Two-thirds of central banks in the East Asia and Pacific (EAP) region have started researching or testing the implementation of a Central Bank Digital Currency (CBDC). At the same time, the region accounts for one-third of world CO2 emissions and is vulnerable to climate risks. As the Group of 7 (G7), European Central Bank (ECB), and Bank of England (BoE) have stated in their public statements, it is increasingly important to consider environmental impact when designing CBDC. However, only a few brief studies have been done on this subject, which will be crucial for the region. This Note explores the environmental implications of CBDC by comparing technical mechanisms and energy consumption within its distributed structure. It also illustrates differences in ecological footprint between CBDC and other payment methods (cryptocurrency, cash, and card networks). As the legitimacy of CBDC is backed by the trust of central banks, CBDC does not need to prove its legitimacy through its technological structure. Therefore, CBDC does not require the energy-intensive consensus or mining mechanisms used by a cryptocurrency, so its energy consumption is lower (comparable to that of a credit card system). CBDC can be designed to use various systems, such as Real Time Gross Settlement (RTGS), Distributed Ledger Technology (DLT), or a mixture of both. Careful deliberation to meet the objectives and implications will be important as CBDC can be a catalyst for financial innovation.