Lacking confidence at WUWT

Today's denier flavour is confidence.  Around the traps deniers are wondering if the IPCC has reduced "alarm" about climate change.  WUWT and other denier blogs have referred to Table 12.4 (see below), trying to claim that the only thing to worry about is the loss of Arctic sea ice - and in their delusion they are not worried about that because it will lower shipping costs and let everyone go into the Arctic to spill oil - and they reckon the polar bears can always find somewhere else to live, or some such argument.

Here is what Barry Brill writes today at WUWT (archived here) in relation to Table 12.4 (my bold italics):

And the other good news is that every one of the “substantial disruption” possibilities are seen as “unlikely” by the IPCC except* Arctic Sea Ice melting. This is mainly positive in opening up new sea lanes – while albedo effects have low significance in a slow-warming world.

Here is what Judith Curry wrote (archived here) (my bold italics):

But the bottom line is this.  The only one of these changes likely to occur in the 21st century is disappearance of the summer sea ice, and by ‘disappearance’ I assume they mean what they usually do when they say this:  < 1 M sq km left.... 

The reference by Barry and Judith to "likely" and "unlikely" is not correct in my view.  Confidence is on a different scale to the likelihood scale.  Take a look at the Guidance Note for Lead Authors of the IPCC Fifth Assessment Report on Consistent Treatment of Uncertainties.  I don't think that the fake sceptics are interpreting these properly.

The particular aspect that seems to be wrongly interpreted are the expressions of confidence.  The Guidance Note has this diagram relating to confidence:

So if something has low confidence it is generally because there is low agreement or limited evidence or both.  Low confidence doesn't mean that something is thought unlikely to happen.  It means that there is low agreement as to whether it will happen or not.  Or there is limited evidence to indicate one way or another.  In other words, it's more like "maybe but don't really know" than "it probably won't happen".  At least that's how I read it.  Confidence and likelihood are described separately by the IPCC.  Here are two short extracts from the Guidance Note:

• A level of confidence is expressed using five qualifiers: “very low,” “low,” “medium,” “high,” and “very high.” It synthesizes the author teams’ judgments about the validity of findings as determined through evaluation of evidence and agreement....
• Likelihood, as defined in Table 1, provides calibrated language for describing quantified uncertainty. It can be used to express a probabilistic estimate of the occurrence of a single event or of an outcome (e.g., a climate parameter, observed trend, or projected change lying in a given range). Likelihood may be based on statistical or modeling analyses, elicitation of expert views, or other quantitative analyses....

Okay, let's test it out.  Fake skeptics today are saying that none of the things in Table 12.4 (refer page 12-78 of the full WG1 report) below pose any real danger.

Table 12.4: Components in the Earth system that have been proposed in the literature as potentially being susceptible to abrupt or irreversible change. Column 2 defines whether or not a potential change can be considered to be abrupt under the AR5 definition. Column 3 states whether or not the process is irreversible in the context of abrupt change, and also gives the typical recovery time scales. Column 4 provides an assessment, if possible, of the likelihood of occurrence of abrupt change in the 21st century for the respective components or phenomena within the Earth system, for the scenarios considered in this chapter.

Change in climate system component	Potentially abrupt (AR5 definition)	Irreversibility if forcing reversed	Projected likelihood of 21st century change in scenarios considered
Atlantic MOC collapse	Yes	Unknown	Very unlikely that the AMOC will undergo a rapid transition (high confidence)
Ice sheet collapse	No	Irreversible for millennia	Exceptionally unlikely that either Greenland or West Antarctic Ice sheets will suffer near-complete disintegration (high confidence)
Permafrost carbon release	No	Irreversible for millennia	Possible that permafrost will become a net source of atmospheric greenhouse gases (low confidence)
Clathrate methane release	Yes	Irreversible for millennia	Very unlikely that methane from clathrates will undergo catastrophic release (high confidence)
Tropical forests dieback	Yes	Reversible within centuries	Low confidence in projections of the collapse of large areas of tropical forest
Boreal forests dieback	Yes	Reversible within centuries	Low confidence in projections of the collapse of large areas of boreal forest
Disappearance of summer Arctic sea ice	Yes	Reversible within years to decades	Likely that the Arctic Ocean becomes nearly ice-free in September before mid-century under high forcing scenarios such as RCP8.5 (medium confidence)
Long-term droughts	Yes	Reversible within years to decades	Low confidence in projections of changes in the frequency and duration of megadroughts
Monsoonal circulation	Yes	Reversible within years to decades	Low confidence in projections of a collapse in monsoon circulations

The thing is that low confidence doesn't mean it won't happen.  Here is what the report states about permafrost.  I've removed all the literature references to make it easier to read.  You can see the full text with references on page 12-80 of the full report:

The conjunction of a long carbon accumulation time scale on one hand and potentially rapid permafrost thawing and carbon decomposition under warmer climatic conditions on the other hand suggests potential irreversibility of permafrost carbon decomposition (leading to an increase of atmospheric CO2 and/or CH4 concentrations) on timescales of hundreds to thousands of years in a warming climate. Indeed, recent observations suggest that this process, induced by widespread permafrost warming and thawing, might be already occurring. However, the existing modelling studies of permafrost carbon balance under future warming that take into account at least some of the essential permafrost-related processes do not yield coherent results beyond the fact that present-day permafrost might become a net emitter of carbon during the 21st century under plausible future warming scenarios (low confidence). This also reflects an insufficient understanding of the relevant soil processes during and after permafrost thaw, including processes leading to stabilization of unfrozen soil carbon, and precludes a firm assessment of the amplitude of irreversible changes in the climate system potentially related to permafrost degassing and associated global feedbacks at this stage.

In other words, there is at this stage insufficient knowledge to say definitely one way or another.  Hence the low confidence.

What about long term droughts?  Here is what the IPCC reports:

As noted in Sections 5.5.2.4 and 5.6.2, long-term droughts (often called megadroughts, see Glossary) are a recurring feature of Holocene paleoclimate records in North America, east and south Asia, Europe, Africa and India. The transitions into and out of the long-term droughts take many years. Since the long-term droughts all ended they are not irreversible. Nonetheless transitions over years to a decade into a state of long-term drought would have impacts on human and natural systems.

AR4 climate model projections (Milly et al., 2008) and CMIP5 ensembles (Figure 12.23) both suggest widespread drying and drought across most of southwestern North America and many other subtropical regions by the mid to late 21st century (see Section 12.4.5), although without abrupt change. Some studies suggest that this subtropical drying may have already begun in southwestern North America. More recent studies suggest that regional reductions in
precipitation are primarily due to internal variability and that the anthropogenic forced trends are currently weak in comparison.

While previous long-term droughts in southwest North America arose from natural causes, climate models project that this region will undergo progressive aridification as part of a general drying and poleward expansion of the subtropical dry zones driven by rising greenhouse gases. The models project the aridification to intensify steadily as radiative forcing and global warming progress without abrupt changes. Because of the very long lifetime of the anthropogenic atmospheric CO2 perturbation, such drying induced by global warming would be largely irreversible on millennium time scale (see Sections 12.5.2 and 12.5.4). For example, Solomon et al. (2009) found in a simulation where atmospheric CO2 increases to 600 ppm followed by zero emissions, that the 15% reduction in precipitation in areas such as southwest North America, southern Europe and western Australia would persist long after emissions ceased. This however is largely a consequence of the warming persisting for centuries after emissions cease rather than an irreversible behaviour of the water cycle itself.

As for boreal forest:

Evidence from field observations and biogeochemical modelling make it scientifically conceivable that regions of the boreal forest could tip into a different vegetation state under climate warming, but uncertainties on the likelihood of this occurring are very high (Lenton et al., 2008; Allen et al., 2010). This is mainly due to large gaps in knowledge concerning relevant ecosystemic and plant physiological responses to warming (Niinemets, 2010). The main response is a potential advancement of the boreal forest northward and the potential transition from a forest to a woodland or grassland state on its dry southern edges in the continental interiors, leading to an overall increase in herbaceous vegetation cover in the affected parts of the boreal zone (Lucht et al., 2006). The proposed potential mechanisms for decreased forest growth and/or increased forest mortality are: increased drought stress under warmer summer conditions in regions with low soil moisture (Barber et al., 2000; Dulamsuren et al., 2009; Dulamsuren et al., 2010); desiccation of saplings with shallow roots due to summer drought periods in the top soil layers, causing suppression of forest reproduction (Hogg and Schwarz, 1997); leaf tissue damage due to high leaf temperatures during peak summer temperatures under strong climate warming; increased insect, herbivory and subsequent fire damage in damaged or struggling stands (Dulamsuren et al., 2008). The balance of effects controlling standing biomass, fire type and frequency, permafrost thaw depth, snow volume and soil moisture remains uncertain. While the existence of, and the thresholds controlling, a potential critical threshold in the Boreal forest are extremely uncertain, its existence cannot at present be ruled out.

The discussion on monsoons in various parts of the world is mixed.  It does state at the end that in regard to the Indian monsoon:

Given that the effect of increased atmospheric regional loading of aerosols is opposed by the concomitant increases in greenhouse gas concentrations, it is unlikely that an abrupt transition to the dry summer monsoon regime will be triggered in the 21st century.

The point of all this is that one has to be careful how to read the report.  Low confidence doesn't mean the same thing as low likelihood.

If anyone has a different take on this, let me know.

PS A final thought - for all her posts about "uncertainty" you'd think that Judith Curry would know the difference between "unlikely" knowns and "known unknowns".  Apparently not!

Wondering Willis Eschenbach is uncertainly sensitive at WUWT

Wondering Willis Eschenbach's sensitive side

Wondering Willis Eschenbach has returned from his hot but remote airports and brings great news (archived here).  He has done an about face and is no longer an insensitive lout, but extremely sensitive when it comes to climate.

No more figuring out feedbacks.  We no longer need to wonder what impact the disappearing Arctic sea ice will have over what time frame, or whether clouds will have a net positive or negative feedback effect.  Wondering Willis has pronounced (in a convoluted post using a circular argument, in which he misses the point of a six year old paper) that climate sensitivity is as follows:

Climate Sensitivity = Climate Sensitivity

No need to worry any more.  Problem solved.  Willis says all the climate models can be dismantled.  There is no need for climate modellers to puzzle any more.  Just ask Willis.  Don't ask Jeffrey Kiehl.  Though Willis does give Dr Kiehl a pat on the head for effort:

Note that Kiehl’s misidentification of the cause of the variations is understandable. .... But as a first cut at solving the paradox, as well as being the first person to write about it, I give high marks to Dr. Kiehl.

(Kiehl attributed differences between the models in regard to climate sensitivity to uncertainty in aerosol forcing.  Willis argued Kiehl was wrong.  As far as I can gather, Willis attributed the difference between those same models in regard to climate sensitivity to differences in climate sensitivity!  These days differences between models in regard to climate sensitivity is attributed to uncertainty in cloud feedback.)

Kiehl, Jeffrey T. "Twentieth century climate model response and climate sensitivity." Geophysical Research Letters 34.22 (2007).

Willis is uncertain about uncertainty (very high confidence)

Despite being certain about climate sensitivity, I can say with very high confidence that Willis is uncertain about uncertainty (same article).  So much so that he "laughed because crying is too depressing".  He thought that when the IPCC report stated:

The model spread in equilibrium climate sensitivity ranges from 2.1°C to 4.7°C and is very similar to the assessment in the AR4. There is very high confidence that the primary factor contributing to the spread in equilibrium climate sensitivity continues to be the cloud feedback. This applies to both the modern climate and the last glacial maximum.

...that it contradicted the fact that there is a degree of uncertainty in cloud response.  But of course he got it all wrong (again).  Willis foolishly writes:

How can they have “very high confidence” (95%) that the cause is “cloud feedback”, when they admit they don’t even understand the effects of the clouds?

What was meant in the report was that there was very high confidence that the difference in estimates of climate sensitivity can be attributed to different estimates of the effect clouds will have on the radiation balance. The authors have high confidence that there is large uncertainty in regard to cloud feedbacks. Higher sensitivity would mean that clouds exert a stronger positive feedback, while lower climate sensitivity would be expected if changes in clouds exerted a less positive or maybe dampen the forcing with a slightly negative feedback.   This is from page TS-54 of the WG1 Technical Summary (my paras and bold italics):

The water vapour/lapse rate, albedo and cloud feedbacks are the principal determinants of equilibrium climate sensitivity (ECS, the equilibrium change in annual mean global surface temperature following a doubling of the atmospheric CO2 concentration). All of these feedbacks are assessed to be positive, but with different levels of likelihood assigned ranging from likely to extremely likely. Therefore, there is very high confidence that the net feedback is strongly positive and the black body response of the climate to a forcing will therefore be amplified.

Cloud feedbacks continue to be the largest uncertainty. The net feedback from water vapour and lapse rate changes together is extremely likely positive and approximately doubles the black body response. The mean value and spread of these two processes in climate models are essentially unchanged from AR4, but are now supported by stronger observational evidence and better process understanding of what determines relative humidity distributions.. Clouds respond to climate forcing mechanisms in multiple ways and individual cloud feedbacks can be positive or negative.

Key issues include the representation of both deep and shallow cumulus convection, microphysical processes in ice clouds, and partial cloudiness that results from small-scale variations of cloud-producing and cloud-dissipating processes. New approaches to diagnosing cloud feedback in GCMs have clarified robust cloud responses, while continuing to implicate low cloud cover as the most important source of intermodel spread in simulated cloud feedbacks.

The net radiative feedback due to all cloud types is likely positive. This conclusion is reached by considering a plausible range for unknown contributions by processes yet to be accounted for, in addition to those occurring in current climate models. Observations alone do not currently provide a robust, direct constraint, but multiple lines of evidence now indicate positive feedback contributions from changes in both the height of high clouds and the horizontal distribution of clouds. The additional feedback from low cloud amount is also positive in most climate models, but that result is not well understood, nor effectively constrained by observations, so confidence in it is low.

It all goes to show that no matter how much effort one takes to clarify meaning, there will always be someone who gets it all wrong.

About that "Hiatus" - IPCC climate models and recent observations

This week the fashion is shaping up to be a look at models vs observation.  Some deniers keep saying  the comparison of recent observed surface temperature anomalies with models is not covered in the new WG1 report but all that shows is that those deniers haven't read the WG1 report.  For example, Judith Curry writes (archived here):

What is wrong is the failure of the IPCC to note the failure of nearly all climate model simulations to reproduce a pause of 15+ years.

Once again, Judith Curry is wrong.  I believe she's wrong to call it a "pause of 15+ years", particularly as this starts close to the extremely hot year of 1998 after which the temperature dropped below the trend only to rise higher still later on.  The first decade of this century was the hottest in the instrumental record and 2010 was equal hottest year ever recorded (with 2005).  If I were to say there was a "hiatus" I'd say it started around 2005, which is hardly long enough to even call it a "pause".  The following animated chart illustrates why I say that and so does the chart further down in this article:

Data source: NASA

Regardless of when the "pause" started, Judith is definitely wrong to imply that the report doesn't address the difference between model average and observations in recent years.  (There is a difference between observations and model averages, but the observations are still within the range of modeled temperatures.)

The IPCC WG1 report does note that there is a difference - and at some length.  I started with the technical summary from page TS-26, which has a box labelled:

Box TS.3: Climate Models and the Hiatus in Global-Mean Surface Warming of the Past 15 years

Before getting too worked up about any discrepancy, I thought it worthwhile to look at how well models and observations lined up in the past.  This strikes me as being relevant because models don't claim to match observations closely on a year to year basis.  They are looking at longer periods of time - those relevant to climate change, not weather change.

If you are on the home page, click here to continue.

Science vs Policy and the ignorance of conspiracists at science-denying blogs

I admit to being surprised sometimes by the antics of science deniers and disinformers.  Anthony Watts and Judith Curry are incredibly ignorant of intergovernmental workings and don't know the difference between science and policy.

Anthony Watts today (archived here) has posted some excerpts from a document that purports to be:

SUMMARY OF THE 12TH SESSION OF WORKING GROUP I OF THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC) AND THIRTY-SIXTH SESSION OF THE IPCC

23-26 SEPTEMBER 2013

The document is from IISD Reporting Services.  I don't know the provenance of the summary itself (click here for pdf and html versions in English, French and Japanese), for example whether it was a formal report of the IPCC meeting or whether the summary was prepared by the IISD reporting service.  I've no reason to doubt it is a reasonable report of the IPCC meetings.  However I couldn't find anything similar on the IPCC website.

This blog post is a bit long - if you're on the home page, click here to read the rest.

Steve McIntyre and Anthony Watts fail climate modeling 101

Anthony Watts and Steve McIntyre show once again that they aren't much chop when it comes to modeling trends or lining up charts.  People might recall how poor old Steve failed dismally when he made a faltering start to psych stats (with Lewandowsky et al) and gave up before getting to first base.  He failed again when he got stuck in core tops with Marcott et al.

Now they fail by pulling up a flawed chart from an early draft of AR5 and complain it's been corrected and revised (archives here for WUWT - updated here; and The Auditor's blog).  Actually, they don't acknowledge that it's been corrected.  Neither of them want to admit there is a flaw in the draft version, which everyone else saw at the outset.  If they had they wouldn't have had an article to write.

The problem was with this chart:

Tamino picked this up very early in the piece when someone called David Whitehouse tried to use it.  Ross McKitrick tried it on again recently.

I guess Steve McIntyre and Anthony Watts aren't very good at charts or models.  But if you look at this HadCRUT chart it's pretty easy to see what the problem is:

Data Source: HadCRUT

The 1990 data point is way above the trend line.  Models shouldn't be aligned with that data point, they should be aligned with the trend line.   Dana at SkepticalScience.com explains this too.

It looks as if the chart that was selected to replace the flawed chart is the one below.  It stretches over a longer time period, up to 2035 instead of 2015.  The notation says "the values are harmonised to start from the same value at 1990".  The key word, presumably, being "harmonised".  So it looks to me that it's Anthony Watts and Steve McIntyre who have it all wrong.

Source: IPCC AR5 Technical Report TFE.3, Figure 1: page TS-96 

Funny thing is it's even pointed out in the thread at Steve McIntyre's blog (archived here), but instead of acknowledging that there was an error in the first version, the commenters get into a raging argument complaining that the "expert reviewers" weren't advised of the correction and revision.  The denialiti aren't doing too well in their attempts to prove all the models and all the IPCC report is "wrong" so I guess they'll have to be satisfied complaining they weren't asked permission to make a correction to the report!

The description of the above chart is long and dense (and has a typo).  It's described as follows:

Estimated changes in the observed globally and annually averaged surface temperature anomaly relative to 1961-1990 (in °C) since 1950 compared with the range of projections from the previous IPCC assessments. Values are harmonized to start form (sic) the same value at 1990. Observed global annual temperature anomaly, relative to 1961–1990, from three datasets is shown as squares (NASA (dark blue), NOAA (warm mustard), and the UK Hadley Centre (bright green) data sets. The coloured shading shows the projected range of global annual mean near surface temperature change from 1990 to 2035 for models used in FAR (Figure 6.11), SAR (Figure 19 in the TS of IPCC 1996), TAR (full range of TAR, Figure 9.13(b)). TAR results are based on the simple climate model analyses presented in this assessment and not on the individual full three-dimensional climate model simulations. For the AR4 results are presented as single model runs of the CMIP3 ensemble for the historical period from 1950-2000 (light grey lines) and for three scenarios (A2, A1B and B1) from 2001-2035. For the three SRES scenarios the bars show the CMIP3 ensemble mean and the likely range given by -40 % to +60% of the mean as assessed in Meehl et al. (2007). The publication years of the assessment reports are shown.

This one's interesting too.  It shows the CMIP5 model runs with observations:

Source: IPCC AR5 Technical Report TFE.3, Figure 1: page TS-96 

Projections of annual mean global mean surface air temperature (GMST) for 1950–2035 (anomalies relative to 1961–1990) under different RCPs from CMIP5 models (light grey and coloured lines, one ensemble member per model), and observational estimates the same as the middle left panel. The grey shaded region shows the indicative likely range for annual mean GMST during the period 2016–2035 for all RCPs (see Figure TS.14 for more details). The grey bar shows this same indicative likely range for the year 2035.

From the WUWT comments

RC Saumarez says:

October 1, 2013 at 8:47 am
The IPCC has throen the gppd name of science into disrepute. (sic)
Are they so stupid that they think that nobody would notice or are they so sure of themselves that they are certain that they will get away with this?

KR picks up on the incorrect alignment in the early draft and also picks up Steve McIntyre and says:

October 1, 2013 at 8:34 am
The draft Figure 1.4 appears to have been incorrectly baselined – set to the 1990 peak rather than the actual trend at that time.
However, the actual caption for the draft figure (as per the leaked document) states: “The 90% uncertainty estimate due to observational uncertainty and 16 internal variability based on the HadCRUT4 temperature data for 1951-1980 is depicted by the grey shading.” In other words, the grey area shows the range of variability around model projection means, which are shown by the colored bands. Observations fall well within the range of projections – something McIntyre somehow… failed to mention.

Alistair Ahs sort of spots the error in the draft version and says (excerpt):

October 1, 2013 at 8:49 am
Look at 1990 in the second graph. In the first graph all the projections start from the 1990 observed value. In the second graph the projections start from below the 1990 observed value, because they are correctly plotted as anomalies with respect to the 1961-1990 mean.

WUWT playground monitor, richardscourtney isn't letting the IPCC get away with correcting a mistake in an early draft and says:

October 1, 2013 at 9:10 am
Alistair Ahs: ... I am curious to know if you really are called Alistair Ahs because I find it hard to believe anybody would put their own name to so stupid and pathetic an excuse as you have written. Anomalies can be normalised to any reference value. The correct reference value for a projection is from the empirically observed value at the time of the start of the projection.
Richard

Dave puts far too much faith in the incompetent Steve McIntyre and says:

October 1, 2013 at 8:29 am
Never mess with McIntyre. He will tear this thing apart line by line.
The IPCC doesn’t have a chance.

The WUWT-ers' comments get worse and worse (updated archive here).  Most of the commenters are innumerate.

From The Auditor's comments 

Wow, Judith Curry is living down to her reputation.  She's even made a "brilliant post" comment to The Auditor's silly article.  (Something we're used to on WUWT when the readers don't have a clue what an article is all about but feel the urge to write something!)

curryja Posted Oct 1, 2013 at 6:03 AM | Permalink | Reply

Steve, brilliant post by the way

Bits and pieces from the IPCC WG1 - methane, AMO and anthropogenic forcing

While I'm working my way through the IPCC reports, here are some more snippets of interest from the AR5 Technical Summary.

On methane emissions (page TS-23)

Models and ecosystem warming experiments show high agreement that wetland CH4 emissions will increase per unit area in a warmer climate, but wetland areal extent may increase or decrease depending on regional changes in temperature and precipitation affecting wetland hydrology, so that there is low confidence in quantitative projections of wetland CH4 emissions. Reservoirs of carbon in hydrates and permafrost are very large, and thus could potentially act as very powerful feedbacks. Although poorly constrained, the 21st century global release of CH4 from hydrates to the atmosphere is likely to be low due to the under-saturated state of the ocean, long-ventilation time of the ocean, and slow propagation of warming through the seafloor. Release of carbon from thawing permafrost is very likely to provide a positive feedback, but there is limited confidence in quantitative projections of its strength. {6.4}

Atlantic Multidecadal Oscillation made little contribution to GMST* (page TS-25)

A number of studies have investigated the effects of the Atlantic Multidecadal Oscillation (AMO) on global mean surface temperature. While some studies find a significant role for the AMO in driving multi-decadal variability in GMST, the AMO exhibited little trend over the period 1951-2010 on which these assessments are based, and the AMO is assessed with high confidence to have made little contribution to the GMST trend between 1951 and 2010 (considerably less than 0.1°C). {2.4, 9.8.1, 10.3; FAQ 9.1}.

*GMST = global mean surface temperature.

Human activities had by far the greatest impact on global surface temperature (page TS-26)

Greenhouse gases contributed a global mean surface warming likely to be between 0.5°C and 1.3°C over the period between 1951 and 2010, with the contributions from other anthropogenic forcings likely to be between –0.6°C and 0.1°C and from natural forcings likely to be between –0.1°C and 0.1°C. Together these assessed contributions are consistent with the observed warming of approximately 0.6°C over this period (Figure TS.10). {10.3}...

...Observed warming over the past sixty years is far outside the range of internal climate variability estimated from pre-instrumental data, and it is also far outside the range of internal variability simulated in climate models. Model-based simulations of internal variability are assessed to be adequate to make this assessment. Further, the spatial pattern of observed warming differs from those associated with internal variability. Based on this evidence, the contribution of internal variability to the 1951–2010 global mean surface temperature trend was assessed to be likely between –0.1°C and 0.1°C, and it is virtually certain that warming since 1951 cannot be explained by internal variability alone. {9.5, 10.3, 10.7}

The instrumental record shows a pronounced warming during the first half of the 20th century. Consistent with AR4, it is assessed that the early 20th century warming is very unlikely to be due to internal variability alone. It remains difficult to quantify the contributions to this early century warming from internal variability, natural forcing and anthropogenic forcing, due to forcing and response uncertainties and incomplete observational coverage. {10.3}

Two denier myths back to back are put down by the IPCC; while richardscourtney shouts in protest

I'm reading the IPCC's AR5 Technical Summary of WG1 at the moment.  I wonder how long it will take deniers to protest these two adjacent snippets from page TS-21.

It won't be "it's the sun"

The recent solar minimum appears to have been unusually low and long-lasting and several projections indicate lower TSI for the forthcoming decades. However, current abilities to project solar irradiance are extremely limited so that there is very low confidence concerning future solar forcing. Nonetheless, there is a high confidence that 21st century solar forcing will be much smaller than the projected increased forcing due to GHGs. {5.2.1, 8.4; FAQ 5.1}

Cosmic ray effect is too weak to influence climate 

Changes in solar activity affect the cosmic ray flux impinging upon the Earth’s atmosphere, which has been hypothesized to affect climate through changes in cloudiness. Cosmic rays enhance aerosol nucleation and thus may affect cloud condensation nuclei production in the free troposphere, but the effect is too weak to have any climatic influence during a solar cycle or over the last century (medium evidence, high agreement). No robust association between changes in cosmic rays and cloudiness has been identified. In the event that such an association exists, it is very unlikely to be due to cosmic ray-induced nucleation of new aerosol particles.

From WUWT

Anthony Watts has let his readers know the draft report is up (archived here).  Being the paranoid conspiracy theorists they are, they've decided "it's not science".  They not only "believe" it's all a giant hoax, they "believe" that on the issue of climate science, all 195 governments are complicit in the hoax and have put aside their multiple differences to fool the world into thinking it's getting warmer.

But 195 governments and all the world's scientists can't fool the astute readers of WUWT.  No way.  They are on top of the biggest and most improbable hoax in the past four billion years (or do they think it's only the last 6,000 years or whatever young earthers believe?).

richardscourtney shouts his deluded Lysenko conspiracy theory to the world of WUWT (punchline excerpts from a very long, very emphatic post archived here):

September 30, 2013 at 9:18 am

...The IPCC does NOT exist to summarise climate science and it does not.

...The IPCC AR5 is pure pseudoscience intended to provide information to justify political actions; i.e.Lysenkoism.

Richard

Fake sceptics have nothing to latch onto given the greater certainty from IPCC

The IPCC AR5 SPM has been reported fairly well in the mainstream media with headlines like the following:

• Australia has 'much to lose' from climate change Sydney Morning Herald
• IPCC climate change report: Human role in global warming now even clearer ABC Online
• Govt pressured to make deeper CO2 cuts Sydney Morning Herald
• Government accepts climate report but declares carbon tax was ‘wrong policy’ Herald Sun, Australia
• U.N. Affirms Human Role in Global Warming The Wall Street Journal
• Science solid on global warming, IPCC declares The Australian
• Global warming 'extremely likely' man-made: IPCC The Australian
• Coalition urged to raise emissions reduction target in wake of IPCC report The Guardian
• IPCC climate report: humans 'dominant cause' of warming BBC
• Human influence on climate change a ‘clarion call’ to global community Irish Times
• Scientists more convinced mankind is main cause of warming Reuters
• IPCC: Global warming is getting deeper The Telegraph
• Climate Change Report “Gives No Reason for Optimism” News International
• Climate panel forecast: Higher seas, temperatures The Seattle Times
• UN panel says humans causing global warming Bangkok Post
• IPCC report: The financial markets are the only hope in the race to stop global warming The Independent
• UN panel's climate report sparks concern AFP
• Around the world, strong reactions to climate-change report Globe and Mail
• An 'alarm clock moment' for the world: IPCC SBS
• Climate change scientists 'unequivocal' in blaming man Herald Scotland
• UN panel 95% sure humans causing global warming Economic Times

There are very few articles still attempting to deny climate science.  And those that do misrepresent it.  There are very few denier articles outside of denier blogs and opinion pieces in right wing rags.

We're heading for hot!

One denier, Michael Barrone penned The Great Global-Warming Disappointment for the National Review Online (archived here), in which he wrote at length about a cult called the Millerites, Jesus and religion.  It was difficult to work out what he was trying to say.  He quoted from other science deniers like Matt Ridley to bolster whatever argument he thought he was making, writing:

“The big news,” Ridley writes, “is that, for the first time since these reports started coming out in 1990, the new one dials back the alarm. It states that the temperature rise we can expect as a result of man-made emissions of carbon dioxide is lower than the IPCC thought in 2007.”

How Ridley came to that conclusion is perplexing.  The IPCC does not say that.  What it does do is provide a wider estimated range for climate sensitivity.  The higher estimate remains at 4.5 degrees (my bold italics):

The equilibrium climate sensitivity quantifies the response of the climate system to constant radiative forcing on multi-century time scales. It is defined as the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2 concentration. Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 6°C (medium confidence)16. The lower temperature limit of the assessed likely range is thus less than the 2°C in the AR4, but the upper limit is the same. This assessment reflects improved understanding, the extended temperature record in the atmosphere and ocean, and new estimates of radiative forcing.

Compare this with AR4 Summary for Policy Makers:

Progress since the TAR enables an assessment that climate sensitivity is likely to be in the range of 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values. {WGI 8.6, 9.6, Box 10.2, SPM}

Scientists are conservative.  However, the fact that the IPCC has high confidence that it's "extremely unlikely" to be less than 1°C and has only medium confidence that it's "very unlikely" to be higher than 6°C  in the top end of the range is not cause for celebration.  Regardless, if we listened to the Matt Ridley's of the world we'd overshoot the doubling way before the end of this century, so we could be looking at very rapid climate change in only a few decades leading to severe climate change over coming centuries.

That's on the millenial time frame, what about the near term.  Here is what the report states:

The transient climate response quantifies the response of the climate system to an increasing radiative forcing on a decadal to century timescale. It is defined as the change in global mean surface temperature at the time when the atmospheric CO2 concentration has doubled in a scenario of concentration increasing at 1% per year. The transient climate response is likely in the range of 1.0°C to 2.5°C (high confidence) and extremely unlikely greater than 3°C.

So this century if we continue on our current emissions path, we would be looking at a rise greater than 2.5°C, and 2°C is considered the upper safe limit!

The Daily Mail is wrong, again!

The Daily Mail lives up to its reputation as a denier tabloid with a mix of fact and fiction.  Fiona Macrae writes (archived here):

Climate change scientists warned yesterday that the Earth is set for more heatwaves, floods, droughts and rising sea levels that could swamp coasts and low-lying islands as greenhouse gases build up in the atmosphere.

But despite these dire predictions, they admitted global warming is likely to be more gradual than they previously thought and that world temperatures have barely changed in the past 15 years.

I looked through the report but could find no "admission" that global warming is likely to be more gradual than previously thought.  On the contrary, what I found was examples that things could be worse, for example estimates of sea level by the end of 2100 could be almost half a metre higher than "previously thought".


There is more to write about denier's thrashing about with nothing to focus their denial upon.  But I've got to go out for a bit.  Back later.  Feel free to add more silliness from deniers in the comments.

"Popularity" of IPCC report on climate change

One of the arguments put up by science deniers is that "no-one cares".  For example on WUWT today (archived here) M Courtney says:

September 27, 2013 at 5:19 am
Pointman’s comment was interesting. I looked at the BBC News website for their post Most Popular news stories at 13:13 today. The end of the world was only number 6.

1: Kanye West angry at Radio 1 parody
2: Goodbye, US passport
3: Two plead not guilty to Rigby murder
4: The man who may have saved the world
5: Cameron says no to Salmond TV debate
6: Global warming now ‘unequivocal’
7: Spain to consider time zone change
8: Quiz of the week’s news
9: Is Breaking Bad’s Walter White one of TV’s truly evil characters?
10: New Syria chemical attacks probed

No-one cares anymore…

Here is the "popularity" or prominence now on various news sites:


BBC most shared items:

The IPCC report is the second most shared item, but only the fifth most read (so far).

Sky News Australia

I couldn't find a "most read" but the IPCC report is ranked No. 1 of its Top Stories, with the early start to the fire season in NSW ranked No. 6. (Click image for larger view.)

UK Telegraph

The actual news item is Ranked No. 1 in the Most Viewed, while Delingpole's denial is the Most Commented.

The Age, Australia

The IPCC reports are the top four most popular items in the Melbourne Age.

Wall Street Journal

The IPCC report ranks as the fourth most popular item in the WSJ.

The New York Times
Justin Gillis' article is on page 1 today, but doesn't make the grade (yet) in terms of popularity.

The Mail - home of tabloid writer David Rose:

Contrast the above with the most read items at the home of denialist David Rose.  Today's science denier for the Mail is Ellie Zolfagharifard, with an article playing down and misrepresenting the IPCC report.

The latest climate science from the IPCC and some early reactions

The summary report for policy makers from the latest IPCC Working Group 1 report was released a few hours ago, at 10:00 am this morning Stockholm time.  For the last five days the IPCC has been meeting to consider and finalise the draft report.  By all accounts it was a mammoth session, with participants working around the clock.  If nothing else, it shows that all the participants took the summary report very seriously.

I watched the live telecast and have skimmed the Summary for Policy Makers.  It's only 36 pages from beginning to the figures and tables at the end.

David Rose asks an "ill-posed question", from a scientific point of view

During the telecast, tabloid writer David Rose asked a question and was told by Michel Jarraud of the WMO that from a scientific point of view it was "an ill-posed question" based on a misunderstanding of how models work.  Good for Michel Jarraud!

How much more can we burn?

One figure that stood out was a plot of temperature against cumulative CO2 and cumulative carbon.  I was going to include the full caption but it's long.  Scientists don't make things simple to follow, do they.  You can read the caption at the top of page SPM-20 here. Click image for larger version.

Figure SPM.10: Global mean surface temperature increase as a function of cumulative total global CO2 emissions from various lines of evidence. 

The thing I like is that it shows our choices in terms of a carbon budget.  If we are happy to send humanity to a dreadful future we can decide to keep burning carbon.  If we want to opt to give future generations a reasonable hope of continuing civilisation, then we will set a budget limit.  From what I can work out that limit will need to be at around 800 Gt of carbon (GtC is shown on the bottom horizontal scale).  I've overlaid lines showing the 2 degree mark and the 800 Gt mark.  The report states:

Limiting the warming caused by anthropogenic CO2 emissions alone with a probability of >33%, >50%, and >66% to less than 2°C since the period 1861–188022, will require cumulative CO2 emissions from all anthropogenic sources to stay between 0 and about 1560 GtC, 0 and about 1210 GtC, and 0 and about 1000 GtC since that period respectively23. These upper amounts are reduced to about 880 GtC, 840 GtC, and 800 GtC respectively, when accounting for non-CO2 forcings as in RCP2.6. An amount of 531 [446 to 616] GtC, was already emitted by 2011. {12.5}

I think that translates to - don't burn any more than 800 Gt of carbon if you want to leave any sort of future for humankind.

IPCC Headline Statements

There are the nineteen headline statements from the approved Summary for Policy Makers (my bold italics).  It seems to me that they are more forceful than were previous reports.  I won't list the lot - you can read them all here in a separate document or as part of the SPM itself.  I'll just list a few of them:

• Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. 
• Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971. 
• Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence). 
• The atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification. 
• Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system. 
• Climate models have improved since the AR4. Models reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions (very high confidence). 
• Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. 
• Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. 
• Changes in the global water cycle in response to the warming over the 21st century will not be uniform. The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase, although there may be regional exceptions. 
• The global ocean will continue to warm during the 21st century. Heat will penetrate from the surface to the deep ocean and affect ocean circulation. 
• Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2.

What the papers are saying

I went to see what the papers were saying.  The Telegraph, where denier blogger James Delingpole has a large if mainly illiterate following, wrote a fairly straight report with a couple of interesting quotes:

One delegate told the Telegraph on Thursday night: "The good news is that the Saudis are not objecting to every word like used to happen [at previous meetings].

"It is pretty tame compared to the early years of the IPCC when you used to have a real scrum between people like the Chinese, who could be quite difficult. There is no-one in there saying climate change isn't real."...

...Ed Davey, the Energy and Climate Change Secretary, said solutions to the problem of man-made greenhouse gases accumulating in the atmosphere “must be set in motion today.”
He said: “The risks and costs of doing nothing today are so great, only a deeply irresponsible government would be so negligent.

“Without urgent action to cut greenhouse gas emissions this warming will continue, with potentially dangerous impacts upon our societies and economy.”

Sky News Australia wrote a straight report with the headline: Man-made warming 'extremely likely'

Australia's Sydney Morning Herald featured a strong editorial:

The new Intergovernmental Panel on Climate Change report should be a game-changer in how Australia tackles global warming. But it won't be - not without strong leadership from Prime Minister Tony Abbott.

Future generations will look back, see the clear evidence of human-induced climate change in this and previous IPCC reports and wonder why more wasn't done sooner to tackle the problem? They will look at the safety-first approach of the Howard Coalition government on, say, terrorism, where substantial policy, investment and cultural change was implemented to minimise that risk.

Why, they will ask, does this Abbott Coalition government at best play down the risk of global warming and at worst deny it to protect vested interests and reinforce the ideological groupthink among its cheer squad?

Read the full SMH editorial here.


The Washington Post wrote a fairly straight article, with some quotes from leaders in the USA inexplicably next to a couple from anti-science blogger, Anthony Watts, presumably to show up just what clowns the fake sceptics are.  A short excerpt (my bold italics):

In the United States, officials reacted favorably to the report. Secretary of State John Kerry said “climate change is real,” happening now, and that the United States is determined to be a leader in curbing emissions.

Sen. Barbara Boxer (D-Calif.), chair of the Committee on Environment and Public Works, called the report a landmark and said it underscores the administration’s recent efforts. “I will do everything in my power to support the administration in their efforts to address the dangerous impacts of climate disruption,” Boxer said.

Frances Beinecke, president of the Natural Resources Defense Council, an environmental advocacy group, called the report “a warning bell to the world.” She said the impact are fierce wildfires, drought, floods and storms that will only get worse with delay. “The science is clear: We are altering the climate,” Beinecke said.

But deniers of climate change dismissed the report. Anthony Watts, a former television meteorologist who writes the blog WattsUpWithThat, called it “comical at best.”

Read the full Washington Post article here.

There's a miscellaneous collection of news items, newspaper blogs and editorials here on Google news.  Mainstream media is doing straight reporting.  I'd say if you want to read what science deniers are saying you'll have to go to their blogs, because they don't seem to be getting much airplay in the news.

What the science deniers are saying

Anthony Watts on his blog WUWT (archived here) says his first reaction was:

That IPCC had a golden opportunity, and blew it due to being unable to adapt to reality.

He didn't say what he thought the "golden opportunity" was or how the IPCC "blew it", only why.

Anthony promised a "bullet point collection" of reactions as they come in, but he left out the bullet points.  There is not a dot to be seen at WUWT.

As for reactions, Anthony did report that Judith Curry went looking through the summary report for her favourite "uncertainty".  Going by what I've read she will be certain to have found less uncertainty than was in previous IPCC reports.  Therefore it is extremely likely that Judith Curry won't be happy (high confidence).

The reaction from the rest of what Anthony has collated is predictable and boring.  The usual "I don't believe it" and "all the world's experts are wrong" mixed in with mostly non-specific grumbles and moans.

From the WUWT comments

The comments are archived here with Anthony Watts bullet-less bullet points.

Mike Bromley the Kurd says:

September 27, 2013 at 7:17 am
They just keep running for the shelter of their old pal CO2. It’s tiresome.

What is BBC Radio 4 doing talking to Bob Carter? son of mulder says:

September 27, 2013 at 5:25 am
Just heard Prof Bob Carter on BBC Radio4 World at One. Brilliant interview putting a sound sceptical perspective on the IPCC report. Well worth a listen again when it is available.

Professional science disinformer, Ross McKitrick,  is running out of gigs and is commenting on WUWT.  He also hasn't read much climate science but thinks he's being "clever" instead of wrong as usual - he says:

September 27, 2013 at 5:32 am
SPM in a nutshell: Since we started in 1990 we were right about the Arctic, wrong about the Antarctic, wrong about the tropical troposphere, wrong about the surface, wrong about hurricanes, wrong about the Himalayas, wrong about sensitivity, clueless on clouds and useless on regional trends. And on that basis we’re 95% confident we’re right.

Bill Illis resides on different planet, or so he says:

September 27, 2013 at 5:35 am
We should just be pointing out the errors now. There is no point discussing the virtual world the IPCC is talking about – they are not talking about the real planet Earth, but some virtual world, planet Nibiru in a climate model.
———-
One major graphic is clearly wrong. The observed change in temperature from 1901 to 2012 – figure SPM.1 (b), particularly the Oceans part. There has been no warming in the central Pacific but it is shown as +0.4C or so in the graphic (large parts of it not shown despite there being a large number of measurements in this region covering the whole period). There has been no warming in the far southern ocean (again it is missing despite a large number of ships being there over the whole period – including whaling ships in the early part of the 20th century). Other areas have no warming over this period yet the entire Ocean area is shown as having warmed. Clearly the Figure is meant to show warming everywhere yet that is not correct.
———–
The graphic showing observed change in temperature relative to the climate models shown in earlier drafts is not included in the report anymore.

Here is the chart to which Bill refers:

Bill provides no evidence of why he thinks the chart is wrong.  I'm going to go with the science rather than a WUWT regular.

Peter Ward is complaining that people are listening to scientific experts instead of anti-science bloggers:

September 27, 2013 at 5:35 am
In the MSM (BBC, CNN, etc) the IPCC report is being portrayed as the gospel truth on climate change. For example the CNN summary is “The world’s getting hotter, the sea’s rising and there’s increasing evidence neither are naturally occurring phenomena”. I think it’s fair to say that the MSM are onside with the warmists. The online debate is not reaching the consciousness of the general public.

Steve C says he refuses to look at the evidence, fearing being shaken and stirred:

September 27, 2013 at 5:39 am
The BBC are all over it today, of course. Fawning interviews with the IPCC crowd to spread their political message and – a new development! – the occasional few words from the likes of Bob Carter, now being allowed as the “minority view” to give the impression of balance. Overall, exactly as you’d expect from “The World’s Most Respected Broadcaster” (© BBC): junk reporting of junk politics.

I, meanwhile, remain unshaken and unstirred. Nobody has yet produced any evidence (that I’ve been able to find) to suggest that humanity has had any effect, still less a “catastrophic” one, on the world’s weather systems, therefore the null hypothesis holds. Still waiting, guys. Show me how evil we are, rather than how evil you are.

Robert W Turner is in a world of his own and says:

September 27, 2013 at 8:06 am
The sad part is most of the policy makers that will read this are going to fall for it. How long can this lie last and will anyone be held accountable when the jig is up?

Matt Ridley couldn't support his ridiculous claims

Update - see below

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Matt Ridley, unsurprisingly, can't get a word in at Slate.  So he's had to lower his sights (again) and turn to a fake sceptic, Anthony Watts and his science-denying blog, wattsupwiththat (archived here). WUWT is much less discriminating about what it publishes :(

Here is what Matt claims:

The argument I made was that climate change has benefits as well as costs and that the benefits are likely to be greater than the costs until almost the end of the current century.

Matt's persisting in his false claim that global warming will have net benefits until 'almost' 2100, by which time he'll be long gone so I guess he doesn't care what happens to the world after that.  His main argument seems to be that "CO2 is plant food".  It's clear he's not a very good farmer.  As CO2 increases and the world heats up, it will increasingly be extreme heat, flash floods, lack of water and greater spread of plant pests and diseases that limit plant growth and agricultural productivity.  These are the result of global warming brought on by our CO2 emissions.

Matt says: Stop the World at 2 Degrees?

Logic shows that Matt's argument assumes once global temperatures rise two degrees the world will be able to stop it rising any higher.  But he also argues against any action to limit the rise.  He doesn't say whether he's arguing that the world keep burning fossil fuels till temperatures hit two degrees above pre-industrial temperatures and then all human activity needs to be stopped.  But that's where his argument leads us. The world would have to come to a standstill.

His own articles don't support Matt Ridley's claim

Matt says that he's managed to dig up two articles that support his claim. He hasn't.  He stretched way back to 2004 for one of them.  Way back before the Stern review, way back before the 2008 WGII report.

Matt's first 2004 article doesn't support his claim of net benefits.  It found that the net costs of a higher temperature increase (above 3-4 degrees) were definitely higher than any benefits.  It also found that the overall net cost/benefits up to 3 degrees wasn't clear and that more work was needed.  The paper does not claim that global warming is a net benefit.  More work was indeed done and it shows that the cost is of global warming is high and increasing.

Matt also cited a recent paper by Richard Tol.  I don't know what Richard Tol's work showed in regard to Matt's supposed "net benefits".  It is paywalled.  In the abstract Richard does say that carbon dioxide emissions are a negative externality (which even Matt Ridley shouldn't dispute). However I don't see any sign that Richard's paper says what Matt claims - that global warming is a net benefit.  Nor would I expect to. Richard has written many papers on related topics and I'm not aware of him ever coming up with the finding that rising atmospheric CO2 will do more good than harm - at any level of global warming.

---

Update

In the comments, Richard Tol states that Matt Ridley "correctly cites my work".  Matt Ridley wrote:

I’d like to direct him to this 2004 survey of many studies, and this 2013 study, which confirm that climate change of 1 or 2 degrees Celsius will probably, in aggregate, do net economic and humanitarian good to mankind. It will do so by lengthening northern growing seasons, reducing winter deaths (which greatly exceed summer deaths even in countries with hot summers) and increasing precipitation, but without raising sea levels sufficiently to do serious harm.

In Richard Tol's 2013 paper, there is no mention of any of the words "humanitarian", "growing season", "rain" or "precipitation" or "summer" or "sea level".  The only mention of death was this:

Arbitrarily stringent climate policy would be a disaster: Billions of people would starve to death.

Unlike Matt Ridley's article, the Tol paper does mention the unequal impact of global warming but from an economic perspective, stating for example:

Fourth, not shown in Figure 1, poorer countries tend to be more vulnerable to climate change. Poorer countries have a large share of their economic activity in sectors, such as agriculture, that are directly exposed to the weather. Poorer countries tend to be in hotter places, and thus closer to their biophysical limits and with fewer technical and behavioral analogues. Poorer countries also tend to be worse at adaptation, lacking resources and capacity (Yohe and Tol 2002). 

The only aspect in which Matt Ridley is correct as far as I can see, is where he writes that the Tol paper indicates that  "climate change of 1 or 2 degrees Celsius will probably, in aggregate, do net economic and humanitarian good to mankind".  That's if I take Richard Tol's Figure 1 as indicative.

And that finding of Tol's I would dispute on the grounds that it must not take sufficient account of the short, and particularly not the medium and long term changes caused by global warming.  Not specific enough?  Maybe.  But I'm not the only one to dispute his findings.  Bob Ward does as well, in this article.

In fairness to Richard Tol, his Figure 1 has huge error margins and his lower bound crosses over to the negative at 0.5 degrees warming.  

It will be interesting to read what WG2 of the IPCC report comes up with when it comes out next year.

Added by Sou 8:47 pm AEDST Sat 2 November 2013.

Maybe my last sentence suggested prophecy - or just some knowledge of agriculture (see here). (Added 3 Nov 2013)

---

While Matt Ridley is trying to convince everyone that lurching into a hot world will be "good" for them, the rest of the world is looking for a better handle on just how big a price we are going to pay for global warming.

The cost of doing nothing is much higher

Business and political leaders around the world don't agree with Matt's contrarian nonsense.  For example, from Bloomberg this week (my bold italics):

Former Mexican President Felipe Calderon is spearheading a study sponsored by seven countries into the economics of climate change, seeking to elucidate the financial benefits of reducing carbon emissions.

Calderon’s panel will draw from the experiences of companies and governments around the world in fighting off the ravages of storms and droughts, and in cutting greenhouse gases. It also will use academic research to show the costs and risks associated with climate change and efforts to stem it, publishing a report next September to guide policy makers.

“We’ve talked about emissions -- this time, we will try to talk about profits, and that will change the equation,” Calderon said today at an event announcing the Global Commission on the Economy and Climate in New York. “The idea is that we can present an economic case. What we’re expecting is that our report cannot be ignored in 2014.”

The effort by a group that includes Unilever NV Chief Executive Officer Paul Polman and the former leaders of Chile, New Zealand and Mozambique is designed to guide global envoys as they devise a new treaty to fight climate change in 2015. Britain, Colombia, Ethiopia, Indonesia, South Korea, Norway and Sweden are sponsoring the panel.

“The alternative of not doing anything is not actually an alternative,” Norway’s Prime Minister Jens Stoltenberg said at the event. “The costs of not doing anything are much higher.”

The panel also includes business leaders such as Vattenfall AB Chief Financial Officer Ingrid Bonde, China International Capital Corp. CEO Zhu Levin and officials from the World Bank and International Monetary Fund.

Most of the above nations can't be described as aggressive when it comes to mitigation.  If they are worried then everyone else should be very worried.

And in the same week, from the UK Guardian:

It would be "absurd" to claim the risks of climate change are small, economic expert Lord Stern said before the publication of a key scientific report on global warming.

The latest international assessment of climate science makes it crystal clear the risks are "immense", and it would be extraordinary and unscientific to ignore the evidence and argue for a delay in addressing the problem, he said.

The former World Bank chief economist and author of the key 2006 Stern review on the economics of climate change also warned that scientific projections and economic predictions were underestimating the risks of global warming.

Here is a link to the 2008 WGII IPCC section discussing cost implications of global warming.  The next report is due in March/April next year.


It's no wonder that Matt Ridley has to turn to an anti-science blogger to get his silly article published.  His "arguments" are baseless.  He didn't cite a single article supporting his ridiculous claim of "net benefits".  The closest he got was a paper from nine years ago that said costs unequivocally outweigh benefits as warming progresses beyond 3-4 degrees, which is what would be guaranteed if people listened to Matt Ridley, and didn't quantify the net impact below that.

Matt Ridley ignores the range of sensitivity and makes wrong projections

Matt finishes with this, which further undermines his argument:

...if you consult the probability density functions of most recent studies of climate sensitivity, conducted by senior IPCC-affiliated scientists, you will find that there is a significantly higher than 50-50 probability of warming of less than 2 degrees Celsius during the next 70 years.

He fails to cite any "recent studies of climate sensitivity" or how they relate to how quickly the world will heat up.  There are a number of studies that suggest a low climate sensitivity of around 1.9 degrees.  There are as many if not more studies that suggest a higher climate sensitivity.  The current IPCC WG1 report states that it is likely that that the upper bound is 4.5 degrees for a doubling of CO2 - but that "values substantially higher than 4.5°C cannot be excluded".

So Matt misrepresents the risk of higher climate sensitivity by ignoring it.  Now for his assertion of "70 years".  He doesn't give any indication of how he arrived at that figure. It hinges on how long it will take for CO2 to double.   Even using low estimates of climate sensitivity, a doubling of CO2 would raise surface temperatures by about two degrees.

Because Matt urges no action to limit carbon emissions the "business as usual" scenario is likely to be conservative.  Atmospheric CO2 might not just double (to 560 ppm), it could be triple or go even higher before the end of this century.  At that point global warming will not suddenly stop unless the world comes to a complete standstill.

From the WUWT comments

Dr Burns says Matt Ridley is not a good scientist, but for different reasons!

September 24, 2013 at 4:56 pm
A good scientist would consider the potential effects of global cooling. A major Ice Age is inevitable in the not too distant future.