Author Archives: niclewis

Climate sensitivity to cumulative carbon emissions

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

Resplandy et al. Part 4: Further developments

By Nic Lewis

There have been further interesting developments in this story Continue reading

Resplandy et al. Part 3: Findings regarding statistical issues and the authors’ planned correction

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

Resplandy et al. Part 2: Regression in the presence of trend and scale systematic errors

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.

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A major problem with the Resplandy et al. ocean heat uptake paper

by Nic Lewis

Obviously doubtful claims about new research regarding ocean content reveal how unquestioning Nature, climate scientists and the MSM are. Continue reading

Remarkable changes to carbon emission budgets in the IPCC Special Report on Global Warming of 1.5C

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

Warming patterns are unlikely to explain low historical estimates of climate sensitivity

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.

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