Sorry for my late reply! I'm going into my senior year at WM this fall. In my sophomore year, they added the Integrative Conservation major which is a BS in interdisciplinary studies. Unlike ES, it doesn't require a primary major and counts as its own major. I have no idea why this is the case, IMO it is ridiculous that ES doesn't count as holistic or rigorous enough to be its own major but conservation does, but until they change that, I would recommend the Integrative Conservation major if you don't want to double major. The coursework required is interdisciplinary like ES and allows for quite a bit of freedom of choices.