See update under the heading of WHY WOULD GLOBAL TEMPERATURES DROP?
The following are my comments on the post Easterbrook on the potential demise of sunspotsat WattsUpWithThat.
MORE MISREPRESENTATIONS ABOUT THE PDO
Don J. Easterbrook wrote: “The evidence consisted of temperature data from isotope analyses in the Greenland ice cores, the past history of the PDO, alpine glacial fluctuations, and the abrupt Pacific SST flips from cool to warm in 1977 and from warm to cool in 1999. Projection of the PDO to 2040 forms an important part of this cooling prediction.”
Since the PDO does not represent the Sea Surface Temperature of the North Pacific, the prediction is flawed. Figure 1 is a graph of North Pacific SST anomalies, north of 20N, which is the area from which the PDO (the 1stPrinciple Component of the detrended SST anomalies of that area) is derived. There’s no flip “from warm to cool in 1999”. In reality, SST anomalies there appear to have peaked in 2004.
And Figure 2 is a graph of the SST anomalies for the North Pacific, all of it north of the equator. There’s no flip from “warm to cool in 1999” there either. Like the subset above, the SST anomalies of the North Pacific may have peaked in 2004.
THE TSI VERSUS TEMPERATURE COMPARISON GRAPH HAS MULTIPLE WRONGS
Figure 3 is Figure 4 from Don Easterbrook’s post. It compares an unspecified temperature dataset to a “modified” Hoyt and Schatten TSI reconstruction. There’s no description of how these modifications to the TSI reconstruction were made. The variations in Hoyt and Schatten TSI reconstruction were created to explain the changes in global temperature until the 1970s. AGW was then said to have been responsible for the rise in global temperatures since the 1970s. Further, the Hoyt and Schatten data is also obsolete. Recent reconstructions of TSI no longer include the variations in solar minimum. Refer to Figure 4. That’s three strikes for that graph: An unspecified Temperature dataset, an undocumented modification to a TSI dataset, and an obsolete TSI dataset.
Source of data for Figure 4 is:
THE UNUSUAL IPCC MODEL VS GLOBAL TEMPERATURE ANOMALY GRAPH
Figure 5 is Figure 5 from the Easterbrook post. It’s is a very, very unusual graph. It appears that the data before the 1997/98 El Niño has been smoothed with a multiyear filter, and after that, an unknown dataset smoothed with a 12-month filter has been spliced to it. It really appears contrived, especially the significant response to the 1998/99/00/01 La Niña.
Figure 6 is a comparison of the IPCC multi-model mean for global surface temperatures and Global HADCRUT surface temperature anomaly data. I’ve used HADCRUT because it has the lowest trend of the surface temperature datasets after the 1997/98 El Niño. The actual dip in global surface temperatures after the 1997/98 El Niño is nowhere close to as deep as the one shown in the Easterbrook graph.
Both of those datasets are readily available through the KNMI Climate Explorer:
WHY WOULD GLOBAL TEMPERATURES DROP?
Don Easterbrook’s Figure 5 shows global temperatures dropping in the future. Why would they drop?
We’re pretty close to solar minimum now. Is TSI expected to drop below the minimums of the last few solar cycles? I’ve never seen this discussed in any paper presented about the current solar minimum. Therefore, where do these expectations of decreased TSI come from?
UPDATE (June 18, 2011): Dr. Leif Svalgaard, Solar Physicist from Stanford University, confirmed my suspicions that there is no reason to expect Total Solar Irradiance (TSI) levels to drop below “normal” solar cycle minimums during the upcoming grand minimum. See Leif Svalgaard’s June 17, 2011 at 10:01 pm comment a WattsUpWithThat. That is, referring to Figure 7, there is no reason to expect that TSI during an extended solar minimum will drop lower than 1365.4-1365.5 watts/m^2. If that’s the case, why would temperatures drop as shown in Figure 5 from Easterbrook’s post?
Arguments about anthropogenic global warming cannot be won by misrepresenting the PDO, or by using outdated TSI data, or by creating unusual global temperature anomaly graphs that are obviously wrong to anyone familiar with the instrument temperature record.