For the past century, global temperatures have tended to mirror 20-to 30-year warming and cooling of the north-central Pacific Ocean, the Pacific Decadal Oscillation (PDO).
The earth warmed from about 1915 to1940, while the PDO was also warming (1925 to 46).
The earth cooled from 1940 to 1975, while the PDO was cooling (1946 to 1977).
The strong global warming from 1976 to 1998 was accompanied by a strong and almost-constant warming of the north-central Pacific.
The new Jason oceanographic satellite shows that 2007 was a “cool” La Nina year.