Archives par mot-clé : IPCC

climate-debate

Serious Errors In IPCC Ocean Report Revealed

by B. Peiser, October 11, 2019 in GWPF

London, 11 October: The Global Warming Policy Foundation (GWPF) has called on the Intergovernmental Panel on Climate Change (IPCC) to correct serious errors in its recent Special Report on the Ocean and Cryosphere in a Changing Climate.

In a letter to the IPCC, Dr Benny Peiser, the GWPF’s director, has highlighted a number of errors and misinterpretations in the IPCC’s report which are based, to a significant degree, on a flawed study which was recently retracted.

In his letter, Dr Peiser points out that the IPCC’s overall conclusion on ocean heat uptake

“is based to a significant degree on a paper by Cheng et al. (2019) which itself relies on a flawed estimate by Resplandy et al. (2018). An authors’ correction of this paper and its ocean heat uptake estimate was under review for nearly a year, but in the end Nature requested that the paper be retracted (Retraction Note, 2019).”

“While the [IPCC’s] conclusion that the rate of ocean heat uptake has increased in recent years may probably be right, the evidence you cite for there being ‘high confidence’ and ‘high agreement’ is rather doubtful due to your inclusion of flawed evidence of the retracted paper by Resplandy et al. (2018).”

What is more, there is also doubt about the IPCC’s conclusion that ocean heat uptake has been accelerating in recent years. According to its own report the overall ocean heat uptake between 0-2000 m was nearly 10% higher over 1993-2017 than over the second half of that period, 2005-2017, suggesting that OHU may have been declining slightly rather than accelerating over the last 25 years.

In light of these flaws, the GWPF is calling on the IPCC to correct the evident errors and reduce its confidence rating accordingly.

Letter to the IPCC (pdf)
https://www.thegwpf.org/content/uploads/2019/10/IPCC-letter-Oct2019.pdf?utm_source=CCNet+Newsletter&utm_campaign=67a9d80e1a-EMAIL_CAMPAIGN_2019_10_11_11_33_COPY_01&utm_medium=email&utm_term=0_fe4b2f45ef-67a9d80e1a-36415357&mc_cid=67a9d80e1a&mc_eid=b9fdc60fd9

better to know...?, climate-debate

It’s Time To Move Beyond The Toy Models that Guide Climate Policy

by Roger Pielke, October 7, 2019 in Forbes

Underlying discussion and debate of climate policies are computer models that bring together idealized representations of policies, economics and climate to estimate the impacts of future climate change and the benefits of mitigation. Such models, typically called integrated assessment models, are incredibly technical and complex. At the same time, they are also simplistic toys. Here I argue that while these models are valuable for exploring concepts and ideas, they have come to serve as a huge distraction when it comes to the development of actual policies that have a chance to accelerate rates of decarbonization in the real world.

Before proceeding, it is important to note that climate change poses real risks to our collective future, and aggressive mitigation and adaptation policies make good sense. However, the pace of progress, particularly on mitigation, has been frustratingly slow.

One way that integrated assessment models warp our discussion of climate policies is through the pervasive use of what are called “baseline scenarios.” These scenarios seek to represent where the world may be headed into the future in the absence of climate policies. Here is how the Intergovernmental Panel on Climate Change (IPCC) defines such scenarios, and their role in evaluating futures with climate policy (called “mitigation scenarios”):

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Methodological debates are of course common in policy research. But in no area of policy that I have encountered over the past 30 years as a policy researcher have I come across a subject matter both as important as climate change and completely captured by one school of thought.

Scenario planning has an important role to play in the tool box of policy analysts. However, in the case of climate change, scenarios generated by integrated assessment models have overwhelmingly become the main tool of analysis in climate policy, to the exclusion of other valuable approaches. The result of this methodological myopia is that much of our collective intellectual attention has been spent on trying to figure out how to address climate change in models, and not in the real world.

climate-debate

WMO Secretary-General Warns Against Climate ‘Doomsters and Extremists’

by  Anthony Watts, Sep. 6, 2019 in WUWT

London, 6 September: The General-Secretary of the World Meteorological Organization (WMO) says that the alarmist narrative on climate change has gone off the rails and criticised the news media for provoking unjustified anxiety.

Speaking to Finland’s financial newspaper Talouselämä (“The Journal”) on 6 September 2019, Petteri Taalas called for cooler heads to prevail, saying that he does not accept arguments of climate alarmists that the end of the world is at hand.

Dr Taalas also spoke of the dangers of green extremism:

“While climate sceptisism has become less of an issue, now we are being challenged from the other side. Climate experts have been attacked by these people and they claim that we should be much more radical. They are doomsters and extremists; they make threats.”

And he called for the media both to challenge experts and allow a broader range of opinions to be heard.

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climate-debate, to keep an eye on...

Climate Scientists Admit Their Models Are Wrong

by Bud Bromley, August 30, 2019 in PrincipiaScientificInternational

Climate scientists who support human-caused global warming, for example Ben Santer and Michael Mann, authored a peer reviewed paper which acknowledges that their climate models are wrong, although their admission is buried in weasel words and technical jargon:

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In the scientific method it is not the obligation or responsibility of skeptics or “deniers” to falsify or disprove hypotheses and theories proposed by climate scientists.  It is the obligation and responsibility of climate scientists to present evidence and to defend their hypothesis.  Alarmist climate scientists have failed to do so despite the expense of billions of dollars of taxpayer money.

https://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2973.html

http://climatechangedispatch.com/the-pause-in-global-warming-is-real-admits-climategate-scientist/

Read more at budbromley.blog

climate-debate, to keep an eye on...

How the Media Help to Destroy Rational Climate Debate

by Dr Roy Spencer, August 25, 2019 in GlobalWarming

An old mantra of the news business is, “if it bleeds, it leads”. If someone was murdered, it is news. That virtually no one gets murdered is not news. That, by itself, should tell you that the mainstream media cannot be relied upon as an unbiased source of climate change information.

There are lots of self-proclaimed climate experts now. They don’t need a degree in physics or atmospheric science. For credentials, they only need to care and tell others they care. They believe the Earth is being murdered by humans and want the media to spread the word.

Most people do not have the time or educational background to understand the global warming debate, and so defer to the consensus of experts on the subject. The trouble is that no one ever says exactly what the experts agree upon.

When you dig into the details, what the experts agree upon in their official pronouncements is rather unremarkable. The Earth has warmed a little since the 1950s, a date chosen because before that humans had not produced enough CO2 to really matter. Not enough warming for most people to actually feel, but enough for thermometers to pick up the signal buried in the noise of natural weather swings of many tens of degrees and spurious warming from urbanization effects. The UN consensus is that most of that warming is probably due to increasing atmospheric CO2 from fossil fuel use (but we really don’t know for sure).

For now, I tend to agree with this consensus.

And still I am widely considered a climate denier.

Why? Because I am not willing to exaggerate and make claims that cannot be supported by data.

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The widely reported Greenland surface melt event around 1 August 2019 (green oval) was then followed by a recovery to normal in the following weeks (purple oval), which was not reported by the media.

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climate-debate

More fake five-alarm crises from the IPCC

by Paul Driessen, August 25, 2019

UN and other scientists recently sent out news releases claiming July 2019 was the “hottest month ever recorded on Earth” – nearly about 1.2 degrees C (2.2 degrees F) “above pre-industrial levels.” That era happens to coincide with the world’s emergence from the 500-year Little Ice Age. And “ever recorded” simply means measured; it does not include multiple earlier eras when Earth was much warmer than now.

Indeed, it is simply baseless to suppose that another few tenths of a degree (to 1.5 C above post-Little Ice Age levels) would somehow bring catastrophe to people, wildlife, agriculture and planet. It is equally ridiculous to assume all recent warming has been human-caused, with none of it natural or cyclical.

Moreover, as University of Alabama-Huntsville climate scientist Dr. Roy Spencer has noted, this past July was most likely not the warmest. The claim, he notes, is based on “a limited and error-prone array of thermometers which were never intended to measure global temperature trends.”

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better to know...?, climate-debate

Michael Mann Refuses to Produce Data, Loses Case

by P. Homewood, August 26, 2019 in NotaLotofPeopleKnowThat

Some years ago, Dr. Tim Ball wrote that climate scientist Michael Mann “belongs in the state pen, not Penn State.” At issue was Mann’s famous “hockey stick” graph that purported to show a sudden and unprecedented 20th century warming trend. The hockey stick featured prominently in the IPCC’s Third Assessment Report (2001), but has since been shown to be wrong. The question, in my view, is whether it was an innocent mistake or deliberate fraud on Mann’s part. (Mann, I believe, continues to assert the accuracy of his debunked graph.) Mann sued Ball for libel in 2011. Principia Scientific now reports that the court in British Columbia has dismissed Mann’s lawsuit with prejudice, and assessed costs against him.

What happened was that Dr. Ball asserted a truth defense. He argued that the hockey stick was a deliberate fraud, something that could be proved if one had access to the data and calculations, in particular the R2 regression analysis, underlying it. Mann refused to produce these documents. He was ordered to produce them by the court and given a deadline. He still refused to produce them, so the court dismissed his case.

 

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climate-debate

Looking behind the scenes of the well-orchestrated climate hysteria

by Sanjeev Sabhlok, August 22, 2019 in TheTimesofIndia

We know there is simply no basis for climate alarm. All “scientific” predictions have failed, life has survived happily with much higher CO2 in the past, the medieval warming period a thousand years ago was much warmer than today, the small temperature variations of the 20th century are easily explained by natural causes, and the IPCC reports confirm that there is no increase in extreme weather events and no economic harm from CO2.

And yet the hysteria is increasing by the day. The “remedies” being suggested are becoming more extreme: it is no longer just about making energy so expensive that the poor can’t afford it, it is now about removing meat from their diet as well.

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better to know...?, climate-debate

What the Climate Change Models Actually Say

by R. Murphy, July 20, 2019 in FoundationEconomicEducation

An Earth scientist’s recent article making the rounds on social media highlights a terrifying conversation he had with “a very senior member” of the IPCC, which is the UN’s body devoted to studying climate science. The upshot of their conversation was that millions of people will die from climate change, a conclusion that leads the author to lament that humans have created a consumption-driven civilization that is “hell-bent on destroying itself.”

As with most such alarmist rhetoric, there is little to document these sweeping claims—even if we restrict ourselves to “official” sources of information, including the IPCC reports themselves. The historical record does not justify panic, but instead should lead us to expect continued progress for humanity, so long as the normal operation of voluntary market interactions continues without significant political interference to sabotage it.

Here is the opening hook from James Dyke’s article, in which he grabs the reader with an apocalyptic conversation:

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climate-debate

La croissance du CO2 dans l’atmosphère est-elle exclusivement anthropique? (3/3)

by J.C. Maurin, 19 juillet 2019 in ScienceClimatEnergie

Effet Bombe et Modèles du GIEC

Les prévisions du climat sont générées par des modèles informatiques. Leurs concepteurs pensent pouvoir décrire l’état moyen de l’atmosphère en 2100, en prenant comme principale donnée d’entrée, le taux futur de CO2 qui constituerait donc le ‘bouton de commande’ du climat.

Il y a deux étages de modélisation : on commence par prévoir le taux de CO2 en 2100 avec des modèles sélectionnés par le GIEC (ces modèles « IRF » du GIEC sont l’objet de l’article).
Cette prévision constitue ensuite l’entrée du second étage, à savoir les modèles types « échanges radiatifs » ou « effet de serre » qui ne sont pas traités ici (mais on peut consulter ceci).
Le présent article ( qui est la suite de deux autres ici et ici) compare la réponse impulsionnelle théorique de ces modèles « IRF » avec la réponse impulsionnelle observée du 14CO2(effet Bombe).

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climate-debate, to keep an eye on...

NO EXPERIMENTAL EVIDENCE FOR THE SIGNIFICANT ANTHROPOGENIC CLIMATE CHANGE

by J. Kauppinen and P. Malmi, July 13, 2019 in Physics.gen-ph

Abstract. In this paper we wil lprove that GCM-models used inI IPCC report AR5 fail to calculate the influences of the low cloud cover changes on the global temperature. That is why those models give a very small natural temperature change leaving a very large change for the contribution of the green house gases in the observed temperature. This is the reason why IPCC has to use a very large sensitivity to compensate a too small natural component. Further they have to leave out the strong negative feedback due to the clouds in order to magnify the sensitivity. In addition, this paper proves that the changes in the low cloud cover fraction practically control the global temperature.

1. Introduction

The climate sensitivity has an extremely large uncertainty in the scientific lit- erature. The smallest values estimated are very close to zero while the highest ones are even 9 degrees Celsius for a doubling of CO2. The majority of the papers are using theoretical general circulation models (GCM) for the estimation. These models give very big sensitivities with a very large uncertainty range. Typically sensitivity values are between 2–5 degrees. IPCC uses these papers to estimate the global temperature anomalies and the climate sensitivity. However, there are a lot of papers, where sensitivities lower than one degree are estimated without using GCM. The basic problem is still a missing experimental evidence of the cli- mate sensitivity. One of the authors (JK) worked as an expert reviewer of IPCC AR5 report. One of his comments concerned the missing experimental evidence for the very large sensitivity presented in the report [1]. As a response to the com- ment IPCC claims that an observational evidence exists for example in Technical Summary of the report. In this paper we will study the case carefully.

2. Low cloud cover controls practically the global temperature

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climate-debate

Human CO2 Emissions Have Little Effect on Atmospheric CO2

by Edwin X Berry , June, 2019 in JAtmOceanSciences

Abstract
The United Nations Intergovernmental Panel on Climate Change (IPCC) agrees human CO2 is only 5 percent and natural CO2 is 95 percent of the CO2 inflow into the atmosphere. The ratio of human to natural CO2 in the atmosphere must equal the ratio of the inflows. Yet IPCC claims human CO2 has caused all the rise in atmospheric CO2 above 280 ppm, which is now 130 ppm or 32 percent of today’s atmospheric CO2. To cause the human 5 percent to become 32 percent in the atmosphere, the IPCC model treats human and natural CO2 differently, which is impossible because the molecules are identical. IPCC’s Bern model artificially traps human CO2 in the atmosphere while it lets natural CO2 flow freely out of the atmosphere. By contrast, a simple Physics Model treats all CO2 molecules the same, as it should, and shows how CO2 flows through the atmosphere and produces a balance level where outflow equals inflow. Thereafter, if inflow is constant, level remains constant. The Physics Model has only one hypothesis, that outflow is proportional to level. The Physics Model exactly replicates the 14C data from 1970 to 2014 with only two physical parameters: balance level and e-time. The 14C data trace how CO2 flows out of the atmosphere. The Physics Model shows the 14 CO2 e-time is a constant 16.5 years. Other data show e-time for 12CO2 is about 4 to 5 years. IPCC claims human CO2 reduces ocean buffer capacity. But that would increase e-time. The constant e-time proves IPCC’s claim is false. IPCC argues that the human-caused reduction of 14C and 13C in the atmosphere prove human CO2 causes all the increase in atmospheric CO2. However, numbers show these isotope data support the Physics Model and reject the IPCC model. The Physics Model shows how inflows of human and natural CO2 into the atmosphere set balance levels proportional to their inflows. Each balance level remains constant if its inflow remains constant. Continued constant CO2 emissions do not add more CO2 to the atmosphere. No CO2 accumulates in the atmosphere. Present human CO2 inflow produces a balance level of about 18 ppm. Present natural CO2inflow produces a balance level of about 392 ppm. Human CO2 is insignificant to the increase of CO2 in the atmosphere. Increased natural CO2 inflow has increased the level of CO2 in the atmosphere.
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better to know...?

Sky Abandon Facts In Favour Of Climate Propaganda

by P. Homewood, June 25, 2019 in NotaLotofPeopleKnowThat

As far as climate change is concerned, Sky News have now abandoned all pretensions to factual accuracy, in favour of blatant propaganda.

They have a new 12-minute special report, to set off a week of special reports, but if this trailer is anything to go by it’s going to be the same old garbage the BBC have served up for years:

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The use of the word “storms” in the link title, along with the phrase “climate crisis” gives a good idea of the junk that is to follow.

Let’s go through the trailer’s claims and statements:

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climate-debate

Climate science’s ‘masking bias’ problem

by Judith Curry, June 22, 2019 in WUWT

How valid conclusions often lay hidden within research reports, masked by plausible but unjustified conclusions reached in those reports.  And how the IPCC institutionalizes such masking errors in climate science.

In the previous post, we discussed the motivated biases of individual climate researchers, stimulated by the paper by Lee Jussim, Joe Duarte and others entitled Interpretations and methods: Towards a more self-correcting social psychology

The Jussim et al. paper provides additional insights that are relevant to the motivated biases in climate change, which become particularly serious and problematic once these biases are institutionalized. Here are additional excerpts from Jussim et al. for the topic I would like to discuss in this post:

<begin quotes>

“In this paper, we consider how valid conclusions often lay hidden within research reports, masked by plausible but unjustified conclusions reached in those reports. These conclusions do not necessarily involve the use of questionable research practices. Invalid conclusions may be reached based, not on failing to report dropped conditions, failed studies, or nonsignificant analyses, but on selective interpretations of data that highlight researchers’ preferred conclusions while masking more valid ones.”

JC comment: This is basically the problem that I have with the IPCC assessment reports. Deep in the chapters, there is much good information that is reliable, although the reports relatively ignore some topics. The problem is with the conclusions that are reached (particularly in the Summary for Policy Makers), and inflated levels of confidence that are ascribed to these conclusions.

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climate-debate

La croissance du CO2 dans l’atmosphère est-elle exclusivement anthropique? (1/2) et Effet Suess

by J.C. Maurin, 13 juin 2019 in ScienceClimatEnergie

Une croissance du CO2 atmosphérique qui serait exclusivement anthropique est contradictoire avec les observations du carbone 13 dans l’atmosphère (ici). Cet article en 2 parties va montrer qu’il existe également des contradictions avec les observations du carbone 14. Celui-ci  est utilisé à des fins de datation jusqu’à 50 000 ans BP  (Before Present)et on dispose de nombreuses études (pour calibration) sur son évolution dans l’atmosphère.  


La première partie s’intéresse, non pas aux datations, mais à la dilution du carbone 14 que provoque l’ajout de CO2 anthropique (effet SUESS)  avant les essais thermonucléaires de 1952-1963.
Dans la seconde partie nous verrons que l’évolution du carbone 14 après 1963 est aussi en contradiction avec une croissance du CO2 exclusivement anthropique.

1. Le carbone dans l’atmosphère [1] [5]

Le carbone existe habituellement sous 3 formes isotopiques : 12C pour ≈ 98.9% , 13C pour ≈ 1.1 % et 14C à l’état de traces (Fig. 1a).

Figure 1a.  La seule différence entre CO2 anthropique et CO2 atmosphérique réside dans les proportions du mélange des isotopes: le CO2 anthropique est appauvri en 13C et 14C.  L’ajout de CO2 anthropique va modifier, au fil des années, les proportions du mélange isotopique dans l’atmosphère.

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climate-debate

German Government Falsified Key IPCC Statement In The Translation Of “IPCC Summary Report To Policy Makers”!

by Prof. dr. H.J. Lüdecke, May 26 2019 in

(German text translated/edited by P Gosselin)
Was it sloppiness or intent? In the IPCC Summary Report for Policymakers published by the Federal Government in German, the most important statement of the original English report was falsified.

IPCC reports are available as comprehensive status reports and get strongly condensed as reports for policymakers. The latter are not to be taken as IPCC-authorized extracts as the governments concerned are allowed contribute in the writing. As a result, information or formulations from the English IPCC original which do not agree with German politics are often omitted in the German IPCC reports for policymakers. This is popularly called censorship. As a result of such falsifications, the status reports and the corresponding reports for policymakers are often contradiction.

Key finding deleted from Summary for Policymakers

One example in the past was the famous Chapter 2.6 of the AR5 Report, in which the IPCC explained in detail that no increase in extreme weather events could be found in climate periods (about 30 years) from 1950 onwards (beginning of more extensive measurements and statistics). EIKE reported on this. But in the accompanying German IPCC report for policymakers, this IPCC finding, which is hardly trivial, was nowhere to be seen.

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climate-debate

Climatologist: Climate Models Are Predicting Too Much Warming

by Dr. Benny Peiser, May 23, 2019 in GWPF

A leading climatologist has said that the computer simulations that are used to predict global warming are failing on a key measure of the climate today and cannot be trusted.

Speaking to a meeting in the Palace of Westminster in London, Professor John Christy of the University of Alabama in Huntsville told MPs and peers that almost all climate models have predicted rapid warming at high altitudes in the tropics:

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A paper outlining Dr. Christy’s key findings is published today by the Global Warming Policy Foundation.

The Tropical Skies: Falsifying climate alarm (pdf)

Contact:
Prof John Christy
christy@nsstc.uah.edu

better to know...?, climate-debate

Refuting the Smear Machine – Part 1

by Donna Laframboise, Lay 22, 2019 in BigPictureNews

When a journalist thinks for herself about climate change, insults and fabrications follow.

Two days ago I reported that a Washington, DC organization called the Government Accountability Project is smearing me on its website. I explained that PR firms target non-conformist climate reporting in an attempt to police what journalists say.

This story begins with a September 2013 opinion piece written by me and published in the Wall Street Journal. It concerned the Intergovernmental Panel on Climate Change (IPCC), and was headlined:

Warming Up for Another Climate-Change Report
Every six years, a U.N. panel issues its findings, and the media hail them as definitive. Skepticism may be in order.

Within hours, a Rockefeller Foundation funded entity called Climate Nexus released an error-riddled 600-word rebuttal that now resides on the Government Accountability Project’s official-looking website. An organization with ‘accountability’ in its name is smearing me by reprinting material whose actual author remains in the shadows, anonymous to this day.

Line by line, over the course of two blog posts, I will now respond to this collection of factual errors and lazy insults. Let us begin with the first sentence:

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better to know...?, climate-debate

‘Gimme Gimme Shock Treatment’

by Joe Bastardi, May 17, 2019 inThePatriotPost

Apparently, the new strategy to fight climate change is shock therapy. It’s like today’s environmental crusaders are channeling the Ramones song “Gimme Gimme Shock Treatment.” Here are some illustrations.

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Shock treatment is for extreme measures. But take, for example, this Dr. Willie Soon plot of solar irradiance (a measure of solar energy) vs. water vapor:

Water vapor is the number-one greenhouse gas. So it’s no secret what temperatures do when water vapor increases.
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climate-debate

New satellite data confirm real world temperature cooler than climate models

by CFACT, May 2nd, 2019

Newly published data gathered by NASA’s AIRS satellite confirm the Earth is warming more slowly than has been forecast by climate activists and the United Nations Intergovernmental Panel on Climate Change (IPCC). Data gathered from 2003 through 2017 confirm temperatures remained essentially flat from 2003 through 2015, finally rising briefly as a strong El Nino formed in 2015 and lasted into 2016 (https://ggweather.com/enso/oni.htm). Even with El Nino adding an illusory warming spike at the end of the period, temperatures still rose just over 0.2 degrees during the 15-year period. That pace works out to less than 1.5 degrees of warming per century.

IPCC initial forecasts called for 0.3 degrees Celsius of warming per decade, while skeptic forecasts have tended to hover around 0.1 degrees. As temperatures warmed more slowly than IPCC predicted, IPCC reduced its forecasts to meet skeptics in the middle, moving to a predicted 0.2 degrees warming per decade. Even so, the newly published data indicate IPCC continues to forecast more warming than real-world data indicate.

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better to know...?, climate-debate

Le GIEC au pays des merveilles

by Drieu Godefridi, 2 mai 2019 in Contrepoints

Réduire le réchauffement global sur Terre de 1,5° ? Dans un récent rapport, le Giec échafaude quatre scénarios pour y parvenir. Mais aucun d’eux ne tient la route.

es quatre scénarios mettent en œuvre à des degrés divers les techniques dites de Carbon Dioxide Removal (CDR), qui compensent les émissions humaines de CO2. Écoutons les experts « scientifiques » du GIEC — dont la plupart ne sont pas scientifiques. Lisons les experts du GIEC :

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climate-debate

What’s the worst case? Climate sensitivity

by Judith Curry, April 1, 2019 in WUWT

Are values of equilibrium climate sensitivity > 4.5 C plausible?

For background, see these previous posts on climate sensitivity [link]

Here are some possibilistic arguments related to climate sensitivity.  I don’t think the ECS example is the best one to illustrate these ideas [see previous post], and I probably won’t include this example in anything I try to publish on this topic (my draft paper is getting too long anyways).  But possibilistic thinking does point you in some different directions when pondering the upper bound of plausible ECS values.

5. Climate sensitivity

Equilibrium climate sensitivity (ECS) is defined as the amount of temperature change in response to a doubling of atmospheric CO2 concentrations, after the climate system has reached equilibrium. The issue with regards to ECS is not scenario discovery; rather, the challenge is to clarify the upper bounds of possible and plausible worst cases.

The IPCC assessments of ECS have focused on a ‘likely’ (> 66% probability) range, which has mostly been unchanged since Charney et al. (1979), to be between 1.5 and 4.5 oC. The IPCC AR4 (2007) did not provide any insight into a worst-case value of ECS, stating that values substantially higher than 4.5 oC cannot be excluded, with tail values in Figure 9.20 exceeding 10 oC. The IPCC AR5 (2013) more clearly defined the upper range, with a 10% probability of exceeding 6 oC.

Since the IPCC AR5, there has been considerable debate as to whether ECS is on the lower end of the likely range (e.g., < 3 oC) or the higher end of the likely range (for a summary, see Lewis and Curry, 2018). The analysis here bypasses that particular debate and focuses on the upper extreme values of ECS.

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better to know...?, climate-debate

Methane warming exaggerated by 400%

by Barry Brill, March 30, 2019 in WUWT

The IPCC’s AR5 estimated the global warming caused by a tonne of livestock methane would be 28 times that of a tonne of carbon dioxide. New research destroys that estimate.

The war on meat has been gathering pace amongst our Western elites. The Economist makes a detailed case for “plant-based food” in the interests of quelling climate change –

The FAO calculates that cattle generate up to two-thirds of the greenhouse gases from livestock, and are the world’s fifth largest source of methane. If cows were a country, the United Herds of Earth would be the planet’s third largest greenhouse-gas emitter.

These calculations are based on figures supplied by the IPCC’s AR5, which contends that the global warming potential (GWP) of methane over 100 years is no less than 28 times the global warming it expects to be caused by an equivalent weight of carbon dioxide. This estimate is up from the GWP of 21 put forward in the IPCC’s previous report.

All this is now challenged by a new and authoritative research paper, Allen et al (2017): “A solution to the misrepresentations of CO2-equivalent emissions of short-lived climate pollutants, under ambitious mitigation”. This paper finds that conventional GWPs misrepresent the impact of short-lived gases (such as methane) on global temperature – and recommends the adoption of a new metric, denoted as GWP*.

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climate-debate

Exagérations climatiques extrêmes

by Jean N., 14 mars 2019 in ScienceClimatEnergie

Il ne se passe pas une journée sans que l’on entende ou lise dans les médias que le climat est “déréglé” et qu’il y a de plus en plus d’évènements climatiques extrêmes. Et de nombreux scientifiques semblent penser la même chose. Par exemple, une pétition publiée fin janvier 2019 et signée par 3400 scientifiques belges, déclare au point 3 : “Le seul réchauffement actuel de 1°C entraîne déjà une augmentation de l’occurrence et de l’intensité des extrêmes climatiques tels que les canicules, les sécheresses ou encore les inondations.” Aucune référence n’est malheureusement donnée par les signataires de la pétition… Ces phénomènes climatiques sont-ils exagérés? Consultons donc le dernier rapport du GIEC, l’AR5 publié en 2013, et particulièrement le chapitre 2 qui traite des évènements climatiques extrêmes (depuis 2013, le GIEC n’a plus rien publié d’aussi complet sur le sujet). Préparez-vous à être surpris!

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Figure 1. Extrait de la Table SPM.1 concernant les évènements climatiques extrêmes dans le résumé pour décideurs du rapport AR5 du GIEC. Sur 9 phénomènes climatiques extrêmes seulement 5 sont présentés dans la table par le GIEC. Le texte noir sont des conclusions tirées par l’AR5. Les textes en rouge et en bleu sont des conclusions plus anciennes (AR4 et rapport SREX). A droite, “OK Ch.2” indique que le résumé est correct par rapport au texte; le triangle rouge “attention”, indique que des informations importantes sont manquantes et peuvent induire en erreur.