to contribute to the development of green roofs, then I believe we could make positive headway on accomplishing the requirement! Raising taxes would not necessarily be a bad thing either don't you think?
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        May 31 2012: It just depends on whether or not people are willing to create a better living environment for their community. And not everyone cares or feels that tax dollars should be spent this way. Though I do think it would be beneficial in the long-run.
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      Jun 1 2012: If green roofs were mandatory in cities, yes it might not stop development. But, it will make development better. Those companies that are creating new development, have the money and would give back to nature the space that it has altered. If the mandate was to stop development then that would be great as well. I see this as a win-win situation.
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      Jun 1 2012: I agree with the fact that I do not think that development will stop. I do however think that the developers will find a way around the 2,000 sq meter requirement for green roofs in a way to "beat the system.
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      Jun 1 2012: I agree that development will continue, even if if is just replacing older buildings and I think that innovation is important in that process, but it also takes a long time for new ideas and building practices to become widespread because there are so many buildings already and replacing them takes a long time. Maybe in 50 years things will look different.
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    May 30 2012: As many commenters have posted, this ultimately boils down to money. The upfront costs of doing a green roof is prohibitive for some builders, even if the roof pays for itself down the road. I think a better alternative would be to provide some sort of reward for including a green roof in building plans. For instance, a tax holiday for a certain period to help offset the cost. The monetary benefit would be realized sooner and may entice more green roofs. Though it may cost the government some money in lost tax revenue, it may ultimately save money in the long run when accumulated environmental costs are realized.
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      May 31 2012: I think a small tax break for including a green roof is a good idea. The major difficulty is deciding on an amount that will entice businesses without significantly reducing tax revenue. Regardless, it could be a great transition point, allowing people to see the benefit of green roofs as a typical building component without initiating a mandate just yet.
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      May 31 2012: This is a very good point and great idea. There are usually multiple ways of implementing things like this and the options are usually the stick or the carrot. Offering something motivational seems like a more likable change, rather than something that will make businesses comply but simultaneously piss them off.
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      May 31 2012: As you stated, it does all boil down to money. But one aspect that I think it's important for businesses in particular to consider is that they gain positive publicity by going green. Because taking steps toward helping the environment and "going green" is becoming more and more popular in today's culture, I think businesses that decide to put up the extra money up front will see a return on their investment from customers that support their decision and choose to associate with that business rather than a competitor.
      • May 31 2012: To put it simply, it is incredible that going green is becoming a trend in the social and political world. Therefore, pushing the more influential people to make more environmentally conscious decisions. The more those in power do it, the more the masses will follow. Do we think it would be a good idea to demand the companies or individuals with a large enough income be required to install green roofs? Or is that too farfetched?
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          May 31 2012: I think that companies would really fight back if they were made to install green roofs using their own money. However, as time goes on and more and more companies start to install them in response to consumer requests, I think that most companies will follow.
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    May 28 2012: Right now I don't think that the benefits of green roofs outweigh the costs. I think that maybe with time and the right advertising, green roofs will become more desirable and therefore the benefits will, in fact, weigh out the costs.
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      May 31 2012: The right advertisement might be the cities themselves. When you start adding more green and better sustainability to structures and show the people you care about the environment as well as those who live in it...well it will attract more people to live in the city.
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    May 28 2012: I suspect that a mandate for green roofs would simply ensure developers move out of the region with the mandate, like how Portland is having so many issues with suburbs trying to get out of the urban growth boundaries in one way or another. It would have to be state or nationwide to ensure compliance. Beyond that, the cost of keeping all those plants alive with be another problem. In apartment complexes and homes, a little education and a lot of coercion would go a long way into convincing people to keep those plants alive. In office buildings, somebody will have to be paid to keep them alive, or else the space could be rented out to families seeking to grow more than their own space might allow.
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      May 30 2012: I agree with you that developers would likely just of the area that mandated them to build a green roof if they really didn't want to. But with more education about the benefits to green roofs, developers may not be as opposed to having buildings with them. Although it may have more upfront cost, in the long run it would save a lot of money that would have been spent on electricity bills to regulate the temperature of the building. Like most things, I feel like the introduction of green roofs will just take time and cannot be expect to be accepted over night.
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      May 31 2012: Education will definitely be the driving factor here. I think it would be great to see public buildings taking the lead in making this happen. There is also the potential for new jobs to be created in regards to caretakers of the roofs. Although, this may only be a possibility for big businesses that can take on the extra payroll. I agree with Amanda that the green roof movement will probably be a slowly occurring one, but the right idea is there.
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    May 28 2012: I think that green roofs are an excellent way to introduce biodiversity to cities, and they are also good because they help to lower the Urban Heat Island effect. I doubt that many developers would be overly excited to include green roofs on their buildings, but if they were informed of all the environmental benefits, and perhaps also of benefits as to how green roofs can increase roof lifespan and help with the insulation of buildings, they might be more open to using them.
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    May 28 2012: I think green roofs are a good idea since it would reduce energy demand and the cost of heating and cooling the building. However, I don't think developers, if given a choice, would use green roofs if the upfront cost was too high. If the upfront cost is high, that cost would then be passed on to tenants at residential buildings. The fact is that unless developers are forced to, they will go with the cheaper alternative to make more money. But, I think green roofing and other sustainable building practices will gain favor among developers as the upfront cost continues to decrease.
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      May 28 2012: I agree that green roofs are a good idea but that building developers will be less inclined to use them in buildings if the upfront cost is too high. I think that perhaps if green roofs and their benefits were advertised more to the general public, there would be an increase in demand for them and more developers would be willing to supply them.
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      May 31 2012: With "today's economy" I have a feeling this would be an added financial hardship that wouldn't be justifiable. It is hard to get people to see the long term effects when so much start up money is needed. Does anyone know some dollar figures for what this might entail? I'm sure it varies drastically depending on the circumstances...just curious though.
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    May 28 2012: I'm interested in how green roofs would effect urban biodiversity. It sounds like the idea is to make the roof's plant life like the natural plant life of that area(or like a farm, depending), but what about animal, fungal, bag bacterial, etc. life? How would the differences between these green roofs and natural areas hinder or be utilized by them? There's of course the issue of elevation, especially on large buildings and perhaps even more importantly accessibility; for instance, I can't see any mammals other than squirrels or bats being able to interact with the gardens in any meaningful way. There’s also things like soil depth, wind exposure, and some crazy edge effects seeing as how we're talking about little patches of soil and plants separated by a bunch of concrete(which I suppose isn't too different from yards...). I know biodiversity isn't the primary reason why people are considering green roofs but it's still interesting to consider.
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      May 28 2012: That _would_ be interesting. For the lower elevations/height (say 1 or 2 stories), I'd imagine the green roofs probably shouldn't cause too much difference for some creatures to go up there if they truly wish to (like, say, cats). Granted, there probably wouldn't be as many variety of insects or invertebrates like worms, unless they were already in the soil that were already laid down, or planted there by the owners themselves.

      As you go higher up, it would stand to reason that there would be a selection for organisms in their ability to reach up to the higher stories (probably mostly birds) and whatever else that may be brought up there by humans (again, whether they be on purpose or accidental).

      That actually sounds like a cool experiment to conduct. 'Would you find a general trend of losing biodiversity as green roofs go to higher elevations?' or something in that line of thought. I wonder if anyone has thought of testing that out?

      It might also depend on what type of plants people want to grow up there, such as purely aesthetic plants, or as people have mentioned before, garden plants for growing food.
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    May 28 2012: I think green roofs are a good idea, but it may not be practical in every situation, an alternative could be solar panels, particularly in areas that get more sun/less rain, where solar panels might produce more energy than a green roof would save. Is it possible to have both solar panels and a green roof?
    I don't think that this would necessarily hinder building development, although in my opinion we could do with less individual homes instead building urban areas upwards to increase density and get rid of suburbia. People may not be willing to pay the extra costs, some may not believe that it will save them heating/cooling costs and others may consider it a hazard, but I think if they became mainstream and all new houses were equipped with them then there would be less resistance.
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    May 28 2012: I think there might actually be more especially if restaurants and families used that space to grow food.
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      Jun 1 2012: Debra, you make a good point. Our society can greatly benefit from green roofs. However, since green roofs can be built now, why would production increase only if it was mandatory?
  • May 27 2012: These seems to be a lot of support for green roofs in this forum and especially in our class, so I think it's pertinent for all of you to know that the new dorms behind the long house that will open next fall were originally going to be LEED Platinum buildings in part because they had green roofs on all three structures. Because of short term budget constraints the green roofs and other sustainability initiatives in the design of the building were cut and it will be designated a LEED Gold equivalent building instead. This is what our institution values, even after students have said that sustainability is the number one issue guiding their decisions about campus (2011 ASUO Student Survey). Because we are here for only four years long term projects escape our grasp, we do not have a place for student institutional knowledge that can help us continually be heard on the long term projects like green roofs that pay for themselves in 10 years.
  • May 27 2012: I'm wondering how these plants on green roofs get watered. Here in Oregon this probably is answered by rainfall, but what about in a place like Arizona? Do they have to pump water up to the top of the building to water the plants? If this is what happens I would be skeptical that green roofs are actually helping the problem in this case, especially on very tall buildings. Maybe I'm completely wrong and green roofs benefits would still outweigh the water cost even on really tall buildings in Arizona, but I have to think that perhaps placing solar panels on top of those buildings may be a better use of the space. I believe solar panels can accomplish the same absorption of light and reduce the cooling costs, and in areas with lots of sun and little rain their energy production may outweigh the other benefits of green roofs.

    I think in certain areas green roofs are a brilliant idea, in Portland for example I would love to see this law implemented. I don't think that requiring green roofs all over the country is a good idea. I think the government should offer incentives to cities to enact this law on their own, but leave it up to the city (or maybe the state) to decide whether they require green roofs. These more local governments should look into what would help their area the most.
    • May 27 2012: It's standard procedure with green roofs to mandate that the plants are native species that will survive in the naturally occurring climate. In the south west this means that green roofs are a lot of desert plants that might not get as luscious as our Northwest plants but they serve the same purpose, and contribute to the concepts of bioregionalism and the cultural values of nature spaces.
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        May 28 2012: Up and coming architects may have a hard time selling the idea of sage brush on building roofs. When most people think of green roofs, they think of them as green. It doesn't matter whether they live in the Northwest or the desert, we have come to expect it.

        I agree with Mat that the movement of water up a building is a terrible waste of energy and water, which is scarce in the desert as is, and Ellen is right that the flora should be native. A national law mandating green roofs, however, will just mean more "inequality." The Northwest will build the desired "green" roofs while Arizona grow their cacti. I wouldn't have it any other way, but this federal law would meet endless resistance if any part of it mentions native plants. We like to design landscapes that oppose nature rather than work with it and many parts of America would oppose their native plants as fixtures for their green roofs because they don't find them aesthetically pleasing. I think a policy such as this would only work at the municipal level.
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          May 28 2012: I disagree. I think you would have to do at the very least a statewide law. Nationwide would be better. I don't think "green" roofs should be the only option (small windmills or solar panels would be perfectly acceptable substitutes) but if you don't implement the law everywhere, companies will just go to a state or county that doesn't have the law to build large structures, and the states or counties with the law will cry foul because they're loosing tax revenue and jobs. Companies change locations for a few percentage difference in taxes, and I have no doubt that they'd move development to get out of paying for a green roof if it added significant amounts of money to building costs.
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      May 27 2012: I agree that in certain places there should be incentives or requirements to have green roofs on new buildings. In the pacific northwest many people are very conscious of the environment and I think most would love the idea. If it can reduce our excessive need for air conditioning and maybe even keep the buildings warmer in the winter, I agree that it should depend on the area and the plants would need to be natives so that they are adapted to the area like Ellen said. I don't agree that solar panels could accomplish the "same absorption of light and reduce the cooling costs" because it takes a lot of energy to make those solar panels and the green roofs need little to no maintenance. Yes sometimes especially when they are being established may need water, but if they are natives they should be fine with the weather of the area. If water is the problem, most tall buildings already have water running to the top floor so what would be the difference between one more floor?
      • May 28 2012: I know that constructing solar panels is not exactly a green process. What I meant is that once they are up the solar panels will do the same job as the plants in absorbing some of the incoming light, which will lower the amount of cooling the building needs.

        Also little to no maintenance? Not to harp on this solar thing, but they require little to no maintenance. I just don't see how plants baking in the sun all day could possibly not require maintenance. Again, I'm speaking with regards to certain areas. In the PNW I'm sure the plants would require little to no maintenance and would be a better solution. I don't mean to say I think we should change the idea to solar roofs instead of green roofs, I just think solar may be a better way to go in certain areas.
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          Jun 1 2012: Okay, maybe in some areas it would be reasonable to use solar panels instead of a green roof, but if in areas such as Arizona, using plants native to the area would allow them to survive as long as they were established. Solar panels would just increase the use of Air Conditioning because people would think that it is not harming anything, when it is just decreasing their reliance on the power grid to power their air conditioner.
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      May 28 2012: While Ellen's point solves the problem about water I he to wonder what about nutrients? Even if something is grown in its native habitat that doesn't mean the provided soil will be able to support it and many plants deplete nutrients that are in the soil with every growth cycle. I'm not an expert on farming but depending on the plant types that grow in that area a lot of external fertilizer would have to brought up, especially nitrogen, yes? Ironically this would be an especially be problem in tropical areas because most tropical plants can only thrive because of the massive amounts of dead plant and animal matter that can be found in the topsoil of rainforest like environments. Of course providing external fertilizer is already business as usual for farms but I'd think that needing to distribute fertilizer to the top of every building would complicate matters considerably, and I could be wrong but I think potted plants (which is essentially what green roofs are, only on a larger scale) usually require more externally fertilizer than plants that are actually grown in the ground. This could be somewhat offset by having people use their compost as fertilizer but still. Again I don't know a whole lot about what I'm talking about so correct me if I'm wrong.
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    May 27 2012: no, it would be just more expensive. P.S. were do you put solar panels on a green roof? :)
    but they r cool, funny how green roofs came before green walls, makes me wonder how the roof was held up... ha
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    May 27 2012: Upon reading many of the responses to this question I found it interesting that there is a stark separation between short term safety regulations/codes, for earthquakes as an example, and long term safety regulations, such as green roofs and the prevention of long terms affects associated with rapid climate change. Are these not the same type of regulations but viewed at different time frames. This makes me hopeful that other governments will begin to take their citizen's long term health into account when addressing safety initiatives. Anyone have ideas on this?
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      May 27 2012: While it seems all too logical that the current generation should invest more money into future safety, it doesn't happen on a regular basis. I think the problem lies in how much we as a society are willing to invest in people and generations we will never know. I think it could be argued it is human nature to think in the short term. In any case, I agree that investments in long-term health and safety should be given more recognition, green roofing being one of them.
      • Jun 1 2012: I agree that we should be looking into the future and not solely focus on short term natural disaster scenarios. Although, short term disasters can be very devastating, long term disasters may make short term problems obsolete. In addition, green roofs may not drastically change the engineering problems a building faces meaning that in many cases no additional structural changes may need to be made.
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    May 27 2012: It is unlikely that a minor building constraint would substantially decrease the overall amount of building that are constructed in heavily populated areas. Although this sort of policy would probably make it more difficult for smaller construction firms to compete with larger firms that are capable of expending the additional time, effort, and money in implementing these roofs, not to mention the different architectural market that companies would have to draw on in order to feasibly design a more environmentally friendly roof, if the demand for the buildings remains, then it is likely that the construction of the buildings is inevitable, regardless of whether or not this sort of stipulation existed. Given that construction is inevitable, it is best that there is some sort of environmental guideline that would allow for the best buildings to be constructed.
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    May 26 2012: If green roofs were mandatory, it would likely open up more employment opportunities rather than omit them. If America followed suit and had similar reduces in daily energy demand, that would create a surplus of money to spend elsewhere, and lessen the weight of our current energy needs. All in all I think green roofs would be a worthy requirement.
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      May 27 2012: I agree with you Bre. If people are worrying about green roof requirements hurting the economy to the point where they would have to decrease spending on housing developments, they should consider the jobs that green roof construction would open. And in the long run, the money we save from energy expenditure, could be used for other important investments.
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        May 27 2012: More directly, the money saved from energy costs would translate to the building costs of the green roof. I wonder then, if there is really much of a "cost" in building a green roof if you consider a 5 or 10 year span of time.
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          May 27 2012: This was exactly what I was thinking. If we did have to cut back on development and building for this new requirement, it would only be for short term.
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        May 27 2012: Besides the economic costs, would the green rooftops create their own ecosystems? Would this help with the fragmentation of the surrounding ecosystems? I think this would allow for predatory birds to come back into the city and help keep the troublesome pigeons.
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          May 31 2012: I think it's very possible that green roofs could provide both permanent habitats, as well as migratory stepping stones for birds crossing urban landscapes. Birds obviously do well in urban parks and gardens, so I see now reason why this extension to the rooftops would not be beneficial as well.
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      May 27 2012: After reading all these comments and the great ideas about how green rooftops can create urban gardens and jobs I am now curious, are green rooftops popular in other countries? Does anybody know??
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    May 24 2012: I will start the "Highrise Landscape bussines" this can give 1000000000´s of work !! and other meaning of urban farming !!
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    May 24 2012: I love the idea of green roofs - I especially like the idea of growing food (veg, salad leaves, soft fruit and herbs). How more local could you get! You could also place a bee hive up there - out of harms way.

    In the UK (before the economic slump) many local authorities were selling allotments to developers (there is a massive housing shortage in the UK). Even today allotments are at risk as LA's sell as many assets as they can to preserve local services. This is at a time when pensioners and the unemployed would benefit from having access to land - not only to provide food for themselves and their families, but also to stay fit, active, empowered and connected with people in their communities. Perhaps we could have community allotments at roof level on all governemnt and commercial buildings. Instead of the WW2 "Dig for Victory" campaign we could have a "Dig out Austerity" campaign.
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      May 24 2012: I really like the idea of turning these green roof projects/mandates into community gardens. I think it is critical for people to start to see "restrictions" (like a green roof requirement) as opportunities for community development. Just as it is difficult to get a group of students or friends engaged in a project unless they feel invested, it will be difficult for people to get behind this idea unless they see how they/their community can benefit. If there are financial issues with the costs of green roofing (which likely wouldn't be major given the money saved from air processing etc), people could pay small fee for some gardens in order to grow crops. Of course this should be limited so that all parts of the city could participate. Change to improve the status of the earth should include social evolution that brings people together to understand why laws are put into place to understand fully how their lives can benefit from them.
  • May 24 2012: It seems like this could be a very promising idea for future developments. If each case is looked at as an individual and the plans were drawn up specifically for the development, the outcome would be great. Not only would heating and cooling costs be reduced but green roofs would also allow for less heat to be reflected off of rooftops, which happens far too much right now. If green roof development was put into place it would be very important to customize each plan for the locality. If the plants are not chosen correctly, the green roof could be costing more than it is worth.
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      May 24 2012: I agree with you. The upfront cost is kind of a problem for businesses that are starting up and trying to make a profit, but for large corporations there is no reason why they should not have a green rooftop. It would be a great way to encourage people to 'go green', and would provide benefits for people working in the building too, especially if the garden grew food greenery.
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    jag .

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    May 24 2012: For buildings that already have been built, one thing to consider is you cant put a green roof on any one, as the building may not have been designed for the extra load (which is considerable), hence alternatives forms of energy reducing technologies/construction methods would have to be implemented.
  • May 23 2012: I am also in favor of green roofs, and think that adding green roofing requirements to existing building codes for all new buildings would be a great idea in most places. I do not believe that the additional costs will be very large relative to the cost of the entire building, and would not slow growth very much at all. These codes could also create new jobs for roof design and maintenance. Taking it a step further, if existing buildings were required to retro-fit with green roofing, this could create a huge boom in employment as developed areas seek to make changes. I like the idea mentioned earlier of tax incentives for buildings that utilize green roofing as an alternative or intermediate model.
    There are places where this would just not be practical however, including areas with high winds, extreme temperatures, and lack of rain. I am not aware of any down sides of green roofing, and am very interested to hear more critiques because it seems like a sure fire great idea to me in most places.
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      May 23 2012: I like that you injected "employment" into the conversation. This kind of work is exactly the kind of employment we need. I like to use the word "productive" for this kind of work, even though that may sound counter-intuitive. To my mind, only activities that aid in the continued habitability of planet Earth should be deemed "productive." All other types of employment are either neutral or counter-productive. If we integrate grey-water systems with green roofing, then this kind of employment is doubly productive (moreso than virtually any other kind of employment). This should be the kind of make-work that can get us out of this economic malaise. That said, we could up the ante even further by putting these roofs over underground buildings, and using all of the other smart/green building technologies (see Mike Robinson's comment below).

      I did want to say a bit about building codes, and law in general (again, see discussion below). The building code in California is montrous and therefore impossible to properly enforce (and therefore only about 80% followed). I really think most codes could be dramatically simplified so that they would be better followed (psychotic corporations will fight this idea tooth-and-nail). For example, all of California's Title 24 Part 6 could be replaced by something like this: "There will be no further gas or propane hookups except at commercial kitchens, and only a single 20 Amp electtrical supply per residence or 10,000 sqft of enclosed floor area." That puts our priorities about where they need to be, and is extremely simple to interpret and enforce. A similarly simple set of rules could be promulgated for water (which is not covered by Title 24 Part 6).
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        May 23 2012: I agree that conversations about about methods of dealing with global climate change and over-consumption of earth resources must include recognition of economic impacts and benefits. Though costs of building roofs with vegetation may initially by higher, most people contracting architects and construction companies would likely be willing to pay these costs in order to reduce the long term expenses of maintaining building temperature and air quality. My stepfather is an architect and he has found that more and more partners demand that at least some part of their building plans including "greening" methods to reduce building impact. This also stems from the desire to advertise new buildings as being earth-friendly. Because of the interest of contractors in having efficient self sustaining buildings that can be advertised with the green label, I doubt that requirements of green roofs would likely not reduce development and building.
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    May 23 2012: Potentially. It is hard to say what the outcome would be due to the multitude of variables with different locations across the globe requiring different plants and methods. I could see it being a benefit to society and the building itself though. Imagine a rooftop garden that supports a restaurant below it. That would be impressive.
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      May 24 2012: I really like the idea of a rooftop garden that supports the produce for a restaurant below. It would have to be a big garden but it's a really good idea. It kind of reminds me of an article I read on modern Hobbit houses. The houses were partially underground with a garden on top. It was a cool idea.
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      May 24 2012: There is a restaurant in Portland, Noble Rot, that is supported by a rooftop garden. I have not had the chance to go there, but I hear they're doing quite well and the food is delicious. There is so much potential for the idea of mandating green roofs. They would benefit the environment and reduce long term energy costs of the building. They could be used to grow crops for restaurants, private homes, and the general public. The produce could be used to support the occupants of the building or be sold at a market. Needless to say, the benefits absolutely outweigh the cost.
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      May 27 2012: Implementing a rooftop garden or solar panels or something would be a really cool way to keep a building self-sustaining. I think that this would be a very appropriate use of resources in places that are capable of meeting these building requirements. But I wonder about buildings that are not capable. How would you suggest that a building that comes to a peak, like the Empire State Building, or a building in an area that does not get much rain or sun meets some sort of green requirement? Would they pay a tax on their emissions as an alternative? What do you think would be the proper solution for buildings that could not live up to code?
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        May 28 2012: This might be a bit of a tangent, but if there's anything to learn from environmental policy and it's history, it's this: for the older buildings like the Empire State building, it wouldn't surprise me if they end up having a Grandfather Clause to make things 'fair', since it's harder to change older designs to match newer standards. This could in turn inadvertently end up causing a lot of people to want to keep the older buildings instead of building them to newer, 'green roof' standards.

        On a brighter note, I believe that there have been cases where, instead of putting huge fines on people for failing to match up to certain environmental standards, if there are smaller, more manageable fines, people are more prone to respond to it.

        So perhaps a good way to make this come about is to have small fines or taxes for the buildings unable to live up to code, while at the same time give subsidies (like how the govt. gave subsidies for highways and freeways) for the construction of green roofs.
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    May 22 2012: http://www.dailymail.co.uk/sciencetech/article-1031438/Pictured-The-floating-cities-day-house-climate-change-refugees.html "Lilypad Cities"

    I direct you all to that link to show how human ingenuity is illimitable. This is not to say that it provides the best, or even good solutions, but green roofs will not hinder architectural designs. We are too creative, and our subjects (plants) are too intelligent and tenuous for that.

    With the idea of "green roofs" we tend to think of roofs that are populated by things that are uniformly green, that is, the types of leafy lollipop spheres that represent a green space on a designer's computer screen. To me, the most exciting thing about green roofs is the potential for intense variation across buildings, across countries--reflecting the particular nuances of the landscape. Is it too warm for cherry trees in Miami? Plant a Japanese garden of mangroves and saw palmetto. Is it too cold for cherry trees in Maine? Plant a forest of white spruces. They are used to shallow, moist soils.

    From the plant's point of view, the greatest problem will be a lack of soil consistent with the constraints of a rooftop. Bonsai trees are bonsai trees simply because they are maintained and pruned in a pot. To avoid this, we can a) start adapting green roofs to the climate b) make roof-building a whole new discipline, in which they become new earths, not merely shelters for those living or working below them.

    Another thing that we must not overlook, however, is that if we start explicitly designing buildings to house incredible rooftop gardens, we may start building bigger roofs, and bigger buildings. That's a long way off though!
    • May 24 2012: That is such an inspiring article! It is sad, however, to see everything we could accomplish in the way of being sustainable that we haven't. Regarding trees on green roofs, I think that food crops would be a better choice than trees per se. It would be a way to make cities less reliant on the commercial farm and transportation systems that provide almost all of our food, so that if ever either of those systems failed, we would have a fallback. Growing crops would also lessen the problem of not having enough soil depth, because the plants' roots would not grow as long as tree roots.
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    May 21 2012: I think that it most likely not slow down development. It anything the buildings would just cost a little bit more but i'm sure that there will be some tax breaks that are give to companies that emploment this type of room just like installing solar panles. I strongly think that this should become more of a habbit for every city. It is proven that it is much more cost effective to insulate a building thiis way and it also could create new jobs for people who need to tend to the roofs and maintain them. This is a step forward if it becomes more wide spread.
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      May 22 2012: I agree with what Brett has said. I don't think it will create less development or even slow down our development. If anything developers will change what they spend money on in order to make these changes. I like the idea that it will create new jobs and in the end be very cost efficient. I think the idea of making it mandatory is a little extreme but tax breaks would be a great solution. I would like to see all buildings have a living roof top someday.

      I also wonder if the idea of living rooftops will become popular in developing countries and how long it will take to be implemented there.
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      May 27 2012: How do the green rooftops keep buildings in warm climates cool? It seems more like a way to just keep the heat inside. And how would plants survive on the tall skyscrapers? Would a green rooftop be able to help regulate the temperature of such a large building?