Table 1. Comparing the SCC and the SCN.

SCC	SCN
Assumes uniform spatial distribution of atmospheric C, regardless of spatial location of emissions	The location where N enters the system needs to be known to route N to end points of interest where damages may occur.
Costs only associated with C in atmospheric pool	Costs associated with N in atmospheric, surface water, groundwater, and coastal pools
All forms of greenhouse gases can be aggregated into a single equivalent form (CO2).	Different forms of N must be accounted for separately based on their differential impacts.
Damages are spatially explicit; populations vary in their exposure to climate risks and vulnerability to impacts.	Damages are spatially explicit; populations vary in their exposure to N-related risks and vulnerability to impacts.
Climate impacts are experienced globally. The most-damaging impacts are in the distant future.	N impacts are local to regional to global and occur over shorter and longer time scales; long-term impacts are poorly characterized.
Damage functions driven by a single proxy variable (changes in temperature)	Multiple damage functions driven by changes in multiple forms of N in different locations
Uncertainty driven by climate sensitivity, expected damages, and discounting	Uncertainty driven by location of emissions, flow, routing, expected damages of N in different pools, and discounting