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Humm, so what makes a drought in a region of the world indicate a warming during the MWP while an identical drought in the identical place indicates a cooling in the LIA? The paper does comment on the shift from wet to dry but does not offer any reason at to why it is true and in fact uses what ever data is handy to support the conclusions regardless of whether it is wet or dry.

For example to support his position he uses the following. In central Argentina, he describes the climate as more humid with increased lake sizes during the MWP. For the North Atlantic he describes the effects of the LIA as being unusually cold and wet. And in Europe, he describes flooding during the transition period between the MWP and the LIA. So increase in wetness can mean the Medieval Warm Period, the Little Ice Age and even the time in between!!! If you want to look at dry conditions, in China extremely dry conditions prevailed during the 16th and 17th centuries. In South America he states that the Patagonia region was abnormally dry during the MWP.

In most cases he presents them with no indication of why they support this particular conclusion. However when he does present a reason, it is pulled out of a hat because it would seem to match his data without any thought given to other possibilities or reasons. For example in discussing the North American west coast he notes that California, the NW Great Basin, and the northern Rocky Mountains/Great Plains experienced drought, then a period of wet, then back to a period of dry. You might think that this would cause problems for his wet = warm hypothesis, but no, the changes were caused by “the contraction and subsequent expansion of the circumpolar vortex.” If there is any justification for this besides the fact that it fits his theory, I can’t find it!

The very best that this paper can do is to show that there were weather anomalies at certain times. He does present some temperature information, but even this is botched. He used the same deMenocal and Keigwin papers as discussed before. Both of these are presented as evidence for the LIA and MWP when in fact what they show was a change in ocean circulation. Now if you want to argue that the change in ocean circulation was caused by climatic conditions consistent with the LIA and MWP, then that is a different and better argument, but he does not argue this and they are taken as temperature proxies.

So, contrary to you I feel that the paper is not well documented and not well supported. On the other hand it does have a heck of a reference section which I know impresses some.

Good night.
Yelling.

For example to support his position he uses the following. In central Argentina, he describes the climate as more humid with increased lake sizes during the MWP. For the North Atlantic he describes the effects of the LIA as being unusually cold and wet.

Reasonable questions, although these aren't "identical" places as you state. Your skepticism matches mine when I wonder where Mann documents the counterbalancing warmth that would be needed to show the whole world didn't cool down during the LIA. And as you dig it out, consider that it could appear to be just as "pulled out of a hat" as Soon's polar vortex changes (which you seem to have no interest in researching).

He does present some temperature information, but even this is botched. He used the same deMenocal and Keigwin papers as discussed before.

And all his other temperature information? All botched? You admit his hypothesis of precip extremes (dry/wet) and local temperature anomalies, but the same evidence fits nicely into global temperature anomalies if you just admit the reality of local effects. Yes, the polar vortices do mean cold=wet or warm=wet depending on location. Global temp changes will always vary by location.

Global temperature variations caused by the sun are the best explanation for the large numbers of climate anomalies clustered in the LIA and MWP, and it is clear that there where nowhere near as many anomalies in the past century.