The American leader, who has been condemned throughout his presidency for failing to tackle climate change, ended a private meeting with the words: "Goodbye from the world's biggest polluter."
He then punched the air while grinning widely, as the rest of those present including Gordon Brown and Nicolas Sarkozy looked on in shock.
One official was later quoted as saying, "Everyone was very surprised that he was making a joke about America's record on pollution;" to which my reaction is, "Did everyone think he was making a joke?" Could it be that he actually wanted this superlative to be part of his legacy?
Furthermore, as sort of a cherry on top of this particular whipped cream of chutzpah, Winnett and Khan observed that this was not the only Bush proclamation that raised eyebrows:
Mr Bush also faced criticism at the summit after Silvio Berlusconi, the Italian Prime Minister, was described in the White House press pack given to journalists as one of the "most controversial leaders in the history of a country known for government corruption and vice".
The White House apologised for what it called "sloppy work" and said an official had simply lifted the characterisation from the internet without reading it.
Might this be a sign that at some time early in the coming year, the White House will issue an apology for the rest of the "sloppy work" executed over the last eight years?