Carbon credits are one potential tool for climate change mitigation. For various reasons, proof of stake (i.e. energy efficient) blockchains are a natural technological choice for trading carbon credits and offsetting emissions. In this talk, we will discuss tokenized carbon credits, or carbon credits which are distributed, traded, and retired on the blockchain. We will discuss challenges to their efficacy as a tool for mitigating climate change. Derek is a member of EEG and has recently submitted his PhD. His work focuses on smart contracts or blockchain-based programs. He studies their difficult-to-specify properties with the aim of developing high-assurance financial smart contracts.