Category Archives: Uncategorized

Milankovitch Forcing and Tree Ring Proxies

Mar 2, 2021. This post was written in 2015 but, for some reason, I didn’t publish it at the time.  Seems just as valid today as when it was written.   Esper et al 2012, Orbital Forcing of Tree Ring Data pdf SI, is one of the few paleoclimate articles in past decade which really […]

A “Good” Proxy on the Antarctic Peninsula?

Nearly all of the text of this article on an interesting ice core proxy series (James Ross Island) from the Antarctic Peninsula was written in June 2014, but not finished at the time for reasons that I don’t recall.  This proxy was one of 16 proxy series in the Kaufman 12K pdf. 60-90S reconstruction. I […]

IPCC AR5 WG2 on Yield Sensitivity: Statistical Malpractice

This post was written on Aug 12, 2014, but not published until Mar 2, 2020 (today). One of the signature findings of IPCC AR5 WG2 has been that climate change has already had a negative impact on crop yields, especially wheat and maize. These findings are prominent in the WG2 Summary for Policy Makers and […]

Gregory et al 2019: Does climate feedback really vary in AOGCM historical simulations?

A guest post by Nic Lewis Introduction The recent open-access paper Gregory et al 2019 “How accurately can the climate sensitivity to CO2 be estimated from historical climate change?” discusses, inter alia, the use of regression to estimate historical climate feedback. As I wrote in a previous article, Gregory et al. consider a regression in […]

Gregory et al 2019: Unsound claims about bias in climate feedback and climate sensitivity estimation

A guest post by Nic Lewis The recently published open-access paper “How accurately can the climate sensitivity to CO2 be estimated from historical climate change?” by Gregory et al.[i] makes a number of assertions, many uncontentious but others in my view unjustified, misleading or definitely incorrect. Perhaps most importantly, they say in the Abstract that […]

CG2 and Ex Post Picking

Jul 31, 2019: Noticed this as an unpublished draft from 2014. Not sure why I didn’t publish at the time. Neukom, lead author of PAGES (2019) was coauthor of Gergis’ papers. One of the longest-standing Climate Audit controversies has been about the bias introduced into reconstructions that use ex post screening/correlation.   In today’s post, […]

Hack, Now Ex-Bellingcat, Gets Climategate Timezones Backwards

Bellingcat’s Iggy Ostanin, [update: who Eliot Higgins says is now ex-Bellingcat]  recently claimed to have discovered that the nomenclature of Climategate-1 emails was based on Unix timestamps and that the nomenclature proved that Russians hacked CRU from timezone +05:00. Amidst much uninformed hyperventilating. Ostanin’s assertions were swiftly retweeted by Andy Revkin, Roger Harrabin, Ken Rice […]

PAGES2K (2017): Antarctic Proxies

A common opinion (e,g, Scott Adams) is that the “other proxies”, not just Mann’s stripbark bristlecone tree rings, establish Hockey Stick. In today’s post, I’ll look at PAGES2K Antarctic data – a very important example since Antarctic isotope data (Vostok) is used in the classic diagram used by Al Gore (and many others) to illustrate […]

PAGES2K: North American Tree Ring Proxies

The PAGES (2017) North American network consists entirely of tree rings. Climate Audit readers will recall the unique role of North American stripbark bristlecone chronologies in Mann et al 1998 and Mann et al 2008 (and in the majority of IPCC multiproxy reconstructions).  In today’s post, I’ll parse the PAGES2K North American tree ring networks […]

PAGES2K (2017) – South America Revisited

The most recent large-scale compilation of proxy records over the past two millennia is PAGES (2017).  They made a concerted effort to archive data (to the credit of Julien Emile-Geay), archiving 692 series, but they perpetuated most other sins within the field.  Rather than abjuring ex post screening, it carried ex post screening to extremes never […]