Communicating climate change risk

You know how some deniers beat up uncertainty every time climate change is mentioned. Well, there's a new booklet that's just been published, which will give you a heap of good tips on how to deal with the subject.

The tips are organised under 12 headings:

1. Manage your audience’s expectations
2. Start with what you know, not what you don’t know
3. Be clear about the scientific consensus
4. Shift from ‘uncertainty’ to ‘risk’
5. Be clear about the type of uncertainty you are talking about
6. Understand what is driving people’s views about climate change
7. The most important question for climate impacts is ‘when’, not ‘if’
8. Communicate through images and stories
9. Highlight the ‘positives’ of uncertainty
10. Communicate effectively about climate impacts
11. Have a conversation, not an argument
12. Tell a human story not a scientific one.

Managing expectations is about pointing out stuff like the fallacy that because something is not known for certain doesn't mean that nothing is known. For example, it is known that CO2 is a greenhouse gas and more of it heats up the planet.

Starting with what you know means starting out with facts like the world is warming and climates are changing. And that heat waves and deluges are getting worse. Rather than starting out with whether or not the planet will heat up by 4C or more or whether we'll act and keep it to 3C or less.

Being clear about the consensus is this:

Shift from ‘uncertainty’ to ‘risk’ because most people don't understand what is meant by uncertainty when used in science. Most people know a bit about risk, though. People typically pay hundreds of dollars a year on insurance against events that have a much lower risk than climate change.

You can read more examples in an article by one of the authors, Adam Corner, at Shaping Tomorrow's World. And the link to the handbook is below.

Reference

Adam Corner, Stephan Lewandowsky, Mary Phillips and Olga Roberts (2015) The Uncertainty Handbook. Bristol: University of Bristol - download here.

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.

Unreasonably "Reasonable" - Uncertainty is No Monster - Live with It or Die by It

Or ... Why Judith Curry is Wrong

A major bushfire is heading straight for your home, getting bigger and faster and fiercer by the minute, fueled by wind and dry vegetation. The fire front is about 900 meters away. You can hear the roar, it's creating its own wind. You can see the glow through the thick pall of smoke that's covered the sky. The daylight is a weird colour, orange-pink - almost peach-coloured. You can't breathe properly, it smells of burning leaves. You can see the embers falling ahead of the fire. You can hear the loud bangs as trees explode in the heat and flames. You know from past fires something of what to expect, including the unexpected.

Your sister from a city a thousand miles away phones you and says, "It's not certain the fire will hit you, is it?"  Sis has always had a Pollyanna streak.  She is afraid for us and is seeking reassurance.

The weather bureau reports a 30% probability of a change in wind direction but not until some time later in the day, with a 10% probability of light rain.

Which of these responses would you regard as 'sensible'?

1. Dump tonnes of kerosene in the fire's path, leaving a trail of kerosene leading straight to your back door?
2. Don't take any action at all.  Wait until you have more information?
3. Send out helicopters, fire trucks with fire retardant to try to contain the blaze and pack up your car with family members, pets and whatever you can grab and get the hell out of there?

Too many people argue for the first response.  Keep adding fuel to the fire.  Keep pouring CO2 into the atmosphere.  Wait until it's 100% certain that the wind won't change in time and stop the fire's momentum.  Continuing to add fuel to the fire is the way to go until we can better 'scope' the uncertainty, they will argue.

A few people will argue for number two.  Don't add any more fuel to the fire but otherwise don't do anything until you know more.  Close all coal-fired power stations immediately.  Shut down the oil refineries.  But don't go building wind turbines or electric vehicles.  Don't plan for higher sea levels. Don't go changing building codes.  Don't shore up water storage for future droughts.

Others will argue for the third option.  Change the source of energy away from fossil fuels and adapt to what climate change will bring.  Minus the "getting the hell out of there".  (People who live in the bush will have their fire plan ready each summer, their valuables and pet cages at hand, their fire retardant clothes in their emergency kit along with a mask and water, and their fire escape route planned out.)  

What do you think about that?  What path would you recommend?

Nowhere else to go

Where I live there's a new classification of Code Red = Catastrophic fire warning.  Code Red is beyond Extreme.  When this is announced people are supposed to leave the area (not mandatory).  Problem is, there's usually nowhere within 500 km that isn't in the Catastrophic fire zone.  Just like with global warming.  We've only got one earth.

Seeking reassurance

Many climate science deniers appear to reject the evidence because they react like Sis did.  They want reassurance.  So much so that they seek it out.  They lap up disinformation and hoard it like gold.  They avoid or dismiss unpalatable facts as "alarmist".  They can't cope with 'alarm'.  Studies suggest the conservative brain is more responsive to fear.  Although this confers some advantages it can also impede reason, resulting in poor judgement and 'wrong' decisions.

There is always uncertainty

As anyone who's done any planning will tell you, there is always uncertainty. Uncertainty is not a monster.  There is almost never only one "right answer".  When facing something like a bushfire or climate change, the "wrongest" answer is to not act at all.  Societal paralysis while climate change continues unabated.  Geological history gives us insight into what to expect, including the unexpected.  If we waited for 100% certainty about everything in the future, we'd never get out of bed in the morning.

The "wrong" answer

To not act is as deliberate a decision as acting based on information at hand.  It is the wrong response.

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Quit Shooting the Messenger!  Demand Leadership from Leaders!

This post was inspired by reactions to Judith Curry's recent written and oral testimony to a US House of Reps subcommittee.  For example:

Shifting goal post alert: The real question that must be settled before any policy actions are taken to address the postulated threat from human-induced global warming is ....(insert shifting goal posts here)

Strawman construction 1:...suggesting (to me) a much more cautious approach to emissions reduction than has been adopted in Australia and elsewhere....Of course, I regard “cautious” as not taking extensive and costly action without more convincing evidence as to the merits of such action, others might interpret it as pre-emptive large-scale precautionary reductions.

Strawman 2: ...Those who posit that there is one (a problem), which requires remedial action, have to show empirical evidence that they know what the hell they are talking about – BEFORE they request any action be taken.

And Curry herself, IMO misrepresenting scientific uncertainty, its nature, how it is scoped and quantified, and the relative importance of different aspects of science and the relevance of different aspects to government policy development - and building her own strawmen.  Even though she states clearly up front that humans are causing global warming, she later implies that scientists are wrong to assert that humans are causing global warming, which is the scientific consensus, writing instead:

Given these uncertainties, there would seem to be plenty of scope for disagreement among scientists. Nevertheless, the consensus about dangerous anthropogenic climate change is portrayed as nearly total among climate scientists. Further, the consensus has been endorsed by all of the relevant national and international science academies and scientific societies.

I have been trying to understand how there can be such a strong consensus given these uncertainties....

...When uncertainty is not well characterized and there is concern about ‘unknown unknowns,’ there is increasing danger of getting the wrong answer and optimizing for the wrong thing.

And her over-simplification of decision-making pitfalls mixed with a bright red herring.  No, Judith, neither of these hits the nail on the head:

There are two situations to avoid: i) acting on the basis of a highly confident statement about the future that turns out to be wrong; and ii) missing the possibility of an extreme, catastrophic outcome. Avoiding both of these situations requires much deeper and better assessment of uncertainties and areas of ignorance, as well as creating a broader range of future scenarios than is currently provided by climate models.

I strongly disagree with Curry.  The main situation to avoid is that of waiting till it is too late.  Waiting until options are reduced to all but a few.  Waiting until atmospheric CO2 gets so high that there are no choices left to humanity.  Waiting until climate change wreaks havoc and destabilises economies such that we can no longer afford to take action.  Or worse, waiting until there are no longer coherent societies or stable governments that can see actions through to completion.  There are a myriad of actions that can be taken now, which won't be "wrong" in any sense of the word.

Leaders, take responsibility! Certain science, uncertain policy response

The biggest sin Curry commits is that of pointing her finger at science, rather than at the leaders, the rule-makers, the legislators.  The uncertainty is in the policy response, not the science.  The science is settled more than adequately to inform policy decisions.  Legislators' efforts need to go towards determining what paths to follow, what suite of policy responses and programs to implement.  It's not the science that's uncertain in this context.

Businesses wants a consistent policy direction.  The science is settled but the policy response, where it exists, is fragmented.  The corporate sector hates a policy vacuum.  Investors look for clear guidance.  The community elects leaders to lead, not fiddle while the bush burns. 

Curry confirms that there is a raging bushfire, that we run the risk of it burning down the house.  She can see the fire bearing down.  Everyone else can see the fire raging and heading in their direction.  But instead of calling for a plan of action to deal with the very real fire, she turns around and says:- "Well, maybe that bushfire we can all see bearing down on us isn't real.  It's red and it's hot and it's got flames and lots of white and black and yellow smoke, and it's leaving burnt forests and grasslands in its wake.  Just the same, I think it needs more analysis.  We need more measurements.  We need more temperature readings, to examine the smoke, analyse the smoke particles, confirm that those flames are really flames.  Build another model. We need to make sure it really is a bushfire before we start to think about getting out of its path or putting it out!  Meanwhile, let's add more kerosene."

IMO Judith confirms her adopted role as that of 'delayer', who wants to keep the bushfire burning by pouring tonnes kerosene onto it, under the guise of "waiting for certainty" about what is already certain.