Presumably by plane? Carbon cost is apparently about 986 kg/passenger, based on average passenger weight of 60kg, so for a 0.5kg bundle of cash, that would be

Presumably by plane? Carbon cost is apparently about 986 kg/passenger, based on average passenger weight of 60kg, so for a 0.5kg bundle of cash, that would be approximately 986/120 = 8.2kg of carbon to send a bundle of cash from NY to Paris, assuming it travels in the cargo hold.