The former Life on Mars star revealed that the forthcoming Fox series presents a version of the future that could be a possibility.
"This is a scary, scary vision of the future," O'Mara told Collider. "This future is what happens, if we don't do anything about it now. It's a worst-case scenario, but it's not impossible."
He continued: "This show points it out and says that this is a possible future for us, unless we do something now."
O'Mara went on to speak about the experience of acting opposite dinosaurs.
"Well, it's not easy," he said. "It requires a very specific concentration, and you have to get your imagination firing on all cylinders to see that thing in front of you, breathing on you and know that it has a very distinct smell.
"I've seen concept art of our dinosaurs and some of the raptors are like wild coyotes. They're mangy and a little crazed, almost like they're really, really hungry, or they're methadone addicts. Our dinosaurs have a lot of personality, and they're extra vicious."
Executive producer Brannon Braga recently insisted that Terra Nova is not like Jurassic Park, saying that it's not all about the dinosaurs.
Terra Nova begins on September 26 on Fox in the US and will debut on Sky1 in the UK this autumn.
> 'Terra Nova' - The next big thing?
Watch a teaser trailer for Terra Nova below: