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JMurphy at 08:47 AM on 21 August 2010Climate's changed before
cruzn246 wrote : "Here is the page for the solar activities" As well as looking at the picture, how about reading the relevant WIKIPEDIA page for context : The scientific consensus is that solar variations do not play a major role in determining present-day observed climate change. Also, the increase of temperature is a little more than you suggest : The updated 100-year linear trend (1906 to 2005) of 0.74°C [0.56°C to 0.92°C] is therefore larger than the corresponding trend for 1901 to 2000 given in the TAR of 0.6°C [0.4°C to 0.8°C]. The linear warming trend over the last 50 years (0.13°C [0.10°C to 0.16°C] per decade) is nearly twice that for the last 100 years. The total temperature increase from 1850–1899 to 2001–2005 is 0.76°C [0.57°C to 0.95°C]. Summary for Policymakers Finally, this picture (also from WIKIPEDIA) seems to disagree with your assertion about temperatures since we "snapped out of our last ice age" :
Holocene Temperature Variations
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TOP at 08:32 AM on 21 August 2010The Strange Case of Albert Gore, Inconvenient Truths and a Man in a Powdered Wig
Dave Horton Actually the denier movement is more religious. This is because of certain presuppositions that differ on either side of the argument. Phil Political agendas translate into laws and court decisions. In the early 60's psychiatric opinion was that the bible and prayer in schools was harmful to some student's psyches. The Supreme Court used that "science" to overturn 150 years of precedent and history. The Scopes trial got evolution pretty close to being the codified into law in many places. At least you can't teach or even discuss opposing viewpoints. Interestingly in this example the science has changed so much from what Darwin wrote that he would be laughed out of any current discussion on the topic. Generally in these kinds of arguments if you don't get down to the presuppositions and how either side is attempting to change them you can't really see what is at stake. -
nigelj at 08:30 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Theendisfar What basic thermodynamic problems? Exactly and precisely? What data has been missrepresented? What conjecture has been presented as evidence? One example will do. Im intrigued. -
CBDunkerson at 08:23 AM on 21 August 2010How climate skeptics misunderstand past climate change
Eric, no. None of that makes ANY sense. Dry ice: Presumably here you are talking about cloud seeding... though you didn't mention any clouds to be seeded (water vapor is not synonymous with clouds). If you drop dry ice into clouds the chances of precipitation increase. That precipitation would then cause a temporary local cooling effect. No 'extra forcing' is then required to raise the temperature again... water vapor will naturally return to the atmosphere in very short order provided there is a water source nearby (such as the recently fallen rain or the surrounding air for instance). So no... the air does not remain dry after rainfall. All of which is completely irrelevant because you are talking about a short term localized process rather than long term global averages. So one city gets rained on and cools slightly during part of one day.... this is MEANINGLESS on a global scale. Look at it this way. New York City and Miami are both right on the Atlantic ocean. So why is the absolute humidity of Miami on average alot higher than that of New York? Because Miami is closer to the equator and thus on average warmer... which allows more water vapor into the air on more days. If the entire planet gets warmer then that same effect takes place worldwide. How is this not obvious? The connection between temperature increase and atmospheric water vapor which you wrongly state does not exist is known as the Clausius-Clapeyron relation... which has been around since the 1830s. -
theendisfar at 07:46 AM on 21 August 20102nd law of thermodynamics contradicts greenhouse theory
To whom it may concern, Well put, thank you :) -
theendisfar at 07:41 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
KR, I wasn't accusing you of anything Sorry, I wasn't clear. I claim to be able to refute AGW as to having repeatable tests, was just asking that you provide links to it (you did, thanks:) rather than rely on credibility. All to often, we skeptics get 'credibility' tests that are truly moot IMHO, I claim no credibility save what may rise from this exercise. I did, however, ask if you thought the majority of climate scientists are lying, yes or no - you didn't answer that question. :) Calling someone a liar could be considered ad hominem, so you got a carefully crafted answer :) Sorry about that. Without going into motivation, Yes, I think many climate scientists are purposely misrepresenting conjecture as empirical and repeatable evidence quite frequently using subjective terms to provide wiggle room and plugging conjecture into GCM's, passing the predictions off as reliable. Most climate scientists, IMHO, cannot see the forest for the trees and truly misunderstand thermodynamics, or at least are not properly representing/considering Convection and Evaporation in their studies/calculations, especially models. Whether these folks are lying or not makes little difference as to whether they are providing valuable arguments/tests that result in validating conclusions. I believe I can show that they are not. Empirical evidence that we're causing global warming is right on topic, so I'll begin there if you have no objections. The video you linked is on topic for the above link so I think it should be okay to discuss there. Thanks for the challenge, many of the arguments are redundant or can be falsified in chunks, but I agree it will take some time, but I'm confident we have plenty of time before climate disaster strikes :) Pick this up this weekend in the other thread, it's 5:30 here and time for a beer.Moderator Response: Thank you for recognizing the relevance of other threads, and for promising to read them and watch their video before commenting more. Also thank you for your civil tone even when making strong claims. (I want commenters to know that it is indeed possible to do those things, and that everyone appreciates effort to follow the rules.) -
Eric (skeptic) at 07:38 AM on 21 August 2010How climate skeptics misunderstand past climate change
CB, for the first question let me give a simpler example. Take an area with high temperature and humidity (e.g. 80 and 75%) and drop tiny grains of dry ice uniformly over it. The moisture will precipitate out and the temperature will drop. Apply forcing to warm the area back to 85. At that point it will be warm and dry perhaps 30-40% RH. Or warm to 85 without precipitating and the RH will be approx 65%. The only difference in the two scenarios is weather, but one has much lower RH and the rest of the water is in the river (where it flows away without evaporating). There is no physical law of any sort that favors one scenario over the other, or any law that requires balancing scenarios (more evaporation to balance more condensation). Weather simply doesn't balance. So as the world warms, there is no reason that the RH would stay constant unless the weather stayed precisely the same on a globally averaged basis. The problem with the simple math is that there is no physical reality to base it on. There is no global physical mechanism that results in a particular percentage increase in WV for an increase in temperature. It mostly depends on weather as in the above scenarios. Even though there will be more evaporation, it is unevenly distributed and unevenly condensed and precipitated giving an unknowable relationship between the global average temperature and total amount of water in the atmosphere. In the extreme case I merely need to add more dry ice and more forcing to keep the temperature higher with lower RH. -
2nd law of thermodynamics contradicts greenhouse theory
Regarding molecular collisions and heat distributions: At surface temps and pressure each air molecule (CO2, O2, N2, argon, etc.) collides with another molecule roughly one billion times per second (thanks, Ned). The relaxation time for an energized CO2 molecule is 100ns or more, depending on the vibrational state. That means that an IR energized CO2 molecule has on average a minimum of 100 collisions with other molecules before it has a chance to emit IR. CO2 _will_ maintain thermal equilibrium with the rest of the air mass, whether the air mass as a whole is cooling or heating by IR. (Or conduction, convection, latent heat changes, etc.) -
nigelj at 07:32 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Isnt catsotrophic heating a bit loaded? Or a straw man? It paints a picture of the imminent destruction of every lifeform on earth and nobody is predicting that. If the petition had asked do you agree we are causing climate change that could cause serious problems for many countries would 32,000 have said no? Not likely now is it. And thanks to skepticalscience for a great site. -
The Past and Future of the Greenland Ice Sheet
BP, DappledWater - fair enough, I appear to have been quite incorrect about the temperature distributions. However: What I'm reading on the Holocene temperature distributions is that the Northern Hemisphere was much warmer, while the Southern Hemisphere was considerably colder. What I've found here (Vinther et al 2009) and here (Kelly 2009?) seem to indicate that the Greenland ice sheet receded 10's of kilometers during the Holocene, with associated thinning and mass loss. Sea levels rose considerably over the Holocene, but only to present values - perhaps the remainder remained locked up in the (much colder) Antarctic? The paleo data on Greenland ice recession certainly indicates some sensitivity to temperature. -
The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar - I wasn't accusing you of anything, if you read my post; I was pointing out that many organizations promoting doubt in climate change have financial incentives to, well, make stuff up. As to those in charge of various gov't agencies, well, yes, sometimes they do modify the message for political goals. The last Bush administration was notorious for that - political appointees rewrote major portions of scientific reports to dilute the data regarding climate change. The scientists who wrote it, however, objected quite loudly. A number resigned in a very public fashion. I did, however, ask if you thought the majority of climate scientists are lying, yes or no - you didn't answer that question. As to repeatable methods and conclusions? Global warming is still happening Emperical evidence that we're causing global warming CO2 emissions CO2 effects (evidence disproving 'saturation') Greenhouse effect (lots of references) Greenland/Antarctic ice loss Sea level rise Consensus and paper counts, AGW and counter-AGW Tons of other evidence, with links to the various references I believe that provides a cross section of ~60 papers total, which various folks indicate are representative. If you want to invalidate all of those (the vast majority of climate science, in fact), be my guest. It might take a while, though. I would actually suggest you start with the last link, the video, and look up the web page he provides at the end with all the references he used. It's a good review of the various lines of evidence in the field. -
Rob Painting at 06:48 AM on 21 August 2010The Past and Future of the Greenland Ice Sheet
KR - It's not often I agree with a skeptic, however BP is correct about the Arctic being warmer during the Holocene Optimum, due to the Earth's axial tilt being greater than now, and it's closest approach to the sun coinciding with the Northern Hemisphere summer. Globally, however it was much cooler than present. I'll track down a paper on it, I've read. -
Anne-Marie Blackburn at 06:30 AM on 21 August 2010What caused early 20th Century warming?
Thanks Phil - I will think about rephrasing those sentences, especially the first one. miekol, to add to Phil and scaddenp's points, you might be interested in reading this article which tackles the human fingerprint on climate change. It shows quite clearly why scientists have concluded that greenhouse gases are most likely to blame for the warming observed since the 1970s. -
scaddenp at 06:29 AM on 21 August 2010What caused early 20th Century warming?
Miekol - you do proofs in mathematics, not science. Scientific "proof" is a much weaker thing. Maybe tomorrow some new hypothesis will be able to explain all our observations in a completely different way. But thats not the way to bet - at moment I'd say evidence that current model for climate is basically correct is overwhelming. -
theendisfar at 06:25 AM on 21 August 20102nd law of thermodynamics contradicts greenhouse theory
To whom it may concern, Forgive me, but this post is ripe with errors, from my understanding of physics. Would you prefer I ask questions regarding the supposed errors, or would you prefer I explain my reasoning outright?Moderator Response: Whichever is shorter. -
theendisfar at 06:21 AM on 21 August 20102nd law of thermodynamics contradicts greenhouse theory
To whom it may concern, "This absorption is due to trace gases which make up only a very small part of the atmosphere." So are you saying that IR from the surface heats the GHG's and then they transfer the energy to the primary gases N2 and O2? If so, how is that transfer made? Conduction from molecules colliding?Moderator Response: Yep. -
theendisfar at 06:19 AM on 21 August 20102nd law of thermodynamics contradicts greenhouse theory
To whom it may concern, "This is possible only because most of this radiation is absorbed in the atmosphere, and what actually escapes out into space is mostly emitted from colder atmosphere." Are you stating that the primary method of transferring energy from the surface to the Troposphere is via radiation absorption rather than via conduction? When you say 'colder', are you referring to a region or a temperature? -
cruzn246 at 06:18 AM on 21 August 2010Hockey stick is broken
And that makes this time period......the 26th warmest period in the Holocene era. Big deal.Moderator Response: See the Argument "It's Not Bad," also titled "Positives and Negatives of Global Warming." -
CBDunkerson at 06:14 AM on 21 August 2010How climate skeptics misunderstand past climate change
Eric #33: "Where I disagree is that "as global temperature increases the global total amount of water vapor does as well". You are trying to make a global case for a local effect which is not necessarily true and will become false at some level of warming." I'm still not following you. In what way is global warming a "local effect"? If temperatures increase globally then water vapor increases globally... you say you dispute this seemingly obvious fact, but provide no explanation WHY. Also: "what is the physical process that limits the feedback when WV increases warming and warming increases WV" Are you asking why positive water vapor feedback does not cause 'run away' warming all by itself? That was already explained to you in the '0.5 increase' bit. Simple MATH shows why the positive feedback effect is limited. Again, suppose that a global average anomaly of +1 C from CO2 or some other forcing causes a global average water vapor increase sufficient to introduce another 0.5 C of warming from the water vapor... in short, an additional 50%. Well, then 50% of that 0.5 extra is 0.25 and 50% of that is 0.125 and so forth. If you add these fractions up you will see that the result gets closer and closer to 1 C... +0.99999 repeating to infinity. Thus, the limit you are looking for is MATHEMATICS. So long as the water vapor feedback for 1 C of external warming is itself less than 1 C there will always be a finite limit to the feedback warming. As to when weather starts to limit water vapor feedback... NEVER. Yes, rainfall takes water out of the atmosphere... and evaporation puts it back in. In a warmer world both effects are increased, because the total amount of water the atmosphere can hold increases with temperature. Your claim that concentrating water vapor in one hemisphere would somehow cause net global cooling has no basis in science and no explanation that I can see in your post. As you describe it the northern hemisphere, magically devoid of water vapor, would cool drastically... but the southern hemisphere, now holding double the previous global total, would heat up far more than the northern had cooled. Net effect... average global temperatures would increase. -
MichaelM at 06:14 AM on 21 August 2010Waste heat vs greenhouse warming
If you read the last paragraph of section A of the link you posted you will see that figure 2 is in local time and the moon graph represents a lunar diurnal period (lunar day) of 29.5 (earth) days i.e 5 'hours' is just over 6 days. -
cruzn246 at 06:09 AM on 21 August 2010Is the sun causing global warming?
Sunspots don't tell all. -
theendisfar at 06:09 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
KR, I worked for the CDC for a number of years and I can tell you straight forward that many scientists, gov't especially, are paid to deliver a message. Many times it is not the scientists themselves who are lying, but rather those in charge of communications. H1N1 is a perfect example, hundreds of millions of $'s were funneled into it because the 'threat' was completely overstated. I was there. While drug companies gained a great deal, so did the Gov't and it's employees. To be perfectly clear, "I am accusing 97% of Climate Scientists, who support AGW because of the increase of CO2 since the end of the Little Ice Age, of doing less than acceptable science including (but not limited to); research, testing, and/or communication of the results." I have little interest in a scientist's motivation outside the fact that people who cannot defend the AGW argument keep pointing to a lack of financial motivation. Gov't and Grant sponsored scientists have jobs right now, working to falsify the need to have them is the last thing on their minds. Tenure and grant money is a dangerous combination, that is where Peer Review and grant sustainability meet. Consensus is quite valuable here. Should there be any motivation in science other than being able to repeatedly be able to arrive at the same result no matter who pays you? As to repeatable methods and conclusions, can you link to one so we can discuss there? Forgive my Skepticism, I come Missouri, the 'Show me State' and I claim to be able to critically evaluate them. And don't just call me liar, submit your repeatable evidence and I'll prove whether or not I am myself. -
Phil at 06:03 AM on 21 August 2010What caused early 20th Century warming?
miekol @7 It is not a proven fact that nothing can go faster than the speed of light, or that E = mc**2. But the evidence strongly suggests that these statements are correct. -
cruzn246 at 05:57 AM on 21 August 2010Climate's changed before
Well Christ man it is a continuation of a discussion. Where do I have to go to discuss electromagnetic absorption? I guess you just want to split up everything so there is no real big linking pool of info.Moderator Response: The big list of Arguments is the linking pool of info. There is also a "Newcomers Start Here" page linked in the left side of this page. -
johnd at 05:26 AM on 21 August 2010NASA-GISS: July 2010-- What global warming looks like
JMurphy at 05:14 AM, it should be self evident, records are not the norm. Good to stir the emotions, and food for the politicians. -
The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar - when I commented in #29 about my brother, he was specifically paid to make stuff up, harp on minor contradictory opinions, overemphasize uncertainty, and in general to lie about what the science and the scientific consensus were. There's a great financial incentive for industry to do so - if they're making $$money$$, they don't want to change gears. Now, if you're accusing the 97% of climate scientists (whose consensus opinion is that AGW is happening, and will have large effects on all of us) of lying, please be clear and say so. I will, however, point out that they really don't have a financial incentive to do so - every academic institution I know of balances pay for PhD's with incoming grant money so that there is no difference in their income. And I don't see many university professors driving new BMW's! As to "repeatable methods and conclusions" - we have them. That's why 97% of people in the field agree on the conclusions of AGW! There are always always a few people with vested interests in other conclusions, not to mention looneytoons who think it's the Little Green Men or something (no insult intended to LGM, mind you!). But the repeatable science has convinced the vast majority of people who are able to critically evaluate it. -
JMurphy at 05:14 AM on 21 August 2010NASA-GISS: July 2010-- What global warming looks like
johnd wrote : "However for the greater part of the planets surface there are no means to measure precipitation, nor any population to be effected if an extreme rain event occurs, therefore it requires a big leap of faith to draw overall conclusions based solely on what events make it onto front page news or into the record books." This sounds like another so-called skeptical tactic to wish-away inconvenient facts, the way that satellite temperature readings have suddenly fallen out of favour, due to their inconvenient parity to ground-based readings. However, do you feel there can possibly be any records that can possibly be trusted ? E.G. How can we determine the fastest man over 100m ? Someone running for the bus in South Africa, say, may be able to run faster. What about those rainfall records posted by Argus ? Should we ignore them because there might have been more and heavier/faster downpours over the sea, up a mountain or in a forest - unseen, of course. First man on the moon ? The Chinese may have got there first, on the dark side, but it was a disaster so they are keeping quiet. Can that be denied ? Can we be allowed to have any records for anything, do you think, or should we deny them all ? -
cruzn246 at 05:14 AM on 21 August 2010Climate's changed before
The basic stuff about changing Venus' atmosphere is just common sense stuff I derived from taking meteorology. Yes, I took a class. The 2% worldwide average is from the same place. I know in any spot on earth it ranges from near zero to 4%. I just averaged it. It could be 0.5 either way, but it would still be at least 37 times more by mass than CO2(0.04%) at lowest average values (1.5%). -
cruzn246 at 05:06 AM on 21 August 2010Climate's changed before
Look up the stuff for Venus and the earth yourself. It's easy to find. I derived my temp and sun activity from easy to access sites. Here you go. The temp data was derived from ice cores. I took the temp graph and blew it up to capture the Holocene maximum and other features. http://www.geocraft.com/WVFossils/last_50k_yrs.html Here is the page for the solar activities http://en.wikipedia.org/wiki/File:Carbon14_with_activity_labels.svg -
JMurphy at 05:05 AM on 21 August 2010What were climate scientists predicting in the 1970s?
RSVP, you're nearly there. Compare the two sentences you part-quoted, with your sentence here : Even the current article explains that thirty years ago, the science indicated we were possibly heading to an ice age Do you see what careful reading can allow you to discover ? To help, it's the difference between 'some scientists' (which is why I highlighted those words previously, in fact) and 'the science'. Yes ? -
JMurphy at 04:59 AM on 21 August 2010Climate's changed before
cruzn246 wrote : "Bottom line. Climate changes and I am not alarmed. Bottom line is assertions and beliefs are worth nothing. If you have any linkable evidence for even half of the figures you posted concerning temperatures, please let us see them. -
johnd at 04:50 AM on 21 August 2010NASA-GISS: July 2010-- What global warming looks like
Argus at 21:12 PM, the perception of whether a natural event is extreme or not appears to be increasingly driven by the emotional impact it has on those who experience it first hand, or those who observe it from a distance. As you noted there are always other contributing factors which need to be taken into account so that the human tragedy and the natural event can each be kept in perspective. The connection that is trying to be made by the AGW proponents is that such disasters are due to global warming. If the total annual global rainfall can be demonstrated to actually increase, or decrease, as global temperatures increase, or decrease, then they may have the statistics needed to draw some such worthwhile conclusions. However trying to make a case for such an argument that is largely driven by the emotional impact of separate events rather than what occurs more broadly is hardly what one would expect from those who are supposedly more interested in the science than the politics. It's much the same with accident statistics, more attention is drawn to an accident that claims three lives than six accidents that each claim one life. At the end of the day, it is those who calmly compile and analyse all the statistics who are able to draw worthwhile conclusions, not those whose conclusions are drawn according to the emotional impact of any single event. The records that you posted certainly indicate just what is possible. It can also be assumed that such events impacted on local populations to varying degrees. However for the greater part of the planets surface there are no means to measure precipitation, nor any population to be effected if an extreme rain event occurs, therefore it requires a big leap of faith to draw overall conclusions based solely on what events make it onto front page news or into the record books. -
cruzn246 at 04:49 AM on 21 August 2010Climate's changed before
OK, I'll make this short and quick. CO2 levels are about 380 per million here. They are about 965,000 per million in the Venetian atmosphere. Ya think that about .04% of the same concentration is going to throw us way out of whack? The big dog, which no one wants to talk about when it comes to greenhouse gases is water vapor. It goes from about nil when we are in the depths of an Ice age to a worldwide average of 2% during recovery and the following times. THAT is our basic greenhouse gas. CO2 is a bit player. You drop CO2 levels to under 1% on Venus and that place would turn into an iceball without water vapor. Yes climate just keeps on changing. We are in a period where the temperature has fluctuated, sometimes rather quickly, within a 4C range over the last 10,000 years. We are near the middle of that range now. Sun activity is relatively high, higher than it has been for the last 2,000 years. The long range trend has been up since about 1500. We have seen temperatures rise about 0.5C since 1900. Yawn, I hate to say it but a rise of about 3C in about 100-200 years was seen about 8,000 years ago. That's a quick warm-up. BTW, it has been warmer than this about half the time since we snapped out of our last ice age. At least 4 times it was 1C warmer than now and once it was 2C warmer. Bottom line. Climate changes and I am not alarmed. -
theendisfar at 04:48 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Chris G, "Most democratically elected leaders will not do what their voters don't want them to do" This is moot with regards to science as 'want' is moot. Want automatically includes motivation. KR's #29 'Thank you for Smoking' example applies equally to AGW scientists. Scientific 'Authorities' have been proven wrong time and time again throughout history. Piltdown Man is a great example. 'Want' is especially relevant when one has an elected Authority to deal with. Also, changing 'leader' to 'representative' changes the paradigm significantly. Intellectual 'representatives' hold no authority over those they represent. When People instead of Scientific Laws are the source of authority, you not only are subject to motivation, but you are also subject to the fact that People change, Scientific Laws do not. As far as 'most' scientists being convinced, repeatable methods and conclusions send a louder and more importantly a 'clearer' message than "I'm right and your wrong". Both sides are guilty of this. Motivation, credibility, and consensus would all be rendered moot and reduce the questions to a finite and falsifiable set. This is quite valuable as it removes subjection, which is practically infinite. I'm just saying repeatable tests will get us a lot farther a lot quicker, and it is very important for both sides to recognize this. Do you see the value in removing motivation, credibility, and consensus from the debate? Are they important with regards to the people educated enough to make a scientific argument? -
RSVP at 04:44 AM on 21 August 2010What caused early 20th Century warming?
"The climate at any one time is affected by several factors..." When I was a kid, I learned that the Earth was just the right distance from the Sun to make it habitable. This was not true. It should have been a little further away to accomodate global warming. -
miekol at 04:44 AM on 21 August 2010What caused early 20th Century warming?
"The evidence strongly suggests that current warming is mainly the result of increasing greenhouse gas levels." So its not a proven fact? -
RSVP at 04:29 AM on 21 August 2010What were climate scientists predicting in the 1970s?
JMurphy 20 I need to read the article "properly"? "...some scientists suggested that the current inter-glacial period could rapidly draw to a close, which might result in the Earth plunging into a new ice age" "...some scientists were suggesting we might be facing another ice age" We choose to see what we choose to see. I assume by reading the article properly you mean I can only be in agreement with the author. I am sorry, but this time the cherry tastes delicious. -
cruzn246 at 04:22 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Then Marcus was off also. -
How climate skeptics misunderstand past climate change
Excessive rainfall requires excessive evaporation - rainfall doesn't occur without sufficient water vapor present. In regards to cloud cover - there appears to be a slight inverse relationship to temperature over the last 60 years (sorry, can't currently locate where that was discussed on skepticalscience), but all of the analysis I've seen on it indicates that cloud cover feedback (negative or positive) is fairly minor. -
Eric (skeptic) at 04:01 AM on 21 August 2010How climate skeptics misunderstand past climate change
I witnessed a mechanism that locally reduced RH as the temperature rose today and my weather forecast tonight is for RH to be lower than last night. Repeat that globally and there's the global mechanism. No doubt that my mechanism could work the other way or it could keep global RH constant. But the only way to prove that it stays constant is to show that weather doesn't change in a warming world. But there are threads here claiming that climate extremes such as excessive rainfall have increased globally. That's certainly one way to reduce RH globally if it is true. -
cruzn246 at 03:57 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Gee, thanks for deleting a post I worked on for about 30 minutes. I guess the answer was a bit too convincing. See you all in another life. it's clear that censorship of good rebuttal exists here.Moderator Response: It was far off topic. See my Moderator comment on your comment after that one. Maybe John will restore the one I deleted. -
Chris G at 03:34 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar, Regarding "...an undereducated public is not the first people that need to be convinced." Most of us reading this live in democracies. Most democratically elected leaders will not do what their voters don't want them to do. So, undereducated or not, the public has to be convinced before action will be taken. Maybe they aren't the first people who need to be convinced, but most scientists have been convinced for decades and we can see how far that has gotten us. -
John Russell at 03:27 AM on 21 August 2010What caused early 20th Century warming?
TOP at 02:02 AM on 21 August, 2010 I agree with every word you write in your first para. If at the end you added the line, "And now humans are upsetting the balance by increasing the concentration of CO2 in the atmosphere", it would be perfect! -
cruzn246 at 03:25 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
This is an active place. I really like it.Moderator Response: I'm glad. But one of its attributes that makes it a good site is the focus of each of its posts and the comments specifically on those posts. Please use the Search field at the top left of the page, or browse the list of Arguments, to find appropriate threads for your comments. Split your comments by topic, into the appropriate threads. Also, read the post and preferably the comments before writing your comment. If we all (including you) keep the comments on topic, they will be informative. -
Berényi Péter at 03:21 AM on 21 August 2010The Past and Future of the Greenland Ice Sheet
#49 KR at 02:15 AM on 21 August, 2010 the Holocene peak roughly matched 2004 temperatures Much could be said about the holocene temperature reconstruction promoted on Wikipedia, but anyway, we are not talking about global temperatures here, but polar ones. 7500 years ago annual average insolation was 5 W/m2 higher inside 80N than it is today (at the eqator it was 1 W/m2 lower). You can check it here. Even if we accept estimated pre-industrial CO2 levels and the 3.7 W/m2 forcing for doubling of CO2, it is only 1.7 W/m2 up to now, far less than early holocene arctic forcing. Relax, the Greenland ice sheet is not in immediate danger. -
How climate skeptics misunderstand past climate change
Eric - if global temperatures rise, and relative humidity remains constant, the total amount of water in the atmosphere will rise, as the peak absolute humidity, the amount of water the air can hold (driven by the vapor pressure of water at atmospheric pressure and temperature) rises. The relative humidity is the percentage of possible absolute humidity at stated conditions. So - unless you know of some mechanism that will globally reduce relative humidity as temperature rises, the total WV (kg water/kg air) will rise in lockstep with temperature. -
theendisfar at 03:17 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
JMurphy, Interesting reads, thank you. Correction, Evolution in the much more detailed sense that Darwin postulated was not available to Newton et al. It seems that along with concrete, evolution in it's simple postulations was also lost during the Middle Ages, to the West that is. Great credit should go to Darwin for having so little to work from. The general public then and now are not evolutionists and again I would argue that an undereducated public is not the first people that need to be convinced. In essence they are nothing more than a fan club. A person who believes in Calculus is only as useful as their ability to use it. Just because you become a 'fan' of the Calculus Facebook page has no bearing on whether it works or not. -
The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
Consensus is a curious thing. In science, a 90-95% consensus is pretty strong, indicating that there are few loose ends or strong alternative theories/hypotheses. However, in the public domain a tiny percentage of disagreement can be hyped, paraded, and presented to the public as a 'valid alternative', irregardless of the strengths of their arguments. Hyping 'uncertainty' and presenting isolated views as mainstream alternatives are a standard industry tactic of the last 40 years - including the dangers of smoking, of second hand smoke, acid rain, DDT, holes in the ozone layer, the value of the Strategic Defense Initiative, and now climate warming. Many of the same people have been and are involved in all of these anti-scientific campaigns. I'm rather deeply familiar with these tactics - my brother was an apologist/denier for a major tobacco company, arguing uncertainty in the face of second hand smoke dangers. He gave me a copy of "Thank You For Smoking", stating "This is my job - I am this man". But back to science, rather than financially driven white-washing: If 97% (+/- ~3% based on the given sampling statistics) of experts in the field agree that AGW is occurring, while 0.3% of non-experts (no sampling statistics or sampling criteria presented) disagree, well, I'm going to go with the expert opinion. -
JMurphy at 02:54 AM on 21 August 2010The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
theendisfar wrote : "Evolution had not been postulated prior to Newton. Had Darwin come before them I believe they would have agreed with him if they took an interest." Like the myths about Galileo and flat-earthism (and, indeed, the Oregon Petition), that is not true : Contrary to many assumptions, evolutionary theory did not begin in 1859 with Charles Darwin and The Origin of Species. Rather, evolution-like ideas had existed since the times of the Greeks, and had been in and out of favor in the periods between ancient Greece and Victorian England. Indeed, by Darwin's time the idea of evolution - called "descent with modification" - was not especially controversial, and several other evolutionary theories had already been proposed. Darwin may stand at the beginning of a modern tradition, but he is also the final culmination of an ancient speculation. ThinkQuest History of evolutionary thought Perhaps you shouldn't be getting so much of your information from those so-called skeptical sites. -
Eric (skeptic) at 02:48 AM on 21 August 2010How climate skeptics misunderstand past climate change
CBDunkerson, warming from WV forcing depends on the amount of WV (in general, but see below). WV feedback from other warming depends on the amount of that other warming. Hopefully we agree on those two things. Where I disagree is that "as global temperature increases the global total amount of water vapor does as well". You are trying to make a global case for a local effect which is not necessarily true and will become false at some level of warming. My question from the beginning of the thread is "what is the physical process that limits the feedback when WV increases warming and warming increases WV". I stated it poorly as "when does positive feedback stop". The actual question is when does weather start to limit the positive feedback from WV. It already does in the tropics (in fact increasing warmth has negative WV feedback). It does not seem to be limited outside the tropics, so there is positive feedback there (except where there is no available water). So how is that feedback limited? When will we start to reach the limits (i.e. will we reach them soon or will it warm a lot more first)? The most basic error in your statement is that the distribution of water vapor (caused by weather) determines the amount of warming from water vapor, not the "total amount of water vapor". This is easy to prove. Suppose all the water vapor in the world was moved to one hemisphere (case 1). Suppose that amount was doubled. Now do the same doubling without first moving the water vapor (case 2). In both cases the "total amount of water vapor" went from X to 2X. But in case 1 the world would not warm with the doubling, and probably cool because of large increases in precipitation in an overall wet world. In case 2, the world would warm by some amount certainly greater than any warming in case 1.
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