The rejection of Keystone XL today marks a turning point for energy decisions: in future, policymakers will be under pressure to consider climate impacts of any new policies and infrastructure. But it is not only setting a bar for future energy decisions: the climate impact of stopping this pipeline is real. Last week we released analysis finding that the existing pipelines out of Alberta are already 89% full: if no more are built, tar sands production cannot grow. Just hours after we published, Shell cancelled its 80,000-barrel per day Carmon Creek tar sands project, which was already half-built. The sole reason it gave was “the lack of infrastructure to move Canadian crude oil to global commodity markets”.