Mission-oriented climate change research is often unverifiable. Therefore, many stakeholders look to peer-reviewed climate change research for trustworthy information about deeply uncertain and impactful phenomena. This is because peer-review signals that research has been vetted for scientific standards like reproducibility and replicability. Here we evaluate the transparency of research methodologies in mission-oriented computational climate research. We find that only five percent of our sample meets the minimal standard of fully open data and code required for reproducibility and replicability. The widespread lack of minimal openness standards in peer-reviewed climate change research jeopardizes scientific credibility and risks poor societal outcomes as we manage growing climate risks. The scientific community can and must do better. We, the authors, outline necessary openness standards that we commit to as researchers, reviewers, and readers. We invite you to join us.