The Possible Future is an area in Time Tangled Island located 50 years in the future. It is a wasteland due to the time travel shenanigans that you have to fix so that the future doesn't end up like this possible future.
Role In Time Tangled Island
It is the result of a mixup with the time machine which caused a series of events that eventually resulted in a putrid wasteland of a future. You travel here in the large time machine and meet your older self who gives you the Time Device for you to fix the mistakes made by Professor Pendlum.