The observed warming since 1950 is 1.9 + / - 0.1 °C per century, ten times larger than, and of opposite sign to, the urban - rural effects. (skepticalscience.com)
It is associated with synchronous pressure or height anomalies of opposite sign in mid - and high - latitudes, and therefore reflects changes in the main belt of subpolar westerly winds. (ipcc.ch)
I've read the rebuttals on PDO (averages out over the long - term, shows opposite sign since 1975/79, etc), but they don't seem sophisticated enough to completely discredit theses like Curry's, notwithstanding the woeful flaws in her first post on it that inspired the article above. (tamino.wordpress.com)