The Earth in itself is a closed system regarding materials resources, there are no resources from outside the system to add to the stock. Which is the main difference with energy, that has a source outside the system: the sun. At the same time the sun is also the engine behind mass resources that can renew themselves on a human timescale, and are a logical basis for a balanced resource use. These resources have a renewal period that (could) fit with our life style. Mainly erosion sediments and wood based / organic resources. The first is a low quality source, has to be upgraded to be of use., The second is a group of high quality resources, that nature upgrades for us to a useful form.
And although the Earth mineral resources renew itself, this happens on a geological time scale of millions of years, by plate tectonics and volcanism, which is too long for our society to rely on. We have to consider these as fixed amounts. Anything used of these , will decrease the stock. ( later to be specified)
A sustainable and durable way of materials management will have to based on a closed cycle approach, linked to the timeframe in which these "boroughed "resources pass through that cycle, and the energy necessary to create and manage that process.
In order to deal with these issues a new model is needed that can illustrate and help us to manage this closed cycled approach. A model based upon a closed cycle use of materials for servicing our daily needed functions.
Here rises a significant difference with the momentary interest in cradle to cradle approaches as improvement from cradle to grave approach. That still takes raw resources as start, to use in a cycle via products. But with global limits in mind, sooner or later, that not enough, related to our consumption patterns and population growth. Translated for construction this mean rather a buildings to buildings approach, in stead of a dust to dust approach. Circular versus linear approach. And in fact, as with garage example before, a function to function approach: providing shelter in whatever way. Each step separately has to be optimised, but bordered by the integral approach and service of functions.
Energy available in the earth system is by the way not key in this. It's the grease to smooth the operation, and plays a secondary role after mass management, it is regarded as a specific form of mass.
A first step in creating such a closed cycle is of course bringing back in everything that "comes out": there is no such thing as waste, only resources in different forms, locations and composition , and re-use and recycling of everything in the highest degree. Which is nothing new, the Roman and Edo Japanese societies already showed us the way. EDO Japan was shut of from the outside world by their rulers, and created a island position, though much larger then the Easter Islands. Only they managed to go around, with re-using ( 1st option ) and recycling everything. The world is in a same position, though on a larger scale , and can learn from this in up scaling the sustainability lessons, from Easter island, via Edo-Japan, towards global sustainability.
This also implies the least degradation of products and sources, to delay increasing entropy of mass, and avoid extra energy input. Only in a last phase the energy content of mass can be transferred into energy and accompanying nutrients
The input side is determined by available sources, that is stock growth per unit of time. . And a low as possible input of energy to maintain and mange the cycle.
Closing the cycle in itself is no guarantee that we will manage to survive our way of life with the available resources. A wooden beam can survive its regrow time, and stay in function much longer. That does not mean that the global Woodstock is enough to support all our beam needs. Therefore a system approach in different levels is needed, to calibrate each step with the others. In order to manage the cycle according to the available resources, closed cycle management has to address also volumes, time frames and energy input. When we structure things, it comes all together in 4 main steps:
1close the cycle, (make resources part of that cycle)
2 reduce the volume of resources in that cycle
3 reduce the speed by which goods are going through the cycle
4 reduce energy to drive maintain the cycle
Ad 1
Closing the cycle means that there is created a efficient approach with in and output in providing a service. Goods and materials once in the cycle stay in, and additions to the cycle are only allowed if not decreasing the absolute stock, otherwise the system evaluated will change.
Decreasing the stock is measured towards the renewal time during fulfilling their function. Or possibly longer to create space for new additions (step3).
And "There is no such thing as waste, its only a waste not using it" is the basis for the re-input part of the closed cycle. Its only about resources in a different composition and place. The Dutch building materials decree, has already eliminated the difference between primary and secondary materials, they have to meet the same standards.
Ad2
Reducing the volume in the cycle has everything to do with reduction of total consumption, and not in the least by shifting from materialized provisions of function to a serviced way of providing functions. (think of car sharing, greenwheels etc)
Ad3
Delaying the speed of goods going through the cycle is of course obvious, this provides more time for restoring the original stock, and maintain or enlarge potential . This is also an argument against producing for a certain service life, under the assumption that trends, fashion etc will demand for new products. The product should provide the longest lifetime possible, and in any case of the parts it is made of. This is the Cradle to Cradle part of the cycle's products.
Ad 4
Reduction of energy to drive that cycle is in the same line as general energy policy. Any material will consume energy before its fit to use, or re-use, and this amount should be reduced. This can be established by reducing the volume of the cycle, the distances involved for products in the cycle steps, by industry improvements, and by changing towards renewable energy, in the same way ( time, volume, stock) as for mass in general. In fact its resource reduction for driving the cycle itself, with energy as a specific form of mass.
In Cradle to Cradle (McDonaugh et al 200x) two cycles are proposed to create: one technological, that should be forever, and one nutrient cycle, in which nutrients are given back to nature at some point, to restore the earth system. However this implies that new virgin resources have to be added to the cycle to maintain the same basis. Which is not very effective for construction, where for instance a wooden beam should serve as long as possible. In the end it will return to earth again, when downscaled a few times, and incinerated for energy , with ashes are used or spread again. But this moment should be delayed as long as possible, possibly by in between upscaling, and therefore be part of a and the same cycle.
The actions to create this closed cycle approach are listed in table 1.
The table is general applicable, however through the nature of my work more detailed for the building sector. Or better, the "providing shelter sector" .
The actions are categorized under building related, (building-)stock related, and general.
Table 1
