Among the environmental trends undermining our future are shrinking forests, expanding deserts, falling water tables, collapsing fisheries, disappearing species, and rising temperatures. The temperature increases bring crop-withering heat waves, more-destructive storms, more-intense droughts, more forest fires, and, of course, ice melting. We are crossing natural thresholds that we cannot see and violating deadlines that we do not recognize.

No civilization has survived the ongoing destruction of its natural support systems. Nor will ours.

Our early 21st century civilization is in trouble. We need not go beyond the world food economy to see this. Over the last few decades we have created a food production bubble-one based on environmental trends that cannot be sustained, including overpumping aquifers, overplowing land, and overloading the atmosphere with carbon dioxide.

The throwaway economy that has been evolving over the last half-century is an aberration, now itself headed for the junk heap of history.

In this era of tightening world food supplies, the ability to grow food is fast becoming a new form of geopolitical leverage, and countries are scrambling to secure their own parochial interests at the expense of the common good.

Today, more than ever, we need political leaders who can see the big picture, who understand the relationship between the economy and its environmental support systems.

We know what we have to do. And we know how to do it. If we fail to convert our self-destructing economy into one that is environmentally sustainable, future generations will be overwhelmed by environmental degradation and social disintegration. Simply stated, if our generation does not turn things around, our children may not have the option of doing so.