If an economy is to sustain progress, it must satisfy the basic principles of ecology. If it does not, it will decline and eventually collapse. There is no middle ground

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.

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.

If an economy is to sustain progress, it must satisfy the basic principles of ecology. If it does not, it will decline and eventually collapse. There is no middle ground

Each summer, for example, nitrogen and phosphate washing from farmlands in the Mississippi Valley enter the Gulf of Mexico, creating a massive algal bloom covering some 16,000 square kilometers. As the blooms die off, this area-roughly the size of New Jersey-is so deprived of oxygen that no fish survive.

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.

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