"There is a line between public relations and propaganda - or there should be. And there is a difference between using your skills, in good faith, to help rescue a battered reputation and using them to twist the truth - to sow confusion and doubt on an issue that is critical to human survival. And it is infuriating - as a public relations professional - to watch my colleagues use their skills, their training and their considerable intellect to poison the international debate on climate change."