Another agricultural trend of growing concern is the increased nutrient content of coastal waters resulting from fertilizer runoff in agricultural regions. Augmented by urban sewage discharge in some situations, this results in huge algal blooms, which, as they die and decay, deplete the oxygen content in the water, leading to the death of the fish.

Nations are in effect ceding portions of their sovereignty to the international community and beginning to create a new system of international environmental governance.

Another agricultural trend of growing concern is the increased nutrient content of coastal waters resulting from fertilizer runoff in agricultural regions. Augmented by urban sewage discharge in some situations, this results in huge algal blooms, which, as they die and decay, deplete the oxygen content in the water, leading to the death of the fish.

The transition from coal, oil, and gas to wind, solar, and geothermal energy is well under way. In the old economy, energy was produced by burning something - oil, coal, or natural gas - leading to the carbon emissions that have come to define our economy. The new energy economy harnesses the energy in wind, the energy coming from the sun, and heat from within the earth itself.

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

Saving Greenland is both a metaphor and a precondition for saving civilization. If its ice sheet melts, sea levels will rise 23 feet. Hundreds of coastal cities will be abandoned. The rice growing river deltas of Asia will be under water. There will be hundreds of millions of rising-sea refuges. The word that comes to mind is chaos. If we cannot mobilize to save the Greenland ice sheet; we probably cannot save civilization as we know it.

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.