When a caterpillar eats a leaf, then a thrush eats the caterpillar, or when a hawk eats the thrush only 5 to 20% of usable energy is transferred from one level to the next. ... Thus herbivores will account for a much smaller fraction of the biomass [than plants] and the carnivores for a still smaller fraction.

Oil depletion and climate change will create an entirely new context in which political struggles will be played out. Within that context, it is not just freedom, democracy, and equality that are at stake, but the survival of billions of humans and of whole ecosystems.

Surveying the available alternative energy sources for criteria such as energy density, environmental impacts, reliance on depleting raw materials, intermittency versus constancy of supply, and the percentage of energy returned on the energy invested in energy production, none currently appears capable of perpetuating this kind of society.

The real problem is that we use too much oil. It's that simple and that difficult. If we truly want to reduce our vulnerability to high prices, the best way to do so is to reduce consumption.

Today, it is especially difficult for most people to understand our perilous global energy situation precisely because it has never been more important to do so.

When we decline to talk about what is real simply because it's uncomfortable to do so, we seal our own fate.

The idea that we industrialized humans are immune to the natural laws that have restrained growth in other species-and humans in past social regimes-is to me so self-servingly blind as to be morally reprehensible.