Conservation and Sustainable Use of the Biosphere - WBGU

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Conservation and Sustainable Use of the Biosphere - WBGU

Life in the Earth System: BIOSPHERE I F 1.1

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a level to which the inhabitants of Lhasa (Tibet) are

accustomed, but which would cause a North American

difficulties. Tiredness and lethargy were the consequence.

The question now was, what happened to

all the oxygen? (Even in BIOSPHERE I the oxygen

cycle is not fully understood; Kelly, 1994). Overall,

BIOSPHERE II seemed to be collapsing. Since the

insects as pollen carriers were not surviving, important

crop plants were dying. 19 of the 25 species of

vertebrates became extinct. The clear winners were

the cockroaches and busily multiplying ants. The

desert became steppe, the ocean dead sea and the

eight human inhabitants lost a great deal of weight.

The conclusion of this experiment is that currently,

no one knows how to construct stable, life-sustaining

systems that are characteristic of the natural

terrestrial ecosystem. Salt water aquarists are familiar

with the problem. Even in that mini biosphere it

can take months to form stable microbial food chains

and harmonize the communities. For a long time

there is imbalance, fish or plants die, putrid gases

form. The system meanders until apparently all of a

sudden and without cause it ‘locks in’ and is stable.

There is no recipe so far of how to achieve this more

quickly or possibly in a more controlled manner. Just

like the aquariums there is only one thing to do: do

nothing and wait. Possibly, this is a trivial insight, but

one which may be transferable. In BIOSPHERE II they

did exactly the opposite. When things became critical,

the attempt was made to control events, for

example, by lowering the temperature (in order to

store carbon dioxide in sea water) or changing the

pH values. All possible environmental levels were

tinkered with to stabilize the system and possibly it

was precisely those actions that prevented stabilization.

Whatever the case, in the wake of that experiment,

the ability of life in BIOSPHERE I to control its environmental

conditions for its own well-being can be

seen in a completely new light. The key to understanding

‘pre-stabilized harmony’ in the Earth’s system

and the failure of BIOSPHERE II may well lie in

more recent research on the Gaia hypothesis.

F 1.3

A closer look at BIOSPHERE I

The essential difference between BIOSPHERES I and

II is certainly not the composition of the two systems.

The structure of the regulatory systems seems much

more significant. In the case of BIOSPHERE II the

adjustments of the environmental levels took place

via simple regulatory systems. The principle of variance

compensation of individual variables as a rule

only takes into consideration to a small degree linkages

between the correcting variable. In light of the

large number of regulatory levels and the associated

degrees of tolerance, however, such a system is

extremely difficult to stabilize. Particularly, if no

detailed climate or more general environmental

model is available that would allow for a short-term

prognosis, intervention on the principle of trial and

error can have disruption rather than balance as the

outcome and lead to fatal consequences.

F 1.3.1

Homeostasis as a fundamental regulatory

principle

In our natural environment, however, homeostatic

principles appear to dominate. Homeostasis means in

this instance that a system controls itself to achieve

balance and remains within a limited stable area

(Rampino, 1993). Minimal disruptions do not change

the character of the system because they can be neutralized.

This observation demonstrates parallels to

physiological systems: temperature regulation in the

human organism as a physiological system demonstrates

the phenomenon of homeostasis. There is no

objective target temperature, rather the participating

processes are linked to one another via negative

feedbacks with the result that they more or less automatically

establish a stable balance. A simple model

by Watson and Lovelock (1983) aims to illustrate this

effect. Picture a planet that is covered exclusively in

black and white daisies. Their growth rate reduces as

temperatures rise. At a given level of solar radiation

the black daisies effect a higher temperature than the

white ones as a result of their colour. If the rays

lessen, however, the probability of the black daisies

reproducing falls as the temperature rises. The more

reflective white daisies are therefore more competitive

and increase. The overall temperature of the

planet remains more or less constant. The relationship

between black and white daisies may be said to

adapt in a self-organized manner to the increased

radiation levels and regulates the disruption into

non-existence. But if the planet were just an uninhabited

lump of soil, it would warm up as the sun

warms up. The competition between black and white

daisies in the form of a Darwinian selection process

therefore results for the individual in the possibility

of controlling its environment together with other

individuals. From this fundamental idea of ‘Daisy

World’ far more complex and realistic models may be

formed which show the homeostatic capacities and

improve them (von Bloh et al, 1997). Self-regulation

is therefore an extremely robust principle.

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