How much warming/yr will one liter of gasoline's CO2 product cause?

[repoman]

I am having a hard time to find this information - even a very rough, time averaged estimate just at current CO2 levels.

There is all this mention of GWP (Global Warming Potential) and no list of the units of CO2 which is the base as 1 GWP unit.

The number I am looking for will be in the units similar to:

Watts/kg (CO2)


Finally found a website that addressed it from looking at total heating over time, instead of from modeling CO2 trapping heat. Better than nothing I guess.

http://gcconsortium.com/heat_trapping.html

After a very rough estimate it says that CO2 will trap 100x more heat over its residence time than was gained from burning the fuel. To be more specific he says that it will trap 2x the combustion energy/yr and will have a 50 year residence time. If the math he did was good, then the former makes sense, but the latter seems way to short an average NET residence time for CO2.

 

[repoman]

Bumping with some of my own calculations that should be close to accurate:

DATA:

Atmosphere = 1.8*10^20 moles gas total
Surface Area = 5.1*10^14 m^2
Enthalpy of Combustion of Gasoline (Octane) ~ 5.3 MJ/mol
~ 0.66 MJ/mol CO2

Initial CO2 levels = 270 ppm
Final CO2 level = 370 ppm (yes this is an old source) http://www.am.ub.edu/~jmiralda/fsgw/lect3.html

Radiative forcing = 1.5 W/m^2 from added CO2
Assume straight line not logarithmic response (this will overestimate a bit).


Total radiative forcing over surface of earth from added CO2 is:

~7.6*10^14 Watts

Total increase of Moles of CO2 is

~ (370-270)*(10^-6)(moles CO2/moles air)*1.8*10^20 moles air

~ 1.8*10^16 moles CO2


Radiative Forcing ~ 0.042 Watts/Mol CO2
Radiative Forcing ~ 1.32 (MJ/year)/Mol CO2

Well, I'll be darned, I got the same result as the link in the first post. It does trap 2x the energy of combustion per year.

There will be some wiggle room on this number, but not an order of magnitude.

I am having a hard time of thinking how to present this to a completely non-technical audience.

I would think maybe saying that a sizeable fraction of the energy we have ever gained from burning fossil fuels (since 1859) will be trapped AGAIN every six months. Every year for sure, after some more accurate tweaks are applied to this very simple model, such as ocean uptake and that methane and coal have different energies/CO2 numbers than octane.

However, this is scary because it does show that there is already a huge amount of momentum built up in the warming trend that will last for quite a while (how long?) in human terms. It may be too discouraging a reality to be shown too quickly.

This makes me think that large scale geo-engineering is the only hope to avoid total disaster of temperature and sea level. Sequestration, artificial weathering, aerosols, space shades, whatever it takes.