Is "Climate Sensitivity" the main issue that differentiates skeptics/deniers from alarmists?

Climate sensitivity as stated by consensus scientists does seem to be reducing at the moment. This is a good thing because if it comes down enough it means we don't have a problem. Professor Myles ALlen of Oxford University has produced a YouTube video in which he says that an increase of 11 deg C is possible by 2100. Now he is the co-author of a paper that claims 2 deg C is likely.

Hey Dook is quoting from SkS again and slagging off mainstream climate scientists. How ironic that SkS is run by Cook and Nuccitelli. One is a cartoonist and the other is in the pay of Big Oil.

Did the U.S. National Academy of Sciences bother to ask any of its members about their statements, I wonder? Or was it just a politbureau bulletin?

All things global warming in wikipedia are monitored by William (And I've just made my 10,000th edit.) Connelly (AKA Stoat) who is not best known for his fair-minded and even-handed wiki changes.

There is a difference between deniers and skeptics as well as between realists and alarmists. Deniers use whatever tidbit that seems to support their agenda, such as cold weather somewhere and ignoring heat waves, often at the same locales at different dates, as well as some glacier that is expanding while most glaciers are shrinking. They also ignore long term trends in temperature in favor of shorter terms, which can still be up to 20 years long, but have cherry picked start and end dates. And when confronted with evidence they don't like, they call that evidence a lie. It must be convenient for everything they don't want to hear to be a lie.

I think that there are very few actual alarmists. Even Greenpeace does not go so far as to advocate a ban on driving cars. An alarmist may suggest that doomsday scenarios are not only possible, but likely or even certain, unless we immediately stop burning fossil fuels, or even if we do. As I say, I am not aware of many alarmists, unless you count denialists who either claim that we should be afraid of the next ice age or that taking action to stop global warming means the end of Western civilization, or ay least of our freedoms. Another group of alarmists would be opponents of nuclear power, who claim that events like Three Mile Island and Fukushima actually kill large numbers of people.

Regarding the possibility that it could be worse than experts predict, as skeptics and deniers love to point out that computers models are at best, questionable. People say that computer models do not handle clouds very well, even though new empirical data can fix that. More serious is the fact that climate models have underestimated ice melt in the Northern hemisphere and overestimated sea ice gain in the Southern hemisphere. When your beachfront property is six feet umder water, will it matter whether Earth has warmed by 5 degrees C or only by 2 degrees C? The bottom line isn't how much temperatures rise (climate sensitivity) but the effects of what ever warming happens.

<When giving percentages and understanding the difference between Fahrenheit and Celsius we know that the spacing in degrees Celsius will give a higher percentage rate than what Fahrenheit gives.>

Percent change in temperature = Percent change in absolute temperature. The freezing point of water is 0 degrees C = 273 Kelvin = 32 Farenheit = 491 Rankine. A 1.8 Farenheit change is the same percentage of 491 Rankine as 1 degree Celsius is of 273 Kelvin, which is 0.366%

Climate sensitivity is a measure of how responsive the temperature of the climate system is to a change in the radiative forcing of the system.

Although climate sensitivity is usually used in the context of radiative forcing by carbon dioxide (CO2), it is thought of as a general property of the climate system: the change in surface air temperature (ΔTs) following a unit change in radiative forcing (RF), and thus is expressed in units of °C/(W/m2). For this to be useful, the measure must be independent of the nature of the forcing (e.g. from greenhouse gases or solar variation); to first order this is indeed found to be so[citation needed].

The climate sensitivity specifically due to CO2 is often expressed as the temperature change in °C associated with a doubling of the concentration of carbon dioxide in Earth's atmosphere.

For a coupled atmosphere-ocean global climate model the climate sensitivity is an emergent property: it is not a model parameter, but rather a result of a combination of model physics and parameters. By contrast, simpler energy-balance models may have climate sensitivity as an explicit parameter.

Interesting perspective on the math Zippi!

Does a realist understand it though?

I agree with JC to a point. He seems to think there is evidence for action, but I sincerely disagree and agree with Spencer in that climate sensitivity is low.

The Chicago analogy does shed some light on temperatures and how people like antarcticice manipulate the actual temperature data. 10% is a stretch. LOL!

I'm not sure what to think about the 1.3%F and 1.37%C increases, but it seems right. I thought it was closer to 1% and have always used the 1% forcing of added CO2 by humans.

It is certainly one of the main issues, but I agree with the others who differentiate between Skeptics and Deniers-to be fair, there is also a considerable difference between Alarmists and 'Realists,' (or Proponents, Warmists, etc.) Deniers and Alarmists are roughly equivalent in their disconnect with reality and science; it would certainly seem that on both sides of the argument people have become very frustrated with one another and both terms are tossed around rather indiscriminately, which escalates the tension between Realists and Skeptics. Perhaps nowhere is it more evident than here in this category of Y/A.

The Realists and Skeptics aren't really all that far apart on the science/theory itself but I think you are right, that climate sensitivity is where most seem to diverge in opinion. I personally believe (as a non-scientist, BTW) that the evidence suggests greater climate sensitivity than is proposed by the self-avowed Skeptics. One arena I am very interested in is 'average' global temperature increase vs. regional variations and the influences on weather as those variations are equalized. While the average might appear to be minor, the regional variations might be major and as the system works to achieve equilibrium it certainly seems evident that weather extremes would increase. The issue is how much influence mankind's activities have on natural processes.

The greater disagreement between the Skeptics and Realists is, of course, our response to the evidence before us, with some Skeptics taking a 'wait and see' position for economic and political reasons while the Realists believe there is sufficient evidence to warrant action in various ways. Of course, regardless there is already an environmental, economic and political juggernaut that is gaining momentum as alternative energy sources are researched and developed. So what we see are people and organizations digging in their heels to try to slow the increasing momentum of that juggernaut down. So that is why you can see the conservatives among us are more likely to be on the anti-AGW side of the argument, as well as why the science has been co-opted by the ideological argument and that, in turn, feeds denial.

EDIT: Pat suggests that I seem to advocate for action based on my opinion about climate sensitivity but I'm not sure I intended to imply that; rather, my concern is that if we take economic (and geopolitical) action solely to mitigate climate change in the face of uncertainty, that is not a wise course of action and indeed, could upset a tenuous global economy as well as destabilize developed nations in a way that could lead to greater social harm sooner than AGW is likely to. Rather, we need to minimize risk by developing technologies with multiple benefits; alternative energy, although costly to develop relative to the use of fossil fuels, addresses multiple short and long term needs aside from any potential benefit it might offer in terms of helping to minimize the impacts of AGW. I trust in this particular exercise it isn't necessary to elaborate on the specifics. Conversely, I am not in favor of strategies solely designed to remove CO2 immediately, shifting political power through economic measures or worldwide governing bodies from developed nations to consortiums of small countries whose goal is to develop economically with financial aid from the developed countries while simultaneously punishing those same countries for their carbon footprint, or other policies that do not have other benefits for the countries who practice them.

That being said, I would like to study the less/more climate sensitivity issue more, and I think this conversation about it is interesting, very worthwhile and discussed in the spirit I would like to see more of the debate conducted. Great question!

Roy Spencer has been focused for 30 years on proving that random cloud behavior is responsible. Even has his own data continues to show more warming, and he has been unable to convince anybody of his unsupported theory could explain the little warming that had been observed when he started his campaign. Multiple researchers have confirmed that climate sensitivity is around 3 degrees per doubling of CO2; Spencer just ignores how much other research has come together.

I think he is closed-minded to any explanation other than his own, he writes as if there has been no research conducted in the past 30 years. Climatology has passed him by, and he has only established a questionable reputation after several embarrassing mistakes that were driven by his focus on proving what he wanted proved rather than doing good work first and learning what is true. He is not really engaged with the rest of the climate research community, nor even his own data actually.

Yes among the moderate sensible thinking people, that's what it comes down too, no sane person can deny that man has an effect on climate and that CO2 can cause warming, the question is all about how much, is it trivial or is it catastrophic, is it beneficial or harmful?

Skeptic is not a good definition, because one of the requirements to be a good scientist is to be skeptical and question everything.

Antarctic. another lie I was the one who replied 1C rise (not %) in response to a graph you yourself displayed from 1880 to I believe 2010

"Roy Spencer is a Government sponsored climate scientist who has never received a dime from any oil company. I'm wondering why everyone doesn't block you for your own misinformation."

Sorry to burst your bubble, but Spencer is funded they use a technique where they do work for middle parties like Heartland or George C. Marshall, but the funding is there as are the links to most of the 'experts' who deny AGW, they are all linked to these groups.

Heartland where tricked into releasing papers that proved this some time ago showing people like Watts and others get 10's of thousands of dollars and that was just one group, many of these experts have links to many of these groups.

The very reason they have so few is that most scientists would not sell their science to the highest bidder.

But if you look at just Spencer, what is it that you think he has done, he and Christy published some work years ago on satellite data, that denier still use, yet Christy has admitted that work was wrong, other research scientists have also published work showing this was wrong as well.

Most of Spencer's claims are unpublished, because he can't prove them to any real science journal, hence the blog to feed this BS to directly to deniers.

He was involved in a sad attempt to get a paper into the obscure journal 'Remote Sensing' in an attempt to get around this, that paper was torn to shreds by the climate community and the editor of Remote Sensing resigned stating "the paper was not vetted properly" this seems to be a new trend in denial, to use obscure journals or in the case of at least one to actually run it 'Environment & Energy' set up with well known denier experts as chief editor and deputy editor, such tactics didn't really fool the science community for long but the aim is give the denier websites and blogs fodder they can claim is peer reviewed.

Watts claimed for years he was not funded by anybody, the Heartland incident showed he was getting 10's of thousands, now he's switched to saying he is funded but it's only for a new website, I guess he just 'forgot' when making the previous claims.

As to your point of climate sensitivity, that is something scientists do debate, they use science and data, if deniers did that there would be no problem, but deniers want to talk about communist, green, government, scientific and club of Rome conspiracies (i.e. fantasies) or drag in nonsense like HAARP or chemtrails (i.e. science fiction)

Or make claims about volcanic activity that are simply not true or claims about solar activity that are not supported by the data at all.

You seem to buy into this with

"You would think that we’d know the Earth’s ‘climate sensitivity’ by now, but it has been surprisingly difficult to determine."

which in the space of a few lines goes to this

"I am now convinced the scientific community has totally misinterpreted"

You go from we don't fully understand the processes to a conspiracy without the slightest evidence, a common denier trait.

Even the concept of lying or faking their data is repugnant to most scientist, as is seen in the treatment of any scientist found to have done this, they are finished.

Can deniers be reasoned with, not in my experience, they just go off at tangents on irrelevant issues or conspiracies or simply invent maths to suit their purposes, it doesn't even need to add up.

Take the claim made by one denier lately of a "just 1% rise in temperature since 1880"

Where does he pull this percentage from, given the average temperature of the planet was about 14c and is now almost 15c, as a small hint 10% of 14c is 1.4c, I think even a grade school student could figure out that this would put the average rise in temperature at a little over 5%, 5 times the figure the denier has invented.

No, the primary characteristic of deniers is that they will believe (or at least say) anything that supports their denial. Most of them couldn't care less whether it's true or not, if the idea of low climate sensitivity works to support denial, they will be for that; if they think a magical connection between cosmic rays and climate supports denial, they will believe that; if believing that geothermal energy is causing the warming helps their denial, they will support that; if believing that all the world's scientists are in some vast conspiracy supports denial, then they are; if believing that man is too insignificant to have an effect on the Earth, then that must be true; if believing that the Earth really hasn't warmed, it's just that every thermometer is situated near a parking lot, then that must be the way it is.

It just goes on and on, and clearly they're not really interested in the truth--there is one vocal denier in here that is constantly quoting an astrophysicist--despite the denier believing that the Earth is only 6500 years old!!

EDIT for EVERYONE TALKING PERCENTAGES: First, unless you're using an absolute scale, such as Kelvin or Rankine, it's wrong to talk about percentage change in temperature, because the percentage change will depend on what scale you're using, and if you're looking at changes around zero, it could be infinite!

Second, there is little point in talking percentage change in temperature anyway, so why are you doing it? It varies from place to place around the world, so using the global measure for a change in Chicago or the South Pole or in Singapore is silly.

Third, temperature change is just one aspect of a multi-faceted problem, so looking only at temperature change is myopic.

EDIT for your additional details: If you're talking about true skeptics then yes climate sensitivity is an issue--although one I think is emphasized too much. However I find very few skeptics in Yahoo Answers--most of the people that disagree with global warming are lying deniers, and they could not care less about climate sensitivity, except as one more piece of piece of misinterpreted science to be used in their false arguments. As for Spencer, I think he is only taken seriously among the denial crowd. His mistakes are well-known, as is his belief in religious mythology instead of science.

I differentiate between denialists and skeptics. (I also differentiate between alarmists and realists). As several prior posters have suggested, denialists will generally believe anything that they think supports their denial--that it isn't warming, that warming is natural, that it's all cosmic rays, that it's the sun, that it's geothermal, that temperatures drive CO2 but the reverse isn't possible, whatever fabric of lies they can try to cover their shame with.

Skeptics, on the other hand, hold positions that are at least within shouting distance of reality--often, as you suggest, that climate sensitivity to CO2 is less than most scientists think.

And I, at least, reserve the title "alarmist" for the-sky-is-falling types who are predicting results of AGW that are significantly more severe than those predicted by the majority of climate scientists.