Now, so your eyes don't glass over here are some key points:
The AMO: Atlantic Multidecadal Oscillation and the ENSO: El Nino Southern Oscillation are multi decade changes in the massive ocean currents that influence our weather.
The referenced study analyzed these influences and then removed them to reveal an Unexplained temperature rise.
The reader uses logic to challenge conclusions and suggest other possible explanations that might be attributable to longer term frequency oscillations that span hundreds of years and observable with statistics.
When he gets to the "Argument from ignorance ...it must be witches" - this is the AHA! moment.
This is the point that you realize we don't know. The politically driven "Alarmist" are saying it must be the rising CO2 and they have convinced all the right people with their false claims of 95% certainty and "the consensus of world scientist" Blah, Blah Blah.
Anyway, I find it enlightening. As Arthur said in Monty Python's "In Search of the Holy Grail" "..you must know these things if you are to be king"
Let me know what you think. Leave a comment.
Richard S Courtney (03:24:30) :
Thankyou for this cogent
analysis. I have one comment on your method and its effect on your
conclusion. I understand your article to say your analytical method has the following steps. 1.The effect on temperature of AMO and ENSO within the time series is calculated by simple regression (this is possible because AMO and ENSO exhibit several cycles within the temporal range of the data set).
2.The temperature effect of AMO and ENSO is deleted from the time series to reveal a residual temperature trend in the time series.
3.The residual trend is assumed to be an effect of changed atmospheric carbon dioxide concentration over the temporal range of the data set.
4.The assumption in step 3 is used to calculate the climate sensitivity to changing atmospheric carbon dioxide concentration.
This may be correct, but the assumption in step 3 is the
logical fallacy of ‘argument from ignorance’. The assumption amounts to, “The cause of the residual trend is not known so it must be changing atmospheric carbon dioxide concentration”. (If this ‘logical fallacy’ is not clear then consider, “The cause of crop failures is not known so it must be witches”.)
Of course, the residual trend may be a result of changing
atmospheric carbon dioxide concentration. However, the assumption in step 3 does not concur with the implicit assumption of steps 1 and 2 that natural cycles are affecting the temperature trend.
Other natural cycles may also be affecting the trend, and the method is not applicable to cycles with lower frequency than the time series. Such a very low frequency oscillation does seem to exist. There is an apparent ~900 year oscillation that caused the Roman Warm
Period (RWP), then the Dark Age Cool Period (DACP), then the Medieval Warm Period (MWP), then the Little Ice Age (LIA), and the present warm period (PWP).There is no known cause of this apparent low frequency oscillation: some people suggest it could be solar influence, but it could be the chaotic climate system seeking its attractor(s), and it could be … . However, there is no known cause of the AMO and ENSO, either.Therefore, the implicit
assumption of your steps 1 and 2 suggests that the residual trend determined by your steps 1 and 2 could be recovery from the LIA that is similar to the recovery from the DACP to the MWP.
Indeed, since the method adopted the implicit assumption of your steps 1 and 2, consistency suggests that all the observed rise of global temperature in the twentieth century is recovery from the LIA that is similar to the recovery from the DACP to the MWP. Hence, the
calculated climate sensitivity to changing atmospheric carbon dioxide
concentration obtained by your method should be assumed to be a maximum value until this possibility of recovery from the LIA is assessed.
I hope these
thoughts are helpful.
Again, thankyou for your superb work that I trust will
soon be published.