Category Archives: Attribution

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Extremes

Posted on June 13, 2019 by curryja

by Judith Curry Politics versus science in attributing extreme weather events to manmade global warming.

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Critique of the new Santer et al. (2019) paper

Posted on March 1, 2019 by curryja | 124 comments

by Ross McKitrick

Ben Santer et al. have a new paper out in Nature Climate Change arguing that with 40 years of satellite data available they can detect the anthropogenic influence in the mid-troposphere at a 5-sigma level of confidence. This, they point out, is the “gold standard” of proof in particle physics, even invoking for comparison the Higgs boson discovery in their Supplementary information.

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Posted in Attribution

Early 20th century global warming

Posted on January 23, 2019 by curryja | 377 comments

by Judith Curry

A careful look at the early 20th century global warming, which is almost as large as the warming since 1950. Until we can explain the early 20th century warming, I have little confidence IPCC and NCA4 attribution statements regarding the cause of the recent warming.

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Posted in Attribution

Beyond Milankovitch

Posted on September 8, 2018 by curryja | 375 comments

by Donald Rapp

On the terminations of Ice Ages.

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Posted in Attribution

Fundamental disagreement about climate change

Posted on May 30, 2018 by curryja | 703 comments

by Judith Curry

How can the fundamental disagreement about the causes of climate change be most effectively communicated?

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Posted in Attribution

Sea level rise acceleration (or not). Part V: detection & attribution

Posted on March 21, 2018 by curryja | 134 comments

by Judith Curry

In looking for causes, I have applied the ‘Sherlock Holmes procedure’ of eliminating one suspect after another. The procedure has left us without any good suspect. Thermal expansion was the candidate of choice at the time of the first IPCC review. The computed steric rise is too little, too late, and too linear. – Walter Munk

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Posted in Attribution, Oceans

What are the main sources of heat that account for the incremental rise in temperature on Earth?

Posted on March 9, 2018 by curryja | 227 comments

by Judith Curry

Suggestions for the climate ‘red team’ response.

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Posted in Attribution

Will advances in groundwater science force a paradigm shift in sea level rise attribution?

Posted on March 4, 2018 by curryja | 117 comments

A better accounting of natural groundwater discharge is needed to constrain the range of contributions to sea level rise. The greater the contribution from groundwater discharge, the smaller the adjustments used to amplify contributions from meltwater and thermal expansion.

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Posted in Attribution, Oceans

The Rise and Fall of Central England Temperatures: Part II

Posted on March 3, 2018 by curryja | 140 comments

by Tony Brown

This article examines the continued cooling of CET this century

Looks at a similar scenario of regional cooling in America
Examines CET related urbanisation issues, and the current Met office allowances for this
Notes the centuries long general warming of our climate.
Notes considerable English seasonal variability over the centuries
Examines the key component parts of the weather that affect the British Isles
Queries whether wind direction, strength and longevity are major factors in shaping our climate over the centuries.

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Posted in Attribution, Data and observations, History

Nature Unbound VIII – Modern global warming

Posted on February 26, 2018 by curryja | 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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Posted in Attribution, Sensitivity & feedbacks

Nature Unbound VII – Climate change mechanisms

Posted on January 21, 2018 by curryja | 68 comments

by Javier

Climate variations that alter the angular momentum of the atmosphere modify the speed of the Earth’s rotation, which affects the length of day (LOD). Alterations in LOD integrate different climate-affecting phenomena, and can anticipate turning points in climate.

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Posted in Attribution, Solar

Sea level rise acceleration (or not): Part I – Introduction

Posted on January 16, 2018 by curryja | 349 comments

by Judith Curry

Introduction and context for a new Climate Etc. series on sea level rise.

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Posted in Attribution, Climate change impacts, Oceans

Manufacturing consensus: the early history of the IPCC

Posted on January 3, 2018 by curryja | 385 comments

by Judith Curry

Short summary: scientists sought political relevance and allowed policy makers to put a big thumb on the scale of the scientific assessment of the attribution of climate change.

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Posted in Attribution, Consensus, IPCC, Sociology of science

Nature Unbound VI – Centennial to millennial solar cycles

Posted on December 2, 2017 by curryja | 129 comments

by Javier

Summary: Holocene climate has been affected in different periods by several centennial to millennial solar cycles. The ~ 1000-year Eddy solar cycle seems to have dominated Holocene climate variability between 11,500-4,000 years BP, and in the last two millennia, where it defines the Roman, Medieval, and Modern warm periods. The ~ 208-year de Vries solar cycle displays strong modulation by the ~ 2400-year Bray solar cycle, both in its cosmogenic isotope signature and in its climatic effects. The Centennial, and Pentadecadal solar cycles are observable in the last 400-year sunspot record, and they are responsible for the present extended solar minimum that started in 2008.

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Posted in Attribution, Solar

Nature Unbound IV – The 2400-year Bray cycle. Part A

Posted on July 11, 2017 by curryja | 136 comments

By Javier

The existence of a ~ 2400-year climate cycle, discovered in 1968 by Roger Bray, is supported by abundant evidence from vegetation changes, glacier re-advances, atmospheric changes reflected in alterations in wind patterns, oceanic temperature and salinity changes, drift ice abundance, and changes in precipitation and temperature. This is established with proxy records from many parts of the world.

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Posted in Attribution, Data and observations

Nature Unbound III – Holocene climate variability (Part B)

Posted on May 28, 2017 by curryja | 318 comments

by Javier

The Neoglacial has been a period of progressive cooling, increasing aridity, and advancing glaciers, culminating in the Little Ice Age. The main Holocene climatic cycle of ~ 2400 years delimits periods of more stable climatic conditions which were identified over a century ago. The stable periods are punctuated by abrupt changes.

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Posted in Attribution, Data and observations

Nature Unbound III: Holocene climate variability (Part A)

Posted on April 30, 2017 by curryja | 335 comments

by Javier

First in a two part series on Holocene climate variability.

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Posted in Attribution, Data and observations

Nature Unbound II: The Dansgaard- Oeschger Cycle

Posted on February 17, 2017 by curryja | 226 comments

by Javier

Dansgaard-Oeschger (D-O) events are the most dramatic and frequent abrupt climate change events in the geological record. They are usually explained as the result of an Atlantic Ocean salinity oscillation paced by internal variability. Available evidence however supports that they are the result of an externally paced oceanic-sea ice interaction in the Norwegian Sea. A lunisolar tidal cycle provides an unsupported hypothesis that explains all of the known evidence for the 1470-year pacing and the triggering mechanism for D-O oscillations.

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Posted in Attribution

Prospects for a Prolonged Slowdown in Global Warming in the Early 21st Century

Posted on November 30, 2016 by curryja | 274 comments

by Nic Lewis

[W]e estimate that the warming slowdown (< 0.1 K/decade trend beginning in 1998) could persist, due to internal variability cooling, through 2020, 2025 or 2030 with probabilities 16%, 11%, and 6%, respectively. – Knutson et al.

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Posted in Attribution, climate models

Nature Unbound I: The Glacial Cycle

Posted on October 24, 2016 by curryja | 269 comments

by Javier

Insights into the debate on whether the Holocene will be long or short.

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Posted in Attribution

What is the relationship between Arctic sea ice decline and Eurasian cold winters?

Posted on October 11, 2016 by curryja | 116 comments

by Judith Curry

We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. — McCusker et al.

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Posted in Attribution, Extreme events, Polar regions

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

Posted on October 2, 2016 by curryja | 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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Posted in Attribution, Sensitivity & feedbacks

Assessing the causes of early industrial-era warming

Posted on September 1, 2016 by curryja | 171 comments

by Nic Lewis

Was early onset industrial-era warming anthropogenic, as Abram et al. claim?

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Posted in Attribution

Refocusing the USGCRP

Posted on August 29, 2016 by curryja | 371 comments

by David Wojick

Our goal here is to begin to articulate a research program into the role of recent long-term natural variability in climate change.

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Posted in Attribution

Record breaking N. American winters not due to climate change

Posted on June 27, 2016 by curryja | 107 comments

by Judith Curry

A new study finds that human-caused warming in the west tropical Pacific was not responsible for a series of frigid North American winters experienced over the early 2000s.

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Posted in Attribution, Extreme events