Today it was announced that CO2 emission rose dramatically in 2010....bad news as it is, the worst part is that it was an unprecedented increase. Its on the high end of the IPCC's estimates for C02 emissions, trends that equate with a +2 C degree increase by 2100. For those unaware of that number, any increase of 2 degrees or more won't just hurt the earth (and by extension, us) but perhaps hurt its ability to sustain life in general. While we may concern ourselves with trivialities of celebrity life or fashion, we're killing the planet.
Concrete manufacturing (heating kilns to prepare cement), transportation (moving minerals and material), extraction (getting gypsum and aggregates) and impacts related to its use (manufacturing and discarding of formwork, use of rebar, poorly built structures that make building less energy efficient) we can be concerned. Concrete accounts for 7% of CO2 emissions, and we can reduce that significantly if we used 3D printing. But why?
Using local materials, we print everything. Using less formwork and labour, we reduce emission by complimentary goods. By using 3D modelling and programming, we can create more efficient buildings. One way is using the shape of the building to maximize energy use. Another is geometry - more flexibility and freedom in construction = less material used = less emissions. Whatever material we don't use in a DShape is reused. Whatever building we tear down we can reuse by crushing it up into aggregate and using it.
If you're worried about emissions, so am I. But there are solutions. It just means the concrete industry is going to have to realize they have to undergo deep structural change in how they operate, otherwise they'll be going out the door like the oil industry, the music or film industry.