She worked as an editor, writer and publicist, and developed and implemented communications strategies. Her major projects included leading communications for the SEI Initiative on Fossil Fuels and Climate, the Climate Finance Initiative, and the Climate Services Initiative, and collaborating with SEI partners in the New Climate Economy project. She was also part of the Gender and Social Equity Programme, and worked on selected bioenergy, energy access, adaptation and agriculture projects.

Marion organized SEI’s presence at UN climate conferences. She ran the @SEIclimate Twitter feed, and collaborated closely with researchers, often co-authoring blogs and publications. She cares particularly about equity and social justice issues, including gender equity.