daniel sperling professor and director national association of regional councils june 26 2005 institute transportation studies university california davis climate change the carbon challenge to reach stable levels 450 550 ppm world emissions need decline dramatically by as much 90 from projected major driver for 18 12 6 0 1990 2050 2110 2170 2230 baseline 750 350 billion tons co2 total transport 17 7 8 3 19 9 16 5000 10000 15000 20000 25000 1971 1975 1980 1985 1994 mt o f c 2 100 200 300 400 500 600 which sector source international energy agency 2000 reality co increasing worldwide us with share petroleum consumption in 25 50 75 125 1960 1970 2010 2020 2025 m illio n b a r e ls p d y other china fsu w europe japan oil is being re carbonized heavy tar sands coal
