Archives par mot-clé : Model(s)

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PUTTING CLIMATE CHANGE CLAIMS TO THE TEST

by John Christy, June 18, 2019 in GWPF

This is a full transcript of a talk given by Dr John Christy to the GWPF on Wednesday 8th May.

When I grew up in the world of science, science was understood as a method of finding information. You would make a claim or a hypothesis, and then test that claim against independent data. If it failed, you rejected your claim and you went back and started over again. What I’ve found today is that if someone makes a claim about the climate, and someone like me falsifies that claim, rather than rejecting it, that person tends to just yell louder that their claim is right. They don’t look at what the contrary information might say.

OK, so what are we talking about? We’re talking about how the climate responds to the emission of additional greenhouse gases caused by our combustion of fossil fuels. In terms of scale, and this is important, we want to know what the impact is on the climate, of an extra half a unit of forcing amongst total forcings that sum to over 100 units. So we’re trying to figure out what that signal is of an extra 0.5 of a unit.

Here is the most complicated chart I have tonight, and I hope it makes sense:

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climate-debate

Why Climate Models Can’t Predict The Future (And Never Have)

by Jay Lehr, June 11, 2019 in Climate ChangeDispatch

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SEE ALSO: Climate Models Of Incompetence

Consider the following: we do not know all the variables that control our climate, but we are quite sure they are likely in the hundreds.

Just take a quick look at ten obviously important factors for which we have limited understanding:

1- Changes in seasonal solar irradiation;

2- Energy flows between ocean and atmosphere;

3- Energy flow between air and land;

4- The balance between Earth’s water, water vapor, and ice;

5- The impacts of clouds;

6- Understanding the planet’s ice;

7- Mass changes between ice sheets, sea level and glaciers;

8- The ability to factor in hurricanes and tornadoes;

9- The impact of vegetation on temperature;

10- Tectonic movement on ocean bottoms.

Yet, today’s modelers believe they can tell you the planet’s climate decades or even a century in the future and want you to manage your economy accordingly.

Dr. Willie Soon of the Harvard-Smithsonian astrophysics laboratory once calculated that if we could know all the variables affecting climate and plugged them into the world’s largest computer, it would take 40 years for the computer to reach an answer.

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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

unclassified

Circular reasoning with climate models

by Dr. Wojick, March 1, 2018 in CFact

Climate models play a central role in the attribution of global warming or climate change to human causes. The standard argument takes the following form: “We can get the model to do X, using human causes, but not without them, so human causes must be the cause of X.” A little digging reveals that this is actually a circular argument, because the models are set up in such a way that human causes are the only way to get change.

The finding is that humans are the cause of global warming and climate change is actually the assumption going in. This is circular reasoning personified, namely conclude what you first assume.

This circularity can be clearly seen in what many consider the most authoritative scientific report on climate change going, although it is actually just the most popular alarmist report. We are talking about the Summary for Policymakers (SPM), of the latest assessment report (AR5), of the heavily politicized UN Intergovernmental Panel on Climate Change (IPCC). Their 29 page AR5 SPM is available here.

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40387018 – the raging whirlpool
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Global-scale multidecadal variability missing in state-of-the-art climate models

by S. Kravstov et al. 2018, in Nature

Reliability of future global warming projections depends on how well climate models reproduce the observed climate change over the twentieth century. In this regard, deviations of the model-simulated climate change from observations, such as a recent “pause” in global warming, have received considerable attention. Such decadal mismatches between model-simulated and observed climate trends are common throughout the twentieth century, and their causes are still poorly understood. Here we show that the discrepancies between the observed and simulated climate variability on decadal and longer timescale have a coherent structure suggestive of a pronounced Global Multidecadal Oscillation. Surface temperature anomalies associated with this variability originate in the North Atlantic and spread out to the Pacific and Southern oceans and Antarctica, with Arctic following suit in about 25–35 years. While climate models exhibit various levels of decadal climate variability and some regional similarities to observations, none of the model simulations considered match the observed signal in terms of its magnitude, spatial patterns and their sequential time development. These results highlight a substantial degree of uncertainty in our interpretation of the observed climate change using current generation of climate models.

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climate-debate

Reassessing the RCPs

by Kevin Murphy in Judith Curry, January 28, 2019 in ClimateEtc.

A response to: “Is RCP8.5 an impossible scenario?”. This post demonstrates that RCP8.5 is so highly improbable that it should be dismissed from consideration, and thereby draws into question the validity of RCP8.5-based assertions such as those made in the Fourth National Climate Assessment from the U.S. Global Change Research Program.

Analyses of future climate change since the IPCC’s 5th Assessment Report (AR5) have been based on representative concentration pathways (RCPs) that detail how a range of future climate forcings might evolve.

Several years ago, a set of RCPs were requested by the climate modeling research community to span the range of net forcing from 2.6 W/m2 to 8.5 W/m2 (in year 2100 relative to 1750) so that physics within the models could be fully exercised. Four of them were developed and designated as RCP2.6, RCP4.5, RCP6.0 and RCP8.5. They have been used in ongoing research and as the basis for impact analyses and future climate projections.

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Figure 2. History and forecasts of CO2 concentration. RCP8.5 is defined by 936 ppm in 2100.

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Simplest climate model yet – a bathtub

by Charles the moderator, January 18, 2019 in WUWT

Climate change: How could artificial photosynthesis contribute to limiting global warming?

Scientists calculate areas needed for forestation and artificial photosynthesis.

After several years during which global emissions at least stagnated, they rose again somewhat in 2017 and 2018. Germany has also clearly missed its climate targets. In order to keep global warming below 2 degrees Celsius, only about 1100 gigatonnes of CO2 may be released into the atmosphere by 2050[1]. And In order to limit global warming to 1.5 degrees, only just under 400 gigatonnes of CO2 may be emitted worldwide. By 2050, emissions will have to fall to zero even. Currently, however, 42 gigatonnes of CO2 are added every year.

Almost all the various scenarios require “negative emissions”

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climate-debate

Regional Models: 3-10°C Warming In The Next 80 Years. Observations: No Warming In The Last 40-100 Years.

by K. Richard, January 14, 2019 in NoTricksZone

There are large regions of the globe where observations indicate there has been no warming (even cooling) during the last decades to century. Climate models rooted in the assumption that fossil fuel emissions drive dangerous warming dismiss these modeling failures and project temperature increases of 3° – 10°C by 2100 for these same regions anyway.

Image Source: Partridge et al., 2018

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climate-debate

Evolutions récentes du CO2 atmosphérique (3/4)

by J.C. Maurin, 12 novembre 2018 in ScienceClimatEnergie

L’IPCC (GIEC en français) fut créé en 1988 par l’UNEP (United Nations Environment Programme) et le WMO (World Meteorological Organization). Dans les principes régissant les travaux du GIEC (1) on lit : Le GIEC a pour mission d’évaluer … les risques liés au changement climatique d’origine humaine.  Le GIEC respecte son propre principe fondateur : il attribue l’intégralité de la hausse du taux de CO2 depuis 1958 à une cause anthropique. Nous examinerons ici le modèle anthropique du GIEC et nous le confronterons aux mesures contemporaines, puis à un modèle mixte. Cet article fait suite aux deux précédents publiés sur le site SCE au cours des mois de septembre (1/4) et octobre 2018 (2/4).

C.   Modèle anthropique GIEC

C.1   Les contraintes des modèles (Fig. 1)

Le paragraphe A (article 1/4) a montré qu’en 1980 le taux de CO2 atmosphérique était de 338 ppm et le  δ13C de -7.6 ‰. En  2010 le taux de CO2  atmosphérique était de 388 ppm et le δ13C de -8.3 ‰. Il existe une modulation annuelle de ce taux, très marquée dans l’hémisphère Nord.

 

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climate-debate

Interview exclusive: Henri Masson, Université d’Anvers, déclare les modèles du GIEC « aberration statistique »

by Henri Masson, 10 mars 2012, in Contrepoints

Des modèles, cela fait 40 ans que j’en fais », précise d’emblée Henri Masson. Ingénieur chimiste de formation (Université Libre de Bruxelles), docteur en sciences appliquées, professeur émérite à l’Université d’Anvers, expert globe-trotter (notamment pour la Banque Mondiale et l’ONU), l’homme est, de surcroît, doté d’un sérieux sens de la vulgarisation. Lorsque Contrepoints lui propose d’analyser les modèles prédictifs du GIEC, le Belge est catégorique : « Si mes étudiants me présentaient de tels modèles, je n’hésiterais pas à les recaler ! »

Contrepoints : Quelle confiance peut-on accorder aux modèles du GIEC, qui prévoient, parmi d’autres choses, un réchauffement planétaire dû aux émissions humaines de CO2 ?

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climate-debate

Evolutions récentes du CO2 atmosphérique (3/4)

by J.C. Maurin, 12 novembre 2018 in  ScienceClimatEnergie

L’IPCC (GIEC en français) fut créé en 1988 par l’UNEP (United Nations Environment Programme) et le WMO (World Meteorological Organization). Dans les principes régissant les travaux du GIEC (1) on lit : Le GIEC a pour mission d’évaluer … les risques liés au changement climatique d’origine humaine.  Le GIEC respecte son propre principe fondateur : il attribue l’intégralité de la hausse du taux de CO2 depuis 1958 à une cause anthropique. Nous examinerons ici le modèle anthropique du GIEC et nous le confronterons aux mesures contemporaines, puis à un modèle mixte. Cet article fait suite aux deux précédents publiés sur le site SCE au cours des mois de septembre (1/4) et octobre 2018 (2/4).

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C.4.  Conclusions

  • Un modèle qui décrit un monde fixe, en équilibre, un modèle où l’homme est central, un modèle qui parvient à reproduire certaines observations mais pas toutes, un modèle unanimement soutenu par les autorités politiques ou morales, enfin un modèle qui pose a priori un principe intangible… est le type même de modèle qui fut développé  par Ptolémée (6) pour le système solaire. Ce modèle fut jadis l’objet d’un consensus  à  > 97%.

  • L’atmosphère actuelle comporte environ 20 ppm de CO2 anthropique correspondant à 20/400 soit ≈ 5% du CO2 atmosphérique. En un siècle les hommes ont donc modifié la composition de l’atmosphère de 20 ppm soit 0,002% : sur ce sujet également, il semble que nous ne soyons pas au centre du monde.

  • Les évolutions récentes du CO2 atmosphérique ne peuvent pas avoir une cause uniquement anthropique: les observations du δ13C l’interdisent. Les causes sont anthropiques et naturelles. Le modèle purement anthropique du GIEC est donc à rejeter.

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At IPCC talks Trump Administration emphasizes scientific “uncertainty” and “value of fossil fuels”… MAGA!

by David Middleton, October 4, 2018 in WUWT

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95% of the model runs predicted more warming than the RSS data since 1988… And this is the Mears-ized RSS data, the one in which the measurements were influenced to obtain key information (erase the pause and more closely match the surface data).

Their “small discrepancy” would be abject failure in the oil & gas industry.

The observed warming has been less than that expected in a strong mitigation scenario (RCP4.5).

Output of 38 RCP4.5 models vs observations.   The graph is originally from Carbon Brief.  I updated it with HadCRUT4, shifted to 1970-2000 baseline, to demonstrate the post-El Niño divergence.

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The ‘Trick’ of Anomalous Temperature Anomalies

by Kip Hansen, September 25, 2018 in WUWT

It seems that every time  we turn around, we are presented with a new Science Fact that such-and-so metric — Sea Level Rise, Global Average Surface Temperature, Ocean Heat Content, Polar Bear populations, Puffin populations — has changed dramatically — “It’s unprecedented!” — and these statements are often backed by a graph illustrating the sharp rise (or, in other cases, sharp fall) as the anomaly of the metric from some baseline.  In most cases, the anomaly is actually very small and the change is magnified by cranking up the y-axis to make this very small change appear to be a steep rise (or fall).

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climate-debate

A Test of the Tropical 200- to 300-hPaWarming Rate in Climate Models

by R. McKitrick and J. Christy, July 6, 2018 in AGU100

Abstract
Overall climate sensitivity to CO2
doubling in a general circulation model results from a complex
system of parameterizations in combination with the underlying model structure. We refer to this as the model’smajor hypothesis, and we assume it to be testable. We explain four criteria that a valid test should meet: measurability, specificity, independence, and uniqueness. We argue that temperature change in the
tropical 200- to 300-hPa layer meets these criteria. Comparing modeled to observed trends over the past
60 years using a persistence-robust variance estimator shows that all models warm more rapidly than
observations and in the majority of individual cases the discrepancy is statistically significant. We argue that
this provides informative evidence against the major hypothesis in most current climate models.
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climate-debate

Weather and Climate in the Real World

by Tim Ball, August 18, 2018 in WUWT

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All the trillions of dollars spent on AGW have not improved forecasting one bit. Instead, it diverted money that could have helped those large, primary sectors of society and economy that need better and more appropriate information. It is time to close all government weather offices or at least reduce their function to data collection determined by the end users.

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Why does climate sensitivity increase over time in models? A look at two possibilities

by A. Zaragoza Comendador, August 16, 2018 in WUWT

Note: if the terms used in this article seem confusing, check out the previous one.

Introduction

It’s well known that climate models show increasing sensitivity over time: for a given forcing, the true long-term temperature increase (ECS) is higher than what you’d estimate if you simply extrapolated from the past (ECS_hist). In other words, the ECS-to-ECS_hist ratio is above 1. This article tries to work out why climate models behave like that; that is to say, the variable I’m trying to explain is the ECS-to-ECS_hist ratio.

Now, there’s probably too many hyphens and underscores in the text. So it will be more readable if I clarify that, every time I talk simply about ‘correlation’, I mean the correlation of thing X with the ECS-to-ECS_hist ratio. If other kind of correlation is mentioned, I’ll say so explicitly.

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climate-debate

The Major Change in the Global Warming Groupthink Between 1990 and 1995

byTim Ball, August 12, 2018 in WUWT

Somebody said economists try to predict the tide by measuring one wave. This puts them in the same league as climate scientists trying to predict the climate by measuring one variable, CO2. It is no surprise that an amalgam of the two, climate and economics, produces even worse results, but that is what happened early in the anthropogenic global warming (AGW) deception.

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climate-debate

A Global Warming Hiatus in Northeast China

by Sun X. et al., 2018 in CO2Science

Paper Reviewed
Sun, X., Ren, G., Ren, Y., Fang, Y., Liu, Y., Xue, X. and Zhang, P. 2018. A remarkable climate warming hiatus over northeast China since 1998. Theoretical and Applied Climatology 133: 579-594.

A prominent feature of all climate model projections is their prediction that temperatures should be rising in response to ever-increasing concentrations of greenhouse gases. However, for the past two decades global surface air temperatures have not warmed to the degree predicted by the models, which lack of warming has been a conundrum to the climate alarmist movement.

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climate-debate

108 Graphs From 89 New Papers Invalidate Claims Of Unprecedented Global-Scale Modern Warmth

by K. Richard, August 2, 2018 in NoTrickZone

During 2017, there were 150 graphs from 122 scientific papers published in peer-reviewed journals indicating modern temperatures are not unprecedented, unusual, or hockey-stick-shaped — nor do they fall outside the range of natural variability.  We are a little over halfway through 2018 and already  108 graphs from 89 scientific papers undermine claims that modern era warming is climatically unusual.

For the sake of brevity, just 13 (15%) of the 89 new papers are displayed below.

The rest of the non-hockey-stick scientific papers and graphs published thus far in 2018 can be viewed by clicking the link below.

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climate-debate

German Scientists: Chris Folland’s Findings On Climate Models “Good For a Loud Laugh”…”Pulling Tricks Like Troopers”

by Dr S. Lüning and Prof. F. Vahrenholt, July 25, 2018 in NoTricksZone

The temperature of the last 100 years was also the topic of a new publication by Folland et al. 2018. The authors are very much at home in the camp of the IPCC and had to admit that there have been phases of cooling, stagnating or even slow warming: 1896 – 1910, 1941 – 1975, and 1998 – 2013.

Climate models struggle with this because CO2 is climbing steadily. So why does climate warming stall under these conditions? Folland and his colleagues examined the models and are convinced that despite the small problems, the models function perfectly well and thus no other climate factors need to be accounted for.

In 1940s it was a bit too warm and the models were unable to reproduce this. Given, the authors say. Greenhouse gases have been responsible for almost all the warming of the last 125 years.

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Now isn’t it a bit odd that the authors made absolutely no mention of the ocean cycles in the abstract? As our regular readers know, the ocean cycles run surprisingly synchronous with the fluctuations in global temperatures, i.e. the key factors here are the AMO and PDO.

PDO ocean cycle and its fluctuations in the global temperature development. Source: Book ‘Die kalte Sonne‘.

climate-debate

Global Temperature Rise Some 75% Lower Than Models Projected!

by P. Gosselin, July 18, 2018 in NoTricksZone

No matter how hard climate-catastrophe obsessed alarmists attempt to beat out a little doom from the data, their results still fall far way short of their projections. Moreover, the modest warming the planet has seen over the recent decades is tied more to natural cycles.

Chart: P Gosselin, using WoodForTrees data.

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Ross McKitrick: All those warming-climate predictions suddenly have a big, new problem

by Ross McKitrick, June 20, 2018 in FinancialPost

One of the most important numbers in the world goes by the catchy title of Equilibrium Climate Sensitivity, or ECS. It is a measure of how much the climate responds to greenhouse gases. More formally, it is defined as the increase, in degrees Celsius, of average temperatures around the world, after doubling the amount of carbon dioxide in the atmosphere and allowing the atmosphere and the oceans to adjust fully to the change. The reason it’s important is that it is the ultimate justification for governmental policies to fight climate change.

The United Nations Intergovernmental Panel on Climate Change (IPCC) says ECS is likely between 1.5 and 4.5 degrees Celsius, but it can’t be more precise than that. Which is too bad, because an enormous amount of public policy depends on its value. People who study the impacts of global warming have found that if ECS is low — say, less than two — then the impacts of global warming on the economy will be mostly small and, in many places, mildly beneficial.

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climate-debate

100% Of Climate Models Prove that 97% of Climate Scientists Were Wrong!

by Eric Holthaus, May 2018 , in Climatism

SEPTEMBER 2017

Dr. Christy was 100% correct …

A landmark paper by warmist scientists in Nature Geoscience now concedes the world has indeed not warmed as predicted, thanks to a slowdown in the first 15 years of this century. One of its authors, Michael Grubb, professor of international energy and climate change at University College London, admits his past predictions of runaway warming were too alarmist.

“When the facts change, I change my mind. We are in a better place than I thought.”

ANOTHER author, Myles Allen, professor of geosystem science at Oxford, confessed that too many of the mathematical models used by climate scientists to predict future warming “were on the hot side” — meaning they exaggerated.

“We haven’t seen that rapid acceleration in warming after 2000 that we see in the models.” 

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climate-debate

How Not To Model The Historical Temperature

by Willis Eschenbach, March 24, 2018 in WUWT

Much has been made of the argument that natural forcings alone are not sufficient to explain the 20th Century temperature variations. Here’s the IPCC on the subject:

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I’m sure you can see the problems with this. The computer model has been optimized to hindcast the past temperature changes using both natural and anthropogenic forcings … so of course, when you pull a random group of forcings out of the inputs, it will perform more poorly.