While attending the recent AGU conference, some of us were struck by a statistic presented by Professor Richard Alley: On average, a person's contribution of carbon dioxide waste to the atmosphere is forty times greater than their production of solid trash to landfills when measured as mass.
About 45% of the CO2 we put in the air stays there, with 30% going into the biosphere (plants, animals and soil) and the remaining 24% is absorbed into the oceans, (Canadell et al 2007). Of course, the CO2 that goes into the ocean is changing the chemistry of the seawater, with severe consequences for ocean ecology.
Most of the CO2 in the air will stay there essentially forever, trapping heat and changing the climate for many millennia to come. According to David Archer in The Long Thaw, the CO2 emitted by fossil fuels will have an ultimate heating contribution millions of times larger than the energy released from burning it. (Archer claims the number is 40 million, David Appell argues that it is more like—a still impressive—3.5 million times.)
Information like this, warnings if you like, make it obvious that we have to stop emitting carbon just as quickly as we possibly can. We also have to bite the bullet and implement technology to strip excess CO2 out of the atmosphere. Finally we have to accelerate the shift to clean, renewable, non-carbon fuels. Time is not on our side. We have to stop thinking of targets in terms of 2050 or 2100 and start thinking in terms of 2400, 2500 and beyond.