color: rgb(1, 0, 0);">2019 to 2025 across 5.92 million streaming sessions, representing 102.4 million viewer-minutes from eleven professional football clubs and five esports organizers in Europe, Africa, and Latin America. Causal identification combines large-scale randomized field experiments with staggered adoption designs, while mechanisms are examined through agent-based simulation and computational text analysis. Eco-default streaming reduces energy per viewer-minute and emissions per session by approximately 4% to 6%, with negligible impact on engagement. However, gains attenuate at high bitrates, during extended viewing, and in virtual reality, indicating a conditional and partially governable rebound. Identical events routed through carbon-intensive grids or water-stressed basins exhibit materially higher footprints, evidencing infrastructural displacement. In esports, device churn is associated with elevated e-waste leakage risks in weaker regulatory contexts, partially mitigated by take-back schemes. Sustainability claims are negatively associated with verified performance under market-based accounting and omission of life-cycle dimensions, while independent assurance narrows disclosure–performance gaps. Simulation results show that substantial seasonal reductions materialize only when behavioral containment is paired with cleaner infrastructural siting. Digital decarbonization in sport is therefore governance-dependent rather than automatic. The findings position DCJ as a justice-centered framework for evaluating when digital sport reduces environmental burdens and when it redistributes them.

Digital Carbon Justice in Sport