I do not envy Mr. Weaver in this case. IANAL but as I understand Canadian libel law, not only must he prove false claims were made, he must also prove they did damage to his reputation. So he will essentially be required in open court to trash himself.
In addition, I believe this sort of lawsuit is counter productive. I agree that the science should stand on its own, and now, despite his lawyers claims that the libel has 'gone viral,' the supposedly libelous story will witness a new level of exposure.
Also, according to the article, he is suing the paper, three writers and will attempt to sue commentors on the paper's website. I say to him, good luck.