I have good news and bad.  First well start with the bad.  Due to irreversible damage one ecosystem will be wiped away forever.  The good news is that you get to choose which one. 
Which ecosystem would you choose?  Why did you pick this habitat?   Share your choice & justification for that choice.  Think about the chapters in this module (Ecosystems, the Physical Environment, & Organisms).  The disappearance of which ecosystem would have the least impact on the planet?