p.2 The limits are similarly diverse - they may be imposed by a fixed amount of space; by limited time;
by constraints inherent in physical, biological, political, psychological, or other features of a system.
p.25 Whenever a system stock is embedded in a positive feedback loop, that stock has the potential
to grow exponentially. That doesn't mean it will grow exponentially; it does, however, have the capacity to do so if it is
freed from constraints. Growth can be constrained by many things
p.49 How stressed is the physical system that supports the human population, the economy, and all other
species? How resilient is that support system to what kinds and quantities of stress? How much is too much?
p.63 But figure 3-4 also shows how many adaptive responses there could be, depending on the resilience
of the resource base and the technical and social flexibility of humankind.
p.66 Water resource constraints and water degradation are weakening one of the resource bases on which human
society is built.
p.134 The cost of coping with these problems raises the development cost of the land.
p.147-148 As it operates within a finite environment, the expanding economy will begin to create stresses.
These stresses begin to grow long before society arrives at the point where further growth is totally impossible. In response
to stresses, the environment begins to send signals to the economy. These signals take many forms... natural systems
of the earth heal themselves more slowly under the assault from pollution. These rising real costs do not necessarily show
up immediately... the signals and pressures function as important parts of negative feedback loops. They seek to bring the
economy into alignment with the constraints of the surrounding system. That is, they seek to stop the growth of the ecological
footprint that is stressing the planet's sources and sinks.
p.167 It is difficult to quantify erosive mechanisms of any sort, because erosion is a whole-system phenomenon
having to do with interactions among multiple forces. It appears only at times of stress. By the time it becomes obvious,
it isn't easily stopped. But despite these uncertainties, we can say confidently that any system containing a latent erosion
process also contains the possibility of collapse, if it is overstressed.
p.175 Erosion is a stress that multiplies itself if it is not quickly remedied.
p.176-177 By definition, overshoot is a condition in which the delayed signals from the environment are
not yet strong enough to force an end to growth. How, then, can society tell if it is in overshoot? Falling resource stocks
and rising pollution levels are the first clues. Here are some other symptoms: ... Growing chaos in natural systems, with
"natural" disasters more frequent and more severe because of less resilience in the environmental system.
p.203 The most common criticisms of the original World3 model were that it underestimated the power of technology
and that it did not represent adequately the adaptive resilience of the free market.
p.222 One lesson from the six preceding [computer modeling] runs is that in a complex, finite world, if
you remove or raise one limit and go on growing, you encounter another limit. Especially if the growth is exponential, the
next limit will show up surprisingly soon. There are layers of limits.
p.223 Growth, and especially exponential growth, is so insidious because it shortens the time for effective
action. It loads stress on a system faster and faster, until coping mechanisms that have been adequate with slower rates of
change finally begin to fail.
p.272 Visioning means imagining, at first generally and then with increasing specificity, what you
really want... Visioning means taking off the constraints of "feasibility," of disbelief and past disappointments,
and letting your mind dwell upon its most noble, uplifting, treasured dreams.
Some people, especially young people, engage in visioning with enthusiasm and ease... Vision without
action is useless. But action without vision is directionless and feeble. Vision is absolutely necessary
to guide and motivate.
