Limits to Growth

Only one-fifth (1.3 billion hectares) of the Earth’s original forest cover remains in large tracts of relatively undisturbed natural forests.42

The consequences for a society that overshoots its water limit depend on whether the society is rich or poor, whether it has neighbors with water excess, and whether it gets along with those neighbors.

One of the best ways to put these good practices into action is to stop subsidizing water. If water price began to incorporate even partially the full financial, social, and environmental cost of delivering that water, wiser use would become automatic.

Pumping up groundwater faster than it can be recharged is unsustainable. The human activities that depend on it will either have to decline to a level that the renewable recharge rate can sustain, or, if the overpumping destroys the aquifer by saltwater infiltration or land subsidence, cease altogether. Initially these responses to water shortages have mainly local effects. But as they are forced on more and more countries, the consequences are felt internationally. The first symptoms of this probably are higher grain prices.

Water resource constraints and water degradation are weakening one of the resource bases on which human society is built.

—UN COMPREHENSIVE ASSESSMENT OF
THE FRESHWATER RESOURCES, 1997

Water is the least substitutable and most essential resource. Its limits constrain other necessary throughputs—food, energy, fish, and wildlife. The extraction of other throughputs—food, minerals, and forest products—can further limit the quantity or quality of water.

It is a well-documented fact that “organic” farmers need not be primitive or retreat to the agricultural methods and low productivity of 100 years ago. Most of them use high-yielding varieties, labor-saving machines, and sophisticated ecological methods of fertilization and pest control. Their yields tend to be equivalent to those of their chemical-using neighbors; their profits tend to be higher.23

Why have we not mentioned the promise of genetically modified crops? Because the jury is still out on this technology—indeed the jury is in deep controversy. It is not clear either that genetic engineering is needed to feed the world or that it is sustainable. People are not hungry because there is too little food to buy; they are hungry because they cannot afford to buy food. Producing greater amounts of high-cost food will not help them. And while genetic engineering might increase yields, there are plenty of still-unrealized opportunities to raise yields without genomic interventions that are both high-tech (therefore inaccessible to the ordinary farmer) and ecologically risky. The rush to biotech crops is already producing troubling ecological, agricultural, and consumer backlashes.26

Unsustainable use of the agricultural resource base is a consequence of many factors, including poverty and desperation, expansion of human settlements, overgrazing and overcropping, ignorance, economic rewards for short-term production rather than long-term stewardship, and managers who understand too little about ecology, especially soil ecosystems

Farming methods that conserve and enhance soils—such as terracing, contour plowing, composting, cover cropping, polyculture, and crop rotation—have been known and used for centuries.