Definitions of fossil fuel reserves and resources and assessed stock data are reviewed and clarified. Semantics explain a large stake of conflict between advocate and critical voices on peak oil. From a holistic sources-sinks perspective, limited carrying capacity of atmospheric sinks, not absolute scarcity in oil resources, will impose tight constraints on oil use. Eventually observed peaks in oil production in nearby years will result from politically imposed limits on carbon emissions, and not be caused by physical lack of oil resources. Peak-oil belief induces passive climate policy attitudes when suggesting carbon dioxide emissions will peak naturally linked to dwindling oil supplies. Active policies for reducing emissions and use of fossil fuels will also encompass higher energy end-use prices. Revenues obtained from higher levies on oil use can support financing energy efficiency and renewable energy options. But when oil producers charge the higher prices they can pump new oil for many decades, postponing peak oil to occur while extending carbon lock-in. (C) 2010 Elsevier Ltd. All rights reserved.