When it comes to skyscrapers, is taller greener or smaller better?
I heard an interesting debate the other day on the topic of cities and skyscrapers. In a nutshell, when it comes to cities and buildings, is taller greener or is smaller better? In other words, should environmentally minded people like or dislike skyscrapers?
The Taller Greeners:
• Building up, rather than out, combats urban sprawl, means more concentration of people, means better for mass transit which equals fewer
cars and lower emissions.
• Building bigger means more opportunity to use technologies like distributed generation, advanced energy efficiency, lighting and monitoring, which typically are more economic in larger projects.
The Smaller Betters:
• Smaller means more sustainable buildings and lifestyle, more trees and green space.
• Smaller means more neighborhood connectivity for all of us.
• Taller often means more nonsustainable steel, and lots of AC load, which we could avoid with smaller buildings.
• Smaller means less concrete and steel, which are often associated with the increased temperatures in cities.
Perhaps some of the environmentally friendly buildings in progress in places like Dubai or New York can bridge the debate, and make skyscrapers ultra green and ultra cool.
What do you think?
In the interests of full disclosure, I am writing this blog from the second floor of a skyscraper in my office in downtown San Francisco, and because of the lack of good public transport access where I live, I have to drive in to work every day.
Neal Dikeman is a founding partner at Jane Capital Partners, advising the technology and venture arms of multinational energy companies in clean technology. He also edits and writes the Cleantech Blog. He is a member of the CNET Blog Network, and is not an employee of CNET. 
This is illogical. For the same amount of office-space in a smaller office, more land must be clear-cut of existing trees. Replacing a few trees along with some grass on several acres of land does not make up for this loss. In a taller building, one footprint exists for hundreds of offices.
"? Smaller means more neighborhood connectivity for all of us."
Please quantify "neighborhood connectivity". Is this referring to shorter commutes? If so, this is a good thing. Is this referring to a touchy-feel-good-you're-my-neighbor? If so, it has nothing to do with ecology. Tell the people in the skyscraper that regarding the relationships they create with their friends on neighboring floors, the "connectivity" is not real.
"? Taller often means more nonsustainable steel, and lots of AC load, which we could avoid with smaller buildings."
This is illogical. For an equivalent floorspace, the skyscraper will be more efficient, having thermal buffers of equal temperature above and below, and the only external contact being the exterior walls. A smaller office that houses just one facility will have contact on all exterior walls, plus the roof, plus the ground contact. This results in additional surface area for heat loss, resulting in higher HVAC loads.
"? Smaller means less concrete and steel, which are often associated with the increased temperatures in cities."
Associated? But with proper designs, not necessarily causative. Now contrast the single skyscraper with its underground garage and mass transit access, with hundreds or thousands of offices with their individual parking lots and massive road systems to support them, separate HVAC, additional utility inefficiencies, multiple redundant services, and greater loss of forests. At best, you've only distributed the load, but I propose that you've actually worsened it.
IMHO, the "smaller betters" need to work on some better arguments. Oh, and before anyone accuses me of being a skyscraper fanboy, I telecommute out of my home office.