““We might be excused our ignorance in this case, because ocean-atmosphere systems are, after all, almost inconceivably complex. Less easy to excuse is our astounding lack of knowledge of much more visible features of our planet’s natural resources and ecology—features that have a direct impact on our well-being. For instance, we know surprisingly little about the state of the planet’s soils. While we have good information for some areas, like the Great Plains of the United States, soil data are sketchy for vast tracts of Africa, Asia, and Latin America, where billions of people depend directly on agriculture for survival. So we can’t accurately judge how badly we’ve degraded these soils through overuse and poor husbandry, though we do have patchy evidence that the damage is severe and getting worse in many places.18 Similarly, despite extensive satellite photography, our estimates of the rate and extent of tropical deforestation are rudimentary. We know even less about the natural ecology and species diversity inside these forests, where biologists presume most animal and plant species live. As a result, credible figures on the number of Earth’s species range from 5 to 30 million.19 And when it comes to broader questions—questions of how all these components of the planet’s ecology fit together; how they interact to produce Earth’s grand cycles of energy, carbon, oxygen, nitrogen, and sulfur; and how we’re perturbing these components and cycles—we find a deep and pervasive lack of knowledge, with unknown unknowns everywhere. Our ignorance, for all practical purposes, knows no bounds.””
