Search Results for: Logarithmic Formula

More on the Logarithmic Formula

A logarithmic relationship between CO2, radiative forcing and direct impact is reported by IPCC and widely relied on. While this may well be a plausible relationship (Luboš, for one, endorses it), it is not easy finding a proof of the relationship. In a recent post, I noted this in connection with IPCC AR1 (1990), where […]

More on Functional Forms: Wigley 1987

Over the last week or so, I’ve reported on my efforts to locate the provenance of the functional forms for the relationship between levels of CO2 and other greenhouse gases and temperature. Luboš has also chipped in on the topic from a different perspective proposing a derivation of a log formula from first principles. We’ve […]

The impact of recent forcing and ocean heat uptake data on estimates of climate sensitivity

A guest post by Nic Lewis Judith Curry and I have now updated the LC15 paper with a new paper that has been published in the Journal of Climate There has been considerable scientific investigation of the magnitude of the warming of Earth’s climate by changes in atmospheric carbon dioxide (CO2) concentration. Two standard metrics […]

Marvel et al.’s new paper on estimating climate sensitivity from observations

A guest post by Nic Lewis Introduction and summary Recently a new model-based paper on climate sensitivity was published by Kate Marvel, Gavin Schmidt (the head of NASA GISS) and others, titled ‘Internal variability and disequilibrium confound estimates of climate sensitivity from observations’.[1] It appears to me that the novel part of its analysis is […]

Does a new paper really reconcile instrumental and model-based climate sensitivity estimates?

A guest post by Nic Lewis A new paper in Science Advances by Cristian Proistosescu and Peter Huybers “Slow climate mode reconciles historical and model-based estimates of climate sensitivity” (hereafter PH17) claims that accounting for the decline in feedback strength over time that occurs in most CMIP5 coupled global climate models (GCMs), brings observationally-based climate […]

Guy Callendar vs the GCMs

As many readers have already surmised, the “GCM-Q” model that visually out-performed the Met Office CMIP5 contribution (HadGEM2) originated with Guy Callendar, and, in particular, Callendar 1938 (QJRMS). My attention was drawn to Callendar 1938 by occasional CA reader Phil Jones (see here and cover blog post by co-author Ed Hawkins here.) See postscript for […]

Kaufman’s "Classical" Log Regression

I observed yesterday that I had been unable to replicate the archived version of Kaufman’s Hallet Lake series – something that I thought was due to a change in the archived version (since the NCDC archive noted that a new version had been archived in Nov 2008.) This turns out not to be what happened. […]

From Lacis et al 1981 to Archer Modtran

In several recent posts, we’ve been reviewing the provenance of the radiative forcing estimate of about 4 wm-2 and the logarithmic form for estimating climate response to increased CO2 levels. This has led on the one hand to several primary references, including Lacis et al 1981 and, on the other hand, to references to realclimate […]

IPCC and Radiative Forcing #2: 1992 and 1994.

In our summary of IPCC AR1 (1990) on radiative forcing, I noted that the logarithmic relationship and 4 wm-2 values were attributed to: Hansen et al (1988), which in turn cited Lacis et al 1981; and Wigley (1987) which is not presently available to me (or to Wigley himself) and appears not to have been […]

IPCC on Radiative Forcing #1: AR1(1990)

As an innocent bystander to the climate debates a couple of years ago, I presumed that IPCC would provide a clear exposition of how doubled CO2 actually leads to 2.5-3 deg C. The exposition might involve considerable detail on infra-red radiation since that’s relevant to the problem, but I presumed that they would provide a […]