Category Archives: Proxies

Underground Problems with Mann-Holes

Willis writes in: While researching ocean drill cores at the WCDC, I stumbled across Mann’s borehole data. One of the proxies used for historical temperature reconstruction is "borehole temperature", the temperature down in the ground. In 2002, Michael Mann et al. published a study called Optimal surface temperature reconstructions using terrestrial borehole data. It is […]

North and NAS on Bristlecones

BTW, I thought that the Chronicle colloquy was pretty interesting. I don’t usually get to ask people questions directly, so I appreciated that the Chronicle allowed questions through without Gavin Schmidt/realclimate censoring. Now that I think of it, the only other question that I’ve been able to ask a climate scientist directly was to Caspar […]

Tephras in Ecuador

Donald T. Rodbell et al 2002 (with overlaps to Mark et al and Abbott et al) , entitled " A Late Glacial–Holocene Tephrochronology for Glacial Lakes in Southern Ecuador" , here correlates glacial lakes in southern Ecuador according to widespread tephra (volcanic deposits). A couple of interesting points – some BIG differences between radiocarbon dates […]

Glacier Bay, Alaska

George posted up the following link as supposedly supporting Lonnie Thompson’s views on Quelccaya: Early results on Reid Inlet, where Reid Glacier has now backed up out of the ocean, show that the glacier had retreated beyond where it is now more than 10,000 years ago, advanced to the sea by 8,000 years ago, again […]

Laguna Paco Cocha, Peru

A while ago, I summarized an interesting article from the Venezuelan Andes. In that case, they concluded that the glaciers did not exist in the MWP. The post is worth re-reading in the context of Quelccaya. The authors used the continuous deposition of sediments in a proglacial lake to yield evidence of the discontinuous movements […]

No Andean Glaciers from 19 to 27S

Before Caspar Ammann started playing for the Team, he was a geologist who wrote the following serviceable discussion of glaciation in the “dry” Andes between 19 and 27S (Quelccaya is at 12S). Under current climatic conditions, no glaciers can exist in the high Andes of the Western Cordillera in the high Andes of the Western […]

Quelccaya Plant Deposits Again

James Lane here noticed a couple of other useful references on Quelccaya and related the anecdotal information to this information. He observed: It took me ages to put this post together, juggling between different sites. I don’t think one can conclude anything from the information, as presented, except that the moss has grown at higher […]

Plant Deposits at Quelccaya

Thompson et al (PNAS 2006) stated that the discovery of a plant deposit with radiocarbon age of around 4000 BP (calibrated to 5138 BP) near the receding margin of the Quelccaya glacier provided “strong evidence” that the “current retreat of Quelccaya is unprecedented for the last 5 millennia”. The plant deposit is Distichia muscoides, which […]

Some Geologists at Quelccaya

Just when I’d despaired of ever seeing anything as mundane as a site map of the Quelccaya glacier on a scale that did not also show all of South America, I stumbled (due to the wonders of google) on an interesting article by Mark et al (2002), a geologist from Ohio State – the same […]

Thoughts on Alpine Glacier Stratigraphy

Hormes et al 2001 is noted up in passing by the NAS panel, but is given short shrift relative to Thompson. It is not mentioned at all in the IPCC 4AR second draft. This article is one of the underpinnings for the view that there have been 8 warm intervals in the Alps during the […]