A large body of literature has developed over the past several years on the economics of happiness. One of the key insights of this literature is that beyond a subsistence level of income, relative income is often more important than absolute income to individual well-being. This is true for both comparisons against a reference group, e.g., across a community or country, as well as comparisons for the same individual over time. Another key insight is that changes in income have only transitory effects on well-being.

In 1958, as part of the science education efforts for the International Geophysical Year, a National Academy of Sciences (NAS) publication, Planet Earth: Mystery With 100, Clues, explained that the natural greenhouse effect was being altered.

Examining individual consumption behavior is pertinent to both the current sources of greenhouse gas (GHG) emissions as well as policies designed to limit these emissions. A wide variety of private household decisions generate externalities that have environmental ramifications both now and in the future. Because household decisions may not be fully aligned with broader societal objectives, improving these decisions could foster society's environmental policy objectives.

In the United States, the residential sector accounts for a significant proportion of the greenhouse gas (GHG) emissions produced each year. Sixty-two percent of vehicle emissions come from passenger cars and light-duty trucks, and one-quarter of non-transportation emissions come from residential sources.

The price of grain is now directly tied to the price of oil. We used to have a grain economy and a fuel economy. But now they're beginning to fuse.

I. Supersizing Trends

During the climate change meetings at the Group of Eight (G-8) Summit in July 2008, President George W. Bush summarized the results of the meeting:

The G-8 expressed our desire to have a--a significant reduction in greenhouse gases by 2050. We [the United States] made it clear and the other nations agreed that they must also participate in an ambitious goal, with interim goals and interim plans to enable the world to successfully address climate change. And we made progress, significant progress, toward a comprehensive approach.

Before 2006, some American evangelicals were indifferent about environmental issues, but many were hostile, denouncing "environmental wackos" and the quasi-religious language of the environmental movement. But the release of a startlingly pro-environmental document called Climate Change: An Evangelical Call to Action two years ago signaled the sudden emergence of a sizeable group of evangelical environmentalists.

Reducing household energy use is an important policy objective for governments and utilities as it comprises a low-cost and low environmental impact alternative to expanding energy supply. There are two broad approaches to reducing household energy use: (1) conservation; and (2) efficiency. Conservation reduces the level of demand for a useful service, and is often associated with a loss of amenity, e.g., turning the thermostat down in winter.

Editors' Summary: