Category Archives: Sensitivity & feedbacks

Emergent constraints on climate sensitivity: Part I

Posted on March 19, 2018 by | 119 comments

by Nic Lewis

Emergent constraints on climate sensitivity:  their nature and assessment of validity.

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119 Comments

Posted in Sensitivity & feedbacks

Recent research on aerosol forcing of the CMIP5 models

Posted on March 11, 2018 by | 169 comments

by Frank Bosse

A few days ago a paper (Sato et al) dealing with some aspects of the “Aerosol Cloud Interactions”, (ACI, also called “aerosol indirect effects”) was released. It bolsters the conclusions of earlier papers: the effective radiative forcing from ACI (ERFaci) is smaller than thought, perhaps near zero .

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169 Comments

Posted in Sensitivity & feedbacks

Nature Unbound VIII – Modern global warming

Posted on February 26, 2018 by | 871 comments

by Javier

Summary: Modern Global Warming has been taking place for the past 300 years. It is the last of several multi-century warming periods that have happened during the Neoglacial cooling of the past 3000 years. Analysis of Holocene climate cycles shows that the period 1600-2100 AD should be a period of warming. The evidence suggests that Modern Global Warming is within Holocene variability, but the cryosphere displays a non-cyclical retreat that appears to have undone thousands of years of Neoglacial ice advance. The last 70 out of 300 years of Modern Global Warming are characterized by human-caused, extremely unusual, rapidly increasing CO2 levels. In stark contrast with this rapidly accelerating anthropogenic forcing, global temperature and sea level appear to have continued their rising trend with no perceptible evidence of added acceleration. The evidence supports a higher sensitivity to CO2 in the cryosphere, suggesting a negative feedback by H2O, that prevents CO2 from having the same effect elsewhere.

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871 Comments

Posted in Attribution, Sensitivity & feedbacks

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

Posted on February 5, 2018 by | 784 comments

by Nic Lewis

Recently a new model-based paper on climate sensitivity was published by Kate Marvel, Gavin Schmidt and others, titled ‘Internal variability and disequilibrium confound estimates of climate sensitivity from observations’.[1]

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784 Comments

Posted in Sensitivity & feedbacks

Reply to Patrick Brown’s response to comments on his Nature article

Posted on December 24, 2017 by | 286 comments

by Nic Lewis

My reply to Patrick Brown’s response to my my comments on his Nature article.

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286 Comments

Posted in Sensitivity & feedbacks

Greater future global warming (still) predicted from Earth’s recent energy budget

Posted on December 21, 2017 by | 69 comments

by Patrick Brown

A response to Nic Lewis’ post A closer look shows global warming will not be greater than we thought.

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69 Comments

Posted in Sensitivity & feedbacks

Brown and Caldeira: A closer look shows global warming will not be greater than we thought

Posted on December 15, 2017 by | 245 comments

by Nic Lewis

A critique of a recent paper by Brown and Caldeira published in Nature that predicted greater than expected global warming.

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245 Comments

Posted in climate models, Sensitivity & feedbacks

Update on the strength of aerosol forcing

Posted on July 29, 2017 by | 298 comments

by Frank Bosse

Increasing evidence of small aerosol forcing supports the importance of internal variability in explaining inter hemispheric differences in temperature variability.

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298 Comments

Posted in Sensitivity & feedbacks

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

Posted on July 8, 2017 by | 122 comments

by Nic Lewis

A new paper in Science Advances by Cristian Proistosescu and Peter Huybers (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 sensitivity estimates from historical records into line with model-derived estimates.

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122 Comments

Posted in Sensitivity & feedbacks

How inconstant are climate feedbacks – and does it matter?

Posted on April 18, 2017 by | 229 comments

by Nic Lewis

Kyle Armour has a new paper out in Nature Climate Change: “Energy budget constraints on climate sensitivity in light of inconstant climate feedbacks”.

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229 Comments

Posted in Sensitivity & feedbacks

Rethinking the Social Cost of Carbon

Posted on January 17, 2017 by | 203 comments

by Judith Curry

The Social Cost of Carbon is emerging as a major source of contention in the Trump Administration.

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203 Comments

Posted in Economics, Policy, Sensitivity & feedbacks

Beyond Physics: Advanced Biology and Climate Change

Posted on January 15, 2017 by | 286 comments

by Clive Hambler

Reflections on the stabilization of Earth’s climate by life.

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286 Comments

Posted in Sensitivity & feedbacks

Internal climate variability as a confounding factor in climate sensitivity estimates

Posted on December 29, 2016 by | 333 comments

by Frank Bosse

Towards eliminating multi-decadal natural oscillations in determination of the Transient Climate Response (TCR) to CO2.
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333 Comments

Posted in Sensitivity & feedbacks

Tamino’s adjusted temperature records and the TCR

Posted on October 26, 2016 by | 215 comments

by Frank Bosse

Separating out the impacts of internal variability on evaluations of TCR.

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215 Comments

Posted in Data and observations, Sensitivity & feedbacks

Dust deposition on ice sheets: a mechanism for termination of ice ages?

Posted on October 2, 2016 by | 398 comments

by Donald Rapp

In a recent paper, Ellis and Palmer (2016) proposed that deposition of dust on giant ice sheets, thus reducing their albedo, was a principal factor in the termination of Ice Ages over the past 800 kyrs.

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398 Comments

Posted in Attribution, Sensitivity & feedbacks

Broad consistency between patterns of fossil fuel emissions and atmospheric CO2

Posted on August 12, 2016 by | 354 comments

by Guido van der Werf

The 200% increase in fossil fuel emissions Murry Salby claims is about 20% in reality, and the constant CO2 growth rate he found actually increased by roughly 20% as well over the same time period.

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354 Comments

Posted in Sensitivity & feedbacks

Atmospheric Radiation Measurement Program

Posted on July 28, 2016 by | 88 comments

by Judith Curry

The first 20 years.

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88 Comments

Posted in climate models, Data and observations, Sensitivity & feedbacks

Are energy budget climate sensitivity values biased low?

Posted on July 12, 2016 by | 233 comments

by Nic Lewis

In a recently published paper (REA16),[i] Mark Richardson et al. claim that recent observation-based energy budget estimates of the Earth’s transient climate response (TCR) are biased substantially low, with the true value some 24% higher.

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233 Comments

Posted in Sensitivity & feedbacks

Towards reconciling climate sensitivity estimates from climate models and observatiions

Posted on June 28, 2016 by | 386 comments

by Judith Curry

A new paper purports to have resolved the discrepancy between climate response estimates from global climate models versus energy budget models.

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386 Comments

Posted in Sensitivity & feedbacks

Assessment of Approaches to Updating the Social Cost of Carbon

Posted on June 7, 2016 by | 224 comments

by Judith Curry

Some new analyses are shedding some light on deficiencies in the approach to estimate the social cost of carbon.

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224 Comments

Posted in Climate change impacts, Economics, Sensitivity & feedbacks

The cloud-climate conundrum

Posted on June 2, 2016 by | 337 comments

by Judith Curry

Four new papers remind us of the very large uncertainties surrounding cloud-climate feedbacks.

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337 Comments

Posted in Sensitivity & feedbacks

Updated climate sensitivity estimates

Posted on April 25, 2016 by | 149 comments

by Nic Lewis

An update to the calculations in Lewis and Curry (2014).

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149 Comments

Posted in Sensitivity & feedbacks

On inappropriate use of least squares regression

Posted on March 9, 2016 by | 256 comments

by Greg Goodman

Inappropriate use of linear regression can produce spurious and significantly low estimations of the true slope of a linear relationship if both variables have significant measurement error or other perturbing factors. This is precisely the case when attempting to regress modelled or observed radiative flux against surface temperatures in order to estimate sensitivity of the climate system. Continue reading →

256 Comments

Posted in Sensitivity & feedbacks

Are land + sea temperature averages meaningful?

Posted on February 10, 2016 by | 371 comments

by Greg Goodman

Several of the major datasets that claim to represent “global average surface temperature” are directly or effectively averaging land air temperatures with sea surface temperatures.

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371 Comments

Posted in Data and observations, Sensitivity & feedbacks

Huge efficacy of land use forcing in one GISS-E2-R simulation: is an ocean model error involved?

Posted on January 25, 2016 by | 137 comments

by Nic Lewis

In a recent article here, which summarised a longer piece at ClimateAudit, I discussed the December 2015 Marvel et al.[1] paper, which contends that estimates of the transient climate response (TCR) and equilibrium climate sensitivity (ECS) derived from recent observations of changes in global mean surface temperature (GMST) are biased low.

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137 Comments

Posted in climate models, Sensitivity & feedbacks