1687.pdf

GUMBO was designed to provide
a fl exible computational
platform for the simulation of
alternative global pasts and
futures envisioned by diverse
end-users. GUMBO limits historical
parameter values to those
that produce historical behaviour
consistent with historical data. It
then allows one to make explicit
assumptions about future parameter
or policy changes, or to
determine what assumptions are
required to achieve a specifi c
future. It is then possible to
assess how plausible those
assumptions are, and to consider
policy options that might make
the assumptions required for a
desired future more likely to
occur. It is useful to allow the
user to change specifi ed parameters
within GUMBO and generate
alternative images of the
future in order to both stimulate
dialogue about global change
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Figure 1. GUMBO; The Global Unifi ed Model of the BiOsphere
and generate a more complete
understanding of the complex
interrelationships among social
and economic factors, ecosystem
services, and the biophysical
Earth System. This dialogue is
needed in order to achieve sustainable
development on a global
scale.
In GUMBO, three issues are
considered that may provide new
insights into the Earth System:
1. Ecosystem services explicitly
affect both economic
production and social welfare.
This allows the model
to calculate dynamically
changing physical quantities
and values for ecosystem
services based on their
marginal contributions relative
to other inputs into
the production and welfare
functions.
2. Both ecological and socioeconomic
changes are
endogenous, so we emphasise
interactions and feedbacks
between the two,
rather than limiting either
ecological or socioeconomic
change to exogenously
determined scenarios (c.f,
[2-4]).
3. We include natural capital,
human capital, social capital
and built capital as state
variables and factors of
production, and distinguish
between material factors
and factors of transformation
(material cause and effi -
cient cause, in Aristotelian
terms). This allows limited
substitution between factors
of production at the margin,
but also imposes strong sustainability
constraints on the
system as a whole.