Climate-induced species range shifts alter ecological assemblages, yet little is known of the consequences for ecosystem functioning. We combined species distribution model (SDM) projections with species traits to develop an index for assessing the risks of climate change for ecosystem functioning, then applied it to a marine protected area network on Canada's east coast. The 'Climate Ecosystem Disruption Index' (CEDI) is easy-to-interpret, builds on existing approaches to quantifying functional diversity, and provides a novel foundation for evaluating the functional consequences of climate-induced species range shifts to identify areas at risk. The CEDI indicated high potential for ecological disruption in the conservation network, with a maximum value of 0.35 (> 1/3 turnover in functional groups) in Jordan Basin Marine Refuge. Our approach aids spatial conservation planning by translating projected shifts from SDMs into potential ecological disruption, to help build climate-resilience into management and inform conservation planning efforts in a warming world Full Changelog: https://github.com/Future-of-Marine-Ecosystems/cedi-east-coast-canada/commits/1.01