Growing a new climate.

• Author: Robertson, Henry

Concocting plans for a carbon-neutral future is the latest growth industry. In these plans we will continue to drive as much as we want and consume as much as we can afford to. It will be business as usual with a different fuel mix--renewable energy instead of fossil fuels. The planners assume, explicitly or implicitly, that the economy will continue to grow. The problem, says one of such planners, Gar Lipow, isn't GDP growth; it's waste. [1] In other words, we can sustainably grow the economy if we do it efficiently. But swearing off fossil fuels will not by itself usher in the sustainable future. We have to let go of growth.

Yes, we must be as efficient as possible if renewables are to replace fossil fuels, but efficiency must be divorced from growth or growth will swallow up the gains made by eliminating waste. We certainly should decarbonize energy. A one-time investment in renewable generating plants and transmission lines is far better than burning a billion tons of coal every year, as the US currently does. But the goal must be a steady-state economy.

Insidious curve

Economic growth is exponential--it's growth compounded on the growth that went before. If I earn simple interest of 10% on a principal of $100, I earn $10 a year. If the interest is compounded (added to the principal) I earn $10 the first year, $11 the second, and so on. It doesn't look like something that would set a speculator salivating, but exponential growth is insidious.

A parable tells of a sly merchant who asked his king to pay him in mere grains of wheat on a chessboard--one grain on the first square, two on the second, doubling with each square. On the 64th square the number of grains would be [2.sup.63]--over 1,000 times the world's wheat crop on that square alone.

Exponential growth takes the form of the "Typical exponential curve:"

No matter how slow the rate of growth, the curve eventually shoots toward infinity until constraints force it to flatten out. The constraints on growth are now obvious to those willing to see--global warming, ocean acidification, peak oil, mining of groundwater, deforestation, exhaustion of soil, pervasive pollution, overexploitation of fisheries to the point of extinction and, underlying all these, overpopulation.

Lipow talks about a world GDP in 2050 of 1.5 times the present per capita GDP of the US for a population of 9.5 billion. This is not exponential growth, just additive growth with an arbitrary cutoff date.

Suppose China's economy resumes growing at 10% a year, a rate it sustained from 1990-2004. It would double in size every seven years. By mid-century it would double six times, to [2.sup.5] = 32 times what it is now. Such is the logic of economic...