It's too hot there for his dog.
Pointing to a photo of his long-haired German shepherd, Garzon explained to the magazine Semana, "I have turned down the ambassador job because the dog you see on that picture is very hairy and the hot climate of Brasilia could harm its health."
According to the BBC, "Colombian Foreign Minister Maria Angela Holguin has issued an apology to Brazil, a major trading partner. She described the incident as 'very embarrassing'."
Hey, the man loves his dog more than he loves the idea of being ambassdor to Brazil.
Many people are only familiar with the short-haired German shepherd, but long-haired German shepherds are, indeed, very hairy, thick-coated dogs. Here's a video of a long-haired German shepherd hanging out with his cat buddy (and these two are getting long much better than the Colombian and Brazilian diplomatic staffs probably are today):