Sustainability Cradle 4

8/14/2019 Sustainability Cradle 4

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Framework for Sustainability


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In 1989, a framework for sustainability called The

Natural Step emerged from Sweden through the

efforts of Dr. Karl-Henrik Robrt, a leading Swedish

oncologist.


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This framework provides a set of four systemconditions that define a sustainable society based

on the laws of thermodynamics and natural cycles.

The Natural Step System Conditions consider the

Earth as a closed system for materials and as an

open system for energy that sustains life through a

complex interactive network of material cycles that

uses solar energy to counteract the tendency ofmaterials to dissipate and otherwise increase in

entropy.


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For a society to be sustainable, nature must not

be subjected to the following

systematically increasing processes


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1. Extracting concentrations of

substances from the Earths crust.

This condition refers to the extraction of minerals

and fossil fuels.

Substances that are scarce in nature should be

substituted with those that are more abundant.

Mined materials should be used efficiently and

recycled, and dependence on fossil fuels should besystematically reduced.


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2. Building up concentrations of

human-made compounds in nature

This condition refers to the manufacture of

persistent and unnatural compounds.

Persistent and unnatural compounds should be

replaced with those that are normally abundant

and or that break down completely and easily in

nature.

All substances produced by society should be used

efficiently.


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3. Utilizing renewable resources at rates

faster than they are regenerated and

reducing the productive capacity of nature.

This condition refers to the use of natural

resources.

Resources should be drawn only from well

managed ecosystems, systematically pursuing the

most productive and sustainable uses both of those

resources and land, and exercising caution in allkinds of modification of nature.


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4. People are able to meet their

needs worldwide

This condition means using all of our resources

efficiently, effectively, fairly and responsibly so that

the needs of all people, including the future needsof people who are not yet born, stand the best

chance of being met.


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Materials flow in a closed

system comprised of two

loops.

The outer loop representsthe cycling of materials

within earthsecosystems.

The inner loop represents

cycling within theindustrial/economic

system.


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Arrow 1 represents the

extraction of natural

resources for use in the

industrial/economicsystem.

In a sustainable society, the

rate of natural resource

extraction equals the rateof regeneration.


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Arrows 2 and 3 represent

the extraction and

resettling of materials from

theearths

crust, primarilyfossil fuel and mined

materials.

In a sustainable society,

material extraction from

the earths crust will be

displaced by the use of

recycled and recyclable

materials


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Arrows 4 and 5 represent

substances that flow from the

industrial/economic system to

the greater ecosystem.

Substances that assimilatequickly without harm are

represented by Arrow 4.

Arrow 5 represents substances

that are toxic, persistent,

bioaccumulative, or otherwisecause harm to humans or the

environment. In a sustainable

society, Arrow 5 will disappear.

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Sustainability Cradle 4