trends in greenhouse gas emissions 2 recent us i n 2004 total were 7 074 4 teragrams of carbon dioxide equivalents tg co eq 1 overall have risen by 15 8 percent from 1990 to while the gross domestic product has increased 51 over same period bea 2005 rose 2003 increasing 115 3 following factors primary contributors this increase robust economic growth leading demand for electricity and fossil fuels expanding industrial production energy intensive industries also travel requiring higher rates consumption petroleum figure through illustrate annual changes absolute since as largest source fuel combustion accounted approximately 80 global warming potential gwp weighted growing slowly
