The mum-of-three was interviewing environmental campaigner and author Donnachadh McCarthy about his claims that people should give up pets in order to help save the planet.
Speaking to him alongside Adil Ray, Susanna asked Donnachadh: “What are the consequences of what you’re saying? People love their pets like members of their family.”
“It’s about love isn’t it, behind that loving cat or dog we have, there’s a whole ocean of cruelty,” he replied.
Susanna continued: “My point is that you could be talking about human beings as well.
“It’s one thing to give up your car, but you’re not going to give up a loved member of your family, which frankly is what people consider cats and dogs.”
Donnachadh bluntly replied: “Well, if we love our members of our family, if we love our kids, do you not accept that we have to look after the climate crisis?”
Susanna answered: “Firstly I want to look after my kids and my pets,” but she was not banking on Donnachadh’s response.
“That’s quite shocking,” he told the GMB presenter. “Do you understand the level of crisis that the carbon emissions currently are on the planet?”
“What you think I shouldn’t look after my children and my pets?” Susanna quipped back.
“I’m saying that to look after and love your children, you have to look after your carbon emissions because we are in an emergency,” Donnachadh stressed.
Viewers tuning in at home were just as shocked as Susanna and took to Twitter to comment.
“Did He Just Say To Susanna “its quite shocking to look after your kids and pets ? ” Get This Buffoon Off #GMB,” one tweeted.
Another posted: “I would rather have my pet than most humans!!! #gmb what is this man talking about?”
And a third added: “Has this chap ever owned a pet? Doubtful. Bitter old man. Maybe he needs a little cat to love #gmb.”
Good Morning Britain airs weekdays at 6am on ITV.