For about 4 million years, human beings were hunter-gatherers. We couldn’t put much pressure on our habitat because as soon as the food or water ran a little short, we moved on. If we couldn’t find food freely available, our numbers dwindled. Then, just 10,000 years ago, humanity got its agricultural thing going. By some estimates, when agriculture was introduced human population growth rates increased 100-fold. In a geographic area that previously spawned 100 new human inhabitants each year, suddenly there were 10,000 new people every year. The land could accommodate the growth, thanks to agriculture. Studies of population densities from the time indicate that the “carrying capacity” of human habitats also increased by a factor of 100 when agriculture was introduced.
In one way it was a better deal for nature, too. By using a comparatively small space intensively, human beings left more of nature untouched. An agricultural society uses less property, per capita, than a hunting-and-gathering society. A lot less. But as we became attached to particular locales and as our populations, thanks to agriculture, became less vulnerable to variations in the weather, we also invented overgrazing, deforestation, erosion and topsoil depletion.
Desertification is the oldest type of long-term environmental damage we can trace directly to human activities. Biologists and archaeologists read the signs of land abuse and growing deserts in the Middle East dating back to the very earliest years of agriculture 12,000 years ago during the Neolithic Revolution. Almost as soon as humans domesticated their first goats and sheep, it appears we began overgrazing our lands.
Many farms of the 21st Century are, comparatively speaking, biological wastelands. Plowed, fertilized and cultivated from property-line to property-line, much of the world’s most productive land has been stripped of its wildlife. Walk through a soybean field anywhere in the Midwest, then take the same sort of stroll through a native prairie in the same region, if you can find one. The contrast is shocking. The prairie, especially the “tallgrass” prairie, is among the world’s most fecund environments. Hundreds of species thrive in a thick carpet of plants growing unbelievably fast. In three months I have watched a particularly lush acre of my undisturbed pasture grow five tons of grass. One acre, three months, five tons. No artificial fertilizer or irrigation. And Nature has designed the prairie to accomplish varying versions of this miracle every summer, year in and year out, for as long as the rain falls and the sun shines.