People build them because they can. Nobody seems to be thinking about what will happen to them when they are no longer profitable. How do you demolish these monstrosities? Will it cost as much to demolish them as to build them in the first place? Who will be on the hook for the demolition costs?

No building is sustainable, because the needs for land uses evolve. So one should think about sustainability in terms of the ease of transitions from one land use to another.

Let us think about one solution that might spring to mind. Suppose that building developers had to create a fund that would pay for a building's ultimate disposal. The fund would not have to be huge initially (although it should be proportionately larger for the extremely tall buildings), but it could grow to a very large sum over the 80 years or so of building life. What would be wrong with that?

The fund would likely be looted. We have similar funds today. For example, we have funds to handle the maintenance of cemeteries through the future. What do we know about these funds? The large ones are looted. Crooks create an entity which gains control over the cemetery and the fund and voila, the fund disappears along with the entity that was created to rob the fund.

http://www.mlive.com/news/index.ssf/2011/09/cemetery_trust_fund_embezzler.html

I agree with you Peter as many high rise buildings seem to be built for temporary profits.  I shall appreciate your thoughts about Ken Yang Bioclimatic Architecture though.  Any particular thoughts about his bioclimatic skyscrapers?

Ken Yeang's work is interesting, Eleni. I have often thought (in more simple terms) that an architect who designs a building with all facades identical must not understand the world as we find it. The damn sun rises in the East and sets in the West. In the Northern (Southern) hemisphere the South (North) side gets blasted by the sun during the day. Most tall buildings need air conditioning year round. Tall buildings flex so be careful how you connect them to other tall buildings and don't create really good airfoils. Reflective glass on one building can zap the building next door. You know the drill. Be aware of your environment. The sun, the wind, the cold, the hot, the view.

But Ken Yeang's work seems to take all this to a level that I have not contemplated (although I have not seen any really tall buildings from his "board" - probably my loss). There is a reason that I haven't contemplated this level before. I am a simple fellow who tries not to follow fads. For example, the rooftops of tall buildings are not a very good place for gardens. Solar panels are not working out so far (short lifetimes and inefficient). Really tall buildings provide terrible egress. You get the idea, I'm a fuddy duddy.

Dear all, thank you for this interesting debate. I think that skyscraper are the modern symbol of society of "spectacle"  and a sign of financial power.  Aesthetically are ugly and monotonous. For these reasons should be interesting analyse skyscrapers from several point of views: financial factors that encourage their growth all around the world, real cost (to built +  manage, safety, etc ...) , how skyscraper influence social interaction and, more in general, how they influence the well being of people that in it work or live, and what is the environmental impact, both in its surroundings and in term of used materials, 

May be we have got to interview people using skyscrapers as offices or accommodation to get some ideas about their well being.  Mostly people live temporarily as accommodation because their workplace is in there.  Life should be monotonous during office time and beyond if you also look at  commuters lives as well (see cities such as London, Canary Warf area, for example).  Thinking at Brexit though I cannot see so much of financial growth based only upon construction of skyscrapers in London anymore.  It might be that high rise spectacular buildings are going to fail to deliver again.

I had these apprehensions too about tall structures and so posted two questions regarding their design life and imposing limit on height to have control on maintenance apart from safety in this platform and unfortunately the questions had not got attention  so far!

The skyscrappers are being built, in my opinion, as prestige symbols by some countries like Dubai to claim possession of tallest structure and apparently getting revenues too from public, although it is not known whether  the maintenance is taken care purely from income generated from the Tower itself, as digital health monitoring of such skyscrappers is a compulsion for designed loads, while safety methods are not known due to fire and severe seismic intensities beyond design compulsions.

I happened to raise  query to a designer of Burj Khalifa in a conference regarding safety measures adapted to rescue the occupants from top floors in case of a fire, and I was told that they have to come down the stairs all the way!!

Wonder why safety chute systems cant be adapted in stages if we have to build skyscrappers, thereby high cost considerations  will certainly discourage developers over certain critical height of structures and compulsion of such safety measures act as a natural dampener on proposals of very tall structures!

The psychological factors of occupants of top floors also need to be assessed in case of general turbulences of these volatile structures and what guarantees the designer/developer are giving for their life time safety and whether such guarantees can be accecpted by any fraternity?

I agree that safety is not considered most of the times; I am curious to know how many of these buildings have already had an evacuation plan on place and approved by Fire Authorities.

A good historical source is Carol Willis, Form Follows Finance: Skyscrapers and Skylines in New York and Chicago (New York: Princeton University Press, 1995). This book explains the financial parameters that dictated the design of the early skyscrapers in New York and Chicago (ideas like "economic height", for example).

Considering safety and economy in maintenance, a limiting height of around 300M including  Rooftop service structures shall be considered as ideal!

Readers might be interested in a theoretical view of optimal design of a large (possibly tall) building:  https://www.researchgate.net/publication/5141967_A_Note_on_the_Optimal_Design_of_an_Office_Building

Article A Note on the Optimal Design of an Office Building