Key Points: CO2 Warming
¥CO2 levels are rising and will likely double relative to pre-industrial levels by 2070.
¥The greenhouse relationship between higher CO2 levels and warmer temperatures is indisputable.
¥Even with perfect knowledge of future CO2 levels, there is significant uncertainty about how much warming would occur and how fast it would occur.
¥Model results indicate a 1.5 to 4.5oC global warming, with strongest warming in polar regions, and an overall increase in global precipitation.
¥Shifts in precipitation are much more uncertain.