Use Energy, Get Rich and Save the Planet

… Those projections make it easy to assume that affluence and technology inflict more harm on the environment. But while pollution can increase when a country starts industrializing, as people get wealthier they can afford cleaner water and air. They start using sources of energy that are less carbon-intensive — and not just because they’re worried about global warming. The process of “decarbonization” started long before Al Gore was born.

The old wealth-is-bad IPAT theory may have made intuitive sense, but it didn’t jibe with the data that has been analyzed since that first Earth Day. By the 1990s, researchers realized that graphs of environmental impact didn’t produce a simple upward-sloping line as countries got richer. The line more often rose, flattened out and then reversed so that it sloped downward, forming the shape of a dome or an inverted U — what’s called a Kuznets curve. (See nytimes.com/tierneylab for an example.)

In dozens of studies, researchers identified Kuznets curves for a variety of environmental problems. There are exceptions to the trend, especially in countries with inept governments and poor systems of property rights, but in general, richer is eventually greener. As incomes go up, people often focus first on cleaning up their drinking water, and then later on air pollutants like sulfur dioxide.

As their wealth grows, people consume more energy, but they move to more efficient and cleaner sources — from wood to coal and oil, and then to natural gas and nuclear power, progressively emitting less carbon per unit of energy. This global decarbonization trend has been proceeding at a remarkably steady rate since 1850, according to Jesse Ausubel of Rockefeller University and Paul Waggoner of the Connecticut Agricultural Experiment Station.

“Once you have lots of high-rises filled with computers operating all the time, the energy delivered has to be very clean and compact,” said Mr. Ausubel, the director of the Program for the Human Environment at Rockefeller. “The long-term trend is toward natural gas and nuclear power, or conceivably solar power. If the energy system is left to its own devices, most of the carbon will be out of it by 2060 or 2070.” …