tag:blogger.com,1999:blog-7952077824240445451.post940385462245471654..comments2024-02-01T01:41:38.306-08:00Comments on A Chemist in Langley: My Lukewarmer post, or how to lose friends on both sides in the AGW debate:Blairhttp://www.blogger.com/profile/14439598281608282361noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7952077824240445451.post-46809021975827022342015-01-07T13:05:09.803-08:002015-01-07T13:05:09.803-08:00Another point often overlooked is that the warming...Another point often overlooked is that the warming trend seen from the 1970's to the 1990's is almost identical in its slope to that from the 1920's to the 1940's. Clearly the earlier warming must have been natural, and yet we are expected to believe that the later warming was due to greenhouse gases. There is also good evidence that the world has been warmer than the present within the recent past such as in the Holocene (9000 to 5000 yrs ago) the Roman Optimum (500 to 900Yrs ago ) We must accept that there is much that we do not know, including what is causing the "pause". I am not denying that there could be a "greenhouse effect", but I do dispute that it is dominating the climate. The evidence says it is not.Derek Tipphttps://www.blogger.com/profile/07893712146272196994noreply@blogger.comtag:blogger.com,1999:blog-7952077824240445451.post-23137492677823612302015-01-05T10:06:29.189-08:002015-01-05T10:06:29.189-08:00Who are these people?... without ever indicating w...Who are these people?... without ever indicating who these people actually are. <br /><br />Are you seriously asking this question or being subtly ironic? Let’s start with 350.org which states in their documentation that there exists a need to return to 350 ppm or we will see a catastrophic collapse of civilization. I’m not sure how that could be described as anything less than CAGW. There are any number of similar organizations with similar campaigns out there including the David Suzuki Foundation in Canada (Santa will drown campaign), Greenpeace International etc.... The fact you ask this question indicates that you may wish to become more acquainted with the level of discussion on this topic outside the straight-jacket of academia. <br /><br />I'm not really sure what you're implying here. ..However, the evidence at the moment is that the overall effect of clouds is small. Hence the net effect of feedbacks is positive and amplifies the warming. <br /><br />Certainly there are many lines of evidence indicating the possibility that positive feedback mechanisms should be the determining feature. As I note, I tend to believe they will be positive but only minimally so and not in the range of 3 - 4 degrees necessary for CAGW proponents to be correct. The obvious rebuttal is the instrumental record. Models, dependent of your feedbacks, fail to predict current temperatures (they show limited skill). Rather the change in temperatures in the 50 years prior to the pause almost perfectly tracked the changes in total Tyndall gas concentration increases in the atmosphere. Certainly the literature is full of explanations for this phenomenon but until such time as the models can effectively extrapolate then there will be doubters. <br /><br />Well, this is almost certainly wrong. Do you have any actual evidence to support this position?<br /><br />Besides the data for the 50 years prior to the pause? As noted above, prior to the pause surface temperature increases mostly tracked the expected increases in Tyndall gas contributions. The differences indicate a likely minor net positive feedback and indicate that the lower end of the IPCC consensus range is the most likely scenario (in my opinion of course). You are, of course, free to disagree but my opinion is completely in line with the IPCC <br /><br />Again, what do you mean here...feedbacks are positive and amplify the warming is entirely consistent with historical changes. You seem to be suggesting otherwise. Any actual evidence? <br /><br />At some point you should both re-read what I have written and then re-read your basic atmospheric chemistry texts because what I am saying is entirely consistent with the underlying tenets of atmospheric chemistry and we do not have the time here to go into the level of detail that will clearly be needed to satisfy you on this point. <br /><br />You do need to be a little careful here. ...If you read what I said carefully, you'll note I used "maybe as high as", not "definitely".<br /><br />As I note, my prediction is well within the consensus range suggested by the IPCC. You are free to disagree, as do the authors who suggest that the higher end of the IPCC predicted range is the correct one. Ultimately, as I write in a later posting, I currently believe that the models need to be improved so they can better predict the future conditions. Given this and my strong belief in the lower range of the IPCC consensus range, I have emphasized work to improve ecological resilience through habitat protection while working towards a better mix of renewable energy alternatives. As I write in my blog, the current mix is the result of poorly thought out policies and in some cases are resulting in increased Tyndall Gas concentrations with the added issue of reducing ecosystem resiliency in the process. Blairhttps://www.blogger.com/profile/14439598281608282361noreply@blogger.comtag:blogger.com,1999:blog-7952077824240445451.post-65368990236582332962015-01-04T03:19:40.170-08:002015-01-04T03:19:40.170-08:00On the extreme end of the warming side are those w...<i>On the extreme end of the warming side are those who believe in catastrophic anthropogenic global warming (CAGW). </i><br />Who are these people? I'm sure there are some, but - in my experience - those who use the term CAGW the most, are those arguing that there are people who believe in CAGW, without ever indicating who these people actually are. <br /><br /><i>I look at the issue differently, my graduate-level courses in global biogeochemical cycles identified that most geochemical cycles involve negative feedback loops that buffer changes.</i><br />I'm not really sure what you're implying here. We're essentially pushing (forcing) the system away from it's current state. There is no obvious reason why anything should be acting to force us back to where we were prior to the increase in anthropogenic forcings. There's nothing special about that initial state. <br /><br />There are many lines of evidence that suggest that the overall feedback response is positive and that it will amplify the warming. Water Vapour is positive and quite large. Lapse rate is negative and cancels about half the water vapour feedback. Albedo changes are positive but quite small at the moment. Clouds are the big uncertainty, but they can have both a positive effect (basically through blocking outgoing long-wavelength radiation) and a negative effect (increasing the albedo). However, the evidence at the moment is that the overall effect of clouds is small. Hence the net effect of feedbacks is positive and amplifies the warming. <br /><br /><i>People like me are called “lukewarmers”. We do not assume that positive feedback loops dominate the system but rather a balance of positive and negative cycles are at play with the resultant effect being a relatively minor positive effect.</i><br />Well, this is almost certainly wrong. Do you have any actual evidence to support this position?<br /><br /><i>Unsurprisingly, an examination of the historical record demonstrates that changes in global temperature have historically mirrored the direct IR absorbtion characteristics of the increases in the various Tyndall gas concentrations.</i><br />Again, what do you mean here. That feedbacks are positive and amplify the warming is entirely consistent with historical changes. You seem to be suggesting otherwise. Any actual evidence? <br /><br /><i> That is how they translate the naturally expected 1.2°C of warming per doubling of carbon dioxide concentrations into increases ranging from 4.5 °C to over 6 °C per doubling. </i><br />You do need to be a little careful here. The Equilibrium Climate Sensitivity (ECS) is defined in terms of fast feedbacks only (water vapour, lapse rate, clouds). The range for the ECS is something like 2 - 4.5K. There are, however, slow feedbacks (permafrost release, reduction in snow and ice cover, ...) that will likely increase the warming. There is a paper by Hansen that discusses this (but I can't quite find this at the moment) and suggest that the Equilibrium System Sensitivity (ESS) is maybe as high as 6K. It is slow and so will probably not influence us much this coming century, but that's no reason to ignore that the very-long-term warming could be substantially higher than ECS estimates suggest. If you read what I said carefully, you'll note I used "maybe as high as", not "definitely". <br />Anonymousnoreply@blogger.com