It would have to specifically state that he can get a passport without your signature. If you sign an agreement that says that, then he will not need your permission to get a passport.
The Hague Convention is an international treaty that determines jurisdiction for child custody cases. For example, the father and your mutual child would have to live in Canada for two full years, without you taking any action to get your son back, before a Canadian court would take jurisdiction and make any orders regarding your child. Canada would honor the court orders made in the US regarding your child up until that point, and the US would be the country of your child's official residency until then.
However, I did not ask a question that I should have asked previously, is your ex a green card holder or naturalized US citizen? If he has been here for 14 years without a green card then you absolutely should NOT sign an agreement allowing him to take the child there or get a passport without your consent. The possibility that your ex won't be able to come back to the US if he goes to Canada is very real.