Comments on: LIA and MWP in Venezuela

By: Loso: Varves in Alaska « Climate Audit

Loso: Varves in Alaska « Climate Audit — Sun, 14 Apr 2013 16:45:39 +0000

[...] be derived from them. For example, here is a graphic from Polissar et al on Venezuela (discussed here) showing a difference in magnetic susceptibility between MWP and LIA sediments in Venezuela, which [...]

By: Gifford Miller vs AR5 Reconstructions « Climate Audit

Gifford Miller vs AR5 Reconstructions « Climate Audit — Sat, 11 Feb 2012 20:14:34 +0000

[...] et al 2006 studied sediments in a proglacial lake in the Venezuelan Andes (prior CA discussion here). I refer to it here because it also attempted to interpret glacier advance/recession. Polissar et [...]

By: Steve McIntyre

Steve McIntyre — Fri, 22 Dec 2006 20:57:36 +0000

This diagram was used in one of the AGU presentations that I attended – I think that Kurt Cuffey used it, but I don’t recall him mentioning that this was evidence of glacier absence in the MWP in this area.

By: John G. Bell

John G. Bell — Wed, 02 Aug 2006 19:30:15 +0000

OT, TCO – Found one for you. Must have been frozen in a glacier for the last 500 years .

By: Steve Sadlov

Steve Sadlov — Wed, 14 Jun 2006 19:26:26 +0000

RE: #48. This would indeed be something to explore. Consider the case of glaciers in the Himalayas. Quite unlike the Alpine ones at higher latitudes and certainly unlike any Continental ones, they accumulate during the late astronomical Summer, due to Monsoon convection. During the astronomical winter, other than the odd Cold front that makes it that far south, its mostly bone dry in that part of the world. Therefore, logic would argue that Himalayan glaciers are precipitation proxies. It would be interesting to try and get a better handle on what tropical weather was doing during the LIA. Perhaps, it was not abnormal. Meanwhile, perhaps, there was more unseasonable winter precipitation in tropical wet – dry climates where the Summer is usually the precipitation maximum. Of course this is all speculation. The main theme for me is, when people try to claim that tropical glaciers are a proxy, my question would be, a proxy for what? Precipitation?

By: Michael Jankowski

Michael Jankowski — Wed, 14 Jun 2006 17:33:20 +0000

Re#49 TCO, certainly possible. But the hockey stick says it wasn’t so.

By: TCO

TCO — Wed, 14 Jun 2006 16:52:57 +0000

If the system is capable of long periods (centenial) of different temperature across large regions (Europe), isn’t it possible that the system is capable of different temperatures over the overall surface? Expecially given that the departures from norm for the long periods are on the order of what happens in terms of year to year variation, but would just be sustained longer?

By: beng

beng — Wed, 14 Jun 2006 16:38:07 +0000

RE #43 It may be that most of the present tropical glaciers formed during the LIA & are the exception in the present Holocene period. Many long-term Holocene (last ~10000yrs) tropical proxies show the LIA as the coldest in the entire period. Remarkably, this coincides w/a known solar anomaly, the Maunder minimum. Fancy that.

By: welikerocks

welikerocks — Wed, 14 Jun 2006 15:38:53 +0000

Fair enough #45.

Yes#46 surprise surprise..
Europe, Asia, The United States, Greenland, to name a few land masses are just “regions” and the signatures recorded in: lakes, tree rings, ice, caves, bogs, sea sediments, or critters combined with the hand written documentaion found in these places is just an exaggeration. exaggerated all in sync too! Amazing! LOL

I know. I am supposed to “move on” now.

Cheers!

By: Michael Jankowski

Michael Jankowski — Wed, 14 Jun 2006 14:23:29 +0000

Re#45
These two links from RC suggest Mann accepts the LIA and MWP – but basically only as exaggerations and regional events.
http://www.realclimate.org/index.php?p=32
http://www.realclimate.org/index.php?p=33

I don’t think Mann’s hockey sticks show any significantly anomalous warm or cool periods longer than a few decades prior to the 20th century.
http://www.ncdc.noaa.gov/paleo/pubs/mann2003b/hemisphere.jpg