Why the Climate Debate is on a Road to Nowhere
Last summer, when Rick Perry mania was cresting and he was spouting nonsense about climate science and evolution, I said this:
Serious, science-based climate skeptics have a chance to separate themselves from the foaming-at-the-mouth lunacy that defines their public image.
Of course, in that same post, I also that the Texas Governor
will likely saddle up the congealed Republican discontent, anger and culture war politics, and ride all the way to the GOP Presidential nomination.
Hey, nobody bats a thousand.
Anyway, at the time, some of you who are in the climate skeptic camp chafed at being lumped in with the mouth foamers (climate science is a hoax!) in your midst. My point was that, fair or not, the crazies (there is no greenhouse effect!) had come to be the representative face of the climate skeptic position.
It now appears that some well known climate contrarians are coming to this conclusion, too. In the American Thinker (which is no climate science friendly precinct), Fred Singer recently penned an essay titled,
Climate Deniers are Giving us Skeptics a Bad Name
Wait, did he just say climate deniers? And he repeats it a bunch of times in the piece! I thought that term was verboten in the climate skeptic universe? What’s going on here?
It seems that Singer wants to put some distance between him and the crazies (he identifies two different groups of “deniers”). Interestingly, he sees only one position on the other side of the spectrum–the “warmista,” who has “fixed views about apocalyptic man-made global warming.” True, the climate doomer is the public face of the climate campaign, but it is by no means the only position in the climate consensus universe.
Conveniently, Singer places climate skeptics “somewhere in the middle” of the climate landscape, between “climate deniers” and “warmistas.” That middle ground exists only in Singer’s head.
But to be fair to Singer, he also says that “these three categories” [denier, skeptic, warmista] “do not have sharp boundaries; there are gradations.” After making his case against what he considers the two extremes, he ends on this note:
I have concluded that we can accomplish very little with convinced warmistas and probably even less with true deniers.
Well, so long as climate “deniers” and doomers remain the de facto public representatives of the climate debate, their mutual antagonism and contempt will continue to shrink the space for rational discourse, and very little will be accomplished.
True, the climate doomer is the public face of the climate campaign, but it is by no means the only position in the climate consensus universe.
con·sen·sus (kn-snss)n.1. An opinion or position reached by a group as a whole
By definition a ‘consensus’ is singular.
How amusing. Singer, cornucopia of disinformation that he is, seeks to legitimise himself by contrast with the ‘deniers’. This must be a sign that he senses constriction – less and less wriggle-room.
Singer, in comments on the Nature blog, November 2011:
But unlike the land surface, the atmosphere has shown no warming trend, either over land or over ocean “” according to satellites and independent data from weather balloons.
WTF? This chap ran out of road a long time ago. Good luck to him in finding that elusive middle ground where the atmosphere isn’t warming and CO2 just isn’t really going to be a problem at all…
Is it necessarily a fault of the rationalists to jump on such nonsense and to be angered by it (Keith mentions ‘antagonism and contempt’ above)? And in the face of such disinformation, what space is there for rational discourse?
What Mr.Singer said, is very different from what Ms.Tamsin Edwards said? (Link:http://allmodelsarewrong.com/the-sceptical-compass/ )
This is rich. How often do the loony ‘destroy the planet’ nutters get called out by any ‘consensus’ brothers? You have leading names in climate science, editors of IPPC chapters, caught conspiring to subvert the review process and get journal editors removed, and the response from all the good climate scientists is ‘crickets.’ And now you have the nerve to call out one skeptic?
Kloor – perhaps you’ve never heard of luke-warmers? Naw, that’s not possible, I’m expecting too much. I’d be happy to call out the nutters on the skeptical side if anyone would interview me, but they don’t. The skeptic blogs are full of knuckle-draggers and know-nothings, and I’m not responsible for them. There are sufficient boneheads on both sides of this issue to cancel each other out.
The fact is that climate science was a backwater of physics just a couple of decades ago. The idea that they have divined the secrets of planetary climate, a multi-billion year, chaotic process, is laughable to me. If they could actually hindcast the previous hundred years – which they can’t – would mean they had sampled a fraction of the planet’s climate processes the length of which was not significantly different from zero. To then project over the next hundred years on such a basis is the height of folly, and would get you laughed out of any other fiend of science.
When I studied molecular biology, we were given papers to read of the classic experiments of the field. They were described as elegant and beautiful in their design. They locked down answers with their rigor. Now tell me, what are your three favorite climate science experiments? Good luck finding them. When it comes to global warming, there are none. The field is based on surmise, not rigor. A molecular biologist would wrinkle her nose at the entire field if she bothered to waste her time examining it. Climate science as it relates to CO2 and grand predictions of the future is all theory and no meat. Please notice I haven’t mentioned any politicians or WSJ columnists or Heartland Institute board members.
I don’t know – the middle is where things get done.
I have always believed that the Earth has warmed, and agreed that with CO2 increasing on its current path, we could expect about 1.2C of additional warming by 2100.
So put me in the middle, as defined above.
Of course, I don’t deny that climate changes, nor even that the globe has warmed – so I still don’t like the denier label when applied to me (but I will let that go).
I do question what portion of the warming is due to human activities (and specifically CO2), and also the indirect feedback amplification amount of additional warming. I would really like to know how much of the .8C rise in temperatures from 1850 to present is due to 1) natural causes 2) CO2 3) methane 4) land-use changes like concrete, asphalt, cities, air conditioning, cutting down forests, etc. 5) carbon black emissions. I still don’t think we have a really good handle on these numbers, and therefore the error bars are so huge it makes it difficult to do policy.
Still, I see greater and greater prospects for the middle to take action on what we do agree on.
For example, everybody agrees that carbon black is not good to breathe and also bad for global warming. It is pretty cheap to fix the carbon black problem, so we should get every country to tackle that issue.
We know hydro and nuclear is carbon-free, and has to be part of the mix going forward, so lets encourage safer plant designs, and generating more electricity from these forms of power.
Personally, at about 20% in the USA, I would like to see a policy which raised that to 50% nuclear by 2100. I would go with regional storage of waste, and set up recycling like France to reprocess the waste, get more power out of it, make it less radioactive and easier to store. Maybe we could set up eight reprocessing centers in eight parts of the country, and ship all the waste in those regions to the reprocessing center and do storage there (rather than one single yucca).
Bio-fuel from corn is a bad idea (driving up food costs) – but everybody agrees that bio-fuel from algae, crop waste or switchgrass could be good – so lets keep working on that.
We know we need more technology so we can invent cheaper non-carbon energy than oil, gas and coal – so lets allocate a reasonable amount of money (or redirect existing money) to federal research related to power storage, fusion, space-based solar, better solar, wind, bio-fuels, clean-coal, etc. The goal should be to drive the cost of non-carbon power down below current price of around 8 cents per killowatt hour of electricity (for Minnesota anyway). In the USA – I would not be adverse to 100 billion per year for 10 years, to see what improvements we could make in non-carbon power generation. We could redirect 100B of the military budget to energy research.
Propane trucking seems like it is already happening in the USA, purely due to the cost difference between propane and diesel – so lets encourage that.
I am sure there are a lot of other things which are not to controversial.
So why don’t we start out implementing the small stuff we agree on, and revist the larger more difficult stuff in 10 or 20 years.
For sure, more time will improve our understanding of climate.
For example, one day when CO2 hits 560 ppm, we will be able to actually measure climate sensitivity (how much did average global temperature go up from a doubling of CO2 from 280 ppm to 560 ppm) and know what that number is from observation, rather than guessing at it from models. It seems to me that having an actual observation of climate sensitivity will reduce the error bars on the climate models by a huge factor – which will make policy easier to sell.
We can also easily measure sea level rise at 2100 and see if it is between 30 and 59 cm like the IPCC thinks it will be, or is it higher or lower? Once again, an actual measurement will be much better than the huge error bars we have on our model driven estimates – none of which predicted the great slow down we are having on both the rate of increase on temperatures and SLR.
So, I would also budget money for more climate relevant measurements at more locations for much longer periods of time. Lets plan on gathering data over the entire globe, in the oceans, in the atmosphere, at ground level, with automated stations, uniform measurements, for say the next 100 years (maybe forever). Overall, I don’t think this will be to expensive, and we need better data over the long haul. I doubt many people would be against gathering better data, in more locations (rather than making estimates of what observations would be), for longer periods of time.
Anybody else have any ideas which the middle could agree on?
#2
what space is there for rational discourse?
None..zip…Nada…the single ‘consensus’ has spoken and the science is settled.
http://www.mudcitypress.com/globalwarmingreader.html
Arrhenius predicted an ultimate temperature increase of five or six degrees Celsius, which McKibben notes is consistent with projections by today’s supercomputers.
Help me out here BBD…what is the ‘consensus’ again?
Is it this –
http://pubs.giss.nasa.gov/docs/2011/2011_Hansen_etal.pdf
Fast-feedback climate sensitivity has been estimated in
innumerable climate model studies, most famously in the
Charney et al. (1979) report that estimated equilibrium
global warming of 3 C±1.5 C for doubled CO2 (a forcing
of 4Wm−2), equivalent to 0.75 C±0.375C perWm−2.
Subsequent model studies have not much altered this estimate
or greatly reduced the error estimate because of uncertainty
as to whether all significant physical processes are
included in the models and accurately represented
Dr Hansen seems uncertain that the physical processes are accurately represented in the models. That would appear to agree with what Dr Lindzen says.
It’s the information age we live in. Anybody can find multiple sources to feed them what they want to hear. So people just keep going back to their ‘trusted sources’ to find out why they are right and are never exposed to the other side of the story. I wish more people would have the attitude “why am I wrong?”, but that’s just not human nature…
It’s easy to sell “Another plot by government to gain more control of our lives” to the average conservative.
And it’s easy to sell “Another example of big business destroying the world” to the average liberal.
So, who is to blame? The dealer (media pundits, biased bloggers, biased politicians) or the user (the uneducated public / average lemming)?
harrywr2
Hansen estimate for ECS = ~3C
Lindzen estimate for ECS = 0.5C (?) or very, very low and incompatible with known paleoclimate behaviour. Problem there.
Dr Hansen seems uncertain that the physical processes are accurately represented in the models. That would appear to agree with what Dr Lindzen says.
Read closely – Hansen & Sato, Paleoclimate implications for human-made climate change (2011):
Climate sensitivity depends upon climate feedbacks, the many physical processes that come into play as climate changes in response to a forcing. Positive (amplifying) feedbacks increase the climate response, while negative (diminishing) feedbacks reduce the response.
Climate feedbacks are the core of the climate problem. Climate feedbacks can be confusing, because, in climate analyses, what is sometimes a climate forcing is other times a climate feedback. As a preface to quantitative evaluation of climate feedbacks and climate sensitivity, we first make a remark about climate models and then briefly summarize Earth’s recent climate history to provide specificity to the concept of climate feedbacks.
Climate models, based on physical laws that describe the structure and dynamics of the atmosphere and ocean, as well as processes on land, have been developed to simulate climate. Models help us understand climate sensitivity, because we can change processes in the model one-by-one and study their interactions. But if models were our only tool, climate sensitivity would always have large uncertainty. Models are imperfect and we will never be sure that they include all important processes. Fortunately, Earth’s history provides a remarkably rich record of how our planet responded to climate forcings in the past. Paleoclimate records yield, by far, our most accurate assessment of climate sensitivity and climate feedbacks.
[…]
The empirical fast-feedback climate sensitivity that we infer from the LGM-Holocene comparison is thus 5°C/6.5 W/m2 ~ ¾ ± ¼ °C per W/m2 or 3 ± 1°C for doubled CO2. The fact that ice sheet and GHG boundary conditions are actually slow climate feedbacks is irrelevant for the purpose of evaluating the fast-feedback climate sensitivity.
This empirical climate sensitivity incorporates all fast response feedbacks in the real-world climate system, including changes of water vapor, clouds, aerosols, aerosol effects on clouds, and sea ice. In contrast to climate models, which can only approximate the physical processes and may exclude important processes, the empirical result includes all processes that exist in the real world ““ and the physics is exact.
Your ‘scepticism’ is ill-founded. Why do you cling to it with such force?
#8
Hansen & Sato’s paper is based on one rather bold assumption:
There are numerous statements and presumptions in the scientific literature that prior interglacial periods such as the Eemian were as much as a few degrees warmer than the Holocene (e.g., Rohling et al., 2008; Church et al., 2010), and this perception has probably influenced estimates of what constitutes a dangerous level of global warming. These perceptions about interglacial global temperature must derive at least in part from the fact that Greenland and Antarctica did achieve such higher temperatures during the Eemian.
However, we interpret these temperatures on the ice sheets as being local and unrepresentative of global mean temperature anomalies
We argue that global deep ocean temperatures provide a better measure of global mean temperature anomalies than polar ice cores during the interglacial periods. Ocean cores have a systematic difficulty as a measure of temperature change when the deep ocean temperature approaches the freezing point, as quantified by Waelbroeck et al. (2002). However, in using the known surface temperature change between the last glacial maximum and the Holocene as an empirical calibration, we maximize (i.e., we tend to exaggerate) the ocean core estimate of global surface warming during warmer interglacials relative to the Holocene.
Hansen & Sato reach their conclusions by assuming that Eemian warmth was limited to polar regions only. Sea levels 4-6 meters higher than today, hippos in the Thames, forest in the Canadian arcti c islands…. just local warming. Pliocene with sea levels 20 meters higher than today… mainly local warming. Ice cores OK for glacial temps but not for interglacial temps.
Yes, Singer is right if not original. We said it here before and I’m sure we were not original either.
But what are practical implications? How could we collectively improve the public discourse? The dumbest and craziest are typically the loudest. They are nor going to shut up especially when their counterparts on the other end of the rope are doing exactly the same.
Historically, deniers are a social knee-jerk reaction to activist warmists. If the latter suddenly disappeared the former would too. Fat chance.
I am shockecd I tell you that Fred Singer is trying to jimmy the overton window. has he now shame?
On a completely unrelated note, I now have several audiobooks for my dreaded road trip up and down the eastern u.s. seaboard (no thanks to CaS readers I might add). we have these things called ‘libraries’ in Kanada.
Beverly Cleary, Roald Dahl, Margaret Atwood, and Neil Gaiman here I come…
Jarmo
Hansen & Sato reach their conclusions by assuming that Eemian warmth was limited to polar regions only.
That is a misrepresentation of H&S. I notice you clipped out the clarifying sentence (emphasised):
However, we interpret these temperatures on the ice sheets as being local and unrepresentative of global mean temperature anomalies. The polar ice sheet temperature anomalies were likely magnified by the fact that these warmer interglacial periods had little summer sea ice or ice shelves around the Greenland and Antarctic continents.
To get a better sense of H&S reasoning it’s worth completing the quote that you truncated (emphasis added):
Ocean core data is also affected by the location of deep water formation, which may change. However, the location of deep water formation around Antarctica, which affects deep Pacific Ocean temperature, is limited by the Antarctic geography and is unlikely to be shifted substantially in interglacial periods warmer than the Holocene.
Fig. 2 provides unambiguous discrimination between ice and ocean core measures of global temperature change. Climate forcings for the past 800,000 years are known accurately. Climate sensitivity cannot vary much from one interglacial period to another. Ocean core temperatures give a consistent climate sensitivity for the entire 800,000 years. In contrast, ice core temperature (Fig. 2d) leads to the illogical result that climate sensitivity depends on time.
We conclude that ocean core data are correct in indicating that global surface temperature was only slightly higher in the Eemian and Holsteinian interglacial periods than in the Holocene, at most by about 1°C, but probably by only several tenths of a degree Celsius. By extension (see Fig. 6), the Pliocene was at most 1-2°C warmer than the Holocene on global mean.
This sort of selective misrepresentation is a waste of time. And Singer will be cross with you.
Sashka @ 10
Historically, deniers are a social knee-jerk reaction to activist warmists.
No, reactionary conservatism has always been with us.
Last summer, when Rick Perry mania was cresting and he was spouting nonsense about climate science and evolution, I said this:
Of course, in that same post, I also that the Texas Governor
Hey, nobody bats a thousand.
Yeah, Keith, like most alarmists you’re pretty good with the scare-mongering and the name-calling of people who disagree with you, but reality keeps slapping you in the face because none of the catastrophic events called for by your hypotheses ever actually occur.
Back to the subject of the post- nuts va “deniers,”
I’m optimistic. Remember, back in the day the New York Times insisted that Joe Romms blog was the “essential” word on climate, I recall being labeled a “denier” merely for scoffing at the idea that replacing all fossil fuels just might cost more than a postage stamp a day.
Today, Romm is a joke, Obama’s billions for “green energy” are so awful that they’re a serious campaig liability, even Monbiot is admitting greens lied about nukes, and the EU has announced that, shock of shocks, something called “economic growth” is necessary if some shred of the unsustainable welfare state will survive. Remarkably, this is proving to be more important than throwing wads of cash uselessly at green fantasies.
Conservatives and libertarians may not be batting 1000 on this issue- more like 990 to the “concerned’s” 175.
BBD Says:
harrywr2
Hansen estimate for ECS = ~3C
Lindzen estimate for ECS = 0.5C ?
The basic physics of a doubling of CO2 all other things remaining equal says 1.2C. Of that approximately 0.8C should have already happened if all other things remain equal.
Lindzen Spencer, Christy, McIntyre, Watts, et all don’t question the 1.2C for a doubling if all other things remain equal. If all other things remained equal we should have experienced about 0.8C warming since 1880 and that is about what we have experienced.
There is a very small group…that believes that radiative physics violates the Second Law of Thermodynamics. It doesn’t and you won’t find anyone with a degree in physics saying it does.
Unfortunately, explaining the difference between ‘net heat flow’ and ‘heat flow’ causes some folks heads to hurt. The second law of thermodynamics is frequently taught without the ‘net’ heat flow component in order to simplify the math.
I was taught ‘wrong’ in high school and ‘right’ in college’. I was also one of the few people to actually complete my thermodynamics final exam.(1 question…8 hours to finish..open book and calculator’s allowed)
The settled science is the radiative physics and we have already experienced ‘some’ of the expected warming.
If I simply look at the surface temperate record then we have experienced 0.8C which is almost pretty close to what radiative physics says should happen with a CO2 level of 390 ppm. Going to 540 ppm should add about 0.4C more.
To believe it’s more you need to find a big pile of ‘missing heat’ in the deep ocean. We don’t have ‘deep ocean’ heat records going back very long.
I’m in the “uncertain” camp, as far as future climate change is concerned. IMHO there are many different models. And, the models from the late 1990’s haven’t done a good job so far. The models still need to be validated.
What I find disappointing is that lots of people will not agree with what I believe to be objectively true statements, such as
— The earth has warmed over the last 200 years
— The earth has warmed over the last 40 years.
— The earth has not warmed over the last 15 years
— A doubling of CO2 will cause the earth’s temperature to increase by 1.2 degrees C, in the absense of feedback loops.
— Proposed plans for CO2 reduction, such as Kyoto and Cap and Trade, would have little impact on the world’s temperature, according to most or all of the models.
@13 BBD
What about the emotionally driven ding dongs that oppose your beloved nuclear power? How about the perpetually wrong malthusians for whom the clock is always so close to midnight?
You’re a smart fellow, I will never claim otherwise. In your opinion is the ‘boy who cried wolf’ characterization at all valid? If so, does it perhaps contribute to the frustrating lack of action you lament? Is there any degree to which the horribly insular environmental movement is responsible for its own failed ability to persuade? Is the Heartland Institute the sole bearer of middle class persuasion?
Business as usual (stalemate) is a “win” for the skeptics, so it is the warmistas that need to change their course if they want to obtain their goal.
What they really need is simple: A compelling scientific case for change. We can argue over whether this really exists or not, but the facts on the ground is that not enough people believe this is the case for policy action to be a realistic opportunity.
If there was one gift climate science could ask for, it would probably be for 500 years of detailed global climate measurements. This is the only way to validate the models, and to start accumulating trust in their projects, predictions, scenarios, etc.
The chaos of the climate system has some amount of irreducible complexity that cannot be solved. Non linear feedback, incomplete measurements, etc. This is crippling. Adding even more complexity to models of unknown accuracy just makes them worse not better.
Unfortunately the outlook for any kind of marked improvement in this situation in the near term is grim. Historical data is set, and we aren’t going to find a treasure chest of accurate aerosol data buried on a remote island somewhere. Climate science should be putting the measurement systems in place to collect the relevant data they need over the next 50 years.
Collect data, process models, refine algorithms, repeat.
An important parameter that is often overlooked is the “model iteration time”. How long does it takes to collect and process enough data to make meaningful improvements to the models?
Modelling is an iterative process. High complexity such as in climate (probably about as complex as any attempted model ever) require a lot of iterations to begin to hone in on useful output. I would argue we are not even close yet, and we need decades to get there even in the best case scenario.
Example: Hurricane tracking.
Model iteration time: One per hurricane, but major model releases are done usually on a yearly basis. Examine the first graph on this page.
http://www.hurricanescience.org/science/forecast/models/modelskill/
Over a period of 30 years from 1970 to 2000 hurricane tracking made steady progress as the algorithms evolved and were refined.
How do we know they work and are “trustworthy”?. Because they demonstrate it on a yearly basis by successfully predicting hurricane tracks. PREDICTION SKILL leads to trust. It should be noted that hurricane power prediction (cat1 to cat5) is still pretty poor.
Now contrast that against the climate science problem where the model iteration loop is on the order of 30 years.
There is now way around this, climate models need DECADES or CENTURIES before they can successfully demonstrate predictive skill to gain trust the old fashioned way, by earning it. And this assumes it is even within the realm of human knowledge to find the solution.
Mark me down in the “model pessimist” category of climate denier.
Now that Michael Mann has come out with his foaming-at-the-mouth, whacked out, bundle of lies and slander alleging all kinds of bizarre conspiracy theories, it will be interesting to see if there are any serious alarmist scientists who will step forward and separate themselves from his nonsense.
Sigh.
The term “denial” once had a meaning. In my dictionary it meant the refusal to acknowledge a known FACT.
Since the theory/hypothesis of CAGW was never a fact, no one could deny it. Thus denial was never the right word, particularly in what was presented as a ‘scientific’ discussion. That thinking is the opposite of science. But we all know why the Team chose to use the term “denier” which is derived from it.
So Singer threw the same inappropriate word back at the Team. Boo hoo. The difference is that the Team now appears to be in a genuine state of denial about their failed models/projections.
As for this rumored “space for rational discourse,” that never existed in this project. Lysenkoism isn’t about that. Just the opposite. The obvious objective of the relentless fearmongering by the Team propagandists was to promote irrational groupthink and stampede the herd off this cliff.
So Keith, enough of the faux indignation please. It is what it is. And it never was anything but a political project using pseudoscientific leverage.
#12 BBD
If one assumes that Hansen is right, another problem surfaces.
The basis of Hansen’s argument is that since CO2 in the Eemian was 290 ppm tops, the slightly different tilt of the Earth and the sun were responsible for great polar warming.
However, conditions today are different:
During the Eemian interglacial period, 130,000 to 114,000 years ago, the volume of the Greenland ice sheet was about 30″“60% smaller than the present-day volume1, 2. Summer temperatures in the Arctic region were about 2″“4″‰K higher than today3, 4, 5, leading to the suggestion that Eemian conditions could be considered an analogue for future warming6, particularly for the future stability of the Greenland ice sheet. However, Northern Hemisphere insolation was much higher during the Eemian than today, which could affect the reliability of this analogy. Here we use a high-resolution regional climate model with a realistic ice-sheet surface representation to assess the surface mass balance of the Greenland ice sheet during the Eemian. Our simulations show that Eemian climate led to an 83% lower surface mass balance, compared with the preindustrial simulation. Our sensitivity experiments show that only about 55% of this change in surface mass balance can be attributed to higher ambient temperatures, with the remaining 45% caused by higher insolation and associated nonlinear feedbacks. We show that temperature”“melt relations are dependent on changes in insolation. Hence, we suggest that projections of future Greenland ice loss on the basis of Eemian temperature”“melt relations may overestimate the future vulnerability of the ice sheet.
http://www.nature.com/ngeo/journal/v4/n10/full/ngeo1245.html
So how likely is Hansen’s statement:
We conclude that eventual sea level rise of several tens of meters must be anticipated in response to the global warming of several degrees Celsius that is expected under business-asusual (BAU) climate scenarios (IPCC, 2001, 2007).
@ 19 Tom S,
Excellent points about the models that are regularly overlooked. I have sympathy for the climate modeler’s plight; spotty data (in both coverage and accuracy) that id only available for a short period of time and I need to make a predictive model out of that? Plus, how do I know what has been measured are the essential parameters? If I knew the essential parameters do I know how to measure them? How accurately can they be measured?
The best thing that can happen is that the modelers stay with it and over the next 20-30 years openly discuss their model’s FAILURES; if they do that people may start believing that they are interested in models that actually perform.
Menth @ 18
In your opinion is the “˜boy who cried wolf’ characterization at all valid?
If you mean AGW, then no. That’s atmospheric physics. You make the standard sceptic error of incorrectly conflating ‘environmentalism’ with physics.
What about the emotionally driven ding dongs that oppose your beloved nuclear power?
I don’t ‘love’ nuclear power; I just don’t see any alternative to increasing its role in the energy mix in the face of rising energy demand and the requirement to decarbonise electricity generation.
Jarmo @ 22
First, do you accept that you misrepresented H&S by selective omission at # 9? Second, do you agree that H&S make a convincing point wrt the reconstruction of GAT from ocean cores vs ice cores? Namely that the latter are revealed as unreliable as they indicate a degree of variation incompatible with a *consistent* interglacial climate sensitivity?
Third, do pay attention 🙂 Hansen – and many others – are not primarily concerned with the GIS. In fact the latest thinking based on the findings of the NEEM drilling project is that cryosphere contribution to Eemian MSL was ~1m GIS and ~4m WAIS. In the short term, attention is on the WAIS. The concern is over a potential non-linear response to warming W. Antarctic coastal currents and surface meltwater destabilising the ice shelves that currently *impede glacial drainage* of the ice sheet proper. See Hansen (2007) Scientific reticence and sea level rise. Let’s not lose focus here.
Fourth, Eemian GAT was ~1C higher than present with MSL ~5m higher than present. Projected warming by 2100 is >1C (at the very least). Pliocene GAT was ~2C warmer than present and MSL was ~20 – 25m higher than present. Equilibrium sensitivity to 560ppmv CO2 is ~3C. The ice-free Eocene hothouse climate (40ma) GAT was ~4C – 5C above preset with MSL ~70m higher than the present. The correlation between even slight rise in GAT and several metres increase in MSL is robust.
So yes, I think Hansen’s statement is backed by solid paleoclimate evidence and entirely plausible:
We conclude that eventual sea level rise of several tens of meters must be anticipated in response to the global warming of several degrees Celsius that is expected under business-as-usual (BAU) climate scenarios (IPCC, 2001, 2007).
harrywr2
The basic physics of a doubling of CO2 all other things remaining equal says 1.2C. Of that approximately 0.8C should have already happened if all other things remain equal.
First, you are still using the *no-feedbacks* value of 1.2C with the nonsensical qualifier ‘all other things being equal’. All other things are *not* equal. Increasing CO2 will heat the troposphere which will moisten so increasing water vapour feedback. This is the main mechanism elevating the no-feedbacks warming from 1.2C to ~3C for 2xCO2. Other feedbacks include clouds, CH4, natural aerosols, sea ice and snow cover. We’ve been through this before so I’m surprised that you are simply repeating the wrong numbers here.
That you do invalidates everything that follows. But since you are repeating the old Lindzen argument, I’ll continue with the old rebuttal.
The additional forcing from the CO2 already present (~390ppmv) has caused a radiative imbalance within the climate system. Currently, more energy (solar SW) enters the atmosphere than leaves it (as LW). The imbalance will *persist until* the surface – 70% ocean – has heated sufficiently for OLR to match the sum of incoming SW and LW (from the radiating atmosphere). *Even if* CO2 were held at 390ppmv warming would *continue* for decades until the surface – 70% ocean – warmed enough (increasing OLR) to restore radiative equilibrium to space at the top of the atmosphere.
Lindzen’s first error is to treat the climate system as if it were already in radiative equilibrium when it is not. This invalidates the argument that 0.8C is ‘about what we should expect’ for 390 ppmv CO2. It is not. It is less.
It takes time for the oceans to warm (greater heat capacity than land). This thermal inertia explains why the 0.8C atmospheric warming observed so far is lower than the actual warming consisted with 390ppmv CO2.
Lindzen’s second error is not to include the cooling effect (negative forcing) of aerosols. Estimates vary from IPCC AR4 WG1 -1.1W/m^2 to -1.6W/m^2 (Hansen & Sato (2011) Earth’s energy imbalance and implications). This potentially substantial offsetting of the direct effects of CO2 forcing cannot simply be ignored, but that is what Lindzen does when he treats 0.8C as the direct and unmediated effect of CO2 forcing. It is not. It is less.
So when you combine all three errors – use of the no-feedbacks value of 1.2C, discounting thermal inertia and discounting negative aerosol forcing – you arrive at a profoundly mistaken conclusion.
I genuinely hope this has helped to dispel some of the confusion here.
So when you combine all three errors ““ use of the no-feedbacks value of 1.2C, discounting thermal inertia and discounting negative aerosol forcing ““ you arrive at a profoundly mistaken conclusion.
The confusion, BBD, is on your part. You ASSUME a positive feedback. This is, in fact, the main issues with climate modeling. You’ve been told this many times. So I must assume you are willfully misleading the readers.
You would like to include aerosols, which are ‘masking’ the CO2 effect. That is how you can claim high sensitivity and still be able to match historical data, which doesn’t support a high sensitivity. And you are simultenously embedding the claim that all other forcing are known and quantified, which is not true. It the last were true, then modelers would have predicted the ‘no warming’ of the last 12 years. They did not.
Yes there is a response time, but these are not known well. The initial reaction is considerd to be a few years (not decades), the longer (ocean warming) to be centuries. There is debate on how to account fo this. You had an opportunity to offer something meaningful during our last discussion. You did not. Nor do you here.
It’s the same old warminista argumnet. Start with basic physics on which noone disagrees. Then pretend we have ‘solved’ the climate problem – we haven’t. Wave your hands at the un-cooperative real world data. And then accuse anyone who disagrees with you of smoking cigarettes and having lots of money.
It is tiresome.
kdk33
The confusion, BBD, is on your part. You ASSUME a positive feedback.
There is ample evidence for positive feedbacks. Perhaps you could explain to the forum why the average surface temperature of the Earth is 15C *without* invoking positive feedbacks to RF from atmospheric GHGs?
In fact go ahead. Explain. Go on.
BBD’s various rants illustrate why the clmate debate is goes nowhere. In simple (and over generalized terms).
The scary side starts with undisputed physics about CO2, and immediately assumes the answer: climate doom. The realist side looks at the real world data and sees no doom – sees, in fact, great prosperity. The scare side has created a virtual world built on a myriad of assumptions to explain why the data now and in the past says ‘no doom’, but clearly there will be future doom. (And I haven’t even started on the other embedded assumption, that warming is dangerous – it could very well be beneficial). The realist side interesting, but not so fast. Keep working; let’s wait and see.
It’s an argument about beliefs. Scare side ‘believes’ in climate doom, and all the supporting assumptions become gospel. The realists not so much.
It’s no different than arguing about god. Climate just has more magazines. Eventually, we’ll know the answer. To both.
The IPCC is the middle ground.
There should a certain Talking Heads song you tube in the post here.
Besides that, the Singer post is a laugh riot. He condemns those dang deniers for making him look bad and then goes to make himself look bad. Does it really what science you deny? Isn’t it all bad?
kdk33
There is ample evidence for positive feedbacks. Perhaps you could explain to the forum why the average surface temperature of the Earth is 15C *without* invoking positive feedbacks to RF from atmospheric GHGs?
In fact go ahead. Explain. Go on. I’m waiting.
@David in cal
> ““ The earth has not warmed over the last 15 years
This is not an objectively true statement.
The IPCC is many things to many people. It is not in the middle. Saying the earth has not warmed over the last 15 years may not be ‘objectively’ true, although Dave H cannot know any more than kdk33 would know why it ‘hasn’t’ over the past 12. Our measurements are not precise enough and our calculations not fine enough.
It would be more intelligent (and less compromising to either side) to say that the rate of warming that started this political struggle has almost certainly plateaued due to a number of cyclical phenomena that we have seen in action before. As the temperature record since about 1880 is sinusoidal with a secular rising trend, with peak to trough lasting irregular times that are often more than a decade, going beyond that is faith-based for either side.
It would be common-sensical to note that the trend in temperatures corresponds roughly to what climate science and climate models have forecast, but at a lower level. It is warming, but not as much as the ensemble of models led some in science to believe. Over the past decade, if there has been any warming at all, it has been very, very slight.
However, acknowledging the plain truth would undercut too many political arguments on either side, I’m afraid.
#32 BBD,
‘Go ahead explain’.
Okay, I’ll bite.
I’ll put on my ‘Bill McKibbon’ hat.
The average surface temperature of the earth is 15C.
Most radiative physicists will say that without ‘greenhouse’ gases the earth would be 33C colder.
We are currently between the 8th and 9th doubling of ‘CO2’.
So if I do a little rounding 32C/8 = 4C per doubling.
Hey…I’m up in Bill ‘panic monger’ McKibbon land now…just doing some simple math based on ‘boilerplate physics’.
We with any good theory it should run properly in both directions.
So let’s take away 4 of the CO2 doublings. The average temperature of the earth should drop by 16C which takes the average temperature of the earth down to -1C.
Something like 90% of the ‘greenhouse’ effect is water vapor. In our ‘thought experiment’ we dropped the average tempurature to below the freezing point of water. Snowball earth occurs and without any water vapor to provide for a ‘greenhouse’ effect we are frozen for eternity.
Some of Hansen’s writings are quite interesting..here is he rebutting the Milankovich theory.
http://www.columbia.edu/~jeh1/mailings/2011/20110118_MilankovicPaper.pdf
In contrast, atmospheric CO2 during the Cenozoic changed from at least 1000 ppm in the early Cenozoic to as small as 170 ppm during recent ice ages
He’s got a chart on page 3 of his report…at 1000PPM CO2 the earth was 3 degrees cooler then now and at 170 PPM we were in a very long ice age.
My local geology folks tell me that there was 1,000 feet of ice covering the plot of land where my house sits 12,000 years ago.
So if I accept Hansen’s theories I definitely don’t want CO2 to be at 170 PPM. Nor do the residents of NY, Boston, Chicago or Minneapolis.
Since most of the global grain belt would be covered in ice at 170 PPM I doubt anyone who enjoys eating would want the CO2 levels to drop to 170 PPM if we accept Hansen’s theory.
If CO2 is the thermostat for temperature then what is the ‘optimum setting’?
170PPM seems to be teetering on ‘snowball’ earth.
There is a lot of discussion about what may or may not happen in a warmer world. There isn’t any discussion about what would happen in a cooler world. Mass starvation.
Has our emissions of CO2 inadvertently created a ‘climate optimum’ capable of feeding 7 billion people?
Does the benefit of having longer growing seasons outweigh the costs of having to relocate people living in ‘low lying’ areas?
How rich is the farmland sitting under the Greenland Ice Sheets? How many people will it feed?
“So if I accept Hansen’s theories I definitely don’t want CO2 to be at 170 PPM.”
You have this all wrong. He is not “rebutting the Milankovich theory”. Not even sure where to start with that mess. First, do you know the Milankovich theory and how it fits with our current situation?
harrywr2
Some of Hansen’s writings are quite interesting..here is he rebutting the Milankovich theory.
This is hopelessly wrong. Please stop misrepresenting papers you clearly haven’t read. It’s a waste of (my) time.
After summarising some of the complexity surrounding Milankovitch oscillations in section 3.1, Hansen & Sato (2012) Paleoclimate implications for human-made climate change, the authors state (emphasis added out of frustration):
But it is clear that a large global climate response to the weak orbital forcing does exist (Roe, 2006), demonstrating that climate is very sensitive on millennial time scales and implying that large amplifying feedbacks exist on such time scales.
Hansen does not ‘rebut’ Milankovitch. He’s even published on the mechanism of enhanced melting through seasonal changes in insolation* caused by Milankovitch forcing.
Hansen’s argument is that once CO2 had fallen enough for an NH ice cap to form climate became more sensitive to ice albedo than to CO2 hence the emergent instability (ice ages) forced by Milankovitch oscillation.
He’s got a chart on page 3 of his report”¦at 1000PPM CO2 the earth was 3 degrees cooler then now and at 170 PPM we were in a very long ice age.
You have utterly misunderstood this. Hansen is demonstrating that over the Cenozonic (65ma – present) the major climate forcing was CO2. *Nothing else* altered the level of forcing operating on the climate system so much (emphasis added):
In contrast, atmospheric CO2 during the Cenozoic changed from about 1000 ppm in the early Cenozoic (Beerling and Royer, 2011) to as small as 170 ppm during recent ice ages (Luthi et al., 2008). The resulting climate forcing, which can be computed accurately for this CO2 range using formulae in Table 1 of Hansen et al. (2000), exceeds 10 W/m2. CO2 was clearly the dominant climate forcing in the Cenozoic.
Hansen is talking about the slow *cooling* over the Cenozoic from a peak 50ma when the Eocene hothouse climate was ~5C *warmer* that the present to the point ~ 1.7ma when the NH ice sheets formed – hugely increasing climate sensitivity to ice albedo. This came about as CO2 levels fell from ~1000 ppmv 50Ma ago due to the action of the carbon cycle over geological time.
The stuff about CO2 doublings etc is a similar morass of misunderstandings. I really think you need to go back to # 26 and start again instead of skipping over what you don’t want to hear and charging on with yet more contrarian ‘argument’. Please. I ask in the spirit of reasoned discourse Keith mentioned above. This thread is a practical experiment
*Hansen, J., M. Sato, P. Kharecha, G. Russell, D.W. Lea, M. Siddall, 2007a, Climate change and trace gases, Phil. Trans. Roy. Soc., A 365, 1925-1954.
@Tom Fuller
You make my point. “David in cal” claimed it was an objectively true statement. It is not.
Thanks for the interesting item. I’m curious about something: You quote from the Fred Singer piece in The American Thinker, but don’t include a link to it. Was that intentional?
I could imagine it either way: Either that it was just an oversight on your part, or that you intentionally wanted to refrain from linking to the piece, in order to avoid sending more traffic to an essay you view to be misguided. In the latter case, though, I’m curious why you would even mention the article at all, since by doing so you’re bringing more attention to it (albeit without a direct link).
When I blog about an item, even one I’m being critical of, I almost always include a direct link. It seems like a worthwhile piece of bloggy etiquette, if not so much as a courtesy to the person whose work I’m writing about (though it’s that, too), but more as a courtesy to my readers, who may wish to investigate the original in more detail for any number of reasons.
I’m not trying to suggest that you’re in any way obligated to follow my practice. But I was curious, as I said, whether it was accidental or intentional.
Thanks.
@ 30
It’s a free country. You can repeat it as long as you want.
@ 31
Does it really what science you deny?
Sorry, I couldn’t parse it. Care to repeat in English?
#22 BBD
I see you have bought Hansen’s reasoning but refuse to see that it depends on some rather bold assumptions.
There is quite a bit of uncertainty about Eemian temperatures and distribution. The only thing certain from the fossil records is that northern areas were 5 degrees C warmer than today. Same thing with sea level rise estimates that vary between 3-8 meters. Be as it may, this was caused by increase of solar insolation in the north.
Hansen adopts the Eemian glacier melting as a benchmark for modern times. However, he does not take into consideration that today we do not have the same amount of solar insolation as 120 000 years ago. The situations are not comparable.
As for CO2, you can take a look at Vostok ice core results. The temperatures in the Eemian start dropping rapidly, while the CO2 lags them by several thousand years. But I guess you can’t trust the ice core temperature data any more?
John (40),
That was a complete oversight. I wish somebody would have pointed it out earlier–thanks for bringing it to my attention.
I am actually quite a stickler for links. It bothers me a lot when journalists and bloggers don’t link to other posts or articles that they quote or reference.
I’ve been a little distracted the last few days with other work, so I haven’t been as attentive as I usually am. Again, thanks for pointing this out.
Jarmo
I see you have bought Hansen’s reasoning but refuse to see that it depends on some rather bold assumptions.
Not at all. We’ve been through this and now you are dodging the questions I asked you at (25) in favour of reiterative denial. Not rational discourse.
Hansen adopts the Eemian glacier melting as a benchmark for modern times. However, he does not take into consideration that today we do not have the same amount of solar insolation as 120 000 years ago. The situations are not comparable.
Radiative forcing is radiative forcing. It doesn’t matter whether it’s due to a combination of obliquity and orbital eccentricity that intensified Summer insolation at 65N a bit more in the Eemian than the Holocene or whether it’s increased RF from anthropogenic emissions now. The net effect over time is the same. Eemian GAT was ~1C higher than present with MSL ~5m higher than present. Projected warming by 2100 is >1C (at the very least). Polar amplification is evident in modern warming patterns. Arctic ice melt is a matter of record.
Incidentally, there is no solid evidence that ‘northern areas were 5C warmer than present’ either. You go too far. 3C for the NH high latitudes maybe. But even then, it hardly matters. The WAIS is the ice sheet to watch in the short term. As discussed (at least by me). You remain silent on so many points.
Well, this has to hurt…
http://www.washingtonpost.com/national/health-science/young-americans-less-interested-in-the-environment-than-previous-generations/2012/03/15/gIQAGio1ES_story.html
“But an academic analysis of surveys spanning more than 40 years has found that today’s young Americans are less interested in the environment and in conserving resources “” and often less civic-minded overall “” than their elders were when they were young.”
“Steepest of all was a steady decline in concern about the environment and in taking personal action to save it.”
If you are assuming this is because Heartland pamphlets and NIPCC reports are really hot items for the teens and college crowds, well then you’re nuts. The reality is that this is 100% green fail from the boring and patently silly lectures at rock concerts and movies to shrill scolding of the eco-puritans. A movement that wants legislative control of how you live, where you live, and whether you live is a drag to the young. I’m picturing a remake of the Graduate with a party scene where the middle-aged friend of the parents advises the graduate “Windmills!”
Y’all are about that cool
Jeffn
Y’all are about that cool
Ah, but we still share the same planet. The descent of so much youth culture into narcissistic digital barbarism should be of general concern. Irrespective of our views on the arguable failure of the environmental movement to restrain its authoritarian tendencies.
For once, we can leave the physics out of the discussion.
BBD Says:
<i>You have utterly misunderstood this. Hansen is demonstrating that over the Cenozonic (65ma ““ present) the major climate forcing was CO2. *Nothing else* altered the level of forcing operating on the climate system so much</i>
I’ll quote directly from a recent paper by Dr Lindzen
http://www.johnstonanalytics.com/yahoo_site_admin/assets/docs/LindzenChoi2011.235213033.pdf
However, warming from a doubling of CO2 would only be about 1C (based on simple calculations where the radiation altitude and the Planck temperature depend on wavelength in accordance with the attenuation coefficients of wellmixed CO2 molecules; a doubling of any concentration in ppmv produces the same warming because of the logarithmic dependence of CO2’s absorption on the amount of CO2) (IPCC, 2007). This modest warming is much less than current climate models suggest for a doubling of CO2. Models predict warming of from 1.5C to 5C and even more for a doubling of CO2. Model predictions depend on the “˜feedback’ within models from the more important greenhouse substances, water vapor and clouds.
Within all current climate models, water vapor increases with
increasing temperature so as to further inhibit infrared cooling.
Clouds also change so that their visible reflectivity decreases,
causing increased solar absorption and warming of the earth.
In this paragraph has Dr Lindzen in any way ‘misstated’ the ‘consensus’ AGW position?
Is this correct?
Cloud feedbacks are still considered to be highly uncertain
(IPCC, 2007),
I’ll quote the actual paragraph from the IPCC
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch1s1-5-2.html
The modelling of cloud processes and feedbacks provides a striking example of the irregular pace of progress in climate science. Representation of clouds may constitute the area in which atmospheric models have been modified most continuously to take into account increasingly complex physical processes. At the time of the TAR clouds remained a major source of uncertainty in the simulation of climate changes……In spite of this undeniable progress, the amplitude and even the sign of cloud feedbacks was noted in the TAR as highly uncertain, and this uncertainty was cited as one of the key factors explaining the spread in model simulations of future climate for a given emission scenario.
So if Anthony Watts or Roy Spencer or Steve McIntyre or Richard Lindzen agree with the IPCC that the amplitude and sign of cloud feedbacks is highly uncertain what does that make them?
The IPCC ‘consensus’ document says the amplitude and sign of cloud feedbacks is highly uncertain.
Sorry BBD…you are the one wasting everyones time.
The consensus as to the sensitivity to a doubling of CO2 is that it will be between 1.5C and 4.5C depending on the sign of ‘cloud feedback’ which are ‘highly uncertain’.
We can have 3 possible opinions based on the uncertainty
Cloud feedbacks are negative
Cloud feedbacks are neutral
Cloud feedbacks are positive
There is no ‘settled science’ on cloud feedbacks.
#44 BBD
The Eemian solar insolation increase compared to present has been calculated as +50-75 W/m2 during summer months. As the paper I quoted said, solar insolation has associated nonlinear feedbacks. Now, how many watts per square meter is CO2 supposed to contribute?
Hansen claims that GAT during the Eemian was pretty close to present. On the northern hemisphere that claim seems excessively conservative, given the large warming. The claims that Antarctic contributed significantly to sea level rise are kind of dubious because SH solar insolation was much lower than the present. Now, where did that warmth come from as the CO2 level was around 290 ppm and if the SSTs were pretty much the same as today?
Now, these problems could be explained if Eemian GAT was actually higher than Hansen claims, SSTs higher to create warm marine currents to melt WAIS. The proxy network is very sparse and there is room for error. Most information is based on model runs.
Nah, can’t do that. That would blow the catastrophy scenario and calculated climate sensitivity into pieces 😉
#46- just so! How will you be able to retire early with generous benefits if the one little ingrate per two pensioners doesnt agree to live like an Eco monk and shovel all her income into, ahem, “carbon” taxes and fees? For some reason this is especially difficult to explain to recent immigrants. Many of them expect jobs, even incomes!
harrywr2
In this paragraph has Dr Lindzen in any way “˜misstated’ the “˜consensus’ AGW position?
Is this correct?
Yes. But what is missing is the detail:
Cloud feedbacks are weakly negative
Cloud feedbacks are neutral
Cloud feedbacks are weakly positive
Lindzen argues for a low CS (<1C for 2xCO2) on the basis of uncertain cloud feedback. He correctly cautions that modelled studies of necessity reflect this uncertainty. Hansen agrees (H&S12):
Models are imperfect and we will never be sure that they include all important processes. Fortunately, Earth’s history provides a remarkably rich record of how our planet responded to climate forcings in the past. Paleoclimate records yield, by far, our most accurate assessment of climate sensitivity and climate feedbacks.
H&S12 is an attempt to estimate CS empirically (this brings us back to #8):
This empirical climate sensitivity incorporates all fast response feedbacks in the real-world climate system, including changes of water vapor, clouds, aerosols, aerosol effects on clouds, and sea ice. In contrast to climate models, which can only approximate the physical processes and may exclude important processes, the empirical result includes all processes that exist in the real world ““ and the physics is exact.
The central problem with Lindzen’s position is that it does not fit with known climate behaviour which is compatible with an ECS of roughly 3C to 2xCO2 or the equivalent *forcing*. Nothing he has published to date provides convincing support for his hypothesis that cloud *feedback* is significant. Nor do Lindzen’s other arguments for low CS stand up to scrutiny (#26). This should not be overlooked.
So we are back where we started:
Cloud feedbacks are weakly negative
Cloud feedbacks are neutral
Cloud feedbacks are weakly positive
Sorry BBD”¦you are the one wasting everyones time.
Really?
With spenser, Singer and now watts taking on the Slayers, I think we should just adopt the name “Slayer” for anybody who denies that GHGs warm the planet.
And we could call those who argue for an ECS below ~3C ‘the baseless’.
🙂
Don’t worry BBD. Once the septiks die off, carbon freedom will be realized once the Millennial’s take charge. The most environmentally sensitive generation in the history of the Universe:
http://www.thejournal.ie/recent-generations-not-interested-in-giving-back-385583-Mar2012/
OoooHhhh SNAP…. Who could have possibly anticipated that young people smothered with green curriculum in school, green superheros on the telly and green disaster epics on the big screen would ever think of rebelling? Maybe they were tipped off to the big lies by mandatory volunteering for PC causes required for graduation and entrance to college?
Howard
Physics doesn’t care.
Off to bed now.
Who could have possibly anticipated that young people… would ever think of rebelling?
They’ve been reading HI publications, disguised as harmles porn. And underground newsletters. I bet they have a secret handshake. And a motto: 560 ppm, or bust.
Sleep tight, BBD.
BBD.
check what percentage of the PDF falls below 3C
And lets not forget where the science is moving. In the FAR ECS for models was 3.8. in the TAR around 3.6 in Ar4 3.26
As we understand more the mean comes down.
And models averaging 3.26 have over predicted the temps for the past 11 years.
You wanna bet that ECS is greater than 3C? doesnt look like that bet is supportable.
you wanna PLAN for an ECS greater than 3C? different matter all together.
Put another way, if I showed you the PDFs for ECS and asked you to bet an over under bet at 3C.. you’d take the under bet. If I added the information that models averaging 3.2 overestimated warming, youd feel safer abut that bet.
#25 BBD
“Hansen ““ and many others ““ are not primarily concerned with the GIS. In fact the latest thinking based on the findings of the NEEM drilling project is that cryosphere contribution to Eemian MSL was ~1m GIS and ~4m WAIS. In the short term, attention is on the WAIS. The concern is over a potential non-linear response to warming W. Antarctic coastal currents and surface meltwater destabilising the ice shelves that currently *impede glacial drainage* of the ice sheet proper. See Hansen (2007) Scientific reticence and sea level rise.”
What bothers me about these speculations is that they do not fit the known facts about the Eemian.
Solar insolation during the Eemian was much higher than today in the Northern hemisphere summers. Longer and hotter summers due to Earth’s tilt and eccentrity of orbit. We know for sure (from fossil evidence) that present-day Greenland, Russia, Canada, the US and northern Europe were much warmer than today.
In the southern hemisphere the solar insolation during SH summer was much lower than today. And as Hansen argues, GAT was less than 1 degree C higher than today. SSTs in the tropics were according to Hansen possibly lower than today. CO2 was around 290 ppp, 100 ppm less than today.
So now Hansen & co argue that WAIS collapsed. With pre-industrial CO2 levels, much lower solar insolation during Antarctic summers than today and pretty much similar tropical SST’s as today.
Do you really buy this?
And models averaging 3.26 have over predicted the temps for the past 11 years.
This only confirms that models suck but we knew it before. It doesn’t follow that they over-predict in the future unless we understand WHY they over-predicted in the past.
steven mosher
No, I don’t think ECS is >3C. All the evidence suggests something like 2.8C – 3C. Not higher. So TCR of just under 2C for 2xCO2. I write this as “~3C”.
Jarmo
Do you really buy this?
A really good question. You’ve prompted me to do some follow-up reading and I’ll respond once I’m up to speed. Hopefully later tonight (UK time).
Jarmo
Definitely an interesting question 🙂
Van de Berg et al. (2011) attribute 2.2-4.5m of Eemian MSL to GIS ice loss, estimating the GIS to be 30% – 60% smaller than at present. Melt is hypothesised to be 45% insolation (greater during Eemian than Holocene) and 55% to an increase in Greenland SAT of 2 – 4C. This is, of course, a modelled study 🙂
Colville et al. (2011) note the reduced southern GIS relative to the Holocene but disagree with the extent of ice loss and consequent estimate of contribution to MSL argued by vdB et al. (The authors use the term Last Interglacial (LIG) for the Eemian).
To ascertain the response of the southern Greenland Ice Sheet (GIS) to a boreal summer climate warmer than at present, we explored whether southern Greenland was deglaciated during the Last Interglacial (LIG), using the Sr-Nd-Pb isotope ratios of silt-sized sediment discharged from southern Greenland. Our isotope data indicate that no single southern Greenland geologic terrane was completely deglaciated during the LIG, similar to the Holocene. Differences in sediment sources during the LIG relative to the early Holocene denote, however, greater southern GIS retreat during the LIG. These results allow the evaluation of a suite of GIS models and are consistent with a GIS contribution of 1.6 to 2.2 meters to the ≥4-meter LIG sea-level highstand, requiring a significant sea-level contribution from the Antarctic Ice Sheet.
Eemian ice was found at Dye-3 (Oerlemans et al. 2006) down at the south GIS
The estimate of the contribution of the Greenland Ice Sheet (GIS) to the higher sea level stand in the Eemian interglacial (between 2.2 and 3.4 m) is based on the assumption that there was no ice at the location of the Dye-3 ice core in southern Greenland. However, Eemian ice has been found at the base of this ice core. The presence of Eemian ice in south and coastal Greenland implies that the GIS was essentially intact in a much warmer climate and could not have contributed more than 1 to 2 m to sea-level rise.
And as Dahl-Jensen summarises, Eemian ice is found in the central and northern GIS and right out in the east at Renland (noteworthy of itself). And NEEM found Eemian ice up in the north west GIS. Here’s a map for clarity. (NEEM is not marked, but it is inland of Camp Century).
To evaluate the area and volume of the Greenland Ice Sheet during the Eemian period, it is worth noting that we find Eemian ice in the Dye3 ice core in South Greenland, in the central Greenland Ice cores GRIP and GISP2, in NGRIP and in the little 350m thick ice cap, Renland, on the east coast of Greenland.
[…]
It can be concluded that the there was an significant ice sheet covering Greenland during the warm Eemian period and that the reduction of the Greenland ice sheet at most contributed with a sea level rise of 1-2 m of the observed 5 m.
Finally studies of DNA from the basal ice from the DYE-3 ice core in south Greenland reveals that Boreal forest covered South Greenland before it was ice covered. Dating of the basal material indicates that the biological material found in the DYE-3 ice core is older than 400.000 years supporting the above conclusion that ice covered south Greenland during the Eemian period.
So extent is well supported by field work and again the empirical view contradicts vdB11.
But as far as I can see there’s nothing in the literature yet from NEEM. What has emerged is this:
The NEEM ice core contains more that 150 m of ice from the Eemian period and more than 100 m of ice from the previous ice age below the Eemian layer. However, the measurements show that the layer sequence above and below the Eemian ice is broken. This means that they are now carrying out measurements on the ice so that the layer sequence can be reconstructed. Once this reconstruction is completed, you will get very detailed information about the conditions during the Eemian period.
So apparently Holocene ice on top of Eemian ice on top of Holsteinian ice (!). But…
[Dahl-Jensen:] “To summarize, we can say that the NEEM project has accomplished all of its scientific goals. The hope of finding undisturbed layer sequence of Eemian ice was not fulfilled; but it is a basic scientific condition when you are exploring the unknown: that nature always surprises you. On the other hand, we have learned a great deal about how the old and deep ice flows – something that is important for predicting the development of the ice sheet in a warmer period. An unbroken Eemian sequence must wait for another time.
But no stratigraphy to reveal rates of change. Extent without detail.
There’s no clear case that the majority contribution to Eemian MSL was GIS melt but the exact contribution remains debatable, leaving the question of the contribution from the WAIS open.
Sorry:
So apparently Holocene ice on top of Eemian ice on top of Holsteinian ice (!).
Should be:
So apparently Holocene ice on top of Eemian ice on top of post-Holsteinian ice (!).
@bbd
your tiresome reliance on ‘abstracts’, ‘links’, and ‘facts’ simply serve to reinforce the view that you are a ‘tribalist’ ‘partisan’ who is more interested in ‘winning’. ok i’ll stop now.
p.s. my favorite state so far, in terms of the view from the interstate, was west virginia hands down. john denver was on to something. the rest? meh. as a canadian i appreciate the un-bumpy virtue of highways that don’t’ suffer from seasonal freeze-thaw. one wonders if Tol incorporates such things into his models…
p.p.s. those planning on staying in Savannah, Georgia during St. Patrick’s day might want to plan ahead. apparently there’s a biker convention at the same time and rooms are hard to come by. yours truly is of course a man of limited imagination and wisely delegated such responsibilities to she-who-must-be-obeyed. is it a good sign when the elevator ad in the hotel reminds you that they launder their sheets every day? Consider me a skeptic on this one…
@64 is it a good sign when the elevator ad in the hotel reminds you that they launder their sheets every day?
No, that’s a horrible sign. Do you have any idea what the carbon footprint is for daily laundering at hotels? It’s atrocious.
#62 BBD
I have no quarrel against WAIS contributing to Eemian sea levels… or not. What I am basically arguing is that Hansen’s claims that we are about to have a similar situation shortly are exaggerated. He is cutting awfully many corners and disregarding inconvenient evidence in order to arrive to his apocalyptic visions.
Marine cores (with relatively poor resolution and sparse sampling on SH) suggest that equatorial SSTs in many places were about 1.5 degrees higher than today. A study of New Zealand Eemian temps showed up to 4.5 degrees higher temps than today. Remember, these are averages of hundreds of years.
There’s three main points: First, the Eemian and the Holocene have been quite different due to differences in solar insolation. Ocean heat transfer from the equator to the poles, Arctic warming, humidity etc. Quite different climates in many places.
Second, all this took thousands of years. GIS was several degrees warmer than today for thousands of year before its total contribution to sea levels. High sea levels lagged high SSTs by thousands of years. The Eemian peak warmth took place thousands of years after peak insolation.
Third, Hansen’s claims of only slightly elevated GAT during the Eemian are kind of pathetic…. just compare them with the modern world. The recent 1 degree rise in GAT is the result of slight warming in the NH. Imagine ice free Arctic ocean, much warmer Russia, Canada, Europe, the US, melting GIS and WAIS and the associated higher SST’s in high latitudes ….. and then tell me that GAT is 0.5-1 degree higher than today?
OK, the sun is shining, trumpeter swans flew over the house, it’s time to enjoy the spring!
60.
that makes you a luke warmer. welcome to the club
kdk said:
‘It’s the same old warminista argumnet. Start with basic physics on which noone disagrees. Then pretend we have “˜solved’ the climate problem ““ we haven’t. Wave your hands at the un-cooperative real world data. And then accuse anyone who disagrees with you of smoking cigarettes and having lots of money.
It is tiresome.’
I have no idea who he said that to, or what about, but do admit it’s very funny, even if he might be saying it about you. As I am smoking as I type and have above average money I’m sensitive to attribution of reason to what I think being dependant on those two things. Like, determinism gone mad, lol omg.
Relating ECS from highly leveraged and focused insolation changes blasting mile-thick ice sheets with TSI to that of a modest increase in a well mixed GHG is borders on professional misconduct. It does not pass the straight face test.
Nice try BBD, but climate science is to physics as homeopathy (high sensitivity) is to modern medicine… or astrology (hockey-stick) to astronomy… Steve McIntyre is excoriated for suggesting climate science be brought up to the minimum technical standards of economic geology. Until then, sociology will appear to be a hard science by comparison. One day soon, hopefully, climate science will be conducted in a manner similar to physics. When it does, then the kids will know they are not being brainwashed.
The straight face test, of course, being the pinnacle of economic geology.
I’ve always found the smell test to be quite useful when dealing with things I technically don’t and can’t understand. I had customers who refused to give Madoff money (you could say went against the consensus 🙂 ), but couldn’t explain why at the time.
steve mosher
that makes you a luke warmer. welcome to the club
You have claimed this before, and I disagreed last time. ~3C ECS is the IPCC AR4 ‘most likely value’. I am a dull conformist at the centre of the consensus.
I used to be a lukewarmer though 🙂
It’s interesting that you seek to define the nebulous term ‘lukewarmer’ as any value for ECS below 3C. Your definition appears to be – 2.999r C ECS = lukewarm. This is absurd. In the current state of the discourse, lukewarm really does mean lukewarm – 2.8C ECS is mainstream.
You appear to be saying – look, I was right to be a lukewarmer all along – while at the same time accepting the consensus estimate. That’s cake and eating it territory.
howard
Relating ECS from highly leveraged and focused insolation changes blasting mile-thick ice sheets with TSI to that of a modest increase in a well mixed GHG is borders on professional misconduct. It does not pass the straight face test.
Correct. Which is why neither myself nor the studies I discuss above do any such thing. The conversation had moved on from ECS to Eemian insolation at 65N etc.
Best to read before commenting.
Nice try BBD, but climate science is to physics as homeopathy (high sensitivity) is to modern medicine”¦ or astrology
Oh what balls.
Marlowe @ 64
You’re in a horribly good mood 🙂
Savannah’s very pretty but the ghost of antebellum charm will probably flee from the roar of Harleys. An unfortunate coincidence. Perhaps you can try again on the way back?
Safe journey.
BBD,
Here’s a pretty recent study that does a very good job on the uncertainties related to marine cores:
http://epic.awi.de/22309/1/Led2010a.pdf
There’s some interesting graphs as well.
Jarmo @ 66
This has been an interesting exchange – thanks.
A few things to round off with:
First, using Eemian uncertainty to ‘debunk’ Hansen is risky because he (and many others) simply argue that the ice shelves inhibiting glacial drainage from the WAIS are potentially unstable. And we’ve had the example of Larsen B already.
Second, I don’t find Hansen’s methodology as questionable as you do (see # 12), but then I don’t share the universal sceptic loathing of the man which may make me fractionally more open-minded about his conclusions – in this case that Eemian global average temperature was ~1C higher than present. Pointing to regional studies (especially high latitude studies) looks good, but doesn’t really get around the issue of polar amplification vs GAT. Anyway, be that as it may.
Third, there’s ample evidence that the GIS is losing ice mass at an increasing rate. Albedo change seems to be an important factor eg MODIS satellite observations and Tedesco et al. (2011) which examines the record melt in 2010 (full html paper here).
Fourth, if – like me – you feel that the lower bounds of vdB11’s estimate of GIS contribution to MSL and ice sheet shrinkage are the most plausible, then the Eemian saw the GIS reduced by ~30% and the meltwater raised MSL by ~2.2m. The other ~3m can only have come from the WAIS – which was not being subjected to the elevated summer insolation that characterised the Eemian peak orbital forcing relative to the Holocene.
I fully agree that the claim that SLR might rise significantly by century’s end because of a non-linear response by the WAIS needs to be evaluated carefully. I also very much hope that Hansen and others are mistaken.
But as you say, enjoy the spring (good, sunny weather in the southern UK today too!). Wise counsel.
Jarmo
Thanks for the link to Leduc09. Very interesting but I have only skimmed through it. One small point though. H&S11 uses a *deep water* temperature reconstruction (Zachos et al. 2001) that is derived from isotopic analysis of *benthic* forams. Proxy responses to seasonal changes (eg insolation) in surface waters affecting SST reconstructions (per Leduc) are not relevant to deep water temperature reconstructions.
#76 BBD,
The uncertainties can cut both ways, I agree. The Eemian is a fascinating period.
I read a couple of studies, too, and became interested in the timescales and the inertia of change. As vdB11 on GIS illustrates, melting takes a long time. Kukla et al.(2002) stated that the sea level rise in the Eemian from present levels to 4 meters above present level (or 8 meters, depending on study, sites and interpretation) took 5000 years.
One thing about Hansen’s theories sounds like a fallacy to me. He keeps harping about GAT and how the Holocene climatic optimum and Eemian peak warmth were not that different from modern times – and hence the danger of WAIS collapse and GIS melt today.
Hansen and quite a few RealClimate contributors have been active in promoting the idea that tropics were much cooler during the early and mid Holocene and the Eemian MIS5e, and thus balanced the high temps up north and also down south and led to GAT similar to present.
Be that as it may, from the perspective of ice sheet melt, it does not make a difference how hot or cold it was in the tropics. What matters are the SSTs and temps from mid to high latitudes. The question to ask is: Do have similar conditions up north and down south as during MIS5e? I think were not even close.
Bo Vinthner has an interesting paper on Greenland early Holocene melting, it gives perspective.
http://www.nature.com/nature/journal/v461/n7262/full/nature08355.html
Jarmo
Isn’t the argument that a rise in global mean temperature of ~2C by the end of the century *with concomitant polar amplification* will get us in the realm of MIS 5e? Rather… abruptly, compared to the ve-e-e-ry slow change in insolation leading up to peak orbital forcing. And that this abrupt increase in forcing is what makes a non-linear response by the WAIS more, rather than less, likely?
#79 BBD,
There’s couple of interesting questions: First, does GHG forcing have the same effect as higher solar insolation does on ice sheets? In #22 I quoted a study where the modeled Eemian GIS change was caused by about 50 % temperature rise, 50% solar insolation rise (more watts of solar energy, longer and hotter summer, solar feedbacks).
The other interesting question is the relationship between GAT and polar amplification. If I understand the theory correctly, GHGs will warm Earth more uniformly than for example solar insolation during the Eemian.
Now, past interglacials have been used as a measure of how much polar
amplification we get per rise of GAT. This measure may be incorrect and there is uncertainty even in studies which consider this measure adequate:
Circumstances in the past provide imperfect analogues for the near future, when greenhouse gases alone are expected to dominate the forcings, and timescales are too short for slow feedbacks to have a strong contribution. Furthermore, the paleoclimatic data summarized above are from climate states that were relatively stable over millennia or longer, and do not provide detailed information on the path by which Arctic and other regions reached those climate states.
http://www.sciencedirect.com/science/article/pii/S0277379110000405
To sum it up, with GHG forcings alone, the ice sheet melt may well be slower and less than during past interglacials for the same GAT increase.
Jarmo
As I said earlier, I hope Hansen is mistaken and that you are correct. Unfortunately, the study you link contradicts your own argument. From the abstract:
Despite differences in forcings and feedbacks for these reconstructions compared to today, the Arctic temperature change consistently exceeds the Northern Hemisphere average by a factor of 3″“4, suggesting that Arctic warming will continue to greatly exceed the global average over the coming century, with concomitant reductions in terrestrial ice masses and, consequently, an increasing rate of sea level rise.
This is exactly the point I am making at # 79. In fact Miller10 is one of the papers I had in mind 🙂
Anyway, enough for now. The insolation factor may well be under-weighted but I suspect polar amplification of the generalised anthropogenic forcing is not – and this is why the problem of GIS/WAIS melt cannot be dismissed by argument from insolation alone.
#81 BBD,
Miller10 is a study that regards past relationship between GAT and polar amplification also adequate in the future. With Mark Serreze as one of the authors, that is to be expected. Like I said, I disagree with that view.
Be as it may, scientists are probably studying this more as we write. There’s some new climate sensitivity studies that suggest lower CS than AR4. Would be interesting to see their take on the paleo proxies but unfortunately latest studies are behind a paywall.