We need more data to answer that question:
a) what are the costs (CO2 wise) of recycling the paper you dispose of in your country
b) how much of the energy you consume is made up from CO2 emitting powerplants

I'd say my NIT does no more 2-3Wh a day under my average use, which, if 100% of your power is gas/coal powered, means a yearly 700-1000Wh. If we take the top estimate, that would mean a little less than 1kg of coal or a single litre of gasoline.

However, all this calculation is pointless. The energy your CPU consumes (unless you have a monster gaming rig which is on 24/7) is likely ridiculous compared to the amount of electricity/energy you directly (or indirectly) spend on heating, cooling, refrigerating, transportation, lighting, etc.