Net Effect of Atmospheric Water on Global Temperature

[Yarn]

Water is a greenhouse gas, but it also frequently forms clouds. Clouds have very high albedos, and consequently cool the Earth. I once heard an environmentalist claim that for every amount CO2 increases global warming, the effect that this increase has on evaporation leads to it doubling. Is this true? How good an idea do we have of which effect predominates; clouds or water vapor's greenhouse effect?

 

 

[JohnB]

You've stepped into the lions den with this one. This is a area of great contention.

 

But going back to basics we know that for a doubling of CO2, and everything else being equal, then temps should rise by about 1.1 degrees. The IPCC estimates the rise using climate models to be somewhere between 2.4 and 4 degrees due to water vapour enhancment. The amplification of warming by water vapour is a main leg of AGW theory, however it has not been demonstrated in the lab or by any real world experiment to exist. WV is a much more powerful GHG than CO2 and logically if the world is warmer then there should be more WV and therefore the warming should be amplified.

 

However, as you rightly point out, more WV means more clouds and depending on type, clouds can have a tremendous cooling effect. Watch the temps drop on a sunny day when a cloud passes in front of the Sun.

 

AGW standard theory also requires that clouds be feedbacks of temperature and never a forcing. This is disputed in the literature by a number of climatologists, but mostly by Dr Roy Spencer who does the UAH satellite temperature series. Put simply, the sats show us that warmer years tend to have slightly less cloud coverage than cooler years so the question being argued is this "Is there less cloud because it is warmer or is it warmer because there is less cloud?" If the standard theory is correct then the first is the case and clouds are a feedback, if the standard theory is incorrect then clouds can be a forcing in their own right and the second part is correct.

 

Messing the whole question up is the fact that clouds most certainly are a feedback effect from temperature, but can they also be a feedback effect from another factor besides temperature and therefore become a temperature forcing?

 

This is probably the least well understood part of the climate system and the quantities we are dealing with are quite small. The energy figures themselves are large, but the change in the budget is less than 1% since 1850. For example a change (drop) in average annual cloud cover of less than 1% between 1850 and 2000 is quite enough to allow the extra energy into the system to explain all warming since 1850. Since we have been putting CO2 into the atmosphere since 1850 and therefore must have caused some rise in temps this cannot be the only answer, but it is a reason why we sceptics are sceptical of climatologys claims of confidence in their attribution.

 

I hope that the above has helped a bit, but this is a very complex area of climate.

[Xelloss]

However' date=' as you rightly point out, more WV means more clouds and depending on type, clouds can have a tremendous cooling effect. Watch the temps drop on a sunny day when a cloud passes in front of the Sun.

 

AGW standard theory also requires that clouds be feedbacks of temperature and never a forcing. This is disputed in the literature by a number of climatologists, but mostly by Dr Roy Spencer who does the UAH satellite temperature series. Put simply, the sats show us that warmer years tend to have slightly less cloud coverage than cooler years so the question being argued is this "Is there less cloud because it is warmer or is it warmer because there is less cloud?" If the standard theory is correct then the first is the case and clouds are a feedback, if the standard theory is incorrect then clouds can be a forcing in their own right and the second part is correct.

 

Messing the whole question up is the fact that clouds most certainly are a feedback effect from temperature, but can they also be a feedback effect from another factor [i']besides[/i] temperature and therefore become a temperature forcing?

 

Are you sure? As far as I know, cloud and surface albedo is indeed counted as a radiative forcing. The key point is that greenhouse gas emissions have a much larger positive radiative forcing. You can see the graph below for more details:

 

 

SOURCE: IPCC

 

To make a long story short, there is much more energy being poured into Earth's climate system than is being reflected out. Therefore the planet is warming. The source of the excess carbon dioxide and other greenhouse gases is caused primarily by fossil fuel combustion. This effect is very well known.

 

Also keep in mind that a warmer atmosphere holds more water; thereby making the surface drier (i.e. there is on average less cloud formation and rain). Though there will be more water vapor in the atmosphere, that doesn't necessarily mean that there will be more clouds in the future.

 

 

But going back to basics we know that for a doubling of CO2, and everything else being equal, then temps should rise by about 1.1 degrees. The IPCC estimates the rise using climate models to be somewhere between 2.4 and 4 degrees due to water vapour enhancment. The amplification of warming by water vapour is a main leg of AGW theory, however it has not been demonstrated in the lab or by any real world experiment to exist. WV is a much more powerful GHG than CO2 and logically if the world is warmer then there should be more WV and therefore the warming should be amplified.

 

First, water vapor is not the main leg of anthropogenic global warming. Second, water vapor doesn't really stay in the atmosphere for a long enough time to contribute greatly to temperature rise. That's why it is seen only as something that has an amplifying effect; it will make the effect of CO2 even bigger than it would be.

 

This is probably the least well understood part of the climate system and the quantities we are dealing with are quite small. The energy figures themselves are large, but the change in the budget is less than 1% since 1850. For example a change (drop) in average annual cloud cover of less than 1% between 1850 and 2000 is quite enough to allow the extra energy into the system to explain all warming since 1850.

 

Since we have been putting CO2 into the atmosphere since 1850 and therefore must have caused some rise in temps this cannot be the only answer, but it is a reason why we sceptics are sceptical of climatologys claims of confidence in their attribution.

 

Where are you getting these figures from??? If you are cite figures, at least post a graph or a table.

Edited June 4, 2012 by Xelloss

[Bored.Wombat]

But going back to basics we know that for a doubling of CO2, and everything else being equal, then temps should rise by about 1.1 degrees.

 

I get about 0.7 K for an increase of 3.7 W/m^2 to a black body at about 288K.

 

(Maybe you're talking degrees Fahrenheit?)

 

The IPCC estimates the rise using climate models to be somewhere between 2.4 and 4 degrees due to water vapour enhancment.

 

No, the IPCC doesn't estimate anything. What the IPCC do is organise scientists to collate the findings of climate science into a report every few years, to help with policy making the world over.

 

The amplification of warming by water vapour is a main leg of AGW theory

 

This is wrong. The main leg of AGW theory would be the greenhouse effect. Water vapour amplification is certainly measured, but it's not a critical aspect of the physics.

 

, however it has not been demonstrated in the lab or by any real world experiment to exist.

 

Which part do you claim has not been demonstrated? That absolute humidity increases when it gets warmer, or that H2O is a greenhouse gas?

 

WV is a much more powerful GHG than CO2 and logically if the world is warmer then there should be more WV and therefore the warming should be amplified.

 

Quite.

 

AGW standard theory also requires that clouds be feedbacks of temperature and never a forcing.

 

I wasn't aware that there was an "AGW standard theory". When I put that phrase into google scholar, I see why:

 

Your search - "AGW standard theory" - did not match any articles.

 

The term doesn't exist in the scientific literature.

 

Can you be a bit more clear about what you are trying to say "requires that clouds be feedbacks of temperature and never a forcing"?

 

This is disputed in the literature by a number of climatologists, but mostly by Dr Roy Spencer who does the UAH satellite temperature series. Put simply, the sats show us that warmer years tend to have slightly less cloud coverage than cooler years so the question being argued is this "Is there less cloud because it is warmer or is it warmer because there is less cloud?" If the standard theory is correct then the first is the case and clouds are a feedback, if the standard theory is incorrect then clouds can be a forcing in their own right and the second part is correct.

 

You are misunderstanding what a feedback is.

 

For a positive feedback, both the first and the second part must be true. This way the temperature increase causes clearer skies, which in turn causes further warming. Hence "feedback".

 

If cloud cover were to be a forcing, it would be controlled by some aspect independent of the temperature (such as GCRs as proposed by Henrik Svensmark) that independently cause a warming (or cooling).

 

Messing the whole question up is the fact that clouds most certainly are a feedback effect from temperature, but can they also be a feedback effect from another factor besides temperature and therefore become a temperature forcing?

 

Yes, it can be a combination. GCRs seem to be responsible for about 3% of the variation in cloud cover, so clouds are mostly feedback, but perhaps (and the literature is mixed on this) partly a vector for GCR forcing. (Note though, that there is not trend in GCRs over the last 100 years, so while they may be responsible for some of the variation in temperature that we are observing they cannot be responsible for the warming trend).

[JohnB]

Well, that'll teach me for trying to offer a simpler description of a complex problem, won't it?

 

Xellos. Yes, I'm sure. All climate models treat cloud as a feedback only. While the effect is measured in the same units as a forcing they aren't viewed a forcing in their own right. The standard theory is that clouds change in response to warming or cooling and therefore their radiative effect changes as well.

 

The term "Radiative Forcing" as used in the IPCC graph refers to the value of the radiative effect expressed in w/m-2, it doesn't separate forcings from feedbacks.

 

First, water vapor is not the main leg of anthropogenic global warming.....

 

First, read what a person writes before responding. I never claimed water vapour is "the" main leg, I said "a" main leg, as in, "one of many". All except the fools agree that "all other things being equal" the temp rise directly resulting from a doubling of CO2 will be about 1.1 degrees C. Climate models used by the IPCC currently use a value of around the 2.4 degree C mark. The extra 1.3 degrees comes from the WV amplification.

 

This amplification is required by warming theory because othwerwise there is simply nothing to get concerned about. If there is no amplification, then of the 1.1 degrees expected we have already had some .8 degrees with out any ill effects. Okay, the ice fairs on the Thames got cancelled and people no longer have to dig themselves out from under 20 feet of snow in the winter, but I view these things as basically positive.

 

There has been no increase in extreme weather, ACE is down to the lowest levels in decades, but rainfall patterns have moved around and changed. Queensland for example is down about 100mm of rainfall per year compared to the 1970s, but the tradeoff here is that we no longer get smashed by cyclones every year all the way down to the New South Wales border. Cyclones in general in the Australian region are much, much milder and less common than in the 1970s.

 

Pretty much what you would expect to happen as the climate changes.

 

Where are you getting these figures from??? If you are cite figures, at least post a graph or a table.

 

It's called basic mathematics. If 300w/m-2 reach the surface as a baseline and the cloud cover (Albedo) changes to increase that figure by 1% then an extra 3w/m-2 will reach the surface. As the IPCC estimates the total change at the surface to be about 2.4 w/m-2 the figures are a rough match.

 

If you think that a change in cloud cover could not have contributed to the warming experienced since circa 1850, could you please link to your cloud cover data for the first half of the 19th Century? I thought not. The idea is simply there to point out that it may have contributed some of the warming since 1850.

 

Climate modellers disagree with the idea because that would make clouds a forcing in their own right and all models treat clouds only as a feedback to temperature. I disagree with this on the basis that clouds can change in response to things other than only temperature which makes them a feedback for the other factor and also a forcing for temperature.

 

Wombat.

 

I get about 0.7 K for an increase of 3.7 W/m^2 to a black body at about 288K.

 

AFAIK Earth isn't actually a black body. The generally accepted figure is 1.1 degree C for the pre feedback change due to a doubling of CO2. If you don't believe me go ask at realclimate.

 

No, the IPCC doesn't estimate anything. What the IPCC do is organise scientists to collate the findings of climate science into a report every few years, to help with policy making the world over.

 

Hair splitting. By comparing the published literature with travel brochures and some high school essays the IPCC estimates what they think the values will be. More to the point, they will simply choose what they reference so that it shows the answer they want. That the recently "on hold" and possibly "retracted" paper by Gergis et al is cited by the IPCC before it was even published is a case in point.

 

This is wrong. The main leg of AGW theory would be the greenhouse effect. Water vapour amplification is certainly measured, but it's not a critical aspect of the physics.

 

This is another example of not reading what people actually write. Please learn the difference in connotation in the usage of the word "a" as opposed to the word "the". At best your comment is a strawman, at least in the first part. As to WV amplification actually being measured in the climate system, please post a link to the paper that demonstrates this. Don't worry, I won't hold my breath. The amplification effect has not been measured, it has been estimated by climate models. And as much as it galls some people, the output of a model is not "real world data" or "measurement".

 

I wasn't aware that there was an "AGW standard theory". When I put that phrase into google scholar, I see why:

 

Your search - "AGW standard theory" - did not match any articles.

 

The term doesn't exist in the scientific literature.

 

Can you be a bit more clear about what you are trying to say "requires that clouds be feedbacks of temperature and never a forcing"?

 

More hair splitting. The physics and theories behind the AGW theory are built into the assumptions of the climate models. Some of this is straight physics and maths and some of it is assumption. One of the assumptions built into climate models is that cloud cover only changes as a result of changes in temperature. Hence clouds act as a feedback for a temp forcing but not as a forcing in their own right.

 

If however, Henrik Svensmark is correct with his Cosmic Rays ideas the situation changes dramatically. Changes in cloud cover would now become a reaction to changes in cosmic rays (so a feedback response for GCRs) but would be a forcing effect on temperature.

 

You are misunderstanding what a feedback is.

 

For a positive feedback, both the first and the second part must be true. This way the temperature increase causes clearer skies, which in turn causes further warming. Hence "feedback".

 

If cloud cover were to be a forcing, it would be controlled by some aspect independent of the temperature (such as GCRs as proposed by Henrik Svensmark) that independently cause a warming (or cooling).

 

Which is what I said and repeated above. I'm quite, quite certain of what the difference between a feedback and a forcing is. I was trying to keep it simple because the tone of the OP suggested a lack of knowledge of the climate system. In going for simplicity I have to drop off some of the detail.

[SeekingLeviathan]

John B.

 

In the various comments you have made it sounds as if you believe that climate change is taking place (as it always is and always will be right?), but that you do not believe it to be caused by or at least greatly affected by human beings. Sorry if I'm making assumptions, and feel free to correct me if I'm wrong. Are you suggesting that human beings cannot, and do not shape the planet around them? We could probably level the whole thing if we tried hard enough. Yet, you are suggesting that our burning of fossil fuels couldn't possibly be to blame for rising temps and sea level?

"In 2004, the United States consumed about 140 billion gallons of gasoline, more than any other country. Consumption averages about 380 million gallons of gasoline per day in 2004 and is reaching 400 million gallons per day in 2006."

Source

: U.S. Department of Energy Office of Science

more than any other? yes, but that is still just one country, one year, and one type of fuel.

Here's a link to another more recent article

http://news.discover...ate-110627.html

"While there is uncertainty in the measurements--researchers estimate between 0.13 and 0.44 billion metric tons per year, with their best estimates between 0.15 and 0.26 billion tons--even the highest end of the range is dwarfed by anthropogenic emissions of 35 billion metric tons in 2010."

that's CO2 output from volcanoes vs. human beings

.

I just don't understand why you are willing to accept that these "natural" factors (such as volcanic activity) can account for climate change, but the irresponsible activities of 6,894,594,844 primates (with guns) cannot.

Edited July 8, 2012 by SeekingLeviathan

[JohnB]

Hi SeekingLeviatan. It looks like you registered just to ask that, so I'm pretty chuffed. Welcome to SFN and I hope you enjoy it here.

 

Your questions are fair and reasonable but slightly over state the case. (In the case of volcanoes, you're very wide of the mark.)

 

So let's get the volcano thing out of the way. Even though recent research has virtually tripled the estimate for volcanic output of CO2 this makes little difference. The output of human CO2 emissions are far greater. The major effect of volcanoes on the climate is probably more from ash and dust cooling the planet rather than the CO2 emissions warming it.

 

Compared to the actual annual flux both natural and man made emissions are quite small. For example a change of less than 1% in the flux would result in the increase in CO2 that we have seen since 1850 or so. We also know from the long term records that CO2 increases lag behind warming by about 1,000 years and the last warming period was 1,000 years ago. It is possible that some of the increase in CO2 since 1850 is natural. The vast majority however should come from the burning of fossil fuels.

 

The reason for kicking off with volcanoes is simple. Excepting for periods of prolonged and well above average volcanic activity, they pretty much don't do anything to the climate. So it's not a case of believing that natural factors "such as volcanic activity" have an effect and man does not. Except for their cooling effect, volcanoes aren't worth considering.

 

However, a shift in cloud cover of less than 1% would explain all the warming since 1850. Can you show that cloud cover has not changed by less than 1% in the last century and a half? Of course not. The natural forcings aren't as small as you think, the energies in nature dwarf the best efforts of mankind.

 

The question is about attribution. Since 1850 or so there has been warming of about .7-.8 degrees globally and this roughly equates to about a 2.4 W/M-2 change in radiative forcing. How much of this increase is from CO2 and how much from land use changes, solar influence, cloud cover, etc? This is the question. It's a vital question because if there is a problem then we should be spending money in the right areas to actually do something about solving the problem. Money is limited and should be spent where it will have an effect beyond giving somebody a warm fuzzy.

 

Attribution is also part of the answer about sea levels etc. When it warms, sea levels go up, when it cools they go down. (Generally speaking) SEa levels going up and ice melting are symptoms of a warming world regardless of the cause. Just because they happen does not in any way go to prove the actions of man are responsible. Forest fires start from both natural and human causes. The existence of a fire is not proof that there was an arsonist. Far too often in this debate "proof of warming" is put forward as "proof of attribution". A ssoon as someone mentions ice, sea levels or bloody polar bears then they are conflating the two.

 

To illustrate let's assume that there are only three factors involved; Natural forcings, CO2 and Land use. If natural forcings are responsible for .7 of the .8 degrees of warming, then spending money on CO2 reduction will have no real long term benefit will it? Similarly if it is land use changes then messing with the CO2 emissions will not have a useful effect. Only if CO2 is the major driver and it is going to be a problem, do we need to do anything at all.

 

So is warming a problem? We have had some .8 degrees in the last 150 years or so. The growing season is longer, people don't get to skate on the Thames any more, winters are milder. Despite what you may have read in the MSM there is no documented increase in any form of extreme weather. Big storms, cyclones and tornadoes are down. Frankly I'm not seeing any problems here, what ones do you see?

 

Will warming be a problem in the future? So far the only reason to say yes are the predictions of the models and they are not properly tested and verified. As I noted in another thread the climate models are about as accurate as having a monkey throwing darts. This level of accuracy leaves me very underwhelmed and with little inclination for concern. The doomsday predictions come from the fact that models consider water vapour to be an amplifier, changing the direct increase caused by a doubling of CO2 from about 1.1 degrees to around 2.4. This amplifying effect has not been observed in either the lab or nature and except for the model assumptions there is no reason to believe it exists at all. If the amplification idea was correct, then we should have seen about 1.6 degrees by now, so where is it? We are on track for slightly less than the basic figure of 1.1 degrees for a doubling of CO2 and as I pointed out above this has come pretty much without a downside.

 

In a way this answers your final question;

I just don't understand why you are willing to accept that these "natural" factors (such as volcanic activity) can account for climate change, but the irresponsible activities of 6,894,594,844 primates (with guns) cannot.

Because the natural forcings are so vast and powerful that they can easily change the climate but for the anthropogenic theory to work you need to have magical, invisible amplification factors that nobody has ever seen and energy has to be ably to "hide" in the system for decades without being detected so that future warming can be "in the pipeline". For climate, I believe in science not magic. Do you realise that everybody has been running around like headless chooks over .8 degrees in a century and a half when nature could plummet us into near ice age conditions in under 30 years? Each winter colder than the one before, the snow coming earlier and staying longer until it doesn't melt at all. and you know what? If it happens then the period 2000-2010 will still be the "warmest on record".

 

I've posted this graph before in an attempt to get people to understand a bit of perspective on this.

 

 

Even if man was responsible for all the warming since 1850, his bit is the little uptick on the very right hand end. Compare that to what nature can do all on it's own without any help from us at all. Extreme or unprecedented aren't the right adjectives here, small, tiny and boring are.

 

Does that help? Or clear things up a bit?

 

Frankly, if I have a nightmare on climate it is this. That the apocalyptic predictions are right and the cause is land use changes. If this were the case then the only way to change the future would be to exterminate about 3/4 of the planetary population. This is not a pleasant prospect.

[zapatos]

JohnB,

 

Great response. Very logical and clearly articulated.

 

It appears to me that scientists generally believe that man is a large contributor to climate change. If your evaluation of the situation is correct, what is your explanation for the rather strong difference of opinion between them and you (and others of course)? For example, do you feel they are misinterpreting data, or have a social/political agenda?

[JohnB]

Zapatos, I think that there are many reasons involved. One problem in the climate debate is that people are constantly trying to reduce it to one factor or another while in truth the debate, like the climate is extremely complex.

 

What scientists "generally believe" depends on their field. Unless you check the actual figures (and most don't have time to) then you believe what the people in the field tell you. In the same way you "take the word" of the aero engineer that the plane will fly or the structural engineer that the building will stand up. So what scientists generally believe is worth no more than what joe bloggs in the street believes. Unless you have looked at the data and methodology involved to see for yourself then you are just echoing the opinion of others.

 

An often quoted figure is that "97% of scientists believe" but this is a lie. By now, anybody using that argument is perpetrating a known falsehood and is lieing. A bit blunt perhaps, but I'm tired of being polite about people with poor moral compasses. The figure comes from a 2009 internet survey that was sent to 10,257 Earth scientists. Of that number only 3,146 bothered to answer the two question survey. This gets further cut down to the money shot of;

In our survey, the most specialized and knowledgeable respondents (with regard to climate change) are those who listed climate science as their area of expertise and who also have published more than 50% of their recent peer-reviewed papers on the subject of climate change (79 individuals in total). Of these specialists, 96.2% (76 of 79) answered “risen” to question 1 and 97.4% (75 of 77) answered yes to question 2.

 

(Emphasis mine.)

 

75 out of 77 agree out of 3,146. What is actually saddening is that the two questions were;

1. When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?

2. Do you think human activity is a significant contributing factor in changing mean global temperatures?

 

And only 90% said that temps had risen. Since "more than 90%" of respondents had PhDs, this is not a good figure, it should have been 100%. The thing here is that most sceptics, including myself would answer "Risen" to Question 1 and probably answer "Yes" to Question 2, depending on your definition of "significant". If you think man is responsible for 10% of the rise, then that may be a "significant" percentage to some but not others. An absolute garbage of a survey. For those interested the survey itself is here.

 

A similar stunt was pulled in 2010 by Anderegg et. al. who starts with 1,372 people and pares it down to get the result desired. I especially like that "expertise" is judged by the number of papers written and nothing about cites or actual quality of research.

 

Another reason for the apparent widespread acceptance is funding. Sorry, but if the political money is on a topic then you get funding if your research is deemed "relevent". From acne to shark attacks, link it to "Global Warming" or "Climate change" and you're on a winner. Numberwatch from the UK has a great Warmlist of things linked to "Global Warming". Yes even "Witchcraft Executions" are on the rise due to "Global Warming". I was quite pleased that the harder sciences had managed to keep some modicum of decorum but in May this year came the classic paper; "X-ray emission from high-redshift miniquasars: self-regulating the population of massive black holes through global warming." They even manage to get the term "Climate Change" into the abstract. And so we have another paper and group of authors for Naomi to add to her list of "believers".

 

The rule of government funding is to get it you need to find a problem. Then to continue to get it you need to find that the problem is worse than you thought and is likely to get bigger over time and so will require much more research. Ignore climate for a minute. Let's say a researcher is asked by a government dept to investigate the problem of juvenile graffiti in the central city. He gets funding for a year. If at the end of the year he comes back and says "There is no problem" he's out of work, but if he comes back with "There is a problem and more research is needed to identify the causes" then he has a job for life. This isn't to denigrate anybody, it's just how the system is set up and how the game is played. In a similar fashion pay rates in government jobs are generally rated by how many people work under you. So the bigger you find the problem to be, the more researchers are needed to investigate it and the higher the pay grade you get as the "Boss". And the money is not small potatoes either. 15 years ago there was little money for the climate modellers to buy new toys with, last year (IIRC) in the USA they got some $600 million. Paleo-climatologist Michael Mann picked up some $2 million to study "mosquito bourne disease vectors" which isn't bad for a bloke whose expertise is in tree rings.

 

We'd all like to believe in the wonderful independent scientist doing his job for the sheer joy of discovery, but like Joe Bloggs the factory hand, there are bills to pay and a family to keep housed and fed. Reality bites.

 

You're also given the impression by the recurring use of the meme that "thousands" are responsible for an IPCC report. The number is actually much lower. It should also be remembered that the number of reviewers etc is actually irrelevent as the Lead author does not have to modify the text to respond to reviewers comments and can simply "reject" the reviewers complaint without explanation. The supposed "mistake" of Himalyan glaciers disappearing by 2035 was actually noted as wrong by reviewers in all drafts and the comments were ignored.

 

IPCC WG1 Chapter 2 which deals with changes in radiative forcings has an impressive list of authors, contributing authors etc and is responsible for the idea that solar variance is very low and modern warming cannot be attributed to solar influences. But how many of those august personages are actually qualified to judge solar forcings? One actually,the Lead Author Dr. Judith Lean. I'm not suggesting impropriety here, but it certainly does seem strange that the only person qualified to comment on solar forcings happens to choose the value given by the paper that she co-wrote. Hers is the only paper BTW, that is remotely near the low value of .5W/M-2 for an increase in solar forcing, all others put it at between 3 and 10 W/M-2. Out in the real world we have things called "Conflict of Inerest Policies", the IPCC has them too but has decided that it will be too hard to actually impliment them before, say, maybe, AR6 in about 2018.

 

We have to remember that each area depends on other areas getting their bit right. If the solar forcing people don't give the correct numbers to the modellers, then the modellers models won't work properly or will give very wrong answers. But would the modeller know it was wrong? Possibly not as they would be reasonably sure that their model was correct and are trusting that the figures given to them by others are also correct. So if an area is gven the wrong data it is easy for them to wander down the wrong path, after all they are only following where the data leads them.

 

Climatology also makes a number of assumptions and there is no way to prove that these are true. Like cloud cover changes only being a response to temperature changes. Those outside the field are neither told or know that this assumption istenuous at best and totally unproven.

 

Bluntly, scientists outside the field believe that scientists inside the field are playing by the rules of normal science. This simply isn't true. Have a look at the "Denizens" list over at Judith Currys site and see the various fields that people are from and why they became sceptics. Maybe, not being a scientist myself my view is too black and white but I can only go with what I know. Science follows the rules and ideas of Popper and Feynmann, pseudoscience does not. Climate science does not follow the rules of Popper and Feynmann, data is not open and shared. Should it really require legal action to find out which temperature stations were used as the data for a paper? Data is cut, modified and hidden. They aren't playing by the rules.

 

And there are advocates. These are "scientists" who will falsify data and do anything else they can to "help the cause". And before anybody gets on their high horse demanding "proof" I will remind them that to deny my comment is to claim that scientists as a group are incorruptable. A percentage of all people are corruptable, scientists are a group and therefore a percentage will be corrupt. Deal with that. It's rather interesting reading the papers on curruption in science. Something over 1% of scientists admit to falsifying data themselves but more than 17% claim to know somebody else who has done it. Somebody is telling porkies.

 

If the advocate is in a position to supply data to others........

 

We also have confirmation bias and plain old peer pressure. Try to publish against the "Consensus" and be prepared to cop a flogging.

 

There is also the propensity in climate science to mistake a model for reality. Models are important in most fields of science this is true but reality is the ultimate arbiter. But in climate science they call model runs "experiments" and treat the outcome as data as real as that collected by physical instruments. Quite often if the models disagree with the instruments it is used as an argument that the instruments need "recalibrating". This gave us the Sherwood paper a couple of years ago that claimed that the groundspeed of a weather balloon was a more accurate measure of temperature than the thermometer carried by the weather baloon.

 

But people outside the field who haven't read the literature don't know that, do they?

 

I think that there is also a political component. Before the fall of communism there were plenty of communists around, holding rallies and complaining about American Imperialism and demanding global financial restructuring, rich nations giving to the poor, that sort of thing. where are all those people now? When communism fell did they all change their minds and go "Gee, I guess capitalism is pretty good" and started businesses? Nope, many joined and now quite control the Green movement. We are talking about people who took lessons in journalism from Pravda. Their goals have not changed, just the words. Now it's the evil CO2 that must be destroyed not the Great Satan America. If people think I'm wrong in this then do tell, where did they go? Is it just an accident that the language and aims of the environmental movement are so similar to the old style communists?

 

America seems to be very easily split on political lines so it wouldn't surprise me if quite a number of people either believe or disbelieve simply because Al Gore pushes the idea. He's an ex Democrat VP and so must be telling the truth for some and will be viewed automatically as a liar by others.

 

I should include the statements by august bodies somewhere about now. Frankly, so what? That this body or that agrees is nothing more than "Appeal to Authority" or "Appeal to Popularity" and is also untrue. Those bodies did not put it to a vote of their members, the Board made the statement. Assuming a standard quorum it wasn't the 6,000 or whatever members of the American Meteorological Association that made the statement, it was 4 members of the Board. Note that people have resigned from organisations in protest and others have demanded a vote.

 

Also there is ego. Anyone who reads history will see a common theme running through our societies. We don't want to be victims of the mindless forces of nature, we want to believe that we are in control somehow. From early pagan rites for harvest fertility to rain dances to praying in a church or temple for rain, we want to believe that we are in control and are not insignificant little specks that can be wiped out in an instant. Note the words being used today "If we don't do something the climate change will become uncontrollable and....". Since when was it actually "controllable"? When did we learn to control the climate? I must have missed that memo.

 

So there are many reasons for accepting the "Consensus" and I think high on that list is people simply accepting what is said and not looking at the nitty gritty themselves and ego.