“Across the Narrow Sea, your books are filled with words like “usurper“, and “mad man“, and “blood right“. Here our books are filled with numbers, we prefer the stories they tell. More plain. Less… open to interpretation.” – The Iron Bank of Braavos
(Graphs from Tol, R.S.J. (2005). ‘The marginal damage costs of carbon dioxide emissions: an assessment of the uncertainties’, Energy Policy vol. 33(16), pp. 2064-2074.)
The Rationalist Conspiracy 
Dollars/ton seems like a really hard unit to think about.
How are they putting dollar values on things like death and suffering? I’ll grant the general principle that doing that is a good idea, but there’s still no one obviously correct way to do it.
How big is a ton of carbon? Do they mean just the weight of the carbon or the oxygen as well? How does this convert into miles driven, coal-derived kilowatt hours run through an air conditioner or the manufacture of a toaster oven?
I believe it’s tons of carbon dioxide gas emitted into the air.
According to the Energy Information Administration, a gallon of gasoline produces 19.64 pounds of CO2, so slightly under 0.01 tonnes.
http://www.eia.gov/tools/faqs/faq.cfm?id=307&t=11