Dude, just start looking. Don't wait for somebody else to leave, be that person.
If somebody else leaves, your workload will increase even more while you try to find a new job. Just take the initiative. And next time, be quicker about it too. Protect yourself.
I symphatize with that, but it would seem they are definitely not going to last until they are successful. I respect that you work towards renewable energy, but they won't lose one night of sleep if they have to fire you down the road.
Take care of yourself, good luck.
Edit: I just remembered from another thread. Somebody shared a gem about hoping: Hope in one hand, shit in the other and see which one gets filled first.
Not to say hope is bad, but I also believe in being realistic about things.