Fred Goldberg: PDO changes might be caused by changes in Earth’s rotation speed. The PDO then in turn effects the climate. An increase in LOD means the Earth rotation slows down, which causes the PDO to turn positive. A decrease in LOD causes that Earth rotation to speed up a little bit, which causes the PDO to turn negative. Changes in LOD may be caused by changes in gravitional forces of the sun and the planets.
Craig Loehle: There is a divergence problem with the tree ring data and the temperature records. Perhaps trees respond more to precipitation than temperature changes? Assuming linear growth response is wrong.
Also, oceans have been cooling since 2003, according to ARG temperature data down to 700 m. Craig Loehle published this paper in Energy & Enviroment, since both Science and Nature instantly turned the paper down.