As the Scientific committee chair of the SBE16 Conference in Utrecht last week,  which focussed at transition to 0-energy for houses and buildings, I used the key note occasion to bring materials impacts strongly to the table. Yes, we have to move towards 0-energy houses and buildings, but we should be aware that this is shifting impacts to materials, which we have to evaluate integrated with energy! There is no energy without materials or vice versa, of as I put it: “To produce energy requires materials, that require energy to produce these materials”.
And in that case using high impact materials where a low impact application is available, is a offense against humanity fighting climate change.
So far the building sector, all stakeholders, have seen energy efficiency as a interesting feature, as long as they could maintain architectural freedom, and continue selling materials and products. But its not like that anymore: reduction of CO2 emissions to 0 within 35 years is at stake,  ( more specific: 0-man caused emissions beyond carrying capacity of the earth system) and this requires careful decision making for materials as well. Transition to 0-CO2 emissions includes materials ! ( as well as other resources, like food or water with 0-emissions)
As such I must confess, scientists and researchers have failed so far to bring this to the table, and provide clear insight in the relation and combined impacts for stakeholders in practice.
But its about time we name things as they are: When a building has a high embodied CO2, or embodied -fossil- energy impact, we should mark that and act upon.
With a doubling of all cities worldwide to match the growth in urban population, , the worldwide transition towards renewable energy supply, with among others mega wind parks, with at least 1 billion cars to be added , plus accompanying infrastructure, materials are the next in line for which a huge transition is required.
On one side materials become scarcer, that is , the ores will be become lower saturated, which is a problem in itself due to “ depletion” , but in turn it will lead to increased energy input to generate the same amount of resource.  Its a snake biting its own tail : energy and materials are inseparably interconnected in a dance for degradation. (entropy increase in the system)
Especially metals have a very high embodied energy, energy that went into winning processing and transport , and main contributor to exergy loss in the earth system.  Using these materials for all kinds of fashionable applications is no longer socially acceptable. As well as it is a obligation to avoid high impact applications to save resources to be able to maintain a basic level of welfare globally.
Not that high impact materials are bad by definition. However in most cases they have a too high impact for the functions applied: They should only be applied if no alternative is at hand, if no other lower impact material can provide the same performance.
No facade cladding with aluminum, for instance, as was applied in a recent renovation of a office building in the Netherlands, ASR building in Utrecht. Notably a insurance company known for so called usury contracts. Well this, is metals ursury. Or to name one other of many examples: Calatrava is famous for wasting metals to unprecedented levels: The Turning Torso building in Malmo, Sweden , weighs around 3500 kg/m2, while an average m2 house weighs 1000 kg/M2.  Its a 3,5 times higher resource input for the same function, but not only that, its also in steel, which has a much higher impact as a mix of regular housing materials. Such buildings can be seen as “ Carbon Bombs” …
A definition of responsible material use should be: Using the material that can provide the required function or service with the least environmental impact, in terms of energy and materials input. Namely: “sustainable materials” do not exist, only sustainable use of materials exists. No unsustainable materials exist, but only unsustainable use of it, or irresponsible use: ways of use that can not be sustained by the system. And therefor you should not use materials in a overkill or from a overqualified source. No steel or concrete for a simple two level row house, for instance, to end up with a far too high impact.
Its about time we recognizes this and name and shame these examples, as long as we have no set standard for materials, similar as for energy. Mind that we will have to introduce one if we take the global maximum 2 degrees climate change seriously. A “ EEPC” : Embodied energy performance indicator, with as target : 0-embodied energy buildings; To avoid more “ Carbon bomb buildings” .
2 Meinshausen M., Meinshausen N., Hare W., Raper S., Frieler K., Knutti R., Frame D., Allen M., Greenhouse-gas emission targets for limiting global warming to 2C . (2009) , Nature, Vol 458 April 2009.
3 Energy Efficiency and the Demand for Energy Services, 2010, Earthscan book by L. D. Danny Harvey, p.364
4 Valero A. et all,2010, Physical geonomics: Combining the exergy and Hubbert peak analysis for predicting mineral resources depletion , Resources, Conservation and Recycling 54 (2010) 1074–1083
5 Closed materials cycle approach for buildings , paper SASBE2009, Delft (researchgate )