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Rob Honeycutt at 08:50 AM on 14 March 2017CO2 effect is saturated
Here's another graph showing the vertical profile of 4 major greenhouse gases.
Source: Earth and Planetary Sciences » "Global Warming - Causes, Impacts and Remedies", book edited by Bharat Raj Singh , ISBN 978-953-51-2043-8, Published: April 22, 2015
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Rob Honeycutt at 08:21 AM on 14 March 2017CO2 effect is saturated
Wake... "Direct tests have shown a sharp drop in CO2 with altitude."
I don't think so...
[Source]
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michael sweet at 07:56 AM on 14 March 2017Models are unreliable
Tom
Thank you for the update. I apologize to Nic Lewis.
Imagine my surprise to hear that Nic Lewis' result is now consistent with the IPCC. 2016 will bring him higher still. Interesting that Curry reports only the lowest estimate. I wonder why ;P.
Using GISS data baseline 1880-1910 and now as 1996-2016 I get a difference of 0.94C while Lewis shows only 0.75C for similar times. Lewis is probably using HADCRU which is biased low at current times. Before 1880 GISS does not estimate temperature because they think there is not enough data. If Lewis used GISS his estimates would be even more similar to the IPCC.
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Wake at 07:42 AM on 14 March 2017CO2 effect is saturated
I am having trouble following an argument that doesn't take into account the mass of the individual gases. CO2 weighs almost three times what oxygen does and takes up two thirds the space. Direct tests have shown a sharp drop in CO2 with altitude. At the tropopause there is a sharp drop of CO2 presence into the stratosphere demonstrating that while mixing may occur in the heavier, lower, atmosphere the fact that CO2 is a heavier component is still there and CO2 is still much higher near the ground than higher. In the heavier troposphere most of the transmission of heat is due to conduction and not radiation. This leaves one wondering why we are even considering 100 ppm change in a minority gas, that has a lower heat content than other gases, being considered as any sort of problem.
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Tom Curtis at 06:52 AM on 14 March 2017The albedo effect
cMike @84, first many people have produced good, sucinct explanations of the greenhouse effect. Here at Skeptical Science you have two such explanations by Chris Colose (The Planatery Greenhouse Engine Revisited; and Joseph Postma and the Greenhouse Effect Pts 1 & 2). Pitched for easier comprehension, there is also my post on the subject (which, of course, I recommend).
Beyond that, your explanation contains a number of small, and one larger error. The larger error is that greenhouse gases do not simply reemitt the energy absorbed by radiation. Instead that energy is typically transfered to other molecules by collisions as either kinetic energy or changes in excitation states. In short it is thermalized, that is converted into kinetic heat energy. At the same time, a certain percentage of greenhouse gas molecules will always be in an excited state because the temperature of a gas, with the percentage depending on the temperature of the gas. That means the greenhouse gases will radiate at a rate dependent on their temperature, with the radiation going equally in all directions.
With regard to minor points, Ice has an albedo around 0.9, but snow has an albedo that depends on its age, and varies from 0.5-0.9, with lower values to be found in older snow. That is very important because typically sea ice is covered by snow. Further, clouds alone add an albedo of about 0.2 to the Earth, but the total albedo is only 0.3 because of overlap.
Finally, here are the relative strengths of various feedbacks as determined by the IPCC AR5:
P is the Planck feedback, which determines the temperature response to a forcing with no other feedbacks. WV is the Water Vapour feedback. LR is the Lapse rate feedback. WV&LR is the Water Vapour plus Lapse Rate feedback. They are shown coupled like that because they are related to each other, with the result that uncertainty is the combined feedback is much less than that in each seperately. C is the cloud feedback, which is the most uncertain of all the major feedbacks. Finally, A is the albedo feedback from changes in ice and snow. It is 18.75% of the strength of the water vapour feedback, which is the strongest of the positive feedbacks.
The figure is Figure 9.43 and the tabular data from which I calculated relative strength is from Table 9.5.
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michael sweet at 06:49 AM on 14 March 2017Extreme weather isn't caused by global warming
SemiChemE,
It is more complicated that just the change in diurnal temperature. The US Climate Change Assessment (from 2014) is the best source of scientific information about changes in the USA. If you are not from the USA, the information there will generally be similar to other parts of the world. Effects vary a lot from region to region.
The most consistent predictions are that heat waves, drought and flooding will increase. During the winter that means heavy snows (like they currently are having the the USA). Significant increases in heavy precipitation have been measured across the entire USA but are most pronounced in the North East where there has been a 70% increase in the heavist precipitation events. (Heavy precipitation = more floods). Hurricanes like Sandy are more common already. Indeed, Sandy was the latest hurricane in recorded history in the North East by several weeks. Record heat waves are already common.
It is unclear if the total number of Hurricanes will increase or decrease, but the strongest hurricanes are expected to be more common. Already hurricanes average about 15mph stronger than 50 years ago. Since the power of the wind goes up with the cube of the speed, 15 mph is a big effect. Some models suggest that the melting Greenland Ice sheet will cool off the North Atlantic so much that super storms start to occur. Hopefully those models will turn out to be incorrect.
We may get lucky and less diural difference means less extreme weather. Or we may not be lucky and more energy in the system means more and stronger storms. In either case we expect more floods and more drought. Meters of sea level rise are also a given. The question is how fast the sea level will rise. Don't buy land in Miami.
The report I cited is much less biased than I am. See what they say.
Watts Up With That is a site well known for misleading and outright false reports. If you want to understand the science be careful about who you trust on the internet. Scientists recommend Skeptical Science.
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Tom Curtis at 06:22 AM on 14 March 2017Models are unreliable
michael sweet @1009, in fact Nic Lewis has updated his estimates, at least to include 2015 data. As he needs updates on forcings and OHC as well as temperatures, we may need to wait until late April for his 2016 update.
The update is in fact the Lewis (2016) cited by Curry. He produced a table of updates and alternative estimates as follows:
Unsurprisingly, Curry reports only the lowest estimate of ECS on the table.
The other estimates are consistent with, or higher than the AR5 estimate (bearing in mind they are modal values). The differ significantly from the AR5 estimate only in having (for the most part) tighter uncertainty bounds. That in turn is due to their all coming from a single method, whereas the IPCC allowed consideration of other emperical estimates as well. That is, Nic Lewis (and Judith Curry) increase their certainty that ECS will be in the low end of the IPCC range by the easy expedient of excluding relevant data (and other methods of analysing the data they use).
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Rob Honeycutt at 06:00 AM on 14 March 2017The albedo effect
cMike... Your description is okay, but it's really only one piece of the puzzle, and is something that's been well understood for many decades. There's quite a lot more science involved to explain how CO2 operates in the atmosphere to warm the planet. We have lots of articles here at SkS that you can read. A good place to start is the SkS welcome page.
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cMike at 05:47 AM on 14 March 2017The albedo effect
The doubts about CO2 warming effects have never so far been answered by useful dialogue describing in compelling ways how CO2 warming actually happens. Let me offer the following:
The sun warms the earth but about 30% of the sun's energy is reflected back into space by snow and ice, which perfectly reflect the wavelengths of energy coming from the sun. The atmosphere is transparent to the sun's energy so all that reflected energy escapes to space. The other 70% is absorbed by the earth and then re-radiated at longer wavelengths. Most of those wavelengths pass on through to space but a cluster around 15 nanometers is absorbed by CO2 and then re-radiated, half toward space half toward earth. That incoming 15 nanometer energy is not reflected by snow and ice. Instead they absorb it completely and it causes them to melt. That's why glaciers all over the world are melting (not because the air is warmer). That also explains why the sea ice in the Arctic has been disappearing in the summer. Now that the ice is gone the energy of the summer sun beams down on open Arctic water instead of ice and is absorbed instead of being reflected. That changes the energy balance of the earth. The effective albedo around the North Pole has changed enormously. I submit that this is probably the largest contributor to global warming and find it more than strange that nobody seems to have commented on this as a compelling explanation of global warming. -
michael sweet at 05:05 AM on 14 March 2017Models are unreliable
Tom,
I am puzzled to learn how Nic Lewis can estimate that the sensitivity to a doubling of CO2 is 1.5 - 1.6C when in 2016 the temperature was already about 1.5C above pre-industrial. Hansen estimates about 0.6C in the pipeline and we are nowhere near doubing CO2. Granted that 2016 was an El Nino year, but that only adds about 0.1C to the temperature.
Nic Lewis initially made his estimates in about 2012 when the temperature had risen slowly for a few years. SInce the temperature has risen so quickly the last three years, I would epect that Nic would need to rework his calcualtions. I doubt that Mr. Lewis or Dr. Curry will redo the calculations.
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Tom Curtis at 03:44 AM on 14 March 2017Models are unreliable
michael sweet @1007, to add a bit of irony, the two estimates of climate sensitivity on which Curry, and hence SemiChemE rely on depend on comparing current temperatures and Ocean Heat Content with that from the late 19th century. What is worse, they do not use the only empirical data regarding the change in OHC since the late 19th century. Rather, they use model estimates. That means that if we reject the models as insufficiently accurate, we must also reject Nic Lewis's estimate of the ECS.
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Tom Curtis at 03:35 AM on 14 March 2017We're heading into an ice age
CO2 levels are now above 400 ppmv, 33% higher than at anytime in the last 800,000 years:
Of course HydrogenOne concludes from this that temperature in the Eemian was similar to that today, and in the face of strong orbital forcing, it fell back into an interglacial, the much stronger CO2 forcing, and much weaker orbital forcing today will also drive us back into an interglacial. No doubt it is the massive loss of NH albedo due to the loss of sea ice that convinces him of this:
(2012 Aug arctic sea ice (purple) overlaid on 1938 Aug arctic sea ice.)
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Tom Curtis at 03:26 AM on 14 March 20172017 SkS Weekly Climate Change & Global Warming Digest #10
The chart of changes in atmospheric CO2 is very interesting because it shows a relationship between changes in CO2 level and annual temperatures. The dip in temperatures relating to the Mount Pinatubo eruption (1992) is very prominent, as are the peaks in 1987/88, 1998, 2005, 2007, 2010, 2015 and 2016, all of which set globa temperature records at their time (and most of which were El Nino years). There are some exceptions. 2012 shows a massive increase despite being a cool year (for its decade), and 2014 barely increases over 2013, despite being a record warm year at the time.
This relationship at least partly is caused by the fact that the ability of sea water to absorb CO2 is a function of temperature. In cool years more of the annual anthropogenic emisssions are absorbed. In warm years less. That results in a smaller atmospheric increase in cool years, and a larger one in warm years, even though the total increase is always 100% anthropogenic.
It does mean, however, that looking at the annual atmospheric increase is a poor way of estimating annual anthropogenic emissions. Annual anthropogenic emmissions increased by an average of 3.28% per annum from 2000-2007, but at half that rate thereafter (1.62% per annum). The increases for 2012, 2013, and 2014 (the last year for which data is available) were 0.76%, 1.70% and 0.78% respectively. In absolute terms, that makes 2012 and 2014 the smallest annual emmissions in the 21st century excluding 2008 and 2009.
There is reason to hope, given this data, that the world is on the verge of stopping the annual increase in fossil fuel emissions. That hope is, of course, severely challenged by the advent of the Trump administration. We cannot, however, conclude from the annual mean growth of CO2 that the world has resumed its former, precipitate growth the use of fossil fuels. Nor can we conclude from that possible stabilization of CO2 emissions that we are effectively tackling climate change, for which CO2 emissions have to reduce rapidly.
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Tom Curtis at 03:00 AM on 14 March 20172017 SkS Weekly Climate Change & Global Warming Digest #10
HydrogenOne @2 is plainly sloganeering, so I do not expect it to survive the moderators attentions (see the comments policy). I will restrict my comment to note that typically when "... we have seen en elevation in temperature, CO2 levels, Volcanic activity, and a decrease in Solar Activity" an ice age has not followed. Typically those conditions have resulted in soaring global temperatures because the changes in solar activity over time are very small relative to the change in forcing that has followed on changes in CO2 levels.
HydrogenOne merely demonstrates again (as if we needed another demonstration) that it is very easy to convince yourself of what you wanted to believe in the first place if you allow yourself the luxury of fake facts.
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HydrogenOne at 02:46 AM on 14 March 20172017 SkS Weekly Climate Change & Global Warming Digest #10
What has happened in the past everytime we have seen en elevation in temperature, CO2 levels, Volcanic activity, and a decrease in Solar Activity? An Ice age. Every single time in history this has happened an Ice age as always followed. So we are in fact headed for another Ice Age. Global Warming is a joke.
Moderator Response:[RH] Sloganeering. Please read the SkS commenting policies before continuing to contribute.
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HydrogenOne at 02:39 AM on 14 March 2017We're heading into an ice age
As you can see the data provided by SS proves that this is not the first time temperatures have reached this point. Just like the upcoming ICE age will not be the first time Tempertures dropped significantly after a decrease in solar activity and increase in volcanic activity. Yes we are in deed headed for another Ice age.
Moderator Response:[JH] Sloganeering snipped.
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michael sweet at 21:32 PM on 13 March 2017Models are unreliable
SemiChemE,
You should read more about satalite temperature records. Carl Mears, head scientist at RSS says the surface record is more reliable. The model to convert measurements into temperature is very complicated and major errors are found all the time. The final result is the temperature several miles up into the air. How useful is that?
By contrast, the surface results have been consistent for decades. BEST used a new method of analysis and added a great deal of data and got an identical result. The surface station project eliminated a great deal of data and the result was identical. Both BEST and the surface station were run by deniers.
You should look more at paleo results. Compared to satalite records they are great. They give insight into very long data series.
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Tom Curtis at 17:32 PM on 13 March 2017Models are unreliable
I should note that while some estimates from Heydt et al are in the low end of the AR5 range, all are higher than those cherry picked by Judith Curry.
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Tom Curtis at 17:20 PM on 13 March 2017Models are unreliable
SemiChemE @1004, neither Judith Curry, the Global Warming Policy Foundation nor Nic Lewis have a sterling reputation when it comes to climate science. All have shown a strong prediliction to cherry pick results in favour of low sensitivity/low impact projections. That is evidenced again in the report for which you provide the URL.
More specifically, in Table 1 Curry reports the climate sensitivity estimates of the IPCC AR4, the IPCC AR5, and the CMIP5 model ensemble, along with just two recent estimates. Nic Lewis is an author of both of those estimates, with Judith Curry being his coauthor in the first, and higher estimate. The two climate sensitivity (best) estimates are, respectively, 1.64 oC and 1.54 oC per doubling of CO2. Both estimates are by the energy balance method. I should note that by "best estimate", Curry means the modal value. Given the use of estimates of ECS in estimating likely damages from global warming, it is more appropriate to report the mean value. Given the assymetry in the uncertainty ranges, the mean value is likely to be higher than the modal value.
For comparison, using the same method but less controversial assumptions, Otto et al (2013) found a most likely (ie, modal) estimate of 1.9 oC with a 5-95% confidence range of 0.9-5.0 oC. That is warmer than the effective IPCC estimate of the modal value as determined by Rogelj et al (2014) (See supplementary data, tables 1 & 2, case f).
Further, when we look outside the strict confines of energy balance based estimiates of ECS, the range of values becomes much larger. Bodman and Jones (2016) report estimates of mean values for the ECS of 2.0, 3.2, 1.8, and 2.6 oC per doubling of CO2 for a range of studies, the oldest of which was published in 2012. An even greater range is obtained if we consider studies of paleo data, as shown in Figure 1 of Heydt et al (2016):
(To read the graph, the x axis shows the approximate GMST relative to 20th century values, while the y axis shows the climate sensitivity parameter. To obtain the ECS for 2xCO2, multiply that value by 3.7 W/m^2. As can be seen a range of values are obtained, most commensurate with the IPCC AR5 and CMIP 5 estimates, though with some lower and some much higher.
Lewis likes to argue that energy balance estimates are incontrovertibly superior to other estimates, but there are good reasons to doubt that. Indeed, there are good reasons to think that such estimates are biased low. Nic Lewis' results are further biased low on top of that by his controversial assumptions all of which tend towards a lower estimate of ECS.
To summarize, Judith Curry's GWPF report is typical of their productions in being based on extreme cherry picking of data to drive an ideological point. It is not a fair summary of the science, and therefore need not be considered in a science based blog.
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SemiChemE at 15:00 PM on 13 March 2017Models are unreliable
I'm new here, but here's a quick intro, I'm a chemical engineer with approximately 20 years experience in the semiconductor industry. A significant portion of that time involved computational fluid dynamics (CFD) modeling of reacting flows. Thus, I'm quite familiar with the capabilities and limitations of CFD models. All GCMs are at heart, large-scale CFD models.
@1003 - The video gives a nice overview of the climate models for the layman, but I can't help but think the scientists are downplaying many of the model limitations.
Yes, for most of the phenomena of interest the basic physics are pretty well understood, but to model them on a planetary scale, gross simplifying assumptions must be made due to computational limitations. The skill of the model is intimately tied to the accuracy of these assumptions and that is where the model can easily go astray.
Dr. Judith Curry gives a pretty good summary for the layman of some of the most salient model limitations in an article linked here:
https://wattsupwiththat.com/2017/02/21/curry-computer-predictions-of-climate-alarm-are-flawed/
The bottom line is that while some of the approximations are extremely accurate, by necessity the models for some processes are quite crude. This latter set, varies from model to model depending on the specific model purpose and is one reason for the spread in reported model results. It is these crude approximations that ultimately must be tuned to fit the available data, but with such tuning comes the ever present risk of getting the right answer for the wrong reason, in which case there is no guarantee that the model will be useful for future predictions.
If we had several earths to experiment on, we could run multiple experiments with different forcing conditions and sort out the various contributions of different effects, but since we have only one earth, we don't have any way to completely distinguish the impact of the various forcings (eg. CO2 levels, solar radiation, cloud formation, SO2 and aerosols, Natural variability, etc...) from each other. This means we have to make educated guesses about the various sensitivities. Over time, these guesses will get better, as we get more data to compare them to and we better understand the various sources of natural variaton (eg El Nino/La Nina).
However, at the moment, we really only have about 40 years of reliable, high-density data (the satellite era) and we're trying to decouple the impact of increasing CO2 from a natural variability signal that also seems to have a 30-60 year period. Dr. Curry contends that the due to such factors, the IPCC has over-estimated the sensitivity of the climate to CO2, possibly by as much as a factor of two.
If true, this means that climate change will happen much more slowly and to a lesser degree than originally predicted.
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Digby Scorgie at 14:34 PM on 13 March 20172017 SkS Weekly Climate Change & Global Warming Digest #10
Um, a 5055% chance of an El Nino?
Moderator Response:[JH] A little dash will do it! Thanks for catching this glitch.
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SemiChemE at 12:45 PM on 13 March 2017Extreme weather isn't caused by global warming
How does Green-house-gas driven warming effect the diurnal temperature cycle and what impact would that be expected to have on weather?
My understanding is that one would expect night-time lows to rise more than day-time highs. I believe this has been observed and stated as evidence for AGW. Thus, the difference between daily highs and lows should actually be reduced by AGW, which in turn presumably would tend to moderate extreme weather events (winds and precipitation).
Of course, I'm not a weather expert, so I may be missing some important effect. For example, the changes in surface temperatures may be different from those at higher altitudes, driving cloud formation.
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David Kirtley at 11:27 AM on 13 March 2017How Green is My EV?
Another issue which sometimes comes up as an "argument" against EVs is that us hippies are not paying our fair share of fuel taxes which go towards roads, etc. David Robert's had a recent post on this: Buying an electric vehicle? A growing list of states will charge you extra yearly fees.
Here in Missouri we already have a "yearly fee" of $75.00. But I wondered if that amount really covers my "fair share" and offsets what I would normally pay in fuel taxes at the gas pump, so I made another table:
For each month, the number of gaIlons is the amount I avoided using by driving the EV instead of the ICE car. It looks like Missouri is getting $26 more from me because of the EV. And the Feds are out $52.
I don't really mind paying $75 for the sticker each year, but I think there is probably a better solution(s) for collecting "taxes" to pay for roads. Especially since the Feds are left holding the bag in Missouri.
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bogfetto at 23:07 PM on 12 March 2017CO2 effect is saturated
Tom Curtis at 10:19 AM on 12 March, 2017
Moderator Response:[DB] The user is a sock puppet of a previously banned user, which was also a sock puppet of another previously banned user. Posting rights rescinded.
[JH] The person behind the bogfetto screen has retuurned as beardface. All of his/her posts will be summarily deleted.
As time permits, I will also delete all of bogfetto's prior posts.
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Paul D at 20:49 PM on 12 March 2017How Green is My EV?
Robert Llewellyn (Red Dwarf) has a good Youtube channel that covers EVs and renewable energy:
https://www.youtube.com/user/fullychargedshow
He used to drive a Nissan Leaf, but now has a Tesla.
Lets not forget electric bikes which have had a much greater rate of success than cars. Pensioners and other 'reluctant' cyclists now use electric cycles to get to work.
On the issue of electric motor vehicles the positives out weigh the negatives and there is a much bigger issue in general regarding the electrification of the energy system. This enables all sorts of advances in technology. Electric motive power is generally revolutionising many areas of transport and technology. This includes use of electric drive in ships and the beginnings of electric flight.
If you also factor in superconducting motors and generators, sodium-ion battery developments and numerous other ongoing advances, then the negativity regarding renewables and EVs is larger misplaced due to lack of knowledge or ignoprance.
EV positives:
1. Energy used to move the vehicles is low carbon and this energy represents the greatest carbon footprint over the vehicles life time. The issue of manufacturing emissions is one that is both insignificant and resolvable through evolving improvements.
2. Particulate pollution is reduced. Diesel emissions are a growing problem and EVs are the only solution that tackles both carbon and particulate emissions.
3. EVs accelerate very quickly which is a selling point. They do so because the energy transfer is very efficient.
4. They are very reliable, this is important since modern cars are almost impossible to maintain for the average person, so less trips to a car servicing garage, the better.
5. The batteries last longer than the cars themselves and can be used in the second hand energy market (grid balancing, smoothing).
There is a bigger picture out there and its electric. -
michael sweet at 12:29 PM on 12 March 2017CO2 effect is saturated
Interesting picture of a cloud showing at least five atmospheric layers that are not mixing.
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michael sweet at 12:08 PM on 12 March 2017CO2 effect is saturated
This picture shows at least three layers of the atmosphere that do not mix. This disproves the wild claim that the atmsosphere "moves freely"
Heat is ony transferred slowly by wind and thermals through the troposphere. Uninformed people think it is fast because they do not consider how big the Earth is. Wind takes days to cross even the distance across a single ocean. It takes weeks and months to transfer energy to the Arctic from the equator. The Atmosphere has many layers that do not freely mix. IR transfer of heat is much faster than thermal transfer. IR heat is blocked by CO2, causing greenhouse warming.
Bogfetto,
Please provide data to support your wild claim that the atmosphere "moves freely" at a rate that is significant to release of energy from the top of the atmosphere. I have provided data showing that the atmosphere does not freely mix to a significant extent.
Moderator Response:[JH] Bugfotto has relinquishd his privilege of posting comments on this site.
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Cid_Yama at 10:36 AM on 12 March 20172017 SkS Weekly Climate Change & Global Warming News Roundup #10
Maybe someone can delete the 2 prior posts.
Link is to a paper released December 2016, that is a good follow-up to your article -Just how ‘Sapiens’ in the world of highCO2 concentrations? - dated 17 November 2014.
Moderator Response:[RH] Shortened link.
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Tom Curtis at 10:19 AM on 12 March 2017CO2 effect is saturated
Tom Dayton @440, that is not an improvement of the analogy. Specifically, the air between the shirt and the skin quickly obtains the same temperature as the skin, which does not occur in the atmosphere. A better defense of the analogy is to point out that there is a temperture gradient within the fabric of the shirt, with the inner most layer of the shirt being skin temperature, and the outermost layer being room temperature. That is, as bogfetto points out, because of the restricted circulation of air within the shirt - but such restricted circulation is not necessary to set up a temperature gradient, and thereby an insulating effect. Specifically, the troposphere also has a distinct energy gradient which is a product of the inefficiency of energy transfer within the atmosphere. Absent convection, it would be even more inefficient and the surface temperature would be higher (as shown by Manabe). If the atmosphere were perfectly efficient at transfering energy, as appears to be assumed by bogfetto, then the temperature of the atmosphere would be constant with altitude.
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Cid_Yama at 10:13 AM on 12 March 2017Just how ‘Sapiens’ in the world of high CO2 concentrations?
In response to the questions posted by posters:
Chronic Respiratory Carbon Dioxide Toxicity: a serious unapprehended health risk of climate change
Moderator Response:[RH] Shortened link.
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Tom Dayton at 10:08 AM on 12 March 2017CO2 effect is saturated
bogfetto, you claimed "The atmosphere is air that moves freely."
But the atmosphere does not move freely into outer space. Only trivial amounts of atmosphere escape to space. So outer space is the equivalent of the shirt. The atmosphere is the equivalent of the air inside the shirt. The atmosphere insulates the surface from the cold of space. The air trapped inside the shirt insulates the skin from the cold of the air outside the shirt.
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Chris Snow at 08:51 AM on 12 March 2017How Green is My EV?
We bought a second hand Leaf just over a year ago and, since we live in the UK where fuel costs are much higher (currently around £1.18/litre or around £5.40/gallon) the savings are much greater. Assuming that all the extra electricity we have used over the past 12 months is due to recharging the car, we've saved over £1,200 compared to the previous year when we had our ICE.
As we're with a 100% renewable energy supplier, our only direct fossil fuel use is the natural gas we use for heating and cooking. That was around 9000 kWh last year, which gives annual CO2 emissions of around 1.7 tonnes of CO2. That's for a family of four.
From our experience, I'd say that massively increasing the renewable energy generating capacity and moving to EVs will go a long way to reducing CO2 emissions to the level that we need to. It will also have other benefits such as cleaner air in towns and cities and less noise.
There are still a few annoyances though. The range can be a pain sometimes but I expect the next generation of EVs to have a much greater range. Also, we need more recharging points, especially where we live!
There are no insurmountable problems to reducing CO2 emissions; what is lacking is leadership in tackling the issue.
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Eclectic at 08:49 AM on 12 March 2017Correcting Warren Meyer on Forbes
Tom @32 , my apology for not making my statement clearer.
When I said "these few", I was referring to the "very tiny" number of climate-knowlegeable scientists (such as Curry and Christy, for example) who are "lukewarmers" in the sense of bending over backwards to minimise the importance of the present-day global warming process.
Mr Warren Meyers quite evidently does not fit that description, though he seems to wish to masquerade as lukewarm. His advocacy/sophistry fails to be scientifically logical. He would benefit from some self-examination, as to why he (as an intelligent man) is striving to be in denial about the very straightforward findings of climatological science and about the major global warming changes that have already occurred in the physical world.
The effect of denialism is much the same, regardless of whether the intention is anti-scientific advocacy or semi-scientific Lukewarmism.
As you imply, Tom :- those who aim to be "semi-scientific" are really aiming to be semi-pregnant.
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sauerj at 05:03 AM on 12 March 2017How Green is My EV?
nigelj @15: I think nomorewoo is talking about battery life. I have read 5-10 years, or ~100,000 mile lifespan. At a cost of $10k to replace them (LINK), this is an important point in terms of determining the true net life-time CO2 emission differences.
Similar to Dave's study, I did a similar but "theoritical" analysis based on my state's Indiana power. IN's power fuel mix has an even higher lbsCO2/kwh footprint than MO. I came up with the following theortical results.
EV: 3.2 lbsCO2/kwh (power delivered to the wheels). Based on 1) 62% EV "grid-to-wheels" efficiency for grid+batteries+motor inefficiencies (link). And, 2) for the CO2/kwh factor, I derived the weighted avg IN power to be 1.85 lbsCO2/kwh (based on 77% coal (2.1), 19% gas (1.22), 4% non-carbon (zero); sources: IN fuel %split #'s & CO2 by fuel type). Then, 3) I applied a mine-to-PP for coal (or well-to-PP for gas) extraction/refinement scale-up factor of 1.09 (I assumed the same # for both coal & gas) which increased this 1.85 to 2.01 lbsCO2/kwh (exactly the same # as Dave has here but I clarify that this is for IN power & does include what I think is appropriate factor for the coal&gas extraction+refinement CO2 scale-up factor). Source for this 1.09 "extraction+refinement" scale-up factor is HERE (math=1205/(1205-100)). ... Final complete math: (2.01lbsCO2/kwh)/(61%grid-to-wheel eff) = 3.2 lbsCO2/kwh (to wheels)
ICE: Range of values depending on ICE eff: 3.5 lbsCO2/kwh to 4.4 lbsCO2/kwh (power delivered at the wheels). Based on 1) ICE "petro-to-wheels" efficiency varies from 17% to 21% (link). And, 2) based on 19.0 lbsCO2/petro-gal w/10%Eth (link). Then, 3) I applied a well-to-station extraction+refinement scale-up factor of 1.28 which increased this 19.0 to 24.4 lbsCO2/gal (which is a bit more than Dave used here but I clarify that this does include what I think is appropriate factor for petro extraction+refinement CO2 scale-up factor). Source for this 1.28 "extraction+refinement" scale-up factor is HERE (math=(95/74)). ... Final complete math: (24.4lbsCO2/gal)/(range: 17%-21% petro-to-wheel eff)/(112000btu/petro-gal)*3412(btu/kwh) = 3.5 to 4.4 lbsCO2/kwh (to wheels)
Dave's real-life study resulted in EV/ICE CO2 ratio of 0.68. I calculate the range of EV/ICE CO2 ratios to be 0.74 to 0.92 depending on the fuel efficiency of the ICE. The ICE efficiency site that I used (here) does not correlate its ICE eff #'s w/ mileage #'s so it is hard to correlate Dave's 30mpg to the petro-wheel %eff #. However, I would expect that Dave's 30 mpg hybrid to be on the high-end of what this site would consider available ICE efficiencies (i.e. therefore closer to 21% eff), thus I would have expected an EV/ICE-hybrid CO2 ratio to be closer to 0.92.
My calculations are all theoretical; Dave's are real life. One thought for possible real-life study issues: 1) It would have been ideal if the Leaf's power consumption was truly metered and not based on Nissan "book" numbers. Lastly, 2) Was the hybrid's driving "route & style", in determining its average ~30mpg factor, similar in terms of power duty compared to the driving "route & style" of the Leaf? I assume the car weights are similar, but what about avg speed & hill differences? Was the load duty on the hybrid possibly "worse" than the Leaf's?
Jim Eager's point (@6) is right in. Same logic would apply to WA state residents, where the weighted avg mix for its power is only 0.47 lbsCO2/kwh (vs 2.01 in IN). So, in WA the EV's would only emit 0.76 lbsCO2/kwh (power delivered at the wheels). Resulting in an EV/ICE CO2 ratio of only 0.17! This would result in ~$256 monthly savings if a $100/UStonCO2 tax was applied to all FF carbon, making it very attractive for everyone in WA to switch to EV's.
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It's too bad that net comparison calculations like this are so difficult. This difficulty is only because energy cost does not include the external cost of CO2 emissions. If it did (at a rate that is equal or more than the external cost of CC impacts), then this net comparison calculation would be plainly transparent to us (& directly to our pocket books). And, all the difficulty to figuring the assorted costs here (including coal extraction, petro refining, the 17%-21% ICE efficiency factor (LINK), the 62% EV efficiency factor (LINK), the 40% efficiency of the typical power plant rankine cycle, battery life cycle, etc, etc). All of those net calculation complications would be transparent & real making it plainly obvious to our personal & industrial balance sheets as to what is the right choice (and, most convincing, the profitable choice). If only energy costs included CO2 external cost ...
Micro pursuits like this are important to us individually, but macro pursuits (i.e. changing energy policy) are more important because it is these that will make for truly substantial carbon emission reductions. A plug here to promote enacting Carbon Fee & Dividend (especially the least burdensome revenue neutral flavor, i.e. as advocated by Citizens' Climate Lobby) and then serious carbon emission reductions will start to happen. If energy is priced sustainably positive, then the right technologies will take off because they will become the profitable ones. Consider joining your local CCL chapter!
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Tom Curtis at 04:37 AM on 12 March 2017CO2 effect is saturated
bogfetto @433:
"Give me a source supporting a claim that heat is transferred from the freezing fluid to the hotter surface. In what other situations do you experience heat coming from low temperature fluids?"
In the theory of the greenhouse effect, all heat (ie, net energy flow) is from:
1) The Sun to the Earth's atmosphere and surface, with the vast majority going to the surface;
2) From the Earth's surface to the atmosphere and to space, with the majority going to the atmosphere; and
3) From the atmosphere to space.
In each case, the net energy flow is from a warmer to a colder object. If you do not think this is the case, you simply do not understand the theory. Period. This is so important that I would put it in all caps were that not forbidden by the comments policy.
And if you do not understand the theory, learn to understand it before you pretend to criticize it!
You will certainly doubt my claim about the direction of energy flow in the greenhouse theory. Very well. Here is the Earth's energy budget as determined by NASA:
It shows energy flows from the Sun, to and from the surface, to and from the atmosphere, and to space. Sum the energy flow across any boundary between the Earth and the Atmosphere, and the Atmosphere and Space and you will find the incoming and outgoing energy are approximately equal, with only a 0.6 W/m^2 net imbalance. Sum the energy flows between any warmer and colder object, and you ill find more energy flows from the warmer to the colder object than the reverse.
Attn moderators: I have no strong interest in playing whack-a-mole on these issues again with somebody who cannot bother actually learning the theory they purport to criticize. Would you please restrict bogfetto's responses to just this issue until such time that he acknowledges the simple truth, or proves he is incapable of doing so by excessive repetition. At your discretion, I will shift the discussion to the 2nd Law of Thermodynamics thread, where it is far more on topic.
Moderator Response:[JH] Bugfotto has relinquishd his privilege of posting comments on this site.
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Tom Curtis at 04:22 AM on 12 March 2017CO2 effect is saturated
Bogfetto @429:
1)
"If the altitude of emission is increased, it means that a larger volume absorbs heat from the surface. Your argument is based on that this increase in volume is caused by an increase of a powerful heat absorber."
First, while the second sentence is entirely ungrammatical and difficult to interpret, if I interpret it as saying, "Your argument is based on [the fact] that this increase in volume is caused by an increase of a powerful heat absorber" your claim is false, and you have not understood my argument, or its basis at all. It is clear that it misrepresents my argument in that I limit the discussion to situations in which the mean altitude of radiation to space is lower than the tropopause. If it rises to the tropopause (and assuming the temperature structure with altitude remains constant), further increases will initially have no effect in temperature, and then reduce the Global Mean Surface Temperature. That despite the fact that the volume of gas below the mean altitude of radiation to space will continue to increase. In practise, the same increases in CO2 that increases the mean altitude in radiation to space will also cool the stratosphere, and sufficient CO 2 increase to raise the mean altitude of radiation to space into the current stratosphere may well cool the stratosphere sufficiently that it has a declining temperature with altitude, in which case that will result in further surface warming.
This discussion should make it very clear that my argument is based on the temperature of the mean altitude of radiation to space, something laid out very specifically in my article on the topic. I suggest you move further discussion of that particular point to that article, and make sure you read it before you do.
I will note that on rereading my comment from which you took the quotation, it was very clear and very specific. Your misinterpretation has no justification in the text, and is based entirely on your attempt to shoe horn that discussion into your very rudimentary grasp of physics. If you are going to persist in that behaviour, save us all some time and end the discussion now.
2)
"The only way to increase temperature of a radiating body, is to increase the temperature of the heat source heating it."
If you have a radiant filament (such as in a light bulb) fed with a constant power source, and with a constant resistance, but place that filament in a gas that gradually corrodes its surface, thereby reducing emissivity, the filament will increase in temperature over time even though the amount of energy radiated will remain constant. That is a common place experience in cold climates where low emissivity films are placed over windows to increase the internal temperature while decreasing the power used in heating.
This is an analog the the greenhouse effect in which the increase in CO2 reduces the effective emissivity of the Earth over time in the IR bandwidth while not reducing the emissivity in visible light bandwidths (and therefore not decreasing the incoming energy). The result will be that:
When we compare the quasi-eqilibrium states before and after the introduction of the increased CO2:
1) The IR radiation to space will be the same in both cases (ignoring albedo feedbacks);
2) A reduced proportion of the IR radiation to space will come from CO2 because the CO2 will be radiating to space from a higher, and hence (typically colder) altitude;
3) Therefore the IR radiation from other components of the system, particularly the surface, will have to increase to compensate for that shortfall;
4) The only way for them to increase will be through a rise in temperature.
In the interval between when the first quasi-equilibrium state is perturbed by the addition of CO2 and reaching the second quasi-equilibrium state:
a) Total IR radiation will be decreased (ignoring albedo feedbacks);
b) The resulting energy imbalance will result in an increase in temperature over time; and
c) The time between the two quasi-equilibrium states will be a function of the heat capacity of the system (most of which is in the ocean) and the cumulative energy imbalance in the interval todate.
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ubrew12 at 03:32 AM on 12 March 2017How Green is My EV?
"I... calculated an emissions break-even... what MPG would an ICE car need to... break-even with the EV in... CO2... This worked out to...45 MPG"
This scales directly with the assumed lbs CO2 released per gallon of gasoline burned. Per my comment (ubrew12@8), that may actually be closer to 36 lbs CO2/gal than the 18 lbs CO2/gal you used, due to refining, transportation, and other costs. In that case, a 'break-even vehicle' would have to get closer to 90 mpg to match the performance of your EV. I dare say such a vehicle is not to be found, not even in advanced hybrid vehicles. 90 mpg is twice what most motorcycles are getting.
"my avoided CO2 was 1644 pounds, or about ¾ of a metric ton of CO2." You can be prouder than that. I calculate 6681 lbs CO2 avoided, or 3 metric tons annually.
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Rob Honeycutt at 03:07 AM on 12 March 2017Correcting Warren Meyer on Forbes
I would almost call Warren a climate denier with a hedge. Any argument of near or below 1°C is abundantly rejected within the scientific literature. Saying you agree with radiative physics, but reject all other physics, doesn't buy you a ticket to the lukewarmer club.
I would go even further to state that, such rhetorically hedged statements like Tom just recounted ("might not be high, but might be neg") border on the irrational. It's certainly not a scientifically nuanced point at all. It's a statement designed to defend a cognitive position against scientific facts.
It's the 'Global temperature changes all the time, always has... but feedbacks are negative and climate sensitivity is below 1°C' argument.
I don't see that as lukewarmer in the least. That's just straight up denial packaged up to sound sciency.
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Tom Curtis at 02:37 AM on 12 March 2017Correcting Warren Meyer on Forbes
Eclectic @31, Steven Mosher, as much as anyone, has a right to define the term, "luke warmer". And he has done so at WUWT:
"Over the years a few of us have worked to define what we mean by Lukewarmer and what defines the position.
1. Acceptance of radiative physics.
2. Acceptance of a lower bound to sensitivity. basically the no feedback estimate is 1.2C per
doubling. We think that the true sensitivity will be above 1.
3. over/under line. The over under line is 3C. That is, if offered a bet that the climate sensitivity
is either ‘between 1 and 3 or over 3, we take the under bet.ballpark:
less than 1.2 5%
1.2 to 3. 50%
3 to 4.5 45%
4.5+ 5%So if you believe that GHG can warm the planet and not cool it, and you think that the mean estimate of the IPCC of 3.2 is more likely high than low, then you are a lukewarmer. But you have to drop the crazy refusals over radiative physics."
In contrast, Meyer wrote:
"Not only may the feedback number not be high, but it might be negative, as implied by some recent research, which would actually reduce the warming we would see from a doubling of CO2 to less than one degree Celsius. After all, most long-term stable natural systems (and that would certainly describe climate) are dominated by negative rather than positive feedbacks."
The suggestion that ECS might be less than one removes Meyer from the Luke Warmer camp. (I have discussed his misrepresentation of the nature of climate feedbacks above.)
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Eclectic at 23:29 PM on 11 March 2017Correcting Warren Meyer on Forbes
coyote / Warren Meyer @25 ,
some very good points have been made in reply to you — so I will just add some general observations :-
Firstly, there are very few denialists as intelligent and well-spoken as you are. Exceedingly few. Seemingly even fewer than the very tiny [single figures?] number of climate-knowledgeable scientists who dispute the consensus view about the severity of the present global warming problem. These few could be called "lukewarmers", because they only dispute the degree of AGW. But the consequence (and possibly intention?) of their actions is to reinforce denialism by the science-ignoring groups. *Judging by scientific publications and the expressed position given by the world's peak scientific bodies, it is a fair assessment to describe the "consensus" as well over 99% (rather than the oft-repeated 97% which is really a figure from a decade ago). And in the subsequent decade, the physical evidence supporting the mainstream science has grown even stronger than you were thinking, back in 2012.
Secondly, I enjoyed reading one of your climate-related "coyote blog" articles a few years ago (sorry, I cannot recall which one — but it was lengthy and published in several parts). The initial third of your article was rigorously well-argued, and was impressive and persuasive. Unfortunately, things went downhill from there. The middle part became less rigorously correct, and might be described (colloquially) as getting quite flaky. And the final third was quite atrocious in its large amount of logical faults. It seemed that you had used your utmost "Motivated Reasoning" to convince yourself (and readers) that black was white.
I sincerely hope you will achieve better in the future: though that will require you to overcome your inner emotional bias. The so-called Motivated Reasoning is a powerful force, mis-directing you away from the very clear conclusions reached by mainstream science. Perhaps you enjoy being a maverick despite the scientific evidence being so strongly (or rather, so entirely) against you — or perhaps there is a gaggle of more interesting inner forces!
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MA Rodger at 23:16 PM on 11 March 2017Correcting Warren Meyer on Forbes
coyote @25 is actually a cut&paste of part of a web-page from the commenter's website. What he doesn't bring here is the start of this web-page. In it he is suggesting that the climate forcing since pre-industrial is incompitable with the temperature record given IPCC ECS values. As well as some seriously trivial stuff, he presents two graphics to demonstrate how models cannot be (entirely) trusted. Thus the commenter tells his flock with emphasis "There are good reasons to distrust models. ... There are also good reasons to distrust climate models and forecasts" and less-forcefully "These forecast failures are not meant as proof the theory is wrong, merely that there is good reason to be skeptical of computer model output as somehow the last word in a debate."
The first graphic shown compares the trends from Hansen (1988) Scenario A & B (but not Scenario C) with HadCRUT4 & UAH TLTv6.0. The second is the second-order-draft AR5 Fig1.4 (below), a graphic oft annotated by denialists and so it could perhaps do with some sensible annotating for once - pehaps with a plot of the temperature record 2012-16. Suitably adjusting GISS & NOAA for a 1961-90 anomaly, by 2015 they and HadCRUT are showing respectively anomalies of +0.76ºC, +0.78ºC, +0.76ºC, which are smack the centre of the AR4 projection. Of course 2016 was warmer still, but that was an El Nino year.
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michael sweet at 22:24 PM on 11 March 2017CO2 effect is saturated
Bogfetto,
When you make posts with many questions if in impossible to answer them all in detail. Please ask one question at a time so that they can be answered. After the first misconception is cleared up we can then move on to the next misconception.
I will take a single example form your post to Tom Curtis. You claim:
"The only way to increase temperature of a radiating body, is to increase the temperature of the heat source heating it. And an increase in temperature always have to be initiated by a rising temperature of the radiating body, never by a decreasing temperature (and decreasing intensity) in a colder body heated by the hotter radiating body."
When I got out of bed this morning it was cold. I put on a cold shirt. My surface temeprature increased even though my rate of heat production remained the same. This is experimental evidence that your clain that " an increase in temperature always have to be initiated by a rising temperature of the radiating body" is incorrect.
It appears that you have a basic misunderstanding of how heat is transferred. I suggest you reread the posts you have questioned, and the OP, and ask questions about what seems off to you. Ask about one or two imortant items first. As those misconceptions are cleared up you will start to understand the basics. When you have the basics incorrect it is impossible to understand how the atosphere works.
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John Mason at 19:33 PM on 11 March 2017To tweet or not to tweet at Donald Trump? That was the question!
I agree it's confusing, Rob!
As a geologist I view the whole thing as a pathway between weathering and precipitation. Importantly, as shown by the following weathering equations:
Silicate weathering:2CO2 + 3H2O + CaSiO3 = Ca2++ 2HCO3– + H4SiO4
Carbonate weathering:
CO2 + H2O + CaCO3 = Ca2++ 2HCO3–
the weathering of limestone only involves one mole of atmospheric CO2 whereas silicate weathering involves two. In both cases though, when it comes to the reprecipitation part, a mole of carbon goes into the reservoir and a mole of CO2 is released. So only in silicate weathering is there a net removal of atmospheric CO2; limestone weathering is net neutral.
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Rob Painting at 19:02 PM on 11 March 2017To tweet or not to tweet at Donald Trump? That was the question!
As far as the IPCC definition is concerned, and it's been there for a while, the formation of limestone adds carbon dioxide to the atmosphere. So it cannot be considered a sink.
On the other hand, weathering, the dissolution of limestone, does remove carbon dioxide from the atmosphere. This process satisfies the IPCC definition of a sink.
It's confusing as hell to non-experts given that the ultimate fate of much of that carbon, over geological timescales, is to end up in limestone sediments, but we shouldn't attempt to reinterpret what constitutes a sink.
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Jim Eager at 14:09 PM on 11 March 2017How Green is My EV?
David, yes, Ontario now generates zero of its electricity from coal. The last coal fired generating plants in the Province (Naticoke and Thunder Bay) were closed in 2013 and 2014, and several new peaking power gas plants eliminated the import of coal generated power from the US Midwest during seasonal periods of peak demand (e.g. summer air conditioning season). Quebec, British Columbia and most of the smaller provinces also produce zero from coal power, but Alberta stil burns coal and a few provinces burn oil. Combined it means well over 63% of Canada’s population is able to make very robust CO2 reductions by using EVs.
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Tom Curtis at 12:44 PM on 11 March 2017To tweet or not to tweet at Donald Trump? That was the question!
Rob Honeycutt @12, at a quick perusal, 7 of the 49 tweets include all caps (8,11,14,26,35,36, and 49). That, however, is irrelevant. The tweets are not comments at SkS, so the moderation policy at SkS does not apply. Further, it is not apparent to me that you can use any textual method to increase emphasis on twitter other than by all caps (but I don't tweet and may be entirely wrong about that).
I will go further. I have a serious objection to twitter in that the short character count per message makes any serious discussion impossible. Even the creative method of using a 49 tweet sequence leaves you using short sentences that do not convey any reasonable level of subtlety. Doug Mackie in his responses here appears to be treating this comments section as a twitter account. His responses have been too short to make a reasonable assessment of his objections beyond the mere fact that he objects. They have been rude, and inflammatory to boot.
On top of that, I struggle to see his objection to the content of the tweets. Atmospheric CO2 would be astronomically higher if the carbon locked up in carbonates were free to bond with oxygen in the atmosphere. That is what the tweet he objects to says. It seems incontrovertible. Even on the narrower point of whether adding calcium carbonate to the the ocean by weathering will draw down CO2, he appears to be arguing against the science. Where I discussing this with a denier, I would probably attribute the nature of his posts (as long on bombast as they are short in length) to that fact. As it is, I remain perplexed both as to the nature of his objections, and they way he has argued his point, including his final denunciation.
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Rob Honeycutt at 11:56 AM on 11 March 2017To tweet or not to tweet at Donald Trump? That was the question!
Doug... Please read the comments policy. This has been a long standing policy here on the website, going back as far as I can remember. And a quick look and I don't see anywhere all caps is used for SkS tweets.
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Doug Mackie at 11:48 AM on 11 March 2017To tweet or not to tweet at Donald Trump? That was the question!
You are jerks to use CAPS in tweets but not allow in comments. I no longer wish to be assoc with sks. Please remove OA not OK series by me
Moderator Response:[GT]
Doug. The policy on SkS restricts ALLCAPS as shouting. However you have the option of using bold as an alternative method which says 'this is a bit more important than usual but I don't want to yell at you'
Seemingly Twitter hasn't caught up yet. -
Rob Honeycutt at 09:54 AM on 11 March 2017Correcting Warren Meyer on Forbes
I'll add here... Warren, the frustrating part of what you (and many other skeptics) are doing is, you're asking people to accept your small minority position as absolute. You're asking people to not consider the low probability high end potential, while at the same time you say we must accept your very low probability low end potential.
That is a recipe for disaster.
What the scientific community is saying is, given the balance of all the available research, here is the low end probability, here is the high end probability, and in the middle are our best estimates where thing likely are.
That's not taking an absolute position on any side. It's an act of constraining the probability to a range within which we can take appropriate action.
As I stated in my original article here, you can't just pick and choose the answers you like and exclude those you don't. You must look at the full body of evidence and act within the limitations of our knowledge. That is what risk assessment is.
Based on that, there are no two ways about this. The entire likely range of climate sensitivity is an argument for strong action.
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Tom Curtis at 08:14 AM on 11 March 2017Correcting Warren Meyer on Forbes
coyote @25:
1) "... most of the prominent climate skeptics ..."
I am uncertain how you quantified that "most". Certainly the folks at Principia Scientific do not. Nor do those behind the arrogantly named Galileo Movement in Australia. Even among those who do accept the existence of an atmospheric greenhouse effect, many accept a distorted version of the theory in which the only relevant component is the back radiation at the surface, whereas in the actual theory the most important component is the effect on the Outgoing Longwave Radiation (OLR), and consequently on Earth's overall energy balance.
Incidentally, the theory as regards to the OLR is sufficiently stunningly confirmed, and follows so directly from basic and well confirmed laws of physics that it is, for all intents and purposes, settled science. Further, the 1 - 1.2 C direct impact of a CO2 doubling from that follows directly from that very well confirmed part of the theory.
2) "What we are skeptical of is the very net high positive feedbacks..."
I am skeptical on what basis you consider the feedbacks to be very high. In AR5 Chapter 9, feedbacks are treated as feedbacks on the radiative forcing. As a result they are dominated by the planck feedback of -3.2 +/- 0.1 (units of W m-2 oC-1, 90% confidence interval). Compared to that the 1.6 +/- 0.3 water vapour feedback, or the 1.6 +/- 0.9 total feedback excluding the Planck feedback are not "very high". Figures from IPCC AR5 Chapt 9, table 9.5; figure for total excluding Planck feedback determined by adding the values and summing the uncertainty in quadrature.) Nor are they at significant risk (despite the large uncertainty from the cloud feedback) of making the total feedback (including the Planck feedback) net positive, the precondition of a runaway greenhouse effect.
You may be more familiar with the feedback presented as a response to an initial temperature increase, but in that case the response necessary for a runaway effect is in infinite positive feedback, so again, the approximate doubling to quadrupling of the initial temperature response is not "very high".
3) "... isn't this education of the public about the basic theory useful ..."
Educating the public with a string of "false facts" is never useful. Even getting one basic fact right is unhelpful when it is introduced out of context and surrounded by a cloud of untruths.
In this instance, the consensus surveys do not use questions that delve into feedbacks and planck responses, but can be resolved at a purely emprical level. Further, that the temperature response to a doubling of CO2 is in the order 1.5-4.5 oC (66% confidence interval) can be determined solely on an empirical basis. That it is also predicted on a theoretical basis (ie, by the Global Circulation Models) is just icing on the cake. When historical records since 1850 (including ice core records) show a linear response by temperature to CO2 forcing gives a linear response of 0.58 +/- 0.02 C/(W/m^2) (r^2:0.811), then an effective climate response of 2.15 +/- 0.7 C per doubling of atmospheric CO2 is a matter of empirical observation. When the energy imbalance at the TOA remains unclosed with that temperature responce, that the equilibrium response to a doubling of CO2 will be larger than that is again a matter of empirical observation. (Note, those uncertainties are for the calculations alone, uncertainties from the data will significantly increase the uncertainty range, but not change the observed sensitivity.)
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