The 40-year-old has been in top form this term and is expected to go to Brazil as part of Australia's World Cup squad next summer.
Schwarzer is currently in talks with Fulham about a new contract and Jol is hopeful that it will extend beyond the 2014 World Cup.
"He (Schwarzer) can go on for the next one or two years but it's not like he is 22 and has another 10 years left in him," said the Dutchman.
"But how old are goalkeepers? If you look for evidence of them being 44-45, I can't see it. So 40 is quite remarkable.
"They (Australia) will go to the World Cup and he wants to be there. He will be 42 and then he will come back to us hopefully."
Schwarzer's form is the reason David Stockdale is out on loan with Hull City and with Neil Ethridge waiting in the wings, Jol admits he may have to let one of his goalkeepers leave permanently.
"David wants to be a number one," said Jol. "I'm always looking for a good goalkeeper. I've got another good goalkeeper who's 23, Neil Etheridge, and he's very talented but he needs to play.
"So maybe we will put him on loan. Stockdale is already on loan; so I have a problem. We need one or two goalkeepers. Hopefully we can get competition for places because that's the ideal."