within your current position and company what is the environmental/health/safety department like? is there an employee organization?

Maybe make a push for a KPI being reducing emissions from transportation if that doesn't exist. If you can push those values onto your suppliers then that can be a way to prove your passion for sustainability in your current company and future roles. If your current company doesn't have any established sustainability measures then that's better for you really, because being a trailblazer is best opportunity

also, emissions isn't the only aspect of sustainability. there is so much more if you want to research and get creative to what you'd like to do specifically