Monthly Archives: January 2011

Publication Of “Comments on ‘A Unified Modeling Approach to Climate System” By R. A. Pielke Sr And “Reply” By Hurrell Et Al 2010

After a year and a half (- since September 24 2009 – see), the Bullein of the American Meterological Society has finally published my Comment on the article

James Hurrell, Gerald A. Meehl, David Bader, Thomas L. Delworth, Ben Kirtman, Bruce Wielicki
Bulletin of the American Meteorological Society, 2009: A Unified Modeling Approach to Climate System Prediction; Volume 90, Issue 12 (December 2009) pp. 1819-1832

My article is

Comments on “A Unified Modeling Approach to Climate System Prediction” by Roger A. Pielke Sr.

and the Hurrell at al reply is

Reply –  James W. Hurrell, Gerald A. Meehl, Dave Bader, Thomas L. Delworth, Ben Kirtman, Bruce Wielick.

I am commenting on the Hurrell et al Reply below. I have excerpted text from their Reply and commented below each excerpt

“Modeling evidence to date demonstrates long-term climate change is primarily a boundary value problem associated with changes in radiative forcing.”

This statement conflicts with the extensive evidence that climate is significantly affected by forcings beyond radiative forcings. For example, in

National Research Council, 2005: Radiative forcing of climate change: Expanding the concept and addressing uncertainties. Committee on Radiative Forcing Effects on Climate Change, Climate Research Committee, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, The National Academies Press, Washington, D.C., 208 pp

it is reported that

“Several types of forcings—most notably aerosols, land-use and land-cover change, and modifications to biogeochemistry—impact the climate system in nonradiative ways, in particular by modifying the hydrological cycle and vegetation dynamics. Aerosols exert a forcing on the hydrological cycle by modifying cloud condensation nuclei, ice nuclei, precipitation efficiency, and the ratio between solar direct and diffuse radiation received. Other nonradiative forcings modify the biological components of the climate system by changing the fluxes of trace gases and heat between vegetation, soils, and the atmosphere and by modifying the amount and types of vegetation. No metrics for quantifying such nonradiative forcings have been accepted. Nonradiative forcings have eventual radiative impacts, so one option would be to quantify these radiative impacts. However, this approach may not convey appropriately the impacts of nonradiative forcings on societally relevant climate variables such as precipitation or ecosystem function.”

The recently (2010) adopted official American Meteorological Society statement Inadvertent Weather Modification contains the text

“The cumulative changes in surface and atmospheric heat and moisture profiles [from aerosol radiative effects, cloud-mediated effects of aerosols, and changes in land use] modify atmospheric circulation and weather patterns on all scales, including synoptic storm tracks, in ways that are just beginning to be explored. In the aggregate, these changes can affect air quality, ecosystems, and water resources. The cumulative impacts of inadvertent weather modification may thus result in local or regional-scale climatic alterations superimposed on, and interacting with, natural and GHG-induced climate variability and change”


” High-priority research and new technological capabilities are required to improve understanding of the impacts of inadvertent weather modification………..research efforts on unintended weather modification should be recognized as addressing parts of the broader question of climate variability and change, which crosses geopolitical boundaries.”

Hurrell et al continue in their Reply

Pielke (2010) confuses the distinction between predicting the evolution of individual weather events beyond two weeks or so and the possibility of predicting changes in the statistics of weather events. Changes in forcing external to the climate system, as well as the amplification or diminution of the resulting changes in climate due to feedback mechanisms, can lead to predictable changes in weather statistics.

Unfortunately, the confusion is not mine.  The only difference between weather forecasts of daily weather and the forecasts of the statistics of weather (i.e., “climatology) is the averaging time. For example, a 24 hour average temperature for tomorrow, January 20 2011 is clearly considered weather (an average over 24 hours). However, so is the 2011-2020 average temperature for those ten January 20ths.

Hurrell et al also write

Consider the proven ability of climate models to simulate the annual cycle of seasonal variations (i.e., the changes in climate from winter to summer) or their ability to capture past excursions of climate resulting from changes in both natural and anthropogenic forcing, including the amount of solar energy reaching Earth, the amount of particulate matter in the atmosphere from volcanic eruptions, and atmospheric concentrations of anthropogenic gases and particles. The impressive fidelity of the twentieth-century climate simulations assessed in the latest report of the Intergovernmental Panel on Climate Change (Solomon et al. 2007) is a good example….

The models have been successful in simulating the annual cycle.   However, there has not been skill in predicting changes in the climate system despite what Hurell et al wrote. As just one (excellent) example, the paper

Anagnostopoulos, G. G., Koutsoyiannis, D., Christofides, A., Efstratiadis, A. & Mamassis, N. (2010) A comparison of local and aggregated climate model outputs with observed data. Hydrol. Sci. J. 55(7), 1094–1110.

concludes that

We compare the output of various climate models to temperature and precipitation observations at 55 points around the globe.We also spatially aggregate model output and observations over the contiguous USA using data from 70 stations, and we perform comparison at several temporal scales, including a climatic (30-year) scale. Besides confirming the findings of a previous assessment study that model projections at point scale are poor, results show that the spatially integrated projections are also poor.

Hurrell et al also write

“….there is ample evidence that climate models can capture nonlinear change thresholds and feedbacks (e.g., Holland et al. 2006; Pitman and Stouffer 2006).”

We report in our paper (with specific examples)

Rial, J., R.A. Pielke Sr., M. Beniston, M. Claussen, J. Canadell, P. Cox, H. Held, N. de Noblet-Ducoudre, R. Prinn, J. Reynolds, and J.D. Salas, 2004: Nonlinearities, feedbacks and critical thresholds within the Earth’s climate system. Climatic Change, 65, 11-38

that the

“Earth’s climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilibria are the norm….there is a relatively poor understanding of the different types of nonlinearities, how they manifest under various conditions .and whether they reflect a climate system driven by astronomical forcings, by internal feedbacks, or by a combination of both.”

The claim by Hurrell et al that “climate models can capture nonlinear change thresholds and feedbacks”  grossly overstates their capabilities. They have failed, for example, to skillfully predict (or even simulate) the time evolution of such major climate features as El Niño, La Niña, the Pacific Decadal Ocsillation and the North Atlantic Oscillation. One of the examples that Hurrell et al present to bolster their claim that “that climate models can capture nonlinear change thresholds”   [Holland et al, 2006: Future abrupt reductions in summer arctic sea ice] is a model prediction for the coming decades! 

The excerpt from Hurrell et al is

“We do agree with Pielke (2010) that the effects of initial conditions and the presence of significant nonlinearities become more important when regional climate change over the next few decades is considered…”

This statement appears to almost completely refute what they reported earlier in their Reply where they wrote 

“Modeling evidence to date demonstrates long-term climate change is primarily a boundary value problem associated with changes in radiative forcing.”

Thus while I appreciate the opportunity to have a Comment/Reply interaction with the authors of the Hurrell et al 2009 paper. they remain unresolved issues they have not yet adequately addressed.

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Confessions In The News On The “Predictability” Of The Climate System

I was alerted to a post on Climate Progress (h/t to Dan Hughes) titled

Another terrific ABC News story — on the role global warming is playing in extreme winter weather

where it is written

“ABC news contacted 10 climate scientists to ask their take, if the extreme winter like the one we’re having is the way of the future.  The consensus:  global warming is playing a role by shifting weather patterns in unpredictable ways.  Many say the forecast for the future calls for record-breaking precipitation and extreme temperatures year-round — and that means winter with more snow”

This statement encapsulates where we are in being able to predict the climate in the coming years and decades. Climate, as affected by both natural and human forcings and feedback, is unpredictable on these time scales!

The message that weather patterns shift in unpredictable ways is one the policymakers and others should recognize. While added CO2 undoubtedly plays a role, there are other first order human climate forcings as well as the effect of poorly understood natural variations.

As we wrote in our paper

Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell,  W. Rossow,  J. Schaake, J. Smith, S. Sorooshian,  and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union

we concluded, with respect to human climate forcings,  that

“…..the 2007 Intergovernmental Panel on Climate Change (IPCC) assessment did not sufficiently acknowledge the importance of these other human climate forcings in altering regional and global climate and their effects on predictability at the regional scale.”

The hypothesis that we reported in our paper as being supported by real world data is

“Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first-order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades”

differs significantly from the 2007 IPCC conclusions.

The ABC news article interview of the climate scientists is actually a confession of the failure of the scientific robustness of the 2007 IPCC WG 1 report.

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Guest Post “Global Floods – Why Were They Not Predicted?” By Will Alexander

Will Alexander has provided us with another excellent guest post which is presented below.  WJR (Will) Alexander is Professor Emeritus of the Department of Civil Engineering of the University of Pretoria, South Africa, and Honorary Fellow of the South African Institution of Civil Engineering. See also his previous posts

Climate Change: The West vs The Rest by Will Alexander

A Guest Weblog By Will Alexander “Climategate Chaos”


Memo 01/11

Will Alexander alexwjr[at]

Monday 17 January 2011 while on holiday with our family in Adelaide, Australia.

Global floods – why were they not predicted?

Do you recall the following quote in my semi-final Memo 15/10 of  2 August 2010?

Scientific predictability also raises the question of the scientist’s ethical responsibilities. His conclusions must be guided by respect for truth and an honest acknowledgment of both the accuracy and the inevitable limitations of the scientific method. Certainly this means avoiding needlessly alarming predictions when these are not supported by sufficient data or exceed science’s actual ability to predict. But it also means avoiding the opposite, namely a silence, born of fear, in the face of genuine problems.
    –Pope Benedict XVI, 6 November 2006

My subsequent Memo 16/10 dated 2 August last year was titled Final Summary. It was intended to be my time to say goodbye. The last six months of 2010 were particularly stressful both personally and professionally. Our son died of cancer and I had problems with our Water Research Commission.

In June 2008 my general interest article “Likelihood of a global drought in 2009 to 2016″ was published in Civil Engineering. Droughts followed within months along the southern Cape coast and the adjacent interior as well as elsewhere in South Africa, Australia and other regions. Seawater desalination plants had to be constructed at Sedgefield and Plettenburg Bay as well as in Australia.

Those who took the trouble to study my 2008 article would have noticed the abundantly clear, sudden alternating sequences of high and low values in the hydrometeorological time series. Floods follow droughts as night follows day. This photograph of the flood in the Orange River at Aughrabies Falls in South Africa was taken on the same day as severely damaging floods entered Brisbane in Australia. It was also simultaneous with the loss of life by severe floods in Sri Lanka and Brazil. They were not the worst on record.


Flood in the Orange River at Aughrabies Falls in South Africa on 12 January 2011.

I now have a simple question. Were these global extremes the consequence of weather or climatic phenomena?   Nobody seems to know. In either case the answer is irrelevant. The claimed consensus views of hundreds of climate change scientists are fundamentally erroneous. Hundreds of peer reviewed papers published in the hydrological literature during the past 50 years demonstrated that climate is NOT a steady state phenomenon. Also, together with my colleagues, research assistants and students we demonstrated that variations in regional climate are the consequence of variations in the receipt and poleward redistribution of solar energy via the global oceanic and atmospheric processes. We could not find any evidence to support the views that these variations are the consequence of human activities. Unfortunately we encountered the same indifference that David Livingstone encountered during his missionary expeditions in Central Africa.

UK Met Office in deep water

The following comments are based on information from the Internet. It appears that routine studies by the UK Met Office last October indicated the possibility of severe winter conditions in the months ahead. The Met Office warned the authorities but not the public. This is a routine procedure where there is a measure of uncertainty about the forecast. The authorities then issue standby alerts to the organisations that will be involved should the events occur.

The problem arose when the Met Office also issued its own forecasts that deliberately withheld this information from the public in view of the level of uncertainty. Confusion arose when the authorities failed to issue the standby alerts and subsequent warnings to the public.

Normally this would be a domestic matter for the UK authorities to resolve. However, it is now very clear that this was a global climatic disturbance. So we must now ask a fundamentally important question. Why was it not predicted by all those international agencies with their sophisticated and costly global climate computer models?

Their self-made problem is that they have become so involved in the climate change issue that they dare not predict extreme events without blaming global warming. In this case we have the near simultaneous extreme cold weather and damaging snowfalls in the UK, Europe and parts of the USA, followed almost immediately by damaging floods in Australia, Sri Lanka, South Africa and Brazil that caused loss of life in all these countries. If these events were the worst on record, climate change scientists would have been home and dry. They could claim that they were obviously the consequence of global warming, but this was not so.

Controlled flood discharge from Vaal Dam in 1974

[ I was directly responsible for the operation of Vaal Dam during this period.]

Why did the GCMs fail to predict these extreme global events?

I continue this memo with a very serious challenge. The last time that floods of this magnitude occurred concurrently in South Africa and Australia was in 1974, approaching 40 years ago. There were three other global climatic events at that time. What were they? One had to do with global temperatures (conveniently overlooked by climate change scientists). The second was a well documented global climatic disturbance. The third had to do with the Southern Oscillation Index and possibly other climatic indices. Why have climate change scientists not investigated and reported the obvious causal linkage between these four concurrent global climatic events? This is a fundamentally important question.

I also have a more general question that climate change scientists have yet to address. What causes the El Niño/La Nina phenomena? How often have we been told that climate science is settled when they cannot even answer this obvious question?

It gets worse!

In April 2008 I was granted an urgent interview with the Council of the South African Institution of Civil Engineering. The following are short extracts from my submission titled Urgent submission to the SAICE Council on the likelihood of severe water resource droughts.

Civil engineers and climate change scientists are on a collision course.  The outcome could have very serious, nationally important consequences.  These differences should be resolved as a matter of urgency.

In this submission it is demonstrated with a very high degree of assurance that southern Africa, and possibly the rest of the world as well, is about to enter a period of severe droughts commencing within the next twelve months.  There is an estimated 20% likelihood that they will be as serious as the Great Depression Drought of the early 1930s.  These drought sequences could have disastrous consequences for South Africa if the authorities are caught unawares.

This prediction is based on the well researched multi-year periodic behaviour of the hydro-meteorological processes.  It is shown that this periodicity is in turn causally related to synchronous variations in solar activity.  This linkage is well documented, and has been studied in South Africa for more than a hundred years.

However, climate change scientists vigorously deny both the predictable, multi-year periodicity in the hydro-meteorological processes, as well as the solar linkage.

The diagram below is our river flow prediction model prepared by my co-author Alwyn vd Merwe. We are presently in period year 13 (2007-08).

Note the very clear, well above average recorded river flows for the present hydrological year (13). Even more importantly, note the succession of below average river flows in the period years that lie ahead (14 to 20). Analyses of other long hydrological data series show similar characteristics.    

Climate change scientists use complex global climate computer models to predict a whole range of undesirable consequences.  These include increases in the magnitude and frequency of damaging floods, droughts and threats to water supplies.  They go further, and specifically maintain that there is no linkage between variations in solar activity and climatic responses.  They are forced to do this, as an admission would diminish their claims of exclusive human causality of the postulated consequences of global warming.

I emphasise the word ‘postulated’, because the claims are based on unverified (and unverifiable) computer models.  This is the essence of my problem.  There is simply no evidence in the hydrological data to support these claims. For example, during the 20 years since the establishment of the IPCC in 1988, there have been no floods or droughts that have exceeded the historical maxima. Nor are there any observable trends in the rainfall and river flow data. 

My own position and responsibilities are very clear.  Since 1993 I have devoted considerable time and effort in a search for evidence that would support these claims.  Had I found this evidence, I would not have hesitated for one moment to report it and include it in my teaching, publications, articles and our Hydro course notes.

I therefore have an equal if unpleasant responsibility. It is to report that there is no observable substance to claims related to the effects of climate change on river flow and South Africa’s water resources.

I appreciate that the contents of this document are likely to be hotly contested as lucrative research funding is at stake. This debate should be encouraged, provided it is conducted in an appropriate forum where both sides are given the opportunity to present their views. In this connection I must place on record that my several attempts to have round table discussions on this subject were either refused or ignored. 

My concern was and still is the occurrence of droughts rather than floods. Fifty lives were lost in South Africa during the recent floods, but droughts of equal severity affect the lives of tens of thousands of people.

These were not the only consequences of the recent climatic disturbances that I predicted in 2008. The following information is from a report by the well-known reinsurers Swiss Re. The year 2010 was the year of natural disasters. The last time that so many lives were lost in natural disasters was in 1983 mainly caused by famine in Ethiopia (my emphases).


Putting all the information in this memo together, it is very clear that there have been no systematic increases in natural disasters that can be attributed to human caused global warming during the period of continuous records. Equally, it demonstrates the validity of our studies that demonstrate the causal solar linkage and the predictability of subcontinental scale alternating above and below average hydrometeorological conditions. These conclusions have long been rejected in the IPCC literature.

This whole climate change issue has become chaotic. When chaos prevails the consequences become unpredictable – and dangerous. It will be very interesting to see how this situation is handled in the months ahead as climate change scientists sink deeper and deeper into a quagmire of their own making.                  

My handbooks

April 2000. Flood risk reduction measures. 560 pp

2011. Analytical methods for water resource development and management. 500+ pp.

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Recommended Reading On Why Climate Is An Initial Value Problem

I have urged the recognition that climate prediction is an initial value problem; e.g. see

Pielke, R.A., 1998: Climate prediction as an initial value problem. Bull. Amer. Meteor. Soc., 79, 2743-2746.

There is an excellent discussion and analysis of this subject by Joshua Stults  on the weblog Various Consequences with the latest post

Recurrence, Averaging and Predictability Motivation and Background

The entire post is worth reading including a valuable summary of Ed Lorenz’s published views on this subject.  An excerpt from the  reads

“……. Our ability to predict the future is fundamentally limited. Not really an earth-shattering discovery; it seems a whole lot like common sense. Does this have any implication for how we make decisions? I think it does. Our choices should be robust with respect to these inescapable limitations. In engineering we look for broad optimums that are insensitive to design or requirements uncertainties. The same sort of design thinking applies to strategic decision making or policy design. The fundamental truism for us to remember in trying to make good decisions under the uncertainty caused by practical and theoretical constraints is that limits on predictability do not imply impotence. “

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Recommended Book – “Hailstorm: Prediction, Control And Damage Assessment” By P.Kumar

I would like to recommend an excellent book published by BS Publications

“Hailstorm: Prediction, Control And Damage Assessment”

by P. Kumar

Professor Kumar, who is Professor and Head of the Department of Core Engineering and Engineering Sciences at the MAEER’s MIT College of Engineering in Pune, India has writing a valuable book on hail with a focus on India. In his Preface, he reports that an average of 28 persons die each year in India from hailstones with the worst year in the 1990s had 130 deaths.  Property and livestock damage is also serious.

The abstract of the book reads

“Each year damage due to hailstorm to human life, property, livestock, and agriculture is appalling in nature. Broadly two problems enter into the study of hailstorms e.g., the cloud physics problem of the growth of hailstones and the synoptic problem which relates to the thermodynamic investigation of the conditions that produce hailstorms. This book is divided into five main parts which deal with the climatology, physical properties of hail and its measurements, prediction, its control and damage assessment. As the synoptic and topographical conditions widely vary across the Indian subcontinent hence for the purpose of prediction Indian region has been divided in four parts as NE, NW, Central and South Indian region. Separate chapters discuss the typical features of hailstorm formation. Forecasters in any part of the world could find fair order of similarity in the synoptic models discussed amongst the four regions of India, with their regions, too. This book, therefore, should serve weather forecasters, worldwide. The book would provide useful text material to researchers in the field of cloud physics, meteorology, agriculture scientists, weather forecasters and also a reference material to insurance companies which cover the crop and property damage insurance.”

In terms of the physics of hailstorms and of reducing societal vulnerability to hail, this book provides an invaluble resource.

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Comment On Raymond T. Pierrehumbert’s Article In Physics Today Titled “Infrared Radiation And Planetary Temperature”

Judy Curry comments on the Raymond T. Pierrehumbert Article In Physics Today Titled “Infrared Radiation And Planetary Temperature” in her post

Pierrehumbert on infrared radiation and planetary temperatures [from Climate Cash]

I agree with Judy that this is a very informative and valuable article on the role of CO2 and other greenhouse gases in the Earth’s (and other planet) atmospheres.  However, there is one major error in my view in the article.

Ray concludes that

“… increasing CO2 would warm the atmosphere and ultimately result in greater water-vapor content—a now well-understood situation known as water-vapor feedback.”

This significantly overstates our understanding of the water vapor feedback on Earth since phase changes of water are intimately involved.  In a world without these feedbacks, but in which evaporation from the surface increases if surface temperature increases from the added CO2, his conclusion would be correct.

However, as summarized by Graeme Stephens in my post

Major Issues With The Realism Of The IPCC Models Reported By Graeme Stephens Of Colorado State University

where he wrote (see), for example,

“Models contain grave biases in low cloud radiative properties that bring into question the fidelity of feedbacks in models”

“The presence of drizzle in low clouds is ubiquitous and significant enough to influence the radiative properties of these clouds and must play some role in any feedbacks”

 “….our models have little or no ability to make credible projections about the changing character of rain…”

major uncertainties remain.

The water vapor feedback in the real climate system remains incompletely understood.

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Comments On The AMS Draft Statement “Communicating Science – An Information Statement Of The American Meteorological Society”

The American Meteorological Society is soliciting input on their draft statement (h/t to Joe Daleo)

“Communicating Science” An Information Statement of the American Meteorological Society

They have sent out the following

The following draft statement is currently under review by  the AMS Council:  “Communicating Science”
_ atement.pdf_
If you have comment on this draft AMS Statement currently  under consideration, you may transmit those comments to the AMS Council by  sending a message to the following e-mail address:
_statement_comments@ametsoc.org_ ( before 2 February 2011.

Melissa S. Weston, Executive Officer
American  Meteorological Society
45 Beacon Street
Boston, Massachusetts 02108-3693  USA
Phone: 617.226.3904
Web: _http://www.ametsoc.org_ (

I urge readers of my weblog to send in comments. I have excepted a few statements from the draft text for my comments.

The first excerpt that I am commenting on is

“What Is Science?

Science is an enterprise that systematically acquires and organizes knowledge in the form of testable explanations and verifiable predictions about the natural world.”

This is an excellent succinct summary statement of what science is. This is clearly a requirement that multi-decadal climate predictions for the remainder of the 21st century cannot satisfy.

The second excerpt is

“A model is a physical, mathematical, or conceptual framework for describing reality. Most weather and climate models, for example, are sets of equations that represent the principles and conditions that govern the behavior of energy, mass, momentum, and moisture in the atmosphere.”

The statement needs to have added that only the dynamic core of these models (i.e. the pressure gradient force, advection, and gravity) represent basic physics. All other components of these models are parameterizations , which means they are not fundamental physics but engineering code with tunable parameters.

“Modeling will continue to be an essential tool used by scientists for investigation and prediction. Because models are solidly grounded in mathematics and physical observations, and represent a logical description of the system that they are designed to predict, they offer the best and most effective means for testing the consequence of a full range of inputs to a system, from subtle changes to shocks.”

This statement has an important error. Modeling DO NOT “offer the best and most effective means for testing the consequence of a full range of inputs to a system, from subtle changes to shocks”.  Models are themselves hypothesesThey cannot be used as a “test” without comparing their predictions with actual observed data 

Real world observations, not models, therefore, are the appropriate means for testing the consequence of a full range of inputs to a system, from subtle changes to shocks!  Models can assist in the interpretation of the behavior of the studied system, as well as to make forecasts ONCE the accuracy of their predictions are verified against observed data.

This is clearly a requirement that multi-decadal climate predictions decades from now cannot pass until those decades have occurred.

I discuss this issue in a number of my posts; e.g.

When Is A Model a Good Model?

Recommended Reading – “What Can We Learn From Climate Models?” By Judy Curry

What Are Climate Models? What Do They Do?

Real Climate Misunderstanding Of Climate Models

The bottom line message is the weather and climate models are not basic physics, but are engineering codes with a core of fundamental physics but with much of the atmospheric, ocean, cryosphere and land represented by tunable engineering code (i.e. their parameterizations). 

 I urge the AMS statement be modified to correct this misunderstanding concerning models.

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