"Whether or not human produced carbon dioxide is a major cause of impending climate change (as is being debated in the two articles of this issue), the issue of energy “production” by our Earth-bound societies must be faced. Fossil fuel supplies may become unavailable in this century – or the next – but in a finite system, obeying the laws of thermodynamics, non-fossil energy sources will have to become available to mankind, sooner or later (within the foreseeable lifetime of our planet)."

-- From the original APS article http://www.aps.org/units/fps/newsletters/200807/editor.cfm