By Nic Lewis
In an earlier article here I discussed a Comment on Lewis and Curry 2018 (LC18) by Kevin Cowtan and Peter Jacobs (CJ20), and a Reply from myself and Judith Curry recently published by Journal of Climate (copy available here). I wrote that I would defer dealing with the differences between observed and CMIP5 model-simulated historical warming, which formed the basis of CJ20’s numerical analysis, until a subsequent article. I now do so. Continue reading
Posted in climate models, Sensitivity & feedbacks, Uncategorized
Tagged climate feedback, climate sensitivity
By Nic Lewis
A comment on LC18 (recent paper by Lewis and Curry on climate sensitivity) by Cowtan and Jacobs has been published, along with our response.
Posted in Sensitivity & feedbacks
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.
Posted in Sensitivity & feedbacks, Uncategorized
Tagged climate feedback, climate sensitivity, regression, statistics
by Nic Lewis
*** UPDATE : response to comments by Zeke Hausfather appended
There are a number of statements in Cheng et al. (2019) ‘How fast are the oceans warming’, (‘the paper’) that appear to be mistaken and/or potentially misleading. My analysis of these issues is followed by a reply from the paper’s authors.
Contrary to what the paper indicates:
Posted in climate models, IPCC, Oceans
By Nic Lewis
An observational estimate of transient (multidecadal) warming relative to cumulative CO2 emissions is little over half that per IPCC AR5 projections.
AR5 claims that CO2-caused warming would be undiminished for 1000 years after emissions cease, but observations indicate that it would halve. Continue reading
Posted in climate models, IPCC, Sensitivity & feedbacks
By Nic Lewis
There have been further interesting developments in this story Continue reading
Posted in Data and observations, Oceans, Uncertainty
By Nic Lewis
Introduction
The Resplandy et al. (2018) ocean heat uptake study (henceforth Resplandy18) is based on measured changes in the O2/N2 ratio of air sampled each year, compared to air stored in high pressure tanks originally sampled in the late 1980s and early 1990s, and in atmospheric CO2 concentration. These are combined to produce an estimate (ΔAPOObs) of changes in atmospheric potential oxygen since 1991 (ΔAPO). They break this series down into four components, including one attributable to ocean warming (ΔAPOClimate). By estimating the other three, they isolate the implied ΔAPOClimate and use it to estimate the change in ocean heat content. In two recent articles, here and here, I set out why I thought the trend in ΔAPOClimate – from which they derived their ocean heat uptake estimate – was overstated, and its uncertainty greatly understated. Continue reading
Posted in Data and observations, Oceans, Uncertainty
by Nic Lewis
In a recent article I set out why I thought that the trend in ΔAPOClimate was overstated, and its uncertainty greatly understated, in the Resplandy et al. ocean heat uptake study. In this article I expand on the brief explanation of the points made about “trend errors” and “scale systematic errors” given in my original article, as these are key issues involved in estimating the trend in ΔAPOClimate and its uncertainty.
Posted in Oceans
by Nic Lewis
Obviously doubtful claims about new research regarding ocean content reveal how unquestioning Nature, climate scientists and the MSM are. Continue reading
Posted in Data and observations, Oceans, Uncertainty
by Nic Lewis
A close reading of Chapters 1 and 2 of the IPCC Special Report on Global Warming of 1.5°C (SR15) reveals some interesting changes from the IPCC 5th Assessment Report (AR5), and other science-relevant statements. This article highlights statements in SR15 relating to carbon emission budgets for meeting the 1.5°C and 2°C targets.
It seems fairly extraordinary to me that the AR5 post-2010 carbon budget for 1.5°C, which was only published four years ago, has in effect been now been increased by ~700 GtCO2 – equal to 21st century emissions to date – despite SR15’s projections of future warming being based very largely on the transient climate response to cumulative emissions (TCRE) range exhibited by the models used in AR5. Continue reading
Posted in climate models, IPCC
By Nic Lewis
A critique of of a new paper by Andrews et al., Accounting for changing temperature patterns increases historical estimates of climate sensitivity.
Posted in climate models, Sensitivity & feedbacks
By Nic Lewis
Plain language summary
Posted in Uncategorized
by Nic Lewis
We have now updated the LC15 paper with a new paper that has been published in the Journal of Climate “The impact of recent forcing and ocean heat uptake data on estimates of climate sensitivity“. The paper also addresses critiques of LC15.
Posted in Sensitivity & feedbacks, Uncategorized
