AR5 full report

The final AR5 report is now available here.

Comments

[Donna Laframboise]

This remains a "draft" report. Please note this statement:

This document lists the changes necessary to ensure consistency between the full Report and the Summary for Policymakers...

They intend, as has occurred in the past, to alter the text of the main report written by scientists so that the main report is consistent with the negotiated-behind-closed-doors-by-politicians-&-bureaucrats Summary for Policymakers.

Science is not - and has never been - in the driver's seat at the IPCC.

[rhoda]

I know we are all thinking it, but few are sufficiently crass to put it out there. Where IS that nice Dr. Betts when we need him to explain what look to be massive failures in the report to address reality? Especially in the field of D&A which was once his. Especially in the treatment of uncertainty. Especially in the area of integrity.

Why do they need to lie, cheat and make things up?

[Paul Matthews]

The changes document seems to have mistakes in it, or I'm missing something.
For example it refers to table SPM7 but there are only 3 tables in the SPM.

[SimonW]

Give him a chance Rhoda, I expect he's busy helping Ms Slingo fend off Nic Lewis and Doug Keenan.

I do think AR5 (aka The Dog Ate My Homework) will sort the wheat from the chaff though. How can it not?

You're either shark jumping with Damian Carrington in thinking the Temperature record and Climate sensitivity no longer matter (contrary to previous reports) or you've got to realise the report is just a diversion from what's been going on since the last report (no updates on previous predictions etc).

I sense my Guardian reading brother (moderately interested, apathetically pro AGW) is wavering after seeing the unwarranted hysterical coverage. Being more confident when observations are diverging from predictions is a hard sell. So perhaps we will see a tipping point of sorts!

I must admit I can't guess which way RichardB will play this though as a basically honest bloke faced with backing up a load of hand-waving tosh.

(btw I do agree with you on the inadequacy of GMT and CS as measures but the IPCC chose them so should stick to them!)

[Martin A]

rhoda, why do you think?

"And with me is one of the serious and sober scientists, Peter Stott, from the Met Office, and one of the [IPCC] co-ordinating authors on Detection and Attribution and this is very important, Peter, because… this is saying who dunnit… who is responsible for climate change… so tell us who is it?"

"... in fact it is evidence from the last 15 years… the, the warming ocean, the retreating snow and ice, the changing rainfall patterns, the continuing sea-level rise, and this evidence is so strong, of the dominant role of human influence on the climate system."

[Stuck-Record]

"Why do they need to lie, cheat and make things up?"

Stop, and the money dries up.
Stop, and you go to jail.
Stop, and the public will say, "You told us what?"

[Anything is possible]

"Why do they need to lie, cheat and make things up?"

To paraphrase a lyric from the Doors (Unhappy girl) :

"They are locked in a prison of their own device."

[Stuck-Record]

Actually, I sense a GIGANTIC round of funding about to be granted for ocean heat modelling...

Trebles all round!

[dfbaskwill]

Those goofy looking fish with lights on their heads are in for a rude awakening when the Warmists dive down to investigate the missing heat. Bathysphere stocks, way up!

[Paul Matthews]

I've written something about the muddled changes document.

[eSmiff]

Why does the catholic church not admit that miracles don't happen ?

$$$$$$$$$$$$$

[Rud Istvan]

Even though this is still not final, since changes are being made to conform it to the SPM, there are revealing ( and obfuscating) wording changes throughout compared the the leaked SOD. My favorites are in chapter 7 on clouds, where the uncertainty of any positive cloud feedback has been further obfuscated, and a lot of non GCM cloud modeling brought in to attempt to increase 'certainty'. What they did not say (meta analysis selection bias) was that when clouds were better resolved by superparametrization, rainfall increased, the negative lapse rate feedback reduced the overall positive water vapor feedback, and climate sensitivity to CO2 was about halved. In other words, get clouds closer to 'right' and even a GCM can get closer to observational values. But that would have said AR4 was wrong, and that there is no C in CAGW. So the science was further transmogrified.

[Billy Liar]

@ esmiff

Very true!

I wouldn't mind if the IPCC too turned to voluntary subscription for its good works.

[pesadia]

"This evaluation is based on recent internationally coordinated model
experiments, including simulations of historic and paleo climate, specialized experiments designed to
provide insight into key climate processes and feedbacks, and regional climate downscaling"

Experiments..............er I don't think so.

[James Evans]

I haven't read it yet. Don't tell me the ending.

[Sara Chan]

I haven't read it yet. Don't tell me the ending.

It's not a thriller. Rather, people read it for its character development.

[Pointman]

"This document lists the changes necessary to ensure consistency between the full Report and the Summary for Policymakers..."

Ah, I see. They're busy reverse engineering the source documents to conform with whatever the SPM said they said.

Pointman

[Clive Best]

IMHO they now admit that the models are too sensitive to CO2 and need renormalizing by at least 10%. The main reason for this is that the models were tuned to explain all the observed warming from 1950 – 2000. The hiatus in temperatures post 1999 now show that something between 25% and 50% of late 20th century warming was actually caused by natural processes. They also realise that they can’t have natural processes only working one way – cooling post 2000 while absent before 2000.

This finding provides evidence that some CMIP5 models show a larger response to greenhouse gases and other anthropogenic factors (dominated by the effects of aerosols) than the real world (medium confidence). As a consequence, it is argued in Chapter 11 that near-term model projections of GMST increase should be scaled down by about 10% (Section 11.3.6.3). This downward scaling is, however, not sufficient to explain the model-mean overestimate of GMST trend over the hiatus period.

The one natural process they don’t address directly anywhere in the report is natural changes in cloud cover. The unfairly discredited ISCCP global cloud cover data explains about half the 1950-2000 warming and can also the current hiatus, while agreeing with the less sensitive models having TCR of ~ 1.5C

I am actually encouraged by the full WG1 report that rational non-political science could be returning.

[Richard Betts]

rhoda

Where IS that nice Dr. Betts....

He's busy working on his own contribution to AR5, ie: his chapter for the Working Group 2 report (due out in March).

He's also occasionally keeping an eye on discussions here to see when the cynicism has calmed down enough to make it worthwhile attempting to have a sensible conversation in good faith. (Not much sign of that yet, although I am encouraged that Clive Best for one does seem to be actually reading the main report - thanks Clive, I hope others follow your example!)

Just one comment in response to Donna and Pointman though - the list of corrections to the chapters is here, and it seems pretty clear that they do not constitute some sort of political re-writing of the chapters as you seem to be implying. For example, see the very first one, which is also repeated several times:

Replace "0.89°C (0.69°C–1.08°C) over the period 1901- 2012" with "0.85 [0.65 to 1.06] °C over 1880–2012"

You can see that this is slightly decreasing the estimated warming (from 0.89°C to 0.85°C) whilst at the same time increasing the time period over which it occurred (from 1901-2012 to 1880-2012) - so a smaller and less rapid warming.

Clearly a scientific correction, and one in the opposite direction to what you would expect under Donna's narrative of science taking a backseat to politicians and bureaucrats.

[Pointman]

Despite my reddened wrist Dr Betts, I prefer to bet on known form.

Pointman

[KNR]

Sorry but its clear that mere mortals cannot understand 'the words of god' without high priests 'interpreting' it for us.

[Martyn]

http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_All.pdf

TS.2.2 Changes in Temperature
TS.2.2.1 Surface
It is certain that Global Mean Surface Temperature (GMST) has increased since the late 19th century (Figure TS.1). Each of the past three decades has been warmer than all the previous decades in the instrumental record, and the decade of the 2000’s has been the warmest. The global combined land and ocean temperature data show an increase of about 0.89°C [0.69–1.08]5 over the period 1901–2012 and about 0.72°C [0.49- 0.89] over the period 1951–2012 when described by a linear trend6. The warming from 1850–1900 (earlyindustrial)
to 1986–2005 (reference period for the modelling chapters and the Atlas in Annex 1) is 0.61°C [0.55 to 0.67], when calculated using HadCRUT4 and its uncertainty estimates. It is also virtually certain that maximum and minimum temperatures over land have increased on a global scale since 1950. {2.4.1, 2.4.3, Supplementary Material 2.SM.3}

Despite the robust multi-decadal timescale warming, there exists substantial interannual to decadal variability in the rate of warming, with several periods exhibiting weaker trends (including the warming hiatus since 1998) (Figure TS.1). Although the trend uncertainty is large for short records, the rate of warming over the past 15 years (1998–2012; 0.05°C per decade [–0.05 to +0.15]) is smaller than the trend since 1951 (1951–2012; 0.12°C per decade [0.08 to 0.14])6. Several independently analysed data records of global and regional land surface air temperature obtained from station observations are in broad agreement
that land surface air temperature s have increased. Sea surface temperatures have also increased. Intercomparisons of new sea surface temperature data records obtained by different measurement methods, including satellite data, have resulted in better understanding of errors and biases in the records. {2.4.1, 2.4.2, 2.4.3; Box 9.2}

http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter02.pdf

Temperature
It is certain that Global Mean Surface Temperature has increased since the late 19th century. Each of the past three decades has been significantly warmer than all the previous decades in the instrumental record, and the first decade of the 21st century has been the warmest. The global combined land and ocean surface temperature data show an increase of about 0.89°C (0.69°C–1.08°C) over the period 1901–2012 and about 0.72°C (0.49°C–0.89°C) over the period 1951–2012 when described by a linear trend.

Despite the robust multi-decadal timescale warming, there exists substantial multi-annual variability in the rate of warming with several periods exhibiting almost no linear trend including the warming hiatus since 1998. The rate of warming over 1998–2012 (0.05°C [–0.05 to +0.15] per decade) is smaller than the trend since 1951 (0.12°C [0.08 to 0.14] per decade). Several independently analyzed data records of global and regional Land-Surface Air Temperature (LSAT) obtained from station observations are in broad agreement
that LSAT has increased. Sea Surface Temperatures (SSTs) have also increased. Intercomparisons of new SST data records obtained by different measurement methods, including satellite data, have resulted in better understanding of uncertainties and biases in the records. [2.4.1, 2.4.2, 2.4.3, Box 9.2]

[Stephen Richards]

warming from 1950 – 2000. The hiatus in temperatures post 1999 now show that something between 25% and 50%

I think you may be over-estimating CO² effects much like their models.

Betts: another of your strawmen. It's irrelevent. The models, your models, are a complete and utter failure and AR5 is an obscenity to science.

[Stephen Richards]

It is certain that Global Mean Surface Temperature (GMST) has increased since the late 19th century (Figure TS.1). Each of the past three decades has been warmer than all the previous decades in the instrumental record, and the decade of the 2000’s has been the warmest.

Before Hansen et al severly manipulated the data the 1930 were the warmest and before that the medieval optimum.

[Marion]

I think Judith Curry has the crux of it

"Here is the relevant text from Chapter 9 of the WG I Report, that attempts to justify their final conclusion:

Box 9.2: Climate Models and the Hiatus in Global-Mean Surface Warming of the Past 15 Years

''''''''''''''''''''''''''''''''''''''''"
"JC summary

My original intention for this thread was to go through and try to map the IPCC’s logical argument. I quickly got dizzy owing to seemingly unwarranted assumptions and incomplete information (such as: did the climate models use the correct external forcing for the first decade of the 21st century, or not?). I was then going to illustrate how any reasonable propagation of uncertainty of individual assertions/arguments through their main argument would produce much lower confidence in their overall conclusions. For example, they seem to have eliminated high CO2 sensitivity as a problem. Not to mention high confidence in increasing trend following 2012 (this high confidence comes right after blowing the prediction of the previous decade). And of course not to mention the relevant journal articles that didn’t get mentioned.

Apart from these obvious flaws, reading that text and trying to follow it is positively painful. Can someone remind me again how and why all this is supposed to be useful?"

http://judithcurry.com/2013/09/30/ipccs-pause-logic/#more-13176

Comments on that, Richard? (not quite the section you picked up on but somewhat more relevent to sceptic concerns!)

[rhoda]

Richard identifies much cynicism here. I wouldn't dream of denying that. But it is justified cynicism, as one tries to reconcile the hand-waving in the SPM pre-release on friday with the uncertainty, the unconcealable uncertainty, of the contributory science. It is not enough to ignore or dismiss the political summary and point to the chapters themselves.

Is the heat in the ocean or not? If it is, doesn't that alone invalidate the entire model ensemble? If it is not, doesn't that invalidate the entire model ensemble?

[lapogus]

Is the heat in the ocean or not? If it is, doesn't that alone invalidate the entire model ensemble? If it is not, doesn't that invalidate the entire model ensemble?

and what is the evidence that the relationship between CO2 emissions and temperature is now linear and not logarithmic? And what is the evidence for changing rainfall patterns? is it over a 30 year period or is this not just weather? Richard, I understand that you are busy and appreciate you popping in here, but perhaps you could ask Peter Stott to pop in here and share with us the beautiful illustration and 'evidence' he presented to the delegates last week, or do we need to do an FOI for this?

Peter Stott (3.25): Well exactly, it is looking at what has caused, eh, the unequivocal warming we have seen, and now we have got this new evidence, which shows very clearly that the dominant cause of the warming is human influence through basically what we have done to the climate system, we have warmed it up, emitted greenhouse gases, so human influence on the climate system is clear, and now we have had this extraordinary thorough analysis of evidence this week, and this is a really strong and robust conclusion about the dominant role of human influence on the climate system.

Matt McGrath (3.55): well, I imagine you are in good voice for someone who has have been up for days, through the night here… um, lots of people talk about the pause, and the fact that the climate temperatures, surface temperatures over the last 15 years have not risen as fast as they were rising before that, and that people have pointed at that and say that there are some holes in your theory, what’s your take on that, after being here?

Peter Stott (4.10): We have always expected to have variability around the longer term trend, and that is exactly what we have seen, in fact we have done a very thorough assessment in this report about the last 15 years, and shown about the important role of the ocean, and also, our understanding of what’s called climate forcing, so these are drivers of the climate system, and we have put all this together, and in fact it is evidence from the last 15 years… the, the warming ocean, the retreating snow and ice, the changing rainfall patterns, the continuing sea-level rise, and this evidence is so strong, of the dominant role of human influence on the climate system.

Matt McGrath (4.45): People have said that the heating, the heating from the pause, might have gone into the oceans, is there enough evidence to substantiate that at the this point ?

Peter Stott (4.55): Um, we have got very clear evidence that the ocean is warming, and that a huge amount of energy that is going into the ocean, and that reflects this imbalance of the climate system that we have, and so we got, we have this beautiful illustration that I presented to the delegates here in Stockholm, that shows that, that continuing rise in energy in the climate system, expressed through not just the warming oceans, but then that melt of the Arctic Sea ice, we had record Arctic sea ice extent, it has changed global rainfall patterns, its, its, its changed extremes as well, more extreme weather…

Matt McGrath (5.25): and it is a clear linear relationship, so that the more you pump into the atmosphere, the more the temperature goes up, its… in a very complex system it is as simple as that?

Peter Stott (5.35): This is a very important new piece of science actually, that again, we explained it in great detail to the delegates here, we all wanted to look at it very very thoroughly, and, despite all the complexities of the climate system, there is this very clear linear relationship between the overall emissions of carbon dioxide and greenhouse gases into the atmosphere, carbon dioxide, and the global temperature rise, so the more we emit, the more the temperature increases. Source Stott and Shuck - the transcript

[Brent Hargreaves]

Page 8-117 states Levels of Scientific Understanding.

Regardless of 'unknown unknowns', by their own confession there is VERY LOW understanding of radiation/aerosol/cloud interaction and LOW understanding of aerosol/cloud interaction. This is indeed a confession, and it's hidden in plain sight.

Cloudy days are cooler than sunny ones, but the science of cloud formation is in its infancy.

It's a good job that the aircraft industry in which I work doesn't have a similar gap in its understanding of - well, you name it. Our governments must follow Australia's example and refuse to accept this report.

[John Peter]

"Our governments must follow Australia's example and refuse to accept this report."
Seeds are being sown by a creeping reality that we are on a hiding to nothing with soaring energy bills. Even some of our ministers are beginning to see the light however faint it is at the moment.
http://www.telegraph.co.uk/finance/newsbysector/energy/10345743/Green-levies-on-energy-bills-unfair-says-Michael-Fallon.html
It would appear that the threat of 10% increases this autumn has set the grey matter spinning in Mr Fallon since the majority of this increase may have been caused by coalition energy Acts and regulations.

[DaleC]

Dr Betts,

Yes, I'm cynical. Let me tell you why. My experience is similar to that of many others. I'm from a soft left background (graduate arts 1970s/1980s, assumed university culture) and now write data analysis software for a living, so when CAGW reached the mainstream in the early 2000s, the responsible action was to confirm the issues and then spread the word. My first attempt to confirm the issues was to look at the MBH hockey stick, which quickly led me to ClimateAudit. Steve McIntyre was pilloried by the climate science establishment for being 100% correct on an issue which required only basic dimension-reduction skills (market researchers do PC all the time, so how hard can it be to get it right?). That made me cynical. Then, with CG1, it turns out that Mann's own colleagues agreed for the most part with McIntyre. That made me cynical. Then the "sleight of hand" as Phil Willis put it whereby the science was ignored, rendered the UK enquiries useless, and this was knowingly done. That made me cynical. Then the various fiascos with AR4 - voodoo science, etc etc and the blatant refusal to do anything about the IAC recommendations. That made me more cynical. And now AR5 continues in the grand tradition. And that's just the short list.

But at the heart of it, I feel betrayed. I came to the climate issue in good conscience wanting to do my little bit to help save us from ourselves, and now over ten years later I'm having a personal crisis about the collapse of the enlightenment. Thanks guys.

[Stuck-Record]

DaleC

Your experience mirrors mine a bit.

My quest was to understand how anyone could doubt 'Global Warming. Searching for evidence against 'deniers' brought me face-to-face with Gavin and co at RealClimate.

Shocked to discover what they were doing definitely wasn't science.

Most people are still at the "...how anyone could doubt 'Global Warming" stage.

[Martin A]

DNFTT

Bish! It's back!

[Athelstan.]

Cynic - moi?

You better believe it.

Believe it................................ or not, seeing as the report summary is clearly 'newspeak' - politicized gobbledegook.

IPCC AR5, the paradigm of the new order - no science but clouds of sophistry and decoy strategems couched in jargon - only bureaucrats can understand bureaucratese and ain't that the idea?

[Peter Crawford]

You can see that this is slightly decreasing the estimated warming (from 0.89°C to 0.85°C) whilst at the same time increasing the time period over which it occurred (from 1901-2012 to 1880-2012) - so a

Richard Betts, at which point are we officially permitted to start s****ing ourselves. You should know. You are an authority.
Do we s*** ourselves at 0.88C or do we wait until an even more terrifying 0'89C comes along?

As a taxpayer, I want to know how much I am paying you. And for what.

My email is Inyrogof@aol.com

[Theo Goodwin]

Judith Curry writes:

"Well here it is, the pause discussion is buried in Box 9.2 of the IPCC Working Group I Report."

And she quotes:

"In summary, the observed recent warming hiatus, defined as the reduction in GMST trend during 1998–2012 as compared to the trend during 1951–2012, is attributable in roughly equal measure to a cooling contribution from internal variability and a reduced trend in external forcing (expert judgment, medium confidence). The forcing trend reduction is primarily due to a negative forcing trend from both volcanic eruptions and the downward phase of the solar cycle. However, there is low confidence in quantifying the role of forcing trend in causing the hiatus, because of uncertainty in the magnitude of the volcanic forcing trend and low confidence in the aerosol forcing trend."

So, the IPCC are certain that "the downward phase of the solar cycle" has caused less radiation to reach the top of the atmosphere? Who would have known?

[michael hart]

I love how Figure TS.12 shows 'successful' simulation of ocean heat content. No real information about when they were done, with what models, what parameters, and what predictions, sorry, what projections were made.

I wonder if the five year Met Office forecast for continued pausing was one of the models employed? I expect we shall learn that from the next met office forecast for total OHC.

[TinyCO2]

Why would they compare the 1998–2012 trend to 1951–2012 rather than 1951-1997/8 or even 1975-1997? Doesn't this make the 'hiatus' seem less remarkable? I'm fairly sure that much of the trumpet blowing of the past was about the rapid rise in the 80s and 90s with little interest in the flat or declining trend of the 50s, 60s and 70s

[M. Stevens.]

On opening AR5 I have just noticed a typo.

The first sentance reads 'The Final Draft Report, dated 7 June 2013'
Shouldn't that read: 'The Final Daft Report....'?

[AntonyIndia]

In WG1 AR5′s 2216 pages final report the last 15 year temperature plateau is named the "hiatus" and is hidden away inside the first bar graph of box TS3 figure 1 and discussed in just 3 pages (TS 26 ..).

Less than 0.2% attention on what actually happened the last 15 years: are they all far sighted (Hyperopia)?

Today's climate science( 95% confidence by the 97% consensus TM, although they missed 93% of the heat vanishing in the deeper oceans):

Couldn't predict the last 15 years of world temperature: check.
Couldn't predict the last years regional season temperatures: check (MET office)
Couldn't predict the last 15 days local temperatures: check
They also don't suffer from Myopia other wise they could have predicted tomorrow's weather accurately.
/sarc off

[Stephen Richards]

But at the heart of it, I feel betrayed. I came to the climate issue in good conscience wanting to do my little bit to help save us from ourselves, and now over ten years later I'm having a personal crisis about the collapse of the enlightenment. Thanks guys.

Sep 30, 2013 at 11:02 PM | Unregistered CommenterDaleC

Dale

Smack on! For years I trusted the UK Met Off. I thought they were the best in the world. The CRU under Lamb had changed the way we thought about climate by concentrating research on the past to understand the future.

Then along came Jones, slow talking Jones and destroyed lamb's work completly to focus on the human damage. This was better for funds. It allowed the socialists wolrd wild to find a way to control the plebs, us.

From that point on jobs for likes of Betts, Slingo, Napier became the goal to pread the misinformation about human global warming. How will they 'interpret 'their useless models when, in 15 yrs, the atlantic has cooled, the pacific has cooled, the arctic has cooled and Antarctic has warmed.

We are not cynical Betts, we are REALIST.

DALE: I think you summarised perfectly for all of us.

[tom0mason]

I think that manicbeancounter has done a fine job on his blog in outlining the differences between AR4 and AR5 and the most significant radiative forcings.

http://manicbeancounter.com/2013/09/28/radiative-forcing-unipcc-ar5-undermines-ar4-but-scientists-have-unshaken-confidence-in-their-work/

[Roger Longstaff]

"Replace "0.89°C (0.69°C–1.08°C) over the period 1901- 2012" with "0.85 [0.65 to 1.06] °C over 1880–2012"

Ok, got it. It's back to just one line of code:

1.5*log2(400/270) = 0.85C

Now where have I seen that before? If you believe that all else follows...

[Justice4Rinka]

I think of this effort as the Protocols of the Elders of Big Green.

[Jace_F]

@roger Longstaff
It reminds me of this comment over at watts up with that:
http://wattsupwiththat.com/2013/04/18/numeracy-in-climate-discussions-how-long-ill-it-take-to-get-a-6c-rise-in-temperature/

1. Jeff L says:
April 18, 2013 at 5:56 pm
TerryS says:
April 18, 2013 at 4:52 pm
You can also use it to calculate what the current rise should be:
With 3C sensitivity: 3 x log2(400/270) = 1.7C
With 2C sensitivity: 2 x log2(400/270) = 1.1C
With 1.5C sensitivity: 1.5 x log2(400/270) = 0.85C
FYI of those that didn’t get what Terry was alluding to , 270 ppm is the pre-industrial CO2 level & 400 is the current CO2 level. Reference :
http://wattsupwiththat.com/2010/12/26/co2-ice-cores-vs-plant-stomata/
And over that time, the rise in temps is about 0.85 C :
http://ete.cet.edu/gcc/?/resourcecenter/slideshow/3/1
So, using our most fundamental & best documented data (temp vs time & CO2 vs time), we come up with roughly +/- 1.5 C per doubling. This is why I consider myself a luke warmer – this calculation is fundamental , simple & has no reliance on any computer model – it is solely based on data. Could it be more simple?
We can take this one step further in this post & the 6 deg C question.
If we use 1.5 for deltaT2, we can substitute that into equation (4) & get :
N= 400 x 2^(6/1.5) = 6400 PPM
or we would have to increase CO2 concentration to 6400 PPM to get the 6 deg C “warming of worry” using the warming & CO2 data we have seen over the last 100 + years
And we can continue with this calculation using the 2 PPM / yr rate of increase to see how long (L) it would take to get 6 deg C of warming :
L = (6400-400) PPM / (2 ppm/yr) = 3000 YEARS !!! …. or in the year 5013 !!!!!
…. just a little different than 2050.
So next time you encounter a CAGW alarmist – ask them to tell you what they think the sensitivity is & how they can defend it. If they throw a high number at you, ask them to justify it with the observed data (270 PPM to 400 PPM & ~ 0.8 to 0.95 C increase in temps, depending on dataset). I don’t care what feedbacks are put into models – this is the data & if the feedbacks don’t fit this data, the model is wrong. Period.
If they don’t know, do the math for them & ask them what they think CO2 concentrations will be in the future – pick a date. Use the 2 PPM / yr & do the math. We don’t need any stinkin’ computer models to tell us the answer. We have ~ 130 years of data & the fundamental equations to calculate sensitivity from that data – and we are all doing it here using hand held calculators.
The fact that we even have to go further to de bunk the CAGW hypothesis is absurd.
…. wow, that turned into a bit of a rant ;))

[Jace_F]

@roger Longstaff
It reminds me of this comment over at watts up with that:
http://wattsupwiththat.com/2013/04/18/numeracy-in-climate-discussions-how-long-ill-it-take-to-get-a-6c-rise-in-temperature/

1. Jeff L says:
April 18, 2013 at 5:56 pm
TerryS says:
April 18, 2013 at 4:52 pm
You can also use it to calculate what the current rise should be:
With 3C sensitivity: 3 x log2(400/270) = 1.7C
With 2C sensitivity: 2 x log2(400/270) = 1.1C
With 1.5C sensitivity: 1.5 x log2(400/270) = 0.85C
FYI of those that didn’t get what Terry was alluding to , 270 ppm is the pre-industrial CO2 level & 400 is the current CO2 level. Reference :
http://wattsupwiththat.com/2010/12/26/co2-ice-cores-vs-plant-stomata/
And over that time, the rise in temps is about 0.85 C :
http://ete.cet.edu/gcc/?/resourcecenter/slideshow/3/1
So, using our most fundamental & best documented data (temp vs time & CO2 vs time), we come up with roughly +/- 1.5 C per doubling. This is why I consider myself a luke warmer – this calculation is fundamental , simple & has no reliance on any computer model – it is solely based on data. Could it be more simple?
We can take this one step further in this post & the 6 deg C question.
If we use 1.5 for deltaT2, we can substitute that into equation (4) & get :
N= 400 x 2^(6/1.5) = 6400 PPM
or we would have to increase CO2 concentration to 6400 PPM to get the 6 deg C “warming of worry” using the warming & CO2 data we have seen over the last 100 + years
And we can continue with this calculation using the 2 PPM / yr rate of increase to see how long (L) it would take to get 6 deg C of warming :
L = (6400-400) PPM / (2 ppm/yr) = 3000 YEARS !!! …. or in the year 5013 !!!!!
…. just a little different than 2050.
So next time you encounter a CAGW alarmist – ask them to tell you what they think the sensitivity is & how they can defend it. If they throw a high number at you, ask them to justify it with the observed data (270 PPM to 400 PPM & ~ 0.8 to 0.95 C increase in temps, depending on dataset). I don’t care what feedbacks are put into models – this is the data & if the feedbacks don’t fit this data, the model is wrong. Period.
If they don’t know, do the math for them & ask them what they think CO2 concentrations will be in the future – pick a date. Use the 2 PPM / yr & do the math. We don’t need any stinkin’ computer models to tell us the answer. We have ~ 130 years of data & the fundamental equations to calculate sensitivity from that data – and we are all doing it here using hand held calculators.
The fact that we even have to go further to de bunk the CAGW hypothesis is absurd.
…. wow, that turned into a bit of a rant ;))

[Roger Longstaff]

Jace,

Thanks for that - I don't remember seeing it at WUWT before. IIRC I wrote the equation in the back of a notebook after a conversation with Richard Betts. I remember thinking, "if the whole thing can be modelled in one line of code, what the hell are the other 999,999 lines for?".

[SimonW]

"if the whole thing can be modelled in one line of code, what the hell are the other 999,999 lines for?"

To generate the squiggles to make it look more "sciencey". HTH.

[lapogus]

what the hell are the other 999,999 lines for?".
Oct 1, 2013 at 10:06 AM | Unregistered Commenter Roger Longstaff

It gives them more options for adding fudge factors.

[Marion]

Re: Sep 30, 2013 at 10:03 PM | rhoda

Beautifully put, Rhoda and worth repeating every word......

"Richard identifies much cynicism here. I wouldn't dream of denying that. But it is justified cynicism, as one tries to reconcile the hand-waving in the SPM pre-release on friday with the uncertainty, the unconcealable uncertainty, of the contributory science. It is not enough to ignore or dismiss the political summary and point to the chapters themselves.

Is the heat in the ocean or not? If it is, doesn't that alone invalidate the entire model ensemble? If it is not, doesn't that invalidate the entire model ensemble?"

Especially that last bit ....

"Is the heat in the ocean or not? If it is, doesn't that alone invalidate the entire model ensemble? If it is not, doesn't that invalidate the entire model ensemble?"

Shame our climate 'scientists' don't seem to do logic and will defend their models to the bitter end...

[splitpin]

Then along came Jones, slow talking Jones
Oct 1, 2013 at 8:25 AM Stephen Richards

The Coasters ! Yeah ! With King Curtis ! Yeah !