Tag Archives: agassiz

Greenland Holocene Proxies

I’m going to Erice next week and will be talking about proxies over the Holocene, a topic that I’ve been studying for a few years, but not written much about.   In today’s post, I’m going to discuss Greenland ice core d18O over the Holocene and comment on very inaccurate commentary from Skeptical Science about […]

An Interesting Graphic in the Esper et al 2012 SI

Rob Wilson (by email) has drawn my attention to the SI to Esper et al 2012 SI, which contains the following diagram relevant to late Holocene treeline changes. Figure 1. From Esper et al 2012 SI.

Kinnard Arctic O18 Series

Kinnard et al 2011 report a highly hockey-stick shaped reconstruction of sea ice. (For a different perspective based on Holocene ocean sediments under the Ellesmere Island ice shelf, see the recent Antoniades et al (PNAS 2011). Kinnard et al use a regression-based statistical methodology that looks at first blush to be a sort of inverse […]

Make a stick, make a stick

NASA blogger Gavin Schmidt as part of his ongoing attempt to rehabilitate Mannian paleoclimate reconstructions, characterized here as dendro-phrenology, has drawn attention to a graphic posted up at Mann’s website in November 2009. In this graphic, Mann responded to criticisms that his “no-dendro” stick had been contaminated by bridge-building sediments despite warnings from the author […]

Sampling from Contaminated Distributions

"Standardization" and averaging are operations that are done time after time in paleoclimate studies without much discussion of the underlying distributions. If one browses through recent statistical literature on "robust statistics", one finds much sophisticated analysis of how to handle outliers. The term "robust" is commonly used in paleoclimate, but the term as used in […]

Mo' Mo' Moberg

Many of you read Moberg. Some of you probably saw the following diagram showing the re-combination from wavelets to yield the final reconstruction. It looks like an even more complicated method than MBH98 – "science moves on". Moberg Figure 2. So if I offered to show you plots of the wavelet decompositions of all 11 […]