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Discussion > GHG Theory step by step

Golf Charlie

I know you are not technical, but you should try to pay attention to the numbers.

The 11 years solar cycle shows a variation of 1.5W/M^2 above and below the average. If there were no ocean heat sink damping the oscillation this would produce a variation of 0.3C.

A Maunder minimum would stick at the minimum value and produce a negative forcing of 0.3C.

The current warming rate is 0.18C/decade. A Maunder Minimum would cancel out 16 years of warming, barely slowing the long term warming trend.

Dec 28, 2017 at 11:16 PM | Unregistered CommenterEntropic man

So, EM, do the models agree with your assessment? Do they forecast maybe 16 years flat before warming resumes? Or do they need to wait until it happens before they can forecast it in arrears?

(and does anybody agree with your expectation that the minimum will be like the minimum of a solar cycle carried on for a while? Which cycle? Are there not more cycles than just the 11 year one? This looks like unwarranted selection of the facts that suit you.)

Dec 29, 2017 at 10:36 AM | Unregistered Commenterrhoda

Do they forecast maybe 16 years flat before warming resumes?

Warming already has resumed. Bigly.

Dec 29, 2017 at 11:46 AM | Unregistered CommenterPhil Clarke

Phil, aren't you buying the 'solar minimum coming' story?

(I don't, but if it happens it happens and to me would be far worse than a couple of degrees of warming)

Dec 29, 2017 at 12:00 PM | Unregistered Commenterrhoda

What story?

http://www.independent.co.uk/news/science/natural-cooling-of-the-sun-will-not-be-enough-to-save-earth-from-global-warming-warn-scientists-10340067.html

Dec 29, 2017 at 12:04 PM | Unregistered CommenterPhil Clarke

Dec 28, 2017 at 11:16 PM | Entropic man

I can get technical, but am wary of how roundings up and down can get incorporated into factually precise numbers, that get carved in tablets of stone, and quoted ad infinitum.

My physics does not allow me to double check your figures, but I only have to look out of a window through the year, at nature, gardens, farms etc to tell that nothing much has changed.

As a trouble-shooter, I am used to hearing "according to our calculations/designs, this should not have happened", whilst looking at some form of wreckage. Obviously something went wrong, but normally those responsible are not going to admit it. Freak events, Acts of God etc do happen, unforeseen circumstances that should have been foreseen or designed for, also occur, but one human error caused by another human's error is all too common.

I also do the quick mental arithmetic, or calculation on the back of a fag packet etc, as a check. I have had to produce educated guesstimates even if caveated to +/-50% to move a decision making process along.

What are the margins of error incorporated into Trenberth's Enery Budget and are there known variables?

Dec 29, 2017 at 12:48 PM | Unregistered Commentergolf charlie

Dec 29, 2017 at 12:04 PM | Phil Clarke

Is that science or journalism?

Dec 29, 2017 at 12:52 PM | Unregistered Commentergolf charlie

Neither.

Dec 29, 2017 at 1:31 PM | Unregistered Commenterrhoda

It was a press report on a paper by Lockwood et al published in the Journal of Geophysical Research: Atmospheres.

You can read the paper here: http://www.personal.reading.ac.uk/~ym901336/pdfs/326_Maycocketal_jgrd52180.pdf

The abstract indicates the reporting was accurate, as does the summary:

The change in global mean near-surface temperature over the second half of the 21st century is O(0.1 K), confirming the findings of earlier studies which have shown that a large decrease in solar activity would do little to offset the projected anthropogenic global warming trend [cf. Feulner and Rahmstorf, 2010, Jones et al., 2011, Meehl et al., 2013, Anet et al., 2013]

Dec 29, 2017 at 1:53 PM | Unregistered CommenterPhil Clarke

Dec 29, 2017 at 1:53 PM | Phil Clarke

Just because it is Peer Reviewed Climate Science, does not make it reliable.

Dec 29, 2017 at 2:23 PM | Unregistered Commentergolf charlie

Deary me, nothing can save us from the infernal dioxide molecule, even the mighty Sun is seemingly powerless according to our calculations. We are doomed.
Oh dear, a small cloud has appeared and the temperature has dropped several degrees.
But soon the full might of the dioxide molecule will resume its trek towards thermageddon.
Repent your evil ways, repeat after me: "wind turbines good, coal exceedingly bad".

Dec 29, 2017 at 2:29 PM | Unregistered CommenterSupertroll

Just because it is unreviewed blog science does not make it reliable

FTFY.

Dec 29, 2017 at 3:15 PM | Unregistered CommenterPhil Clarke

You mean the temp in the remainder of this century isn't going to change much? Well that's my lifetime and fifty years. So forgive me if I can't see a need to do anything about it right now. Except to recommend that the scientific community take the opportunity to do a lot more observation and work out how the climate really works with no fashionable pre-conceptions about whay they find. This will require a new generation of climate scientists, of course, not a bunch of wimps who can't make a falsifiable prediction to take effects within their own working lives.

Dec 29, 2017 at 3:22 PM | Unregistered Commenterrhoda

Rhoda

Climate models depend on three things.

The laws of physics do not change.

RCPs, 11 year solar cycles and Milankovich cycles can be planned for.

Known unknowns such as volcanoes and ENSO can be randomised.

Unknown unknowns such as a potential maunder Minimum cannot be planned for until you becomes of them. The MM may be incorporated into new runs, but another the 2005 and 2011 runs of CMIP5.

Longer cycles are hypothesised, but except for the Milankovich cycles evidence for them is weak.

Dec 29, 2017 at 4:13 PM | Unregistered CommenterEntropic man

The laws of physics may not change, but if they are speculatively parameterised in the setup of a model, that model is only as good as the parameters, and its output cannot be validly compared to another model which uses different values to achieve the same hindcast. Which is what you do, EM. The average of the ensemble is therefore not a useful figure.

And why don't they chuck out the canadian model, wrongest of the lot, apparently?

Dec 29, 2017 at 4:25 PM | Unregistered Commenterrhoda

Golf Charlie

Individual parts of the energy budget have 95%confidence limits between +/-0.1W/M^2 and +/-O.5W/M^2.

In the original 2008 paper the imbalance was quoted as -0.7W/M^2 +/- 0.7. The 2014 estimate was 0.75W/M^2 +/-0.25

Rhoda

From the Climate Lab Book "Comparing CMIP5 with Reality" Note. Whatever is wrong with BH will not let me post links)

Using the 1981-2010 anomaly the actual HadCRUT 2016 temerperature anomaly was 0.5C +/- 0.1C.

The prediction for 2016 made in 2005 was 0.55C +/- 0.25C. (the pale grey band)

The prediction for 2016 made with real world forcings to 2011 was 0.38C +/- 0.18C. ( the dark grey band).

In both cases the observed temperature was within the confidence limits of the prediction, which you would expect if the models work.

These were falsifiable predictions which have been confirmed, not falsified. I fail to see what you are complaining about.

Dec 29, 2017 at 7:25 PM | Unregistered CommenterEntropic man

Golf Charlie

Looking out of an English window and seeing little change proves nothing. You live in one of the parts of the world least affected by climate change.

If you lived on a desert margin, an Arctic coastline or in Miami Beach you might notice that "fings ain't what they used to be."

Dec 29, 2017 at 11:12 PM | Unregistered CommenterEntropic man

EM, you will not impress anyone by hindcasting something using whatever parameters suit you, differently between the models of the ensemble, and getting within the error margins. Calling that a falsifiable prediction is laughable.

Did all the models use that same parameters for their hindcasts? If not, how can they be all put on the same spaghetti graph? If so, why not chuck out the one that is always too high, if not to preserve some semblance of something to be alarmed about?

Dec 29, 2017 at 11:56 PM | Unregistered Commenterrhoda

Rhoda

You might find these of interest.

Jan 1, 2018 at 3:05 PM | Unregistered CommenterEntropic man

Well, I wouldn't trust realclimate as far as I could kick them, but that's just me. I didn't see where the referenced link answered the questions. Do they all use the same parameterisation? Why don't they chuck out the highest?

Jan 1, 2018 at 6:40 PM | Unregistered Commenterrhoda

Rhoda

It is always a mistake to reject information because of its source. Go to the original papers at the bottom of the link. Reject them if you wish, but do so because of the science. If I rejected everything here because it was on BH I would talk to a lot fewer sceptics. Should my philosophy be " Don't believe anything Rhoda says", because she posts on a denier website?

CMIP5 is one basic model, run repeatedly under different expected conditions of forcing and RCP. The best model runs come closest to observations, not necessarily the warmest or the coldest. Don't throw out any of the others, they help indicate the potential range of variation available to the system.

The other models referenced in my link are produced by independant groups over many years, using parameters estimated from observation as they think best. They talk to each other, but there is no They to tell them what to do.

Since all the modelling groups are independant, why should you throw out one and keep others? How would you decide?

Jan 1, 2018 at 10:32 PM | Unregistered CommenterEntropic man

Entropic Man, I can look out of an English window, at a current English scene. I can listen to those who farmed and gardened before I was born, who listened to their parents and grandparents.

I can look at the evidence of history and archaeology, and follow some of the same logical paths as Hubert Lamb.

Saharan desert margins are currently re-greening. Arctic ice expands and contracts. The Florida coastline is not static.

Do Climate Models hindcast those changes, or plot a "Hockey Stick"?

Jan 1, 2018 at 10:54 PM | Unregistered Commentergolf charlie

EM, you might be surprised at the number of people who were neutral on CAGW and then went to realclimate and asked an innocent question only to be brushed off. Then looked harder and ended up as sceptics.

I don't agree that the net of an ensemble is to be treated as somehow a consensus. You see, if one model has a parameter for one or other forcing at half or twice the value used by another, the results are not comparable. Parameterisation is a problem. We do not know, we are not told, how many runs are stopped for going outside arbitrary limits or how many come to a conclusion that the modellers don't like. It would be easy to cherry pick the results that get on the graph. There is plenty of incentive to do so. That's why I wouldn't touch anything from realclimate.

On the other hand, nobody has to trust what I write. But I have no existential need to cheat. I just ask questions, with an occasional quibble about methodology.

Jan 2, 2018 at 12:45 PM | Unregistered Commenterrhoda

"EM, you might be surprised at the number of people who were neutral on CAGW and then went to realclimate and asked an innocent question only to be brushed off."
rhoda

EM has brushed off any attempt on this thread to explore possible errors in Climate Science. Since the science is settled, no questions can be asked.

Quite why we need so many Climate Scientists to keep confirming the science is settled, remains a mystery

Jan 2, 2018 at 6:00 PM | Unregistered Commentergolf charlie

Rhoda, golf Charlie

Read the Realclimate Borehole

I had trouble finding any neutrals asking polite questions. Most of it was the sort of bullshit science I get here.

Jan 2, 2018 at 7:19 PM | Unregistered CommenterEntropic man