Environmental Engineering Reference
In-Depth Information
We dig up substances from the Earth's crust - various minerals, oil and gas, etc. - and use
them in products and processes, and then release them into nature. We do this at a faster
pace than nature re-deposits these substances back into the Earth's crust. And as a result,
they accumulate in natural systems and eventually cause problems
if their concentrations
get too high
. The first principle does not say a sustainable society requires that we not use
any material at all from the Earth's crust. It does not say that there is no mining in a sustain-
able society. It does say that whatever materials we use from the Earth's crust,
we must use
them in a way that prevents their accumulation in natural systems
. This means using them
efficiently, and using them in products and processes where they can be recaptured and
reused, rather than released into the atmosphere, water or soil
[10]
.
There are thresholds beyond which living organisms and ecosystems are
adversely affected by increases in substances from the earth's crust. Problems may
include an increase in greenhouse gases leading to global warming, contamination
of surface and ground water, and metal toxicity which can cause functional distur-
bances both in humans and animals.
Sustainability Principle #2
: IN A SUSTAINABLE SOCIETY, NATURE IS NOT
SUBJECT TO SYSTEMATICALLY INCREASING CONCENTRATIONS OF
SUBSTANCES PRODUCED BY SOCIETY.
Humans combine molecules into new, more complex molecules that nature has never seen
before, and use these complex molecules in products and processes that eventually allow
them to be released into natural systems. Because nature has never seen them before, it
cannot break them down within its regular cycles, and so they accumulate. Note that the
second principle does not say that there are no chemicals in a sustainable society. Rather,
it says that a sustainable society will require that we be efficient in our use of them, and
most importantly that we use them in ways that allow them to be captured and re-used,
rather than dispersed into nature where they can accumulate
[10]
.
Synthetic organic compounds such as DDT and PCBs can remain in the environ-
ment for many years, bio accumulate in organisms and cause harmful effects in
many species. Freon and other ozone depleting compounds may increase the risk
of cancer due to added UV radiation in the troposphere. The solution includes
gradual substitution of certain persistent and man-made compounds with ones that
are normally abundant or break down more easily in nature, and use all substances
produced by society in an efficient manner.
Sustainability Principle #3
: IN A SUSTAINABLE SOCIETY, NATURE IS NOT
SUBJECT TO SYSTEMATICAL DEGRADATION BY PHYSICAL MEANS.
“We physically degrade nature's ability to run natural cycles by encroaching into
natural areas, over-harvesting renewable resources, and eroding nature's ability to
process our waste”
[10]
. Humans must avoid taking more from the biosphere than
can be replenished by natural systems, safeguarding nature's ability to regenerate.
Preserving the integrity of any living system requires that society understands that
what effects one part of a system may ultimately impact the system as a whole. The
downstream effects we witness nowadays - climate change, acid rain, deforesta-
tion, depletion of fish stocks, toxics in toys that accumulate in tissues - can be
traced back to one or more of these three ecological mechanisms. They are all
“downstream” symptoms of more fundamental problems in how our societies are
