The ecological metaphor has its genesis in the observation that natural and industrial systems have certain features in common. Consider three:
1. Both the natural and the industrial systems transform resources— materials and energy—that of nature through growth, that of industry through manufacture. The plant kingdom captures energy from the sun, carbon dioxide from the atmosphere, and minerals from the Earth to create carbohydrates; the animal kingdom derives its energy and essential minerals from those of plants or from each other. The industrial system, by contrast, acquires most of its energy from fossil fuels and its raw materials from those that occur naturally in the Earth’s crust, in the oceans, and in the natural world.
2. Both systems generate waste—the natural system through metabolism and death, the industrial system through the emissions of manufacture and through the obsolescence and finite life of the products it produces. The difference is that the waste of nature is recycled with 100% efficiency, allowing a steady state, drawing on renewable energy (sunlight) to do so. The waste of industry is recycled much less effectively, doing so with nonrenewable energy (fossil fuels).
3. Both the natural and the industrial systems exist within the ecosphere, which provides the raw materials and other primary resources, acts as a reservoir for waste, absorbing and, in nature, recycling it, and providing the essential environment for life, meaning fresh water, a breathable atmosphere, protection from UV radiation, and more. The natural system manages, for long periods, to live in balance with the ecosphere. Our present industrial system, it appears, does not. Are there lessons to be learned about managing industrial systems from the balances that have evolved in nature? Can nature give guidance or at least provide an ideal?
The most important elements in living things are carbon, nitrogen, hydrogen, and oxygen; they make up the carbohydrates, fats, and proteins on which life depends. The only way that plants and animals can continue to take in and use nutrients containing these elements is if they are constantly recycled around the ecosystem for reuse. The most important of these circular paths are the carbon cycle, the nitrogen cycle, and the hydrological (water) cycle. Subsystems have evolved that provide the links in the cycles and do so at rates that match those of the subsystems with which they interface. Figure 10.2 is a sketch of one of these, the carbon cycle. Carbon dioxide in the atmosphere is captured by green plants and algae on land and by phytoplankton and other members of the aquatic biomass in water. Fungal and bacterial action enables decomposition of plants and animals when they die, returning much of the carbon to the atmosphere but also sequestering some as carbon-rich deposits (peat, gas, oil, coal) and, in the oceans, as limestone, CaCO3.
The elements important for manmade products, by contrast, are far more numerous; they include most of the periodic table. Carbon is one. As in nature, the products that use it (in the form of coal, oil, or gas) return most of it to the atmosphere, but the natural subsystems that recycle carbon have not evolved to provide matching rates (Figure 10.3). The problem is more acute with other elements—the heavy metals, for example—where no natural subsystems exist to provide recycling. When rates don’t match, stuff piles up somewhere. Focusing on carbon again, this imbalance is evident in the steep rise of atmospheric carbon since 1850 (Figure 3.8). Burning fossil fuels and calcining limestone for cement generate large masses of CO2. Reduced forestation, rising water temperatures,
The carbon cycle in nature, showing some of the many subsystems that have
evolved to transform resources. They do so in such a way as to give balance and long-term stability.
The additional burden placed on the carbon cycle by large-scale industrialization.
The subsystems that evolved to balance the cycle still exist but work at rates that do not begin to replace the resources that are consumed.
and soil contamination reduce the rate of absorption on the part of the biosubsystems.
What do we learn? Figure 10.4 summarizes the differences between the two systems—the one, sustainable over long periods of time; the other, in its present form, not so. Of the many aspects of sustainability, two relate directly to materials. The first is the lack of appropriate subsystems to close many of the recycling paths, and second is that, where subsystems exist, there is an imbalance of rates. At base, however, there is a more fundamental difference: it has to do with metrics of well-being. That of nature is achieving balance, such that the system is in equilibrium. That of the industrial system is growth: an economy that is growing is healthy, one that is static is sick. Economic growth, our metric of the well-being of a business, nations, or society as a whole, carries with it the need for ever – increasing consumption of materials and energy (Chapter 2) and of waste creation (Chapter 4). The present system of industrial production has been likened to an organism that ingests resources, produces goods, and expels waste. The characteristic that makes this organism devastating for the environment is its insatiable appetite; the faster it ingests resources, the greater is the output of products and the better is its health, even though this does not coincide with that of the biosphere. The comparison, then, highlights the ideal: an industrial system in which the consumption of materials and energy and the production of waste are minimized, and the discarded material from one process becomes the raw material for another, ultimately closing the loop.
The comparison of the natural and the industrial ecosystems.
Are natural systems really at equilibrium? Over long periods of time, yes. The forces for change are minimal, allowing optimization at an ever more refined and detailed level. It leads to an interdependence on a scale that even now we do not fully grasp but which manmade activities too frequently disturb. However, on a geological time scale, there have been disruptions of the natural system on grand scales. Most derived from sudden climate change. Are there lessons in the way the natural system then adapted? When dinosaurs (reptiles) succumbed to one of these, some small, furry mammal—a mouse, perhaps—because of habitat, metabolism, diet— saw its opportunity, survived, evolved, and multiplied. Where, in the technical world of today, are the post-industrial mice, and what do they look like?
We don’t know. But there is a message here. The life raft—the Noah’s Ark, so to speak, of the natural world, allowing continuity in times of change—lies in its diversity: new mice, ready and waiting. The nuclei of the new system existed in the old and could emerge and grow when circumstances change. Without knowing what we will need to do, can we create a society, a scientific society, with sufficient diversity that, painful though change will be, the nuclei of the next phase preexist in it?