The Earth Systems Project
Making Global Models Accessible
Global models such as World3, IFs, and Globus are used in many nations'
planning and policy making. They discuss, for example, transition to a
sustainable demographic and economic future, energy and materials supply,
national strategy, and the stability of international political relations.
By explicitly incorporating interrelationships known and under investigation
by scientists, they provide a quantitative backing for qualitative work
by demographers, economists, environmentalists, political scientists, and
others. They allow scientists to investigate possible complex interrelationships
that would not be evident to those working within a single discipline,
since systems of global development and change concern many academic disciplines.
Traditionally global models have been difficult to find and to use.
The Earth Systems Project is an attempt to create accessible, understandable
versions of important global models. The project was begun in 1989 and
continues to a limited degree today. Information and programs are
available for two models. The information is accessible through this Web
site. The programs are available for Macintosh computers. For information
on other global models, see Peter
Brecke's global models web site, Gottfried
Mayer-Kress's global models site, and Barry
Hughes' IFs web site.
Beyond the Limits
The Beyond the Limits program uses the "World3" computer model of
the book Beyond the Limits. The model and the book investigate possible
ways in which world population and industry might approach their carrying
capacities, and the likely impacts of possible global policies. The program
lets you use the model, change the model, and see the consequences of your
changes. The model can help you think about possible world futures, and
help you investigate possible effects of global policies. Background information
in the program describes how to use the model, diagrams of the model, criticisms
of the model, how to get information about it and other global models,
and how to learn with it.
Go to Beyond the Limits.
The Gaia Hypothesis & Daisyworld
The Gaia Hypothesis and Daisyworld program lets you use the "Daisyworld"
model, which illustrates the Gaia hypothesis that life on Earth affects
Earth's global environment. The program includes an introduction; detailed
information about the Gaia hypothesis, the model, and criticisms of the
model; a simple animated version of the model; and a more detailed version
of the model. You can change the model and see the consequences of your
changes. Classroom exercises are included.
If you have a Macintosh computer with HyperCard (or the HyperCard Player)
2.1 or newer, you can download The
Gaia Hypothesis and Daisyworld (406K) along with its accompanying information.
The file you download is in bin-hexed form, so once it is on your computer,
you may need to "decode binhex" in a program such as CompactPro or StuffIt.
You will be left with a file whose name ends in ".SEA". Just double-click
on the file and the program will be ready to use. You may have trouble
receiving the file with some web-browsers; if so, you can request a copy
by email at the address below.
References for The Gaia Hypothesis & Daisyworld:
Watson, Andrew J. and J. E. Lovelock. "Biological homeostasis of the global environment: the parable of Daisyworld,"
35B, 1983, pp. 284-289.
Lovelock, James E. The Ages of Gaia: A Biography of Our Living Earth.
The Earth Systems Project is spearheaded by Kenneth
L. Simons and Peter J. Poole. Assisting with software development were
Michelle Bell, Jennifer Newbury, Kevin Rathbun, Erik Trimble, and Aaron
Young. Many people deserve a lot of thanks for their help with the project,
involving all aspects including administration, encouragement, feedback,
ideas, and testing. Thanks to Hayward Alker, Gerald Barney, Ann Bostrum,
Vincent Cate, Sallie Chisholm, Nazli Choucri, Pål Davidson, Joseph
Ferreira, Tom Fiddeman, Baruch Fischhoff, Jay Forrester, Allan Heydon,
David Kreutzer, Dennis Meadows, John Miller, Marvin Miller, Edward Moriarty,
Earll Murman, George Rathjens, Diana Shannon, Jane Sherwin, John Sterman,
Ryo Tatsukawa, David White, and David Wood. More information on these people's
role is available in the software. Financial supporters included Dennis
Meadows and MIT's Departments of Civil Engineering, Political Science,
and Urban Studies and Planning; School of Engineering; Center for Global
Change Science; and Undergraduate Research Opportunities Program. Computers
were provided by MIT's Department of Urban Studies and Planning and the
MIT System Dynamics Group. For work by K. Simons: This material is based
upon work supported under a National Science Foundation Graduate Fellowship.
Any opinions, findings, conclusions or recommendations expressed in this
publication are those of the author and do not necessarily reflect the
views of the National Science Foundation. Any errors or omissions are the
responsibility of K. Simons.
A Japanese-language an old version of the Daisyworld program has been
developed, and interest has been expressed in creating Japanese and French
versions of both programs, but I unfortunately do not have information
as to whether these projects have gotten anywhere. If you have more recent
information, please contact Ken Simons.
Copyright ©1992-1997 by Kenneth L. Simons.
Revised 31 May 2001