I will add to this description below as l come across information
An upward trend in global temperatures commenced suddenly around 1975 and continued until 2005 . This upward phase lasted 30 yrs .
Global temperatures rose at a rate of +1.91 deg c per century during this 30 yr period between 1975 and 2005
THE PACIFIC OCEAN ABRUPTLY SHIFTS PHASE IN EARLY 1975
Pacific Decadal oscillation(PDO)
had been negative since 1945 .
The sea surface pattern in the North east pacific had been in the cool phase and a change of phase was underway
The PDO represents a pattern of SST anomalies in the North Pacific
In 1975.. The PDO commenced a strong trend toward a change of phase and commenced its march toward the positive phase.
A strong inflection point in 1975. THe same time as the global temperatures commenced a strong upward turn
This era was later described as the time of the GREAT CLIMATE SHIFT..
The North Pacific ( NP )mode
was neutral in 1977 and was trending into its negative phase at the time of the climate shift
The NP had been in its positive phase since 1945 to 1975 ( 30 yrs)
The North Pacific index represents the sea-level or surface pressure over the region 30-65 deg N and 160 E-140 W. This area encompasses the entire Nth East Pacific atmosphere
This definition would indicate the surface pressure in the North Pacific had been anomalously positive/high surface pressure from 1945 to 1975. A phase period of around 30 yrs and at the time of the 1975 climate shift was at the zero anomaly and was shifting into its negative phase with lower mean surface pressure in the Nth Pacific from 1975-1988 . A short positive 13 yr phase
1975 / 1977 global summary-
1945 -1975..The North east Pacific ocean had been cooler and the atmospheric pressure had been higher.
1975-2005.. THe North east pacific recorded a warm anomaly and atmospheric sea level pressure declined .
The 1977 Pacific hurricane season was, at the time, the least active in recorded history
1977. The worst winter in a century in the USA
Global temperatures commenced a warming phase 1975 to 2005