In the face of the grim data and the stubbornness of the problem, I know it's tempting to tune out, give up, and resign oneself to the way things are. One friend told me that reading this kind of information actually makes her want to go shopping because it is such a relief to be in a situation where your biggest concern is if your shoes match your purse. People everywhere, but especially the poor, are experiencing crisis fatigue. Heck, there are flu pandemics, freak storms, unemployment, and foreclosures to worry about. The thing is, we don't have a choice. In the words of Joseph Guth, a lawyer, biochemist, and the legal director of the Science and Environmental Health Network: "Nothing is more important to human beings than an ecologically functioning, life sustaining biosphere on the Earth. It is the only habitable place we know of in a forbidding universe. We all depend on it to live and we are compelled to share it; it is our only home . . . The Earth's biosphere seems almost magically suited to human beings and indeed it is, for we evolved through eons of intimate immersion within it. We cannot live long or well without a functioning biosphere, and so it is worth everything we have."13
While the challenges are interconnected and system-wide, the responses are often partial, focused on just one area—like improving technologies, restricting population growth, or curbing the consumption of resources.
Proponents of techno-fixes, for example, believe that cleaner, greener, and more innovative technologies will make our industrial and economic activity so efficient with energy and other resources that our problems can be solved this way. They point out that there's less and less environmental destruction per unit of activity (per dollar of gross domestic product or per ton of product made). They're not wrong. Many technologies are getting more efficient. But that progress is canceled out by the fact that—at least adverse environmental impact is still increasing, regardless of more efficient technology.
The reason that green technologies will not save us is that they are only part of the picture. Our collective impact on the planet—how fast we reach the limits of the earth's capacity to sustain us—results from a combination of how many of us there are, what kind of technologies we use, and how much we're consuming. In technical terms, this is often represented by the I=PAT equation, which was conceived in the 1970s during debates between the camp that believed that technologies and consumption patterns were the main driver of environmental destruction and the opposing camp, which argued that increasing population was at fault. The I=PAT equation— in which I is impact, P is population, A is affluence (aka consumption), and T is the technologies used—recognizes the interplay between all these factors.
The equation helps us see how these factors can interact; generally we can decrease our impact by reducing population and/or improving technologies. Generally, but not always: not if other variables cancel out the change. Fewer people consuming much more Stuff, for example, still increases impact. More people consuming less Stuff could decrease impact. There are many ways these variables can relate to one another.