All methods of storing value have some environmental cost associated with them. We explore the environmental costs of US cash notes, which amount to $0.26 annually per note, based on resources used and CO2 released. We then compare our cash estimate to the environmental costs of crypto assets, using Bitcoin as the basis, and totals $70 annually per coin in terms of CO2 released. However, when considering all the US banknotes in circulation in the aggregate, and all the mined Bitcoin currently available, we find that the overall environmental impact of cash notes ($12.9 billion USD) far exceeds the environmental cost of Bitcoin ($1.3 billion USD).