Thanks, Rob.

I hope others contribute too, all views are very welcome.

This thread has been discussing aspects of climate science. I would like to list some of the issues that have emerged. These may be worthy of further debate, or perhaps you think everything has already been said. You may even think it is just conspiracy nonsense. Please challenge or comment.

We are told that AGW really began around 1950. We discussed the MWP and the LIA. Clearly, these were important climate events but we have no firm evidence about why they happened.

We saw a high rate of warming in the fourth quarter of last century. This was matched in terms of rate in the 1930s, nevertheless there was much rhetoric that the later warming was unprecedented and entirely due to anthropogenic carbon dioxide. The claim that it was unprecedented is clearly untrue. We debated the cause.

We now have a clear claim by GISS that all global warming is due to carbon dioxide. I submit that just last year, we saw a spike in global temperatures which was unambiguously attributed to the recent El Nino.

Then we have the pause. I remember being told that nothing could stop the warming. I truly wish I had kept a record of all the times I heard that, because clearly something did stop the warming. Let us not quibble over a few hundredths of a degree. The rate of warming changed dramatically. Why was that?

If natural factors conspired to stop the warming, could natural factors have contributed to the earlier warming?

There is significant discrepancy here between the scientific claims, observation and logical deduction.

Another aspect of our thread examined the GHG mechanism. Rather than re-visit all the detail, let us use climate sensitivity as a measure of the controversy. The alarmists gave this a value in excess of 5 degrees for a doubling of CO2 but this quickly decreased to the IPCC preferred value of around 3. There have been a number of papers since then, reducing the sensitivity to anything between 1 and 3.

The trend is downwards. We spent a great deal of time debating the adventures of individual photons but it seems that after feedbacks, all of that stuff doesn’t really matter. We never seem to get explanations about the factors that change the sensitivity.

Probably low climate sensitivity is the key. Unfortunately it is calculated by the models and the models do not agree with observations. In such circumstances, I look at the bigger picture. Carbon dioxide is rocketing. GISS says CO2 controls our climate and our temperatures are static. Something is wrong. We have already concluded that GISS is not correct on this point.

Schrodinger's Cat
Assuming that the physics is correct, and increased CO2 will lead to Global Warming, there is an incorrect fudge factor somewhere, to account for the lack of warming that has actually occurred.

ECS does seem like a problem area, as evidenced by the vitiolic attacks on Lewis and Curry, by the 97% of Climate Scientists who can't admit being wrong about anything. It would be Poetic Justice to invalidate aspects of Climate Science in this manner.

If ECS is a product of the rest of the maths and physics, then there is a problem in the rest of the maths and physics.

The Pause may simply be the high point of another natural cycle, in which case, a fall in temperature is logical.

I remain unconvinced by Climate Science's abilities at maintaining accurate record keeping.

I remain unconvinced by Climate Science in general, as most of their known mistakes remain uncorrected, and not retracted. There are too many vested interests in maintaining bad Climate Science. The Consensus opinion seems to be that they won't waste their grant funding and damage future opportunities, on proving their mistakes. Climate Science Peer Review combined with in-house magazines act as obstructive gate keepers.

Why was Mann's Hockey Stick dropped by the IPCC but still supported by Climate Scientists? Iconic sacred imagery?

Climate Science has failed to explain the MWP and LIA. The dismissal of UHI has been unjustified.

As a Country Bumpkin, I have not noticed anything getting warmer. There may be fewer days/nights with frosts?

Climate Science is keen to find anything that COULD make Global Warming worse, and will get worse in the event that Global Warming occurs. There has been little attempt to identify natural dampers that are counteracting the fears of Climate Scientists.

We don't know what causes the PDO to swing from Nino to Nina, or indeed very much about any ocean currents, and what causes them to vary.

Plants grow better in higher concentrations of CO2. As they grow, they "fix" CO2. Clearing forests for arable crops will have increased CO2, and reduced the ability for plants to refix it.

Marine/aquatic algae has probably been underestimated.

The cost of heating a swimming pool is high, it is why so many public swimming pools close. If Climate Science has underestimated the energy stored and moved, plus the amount required to change large bodies of fresh and salt water, they have yet to admit it.

Climate Science has proved its own inability to find and correct its own mistakes. 9 out of 7 Climate Scientists say their lifestyles prefer it.

Hubert Lamb identified the cold winters in Europe during WW2. 1947 was far worse. If Global Warming "started" in the 1950s, it was from a recorded low point.

There has been no explanation for the "Ice Age" scare of the early 1970s. Climate Science has gone to some lengths to deny it happened.

There is no financial or credibility incentive for Climate Scientists to find and correct their own mistakes. I do not know specifically what they are, but I can see a consistent pattern of inconsistency.

Politicians are now seeing the folly of Climate Science. Climate Science has avoided/subverted Scientific debate and Legal debate. Climate Science has been dependent on media propaganda. What would happen if politicians finally asked their electorates whether Climate Science has proved value for taxpayers money?

gc - good comments. I think we share more or less the same view of climate science.

Entropic Man, if you are still with us, do you have any doubts or concerns about the subject, or are you totally convinced by everything GISS and others announce? Of course, you may choose not to be drawn into what you regard as conspiracy stuff. I regard some of these questions as important technical challenges which are the basis of the scientific method. If contemporary scientific assumptions are never challenged, science and understanding will never develop.

https://wattsupwiththat.com/2017/11/03/what-you-wont-find-in-the-new-national-climate-assessment/

"The projections in the NCA are all based upon climate models. If there is something big that is systematically wrong with them, then the projections aren’t worth making or believing.

Here’s the first bit of missing information......"

Schrodinger's cat

You. may be familiar with my habit of checking the climate science data by making back-of-the-envelope calculations myself. This gives me an independant test.

Since my own calculations agree with the published work, I am happy to accept it.

This makes me a sceptic by Niel deGrasse Tyson's definition.

A skeptic will question claims, then embrace the evidence. A denier will question claims, then reject the evidence.

Since my own calculations agree with the published work, I am happy to accept it.

Nov 4, 2017 at 9:16 PM | Entropic man

You accept Mann's Hockey Stick, but propose the eruption of Mount Samalas, as the cause of the end of the MWP, that Mann says never happened.

The evidence possibly supports you about Mount Samalas, and therefore not the work published by Mann, that is supported by Climate Science and the IPCC.

Did you check Mann's maths on the back of an envelope?

This plane could cross the Atlantic in 3.5 hours. Why did it fail?

It wasn't designed by computers but through math...

Ouch!

"It wasn't designed by computers but through math..." was not an answer to "Why did it fail?"

EM, I do " back of fag packet" quick calculations myself, for guesstimating ballpark figures, rather than precision calculations, where and when appropriate. Any result is dependent on the reliability and accuracy of the numbers and equations that produced it. Trenberth's Energy Budget does seem to rely on estimates to produce precise figures, and has had to be updated once already. Is it more accurate now?

Earth's Global Energy Budget
Kevin E. Trenberth , John T. Fasullo  and  Jeffrey Kiehl
National Center for Atmospheric Research,* Boulder, Colorado
Bulletin of the American Meteorological SocietyVol. 90: , Issue. 3, : Pages. 311-323
(Issue publication date: March 2009)https://doi.org/10.1175/2008BAMS2634.1

Abstract

An update is provided on the Earth's global annual mean energy budget in the light of new observations and analyses. In 1997, Kiehl and Trenberth provided a review of past estimates and performed a number of radiative computations to better establish the role of clouds and various greenhouse gases in the overall radiative energy flows, with top-of-atmosphere (TOA) values constrained by Earth Radiation Budget Experiment values from 1985 to 1989, when the TOA values were approximately in balance. The Clouds and the Earth's Radiant Energy System (CERES) measurements from March 2000 to May 2004 are used at TOA but adjusted to an estimated imbalance from the enhanced greenhouse effect of 0.9 W m−2. Revised estimates of surface turbulent fluxes are made based on various sources. The partitioning of solar radiation in the atmosphere is based in part on the International Satellite Cloud Climatology Project (ISCCP) FD computations that utilize the global ISCCP cloud data every 3 h, and also accounts for increased atmospheric absorption by water vapor and aerosols.

Surface upward longwave radiation is adjusted to account for spatial and temporal variability. A lack of closure in the energy balance at the surface is accommodated by making modest changes to surface fluxes, with the downward longwave radiation as the main residual to ensure a balance.

Values are also presented for the land and ocean domains that include a net transport of energy from ocean to land of 2.2 petawatts (PW) of which 3.2 PW is from moisture (latent energy) transport, while net dry static energy transport is from land to ocean. Evaluations of atmospheric re-analyses reveal substantial biases.

GolfCharlie. An abstract of the Abstract : we fudged it here, we fudged it there, we fudged it bloody everywhere (and still we can't find some).

Nov 5, 2017 at 9:00 AM | Supertroll

Yes! Guesstimated figures are useful rules of thumb, but I would not build a theory on them, without remembering the approximations, with associated margins of error before multiplying them together to produce a magic number to be carved in stone, and relied upon as accurate to fractions of a decimal point.

We do not know what the "normal" global temperature is, since the end of the Little Ice Age, let alone the last Ice Age, yet Climate Science depends on it being the same, because Mann decreed it to be so, having used tree rings as thermometers.

The graph of approximations, painstakingly produced by Hubert Lamb as an assessment of Climate History, seems more reliable than anything produced since, at or in conjunction with CRU at UEA, that Lamb started. Lamb was not trying to set the earth on fire, and he didn't.

EM - Just to take two examples. I've not read the US Agencies report on climate science, but I'm sure you saw or heard the BBC making a meal of it in recent news bulletins. Over at NTZ, Tony Heller exposes one part of it as wrong, in fact fraudulent. This is a common event in climate science. Usually, you and I have no means or time to hold a full enquiry but we see two opposing views. Do you always take the word of authority? What is your view in this case?

You will know that Gavin of GISS fame claims that all warming is due to AGW. These are his words, so we are talking about warming, not forcing. Given the warming from the LIA and the warming due to the El Nino just last year, is he right or wrong? I say he is wrong. What do you say?

This makes me a sceptic by Niel deGrasse Tyson's definition.

A skeptic will question claims, then embrace the evidence. A denier will question claims, then reject the evidence.

Nov 4, 2017 at 9:16 PM | Entropic man

Is there any "evidence" for Catastrophic Anthropogenic Global Warming that you do question?

Schrodinger's cat

You can access the report here.

Tony Heller's post contains various emotional trigger phrases, insults and an ad hominem attack. I find it difficult to take it seriously as a critique of the science.

It also lacks a link to the original report. Could you let me know which chapter and figure he is referring to, so that I can download it to compare Heller's version with what the actual report shows.

Golf Charlie

I have noticed that "Catastrophic Anthropogenic Global Warming" is a phrase mostly used by deniers, so I would question your description of yourself as a skeptic.

"Catastrophic Anthropogenic Global Warming"

Which bit do you not agree with? Completely disagree, or would prefer to nuance?

Entropic Man, are you denying that Global Warming will be catastrophic? You have recently confirmed there was a Medieval Warm Period, even though that breaks one of the cardinal rules of belief in Mann and his Hockey Stick.

What else do you want to deny about Global Warming, or are you just admitting to being a bit sceptical about Climate Science because Climate Science never admits a mistake?

EM - Ok, forget Heller. Does your silence on the other question imply that you agree that the recent warming due to the El Nino demonstrates that not all warming is directly due to AGW?

According to NTZ there are many papers claiming that the climate has a very low sensitivity to CO2. I find that very credible because I have always found the claims made about its GHG properties to be counter intuitive.

Entropic Man & Schrodinger's Cat

This is what Skeptical Science had to say about Climate Sensitivity - ECS
https://www.skepticalscience.com/detailed-look-at-climate-sensitivity.html
A detailed look at climate sensitivity Posted on 8 September 2010 by dana1981

I have selected some bits for brevity:

"Some global warming 'skeptics' argue that the Earth's climate sensitivity is so low that a doubling of atmospheric CO2 will result in a surface temperature change on the order of 1°C or less, and that therefore global warming is nothing to worry about. However, values this low are inconsistent with numerous studies using a wide variety of methods, including (i) paleoclimate data, (ii) recent empirical data, and (iii) generally accepted climate models."

"Climate sensitivity describes how sensitive the global climate is to a change in the amount of energy reaching the Earth's surface and lower atmosphere (a.k.a. a radiative forcing).  For example, we know that if the amount of carbon dioxide (CO2) in the Earth's atmosphere doubles from the pre-industrial level of 280 parts per million  by volume (ppmv) to 560ppmv, this will cause an energy imbalance by trapping more outgoing thermal radiation in the atmosphere, enough to directly warm the surface approximately 1.2°C.  However, this doesn't account for feedbacks, for example ice melting and making the planet less reflective, and the warmer atmosphere holding more water vapor (another greenhouse gas). "

"A study led by Stefan Rahmstorf concluded "many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2.6–4.1°C, most clustering around 3°C" (Rahmstorf 2008).  Several studies have put the lower bound of climate sensitivity at about 1.5°C,on the other hand, several others have found that a sensitivity higher than 4.5°C can't be ruled out."

"A 2008 study led by James Hansen found that climate sensitivity to "fast feedback processes" is 3°C, but when accounting for longer-term feedbacks (such as ice sheet disintegration, vegetation migration, and greenhouse gas release from soils, tundra or ocean), if atmospheric CO2 remains at the doubled level, the sensitivity increases to 6°C based on paleoclimatic (historical climate) data."

"The main limit on the sensitivity value is that it has to be consistent with paleoclimatic data.  A sensitivity which is too low will be inconsistent with past climate changes - basically if there is some large negative feedback which makes the sensitivity too low, it would have prevented the planet from transitioning from ice ages to interglacial periods, for example.  Similarly a high climate sensitivity would have caused more and larger pastclimate changes."

"Comparisons of observed and modeled coolings after the eruptions of Agung, El Chichón, and Pinatubo give implied climate sensitivities that are consistent with the Intergovernmental Panel on Climate Change (IPCC) range of 1.5–4.5°C. The cooling associated with Pinatubo appears to require a sensitivity above the IPCC lower bound of 1.5°C, and none of the observed eruption responses rules out a sensitivity above 4.5°C."

"In 1988, NASA climate scientist Dr James Hansen produced a groundbreaking study in which he produced a global climate model that calculated future warming based on three different CO2 emissions scenarios labeled A, B, and C (Hansen 1988).   Now, after more than 20 years, we are able to review Hansen’s projections. "

"Hansen's model assumed a rather high climate sensitivity of 4.2°C for a doubling of CO2.  His Scenario B has been the closest to reality, with the actual total radiative forcing being about 10% higher than in this emissions scenario.  The warming trend predicted in this scenario from 1988 to 2010 was about 0.26°C per decade whereas the measured temperature increase over that period was approximately 0.18°C per decade, or about 40% lower than Scenario B."

Therefore, what Hansen's models and the real-world observations tell us is that climate sensitivity is about 40% below 4.2°C, or once again, right around 3°C for a doubling of atmospheric CO2.

Probabilistic Estimate Analysis

Annan and Hargreaves (2009) investigated various probabilistic estimates of climate sensitivity, many of which suggested a "worryingly high probability" (greater than 5%) that the sensitivity is in excess of than 6°C for a doubling of CO2.  Using a Bayesian statistical approach, this study concluded that

"the long fat tail that is characteristic of all recent estimates of climatesensitivity simply disappears, with an upper 95% probability limit...easily shown to lie close to 4°C, and certainly well below 6°C."

"Annan and Hargreaves concluded that the climate sensitivity to a doubling of atmospheric CO2 is probably close to 3°C, it may be higher, but it's probably not much lower."

Summary of these results

"Knutti and Hegerl (2008) presents a comprehensive, concise overview of our scientific understanding of climate sensitivity.  In their paper, they present a figure which neatly encapsulates how various methods of estimating climate sensitivity examining different time periods have yielded consistent results, as the studies described above show.  As you can see, the various methodologies are generally consistent with the range of 2-4.5°C, with few methods leaving the possibility of lower values, but several unable to rule out higher values."

Conclusion

"As the scientists at RealClimate put it, "Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, calling 2°C a danger limit seems to us pretty cavalier.""

● I have already admitted to favouring Lewis and Curry on ECS. Are the number of negative feedbacks closer to the positive ones, and the models were incorrectly programmed?
● The concluding quotes from RealClimate do not seem consistent with what has happened since.

gc, Cook, Hansen and Schmidt are not sources that I would consider if I wanted an objective view if climate sensitivity.