Looking back over our journey through the history of humankind’s changing role in the community of life, and our glimpses of particular places and periods of time, we may ask what this historical experience offers in understanding what is happening today. What has really been going on, ecologically speaking, during human history? Humans have related in multiple ways to the Earth’s systems; some of these ways promise a sustainable balance with them, while others are destructive. Experience could teach us which are which.
Can the processes we see happening now continue indefinitely? No, since activities that are immensely destructive of the biophysical environment now dominate human efforts. The results, mentioned many times in the preceding pages, form an ominous litany: polluted water and air, acidic precipitation, diminution of the ozone layer, global warming, the spread of radioactive materials, deforestation, loss of biodiversity, extinction of species, soil erosion, overpopulation. As we have seen, similar destructive phases, if not as intense, have occurred in the past in more limited areas of the Earth, and they have ended with degraded ecosystems that were unable to support either the continued growth of human numbers or the level of culture and economic prosperity that then existed. The examples are numerous: the Mesopotamian experience with soil salinity, the southern lowland Mayan experience with deforestation, the experience of the Romans with depletion of forests, soils, and wildlife in the Mediterranean basin, and others.
Have humans achieved sustainable lifestyles in particular times and places? If so, it would appear that human exploitation of ecosystems can be kept within limits, and that with appropriate attitudes and actions both human societies and the entire community of life may be spared destruction. It seems the answer is yes; the indigenous agriculture of the Hopis and the Balinese, the ancient Egyptians’ beneficial interaction with the Nile, and the promise of the Inca economy, albeit truncated in each case, give reason for positive evaluations. Even though these are older, agriculture-based economies, the success of such peoples over various periods is worth study for possible applications. It is harder to find examples in the modern industrial world because change is rapid and time has been short; the returns are not yet in, so to speak. But the northernmost European countries, with near stable populations, a relatively clean environment, and a high levels of public and governmental environmental concern within the context of reliable democracy, may serve as potential models.
Some of the trends visible in recent history resist the dominant pattern of destruction noted above. One of these is increasing knowledge of the workings of natural systems, and the advances of the science of ecology. This is not simply growth in information, but hardwon understanding. If our society is to be in a sustainable dynamic relationship with that which supports it, every decision we make must be arrived at in respect to the ecosystem.