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Rob Honeycutt at 08:03 AM on 27 August 2015Tracking the 2C Limit - July 2015
jphsd... Yes, I'm aware of Victor & Kennel. But Stefan Rahmstorf did an excellent response to their paper on Real Climate titled, Limiting global warming to 2 °C – why Victor and Kennel are wrong.
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M Tucker at 07:41 AM on 27 August 2015Here’s what happens when you try to replicate climate contrarian papers
Dana,
I love this piece. I love this web site. You and your comrades do excellent and necessary work but please be careful with history.
"...Galileo, whose conclusions were based on empirical scientific evidence, supported by many scientific contemporaries..."
I’m sorry Dana but that is just not true but it is a widely held belief of those who are not aware of the actual history. Please don’t be one of those.
Sci Am had a great article last year, in the January issue I think, called “The Case Against Copernicus” that discusses the lack of empirical evidence during the time of Copernicus and Galileo. The many scientific contemporaries you mention did not exist. You could also visit a wonderful site called Renaissance Mathematicus. Thony Christie is a superlative historian of science of the Early Modern Period and he has a special section called The Transition To Heliocentricity: The Rough Guides because so many folks keep getting the actual history wrong.
If you get the history wrong when trying to correct the mistakes others are making with the history your argument loses its justified force. This is a friendly suggestion to check your history before publishing.
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jphsd at 07:36 AM on 27 August 2015Tracking the 2C Limit - July 2015
Here's the link to the Nature article: Victor and Kennel (2014)
Moderator Response:[PS] Fixed link. Please use the link button in the editor in future.
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Ed Wiebe at 07:35 AM on 27 August 2015Tracking the 2C Limit - July 2015
It ocurred to me later that my point 5 about being above or below the 2 °C limit can be resolved by saying "above" or "below". No need then for a negative sign.
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Rob Nicholls at 06:56 AM on 27 August 2015Tracking the 2C Limit - July 2015
I think this is a great way to focus people's minds on the looming danger of over 2 degrees C of global warming unless humanity acts very quickly and decisively to build a low carbon energy infrastructure and massively cut its greenhouse gas emissions.
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Rob Honeycutt at 05:16 AM on 27 August 2015Tracking the 2C Limit - July 2015
jphsd... I wouldn't agree that 2C can be defined as "purely" political. If it were purely political then any number could be chosen, and it certainly would be far easier to politically agree on 3C or 4C. And I also don't think anyone defines it as a specific "threshold that we shouldn't cross."
There is a lot of scientific basis that revolve around the figure. We clearly increase our risk of crossing tipping points the higher we go. We also know that the Eemian was somewhere around 2C over Holocene preindustrial.
I think one could define 1C over preindustrial as "dangerous." 1.5C is clearly more dangerous than 1C... 2C more dangerous than 1.5C, and so on. Each point requires different levels of mitigation and adaptation, with a point somewhere along that continuum where mitigation would become ineffectual.
What I would agree with is that the exact selection of 2C is relatively aribitrary. But ultimately, it is important to draw a line in the sand somewhere and stick to that line as a defined measure.
As for the "threshold", no one is saying that this side of 2C is safe and that side is dangerous. Again, it is a continuum of escalating danger. I see the 2C limit as being a sign post continuously warning us that we have a critical global crisis ongoing.
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jphsd at 03:37 AM on 27 August 2015Tracking the 2C Limit - July 2015
Per David Victor, it's always worth pointing out that the 2C target is purely political and has no basis in science as some threshold we shouldn't cross.
2C was chosen by UNFCCC because it was believed (back then) to be an achievable target both technically and politically in the timeframe being discussed.
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bwilson4web at 03:30 AM on 27 August 2015Tracking the 2C Limit - July 2015
Sorry, I see the "12 month" label on the purple line.
Bob Wilson
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bwilson4web at 03:26 AM on 27 August 2015Tracking the 2C Limit - July 2015
The 'purple' line does not look like a 30 year, straight-line average but some smaller interval. I recommend making it 365.25 days or one year so seasonal changes disappear.
Also, a straight-line average is easy to compute, it has the bad habit of suppressing local minimums and maximums in the data. More work, I prefer a Gaussian weight average so random forcing functions like El Nino/La Nina and volcanic erruptions are seen in the data.
The other problem of a time-range, trend is the data lags by 1/2 the interval. You can include today's data in a one year average but the mid-point of the average is six months earlier. There are techniques that can allow showing 'current data' but it leads to subsequent versions 'moving the dot.'
Last, if using excel, use a calculated trend line and compare it to the excel generated trend line. I've been disappointed by the excel trend line function in the past.
Bob Wilson, Huntsville AL
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Rob Honeycutt at 03:26 AM on 27 August 2015Tracking the 2C Limit - July 2015
Thanks for the feedback, ecwiebe. This is definitely going to be an ongoing project with many updates along the way. A few responses, though.
1) We discussed this internally. My own take was that I really wanted to add the CO2 curve in there as a reminder of what's causing this. But adding the second data axis ended up visually confusing. The exact same data is presented as a second chart below with the y-axis data included.
2) Let me think about that one. I've always used the "C" without the degree symbol primarily because in the general course of typed communication, it's impossibly slow to add. But in a static chart like this it's less problematic.
3) That's easy to fix.
4) I'll see if I can squeeze the axis labels in there for next time.
5) Very good point as well about "degrees until 2C." I hadn't thought of what that number becomes when we reach 2C.
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Ed Wiebe at 02:06 AM on 27 August 2015Tracking the 2C Limit - July 2015
This is a good idea. However, I have a few of concerns about the first figure you've shown and since this appears to be the beginning of a long process I'm going put them here for you to consider.
1) You are showing two different quantities on a chart with one axis that has no units defined. That axis seems to be indicating °C at present. Also, these are temperature anomalies. Yes, that is hinted in the figure caption with the words "baseline period ..." but it probably should be stated in the axis label as well.
You need two axes and sets of axis labels for this plot unless somehow the variables have been normalized against the same dimensionless scale. I doubt that's the case but if it is it needs to be explained.
2) The unit for temperature is °C. Think of that as a single character that should be used in place of C. As far as I'm concered not using °C is just wrong regardless of how commonly it's done. °C should be a single character in the character sets of the world as far as I'm concerned. Is it?
3) units should always be preceded by a (non-breaking) space. You've done this inconsistantly in the same figure. e.g. '12m', '1.060 C'
4) though it may seem obvious, the time axis needs to be labelled with years or those units must be explained somewhere.
5) I don't care for the term, "2C Limit" but I recognize it's a name for "2 °C Limit". I don't think I can persuade the world to change that. On the chart you have "Degrees until 2C". This one I can't abide. Try, "Difference from 2 °C". At present you have "0.940 C" which is 2 °C - 1.060 °C = +0.940 °C. When we (inevitably) get above the 2 °C temperature anomaly this number will become negative. Is that really the way you want to think about it? I think it's backwards.
On the whole I think this is a good idea and obviously you can take my comments or leave them, it's your project. -
Here’s what happens when you try to replicate climate contrarian papers
bvangerven - As I see it, the 97% consensus is pretty clear on anthropogenic GHgs, increased radiative effect, attributions, etc. While the remaining 3% couldn't agree that the sky is blue....
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bvangerven at 19:36 PM on 26 August 2015Here’s what happens when you try to replicate climate contrarian papers
The fact that the 3% "skeptics" don't agree with each other is a very strong point. I would like to see some statistics on that : what % of skeptic papers claim "there is no warming", "climate sensitivity is low", "everything is uncertain" etc ? And how many climate skeptics contradict themselves ?
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denisaf at 09:50 AM on 26 August 2015Adapting to air pollution with clean air stands in China
The article deals with only one of the problems created by the operation of industrialized civilization. The holistic problem is that the vast, irrevocably aging infrastructure is irreversibly using up limited natural material resources and producing immutable material waste. Air pollution is one consequnce of the latter. Climate disruption and ocean waming and acidification are others.
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PhilippeChantreau at 07:16 AM on 26 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
MA Rodger, correct. The extra drag is still there and I would be interested to see how airplanes whose mission traditionally requires cruise just below the transsonic range will fare (airliners and business jets). Few people realize when they fly that the safe airspeed window for an airliner at cruise altitude may be only 20 or 30 knots wide. Beyond that lie the risks of strucutral damage or controllability problems, below that a stall waits for you; high altitude stalls are no fun and recovery will likely put you in overspeed, with the issues I just mentioned.
In any case, we would be looking at an entirely new generation of airplanes, built from scratch, with an equally new infrastructure to support them, and a blank slate on safety. Such a transition would take a lot of time and be a little dificult to bridge. Currently existing airplanes can be relatively easily converted to use carbon neutral fuels, already have their infrastrucure, and their development includes all the improvements made every time there was an accident. These are important considerations. Airplanes are always compromises, the best possible for the type of mission to be flown. How we will power them will likely be that way too. I'm all for the best possible solution.
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scaddenp at 06:50 AM on 26 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
ianw01 - using petroleum to create plastics by and large is binding the carbon rather than releasing it into the atmosphere. The problem is petroleum is using it for energy. I dont see 100% renewable energy as being incompatiable with continuing to use oil for plastics.
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shoyemore at 03:46 AM on 26 August 2015Here’s what happens when you try to replicate climate contrarian papers
There is a thorough discussion on this paper at Real Climate, moderated by Rasmus Benestad. It includes contributes to the discussion from Ross McKittick and Richard Tol, who both had opportunities to review the paper in an earlier form and who both advised against publication at that time.
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MA Rodger at 03:19 AM on 26 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
PhilippeChantreau @67,
You get me re-visiting the Cryoplane Report because what you say is familiar but not complete. The summary of the report states:-
Following features resulted from comprehensive calculations and parametric studies for the above listed rage of aircraft categories.
① Due to the bigger wetted surface of the aircraft due to H2 storage in pressure vessels the energy consumption would increase by 9% to 14%.
② The OWE (Operating Weight Empty) may increase by roughly 23% by having additional tank structure,
③ while the difference of the MTOW (Maximum Take-Off Weight) will vary between plus 4,4% to minus 14,8% depending on the aircraft configuration and mission.
All this will result into an increase of the operating costs by 4% to 5% caused by fuel only.
The numbers for ΔMTOW were given as:-
Business jet -5.2%
Small Regional a/c +0.3%
Regional prop a/c +4.4%
Regional jet a/c -2.4%
Medium range a/c -2.7%
Long range a/c -14.8%
Very long range a/c -1.6%Thus the reducted weight of fuel load equals or exceeds the extra weight of the unloaded a/c in all bar one circumstance. Thus, I was mainly correct but perhaps overly optimistic with my all-encompassing "far greater than the structural weight" comment @65.
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Dcrickett at 02:38 AM on 26 August 2015Here’s what happens when you try to replicate climate contrarian papers
Not cherry picking, just nit picking:
"The one thing they seem to have in common is methodological flaws like cherry picking, curve fitting, ignoring inconvenient data, and disregarding known physics."
Are not "cherry picking" and "ignoring inconvenient data" pretty much the same thing?
I am grateful for this research.
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PhilippeChantreau at 01:56 AM on 26 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
MA Rodger, as a long time pilot and flight instructor (although on light airplanes). I do appreciate the fuel load of modern airplanes. As someone familiar with the basic aerodynamics of flight, I also understand the relationship between weight and lift requirements.
The problem of all alternate ways to power aircrafts is energy density, which is very high with hydrocarbons. Hydrogen has a greater energy density per mass, but a much lower energy density per volume, and carrying it at the kind of pressures that would alleviate this problem requires heavy steel tanks. Liquefying it is the best option but carries its share of problems. Here is a excerpt from the source you cited:
"A key issue was to model the liquid hydrogen fuel system architecture - per unit of energy, liquid hydrogen has four times the volume of kerosene - so fuel tanks four times as large needed to be fitted in, or on to, each aircraft category. Modelling showed that, owing to the larger exterior surface area needed to accommodate the fuel tanks; energy consumption would increase by 9% - 14%, as would the maximum take-off weight. Overall operating costs would increase by 4% to 5% due to the fuel alone."
I did not misread this at all. Vast reservoirs containing a much lighter fuel but way more total volume of it. Bulkier and heavier airplane because of the additional storage volume.
Everything in an airplane has a cost. Any item is weight for which lift has to be generated. Large areas to accomodate large volumes of fuel imply more sheet metal, hence more weight, even if the total fuel weight is the same. Large areas also mean more drag, so more energy required for taek-off, climb and cruise. More weight means sturdier landing gear, which itself will have to be heavier as a result. Etc, etc.
Then of course, there is the issue of having fuel in the structure in the event of a crash. Engineers also have to assess the survavibility of a forced landing. Powering an large transport airplane is not a benign problem. I have no particular attachment with any solution.
From purely technical considerations, I remain of the opinion that synthetic hydrocarbon fuels capturing atmospheric carbon are a better option in the short and medium term than hydrogen. And that's not even considering all the infrastuscure associated with commercial transport airplane operations, another non benign consideration.
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One Planet Only Forever at 00:08 AM on 26 August 2015Adapting to air pollution with clean air stands in China
Instead of choosing between adaptation and mitigation, I prefer to think of the required action as an adaptation that will mitigate the impacts of human economic development.
The required adaptation is the open admission that much of the currently developed perceptions of prosperity, wealth and power are illusions that are not justified and need to be shattered.
There is a belief that the current measures of wealth and prosperity must be maintained and that the perceptions of the most prosperous must be maintained and continue to increase.
The required adaptation is a change of the way that wealth and prosperity are evaluated. And that change is required even if it means that many of the people currently considered to be very prosperous and wealthy are realised to not deserve the level of wealth or prosperity they have gotten away with developing.
That adaptation will clearly lead to the required mitigation. And it is also clear that without that adaptation, progress of humanity toward developing a lasting better future and lasting growth of the economy will continue to repeatedly fail as the undeserved perceptions of prosperity and wealth continue to be allowed to develop to the point of being impossible to gather popular support for.
It is also clear why that required adaptation and change by humanity will not be easy to achieve. But the difficulty in achieving it does not change the importance of it being successfully developed, the sooner the better.
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ianw01 at 00:01 AM on 26 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Plastics are made from certain fractions of petroleum. I have not seen any mention of how our demand for them would be met or replaced. The challenge goes way beyond using a cotton shopping bag - just look at all the surfaces and objects in your car, on your desk, at home and at your workplace.
I'm not objecting to the direction we have to move. Just trying to get my head around what for me is an astonishing premise in the original article.
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MA Rodger at 20:23 PM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
PhilippeChantreau @62,
On the weight issue, perhaps you do not appreciate the fuel load of a modern airliner. The ubiquitous Jumbo Jet has a max fuel capacity 43% to 49% of it's max take-off weights, far greater than the structural weight. Using hydrogen would halve these fuel loads but at a price. The first problem is the need to keep the fuel in big deep tanks to reduce the warming of the cold fuel. That means conventional wing tankage has to be replaced by fuselage tanks but that is where the fare-paying passengers & freight usually sit. And with hydrogen more bulky, the fuselage would have to be bigger. The main design consideration would then be the aerodynamic cost of a big fusilage rather than its weight. What CRYOPLANE was saying is that these design considerations are feasible. But the convertion to using hydrogen would be a leap for mainstream commercial aerospace. Certainly the industry as a whole is talking Plan B - getting a 50% reduction per seat/mile in fossil fuel use by 2050 (or whenever) and making that it sound like they are thus doing their bit to counter AGW. Of course with passenger growth, the whole thing turns to a nonsense. The use of bio-fuels would likely allow a partial substitution of fossil fuels through time. Myself, I kind of get the impression that its the fear of the conversion to hydrogen that the industry is baulking at, not the actual technology itself.
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Ron Short at 19:38 PM on 25 August 2015Permafrost feedback update 2015: is it good or bad news?
First post from this non-scientist Andy - re. the recent Princeton paper -
"New research led by Princeton University researchers and published in The ISME Journal in August suggests that, thanks to methane-hungry bacteria, the majority of Arctic soil might actually be able to absorb methane from the atmosphere rather than release it. Furthermore, that ability seems to become greater as temperatures rise."
This has been hailed in some quarters as the end of the "methane scare", because "the bugs will eat it all".
The paper refers to "Arctic soils containing low carbon content — which make up 87 percent of the soil in permafrost regions globally". I suspect that the positive feedback from the other 13% of soil with higher carbon content may be greater than the negative feedback observed by this study, but what do I know?
I have yet to see any feedback from scientists which supports my view, and meanwhile this paper is being used, and possibly abused, by the usual suspects.
I would be grateful for your views.
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New paper shows that renewables can supply 100% of all energy (not just electricity)
Denisaf - Please read #55 and #56 regarding hydrogen as a primary transportation fuel, and why there are alternatives.
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New paper shows that renewables can supply 100% of all energy (not just electricity)
Synthetic fuels created with renewable energy should be close to pollution neutral the hydrogen and carbon in synfuels come from the environment, and go back to the environment.
And I only qualify the statement slightly because the heat of combustion also leads to NOx, unused hydrocarbons and thus ozone, and some particulates burned off the engine components. But that's really small change compared to the GHGs and even SO2 emissions.
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PhilippeChantreau at 11:53 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
MA Rodger, point taken on adressing the arguments and concerns of the other poster. Back to the meat of the issue, the article you linked on the cryoplane specifically indicates that the hydrogen has to be liquefied (hence the name) and that, even in that state, it has a lower energy density than hydrocarbon fuels, which leads to the higher weight necessary to achieve a useable range. Personally I am skeptical of hydrogen as practical solution to power large, long range aircrafts, and I think that producing hydrocarbon fuels through processes that will capture atmospheric carbon may be a better solution.
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michael sweet at 10:37 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Denisaf,
Please read the OP. The electricity will come from wind, solar and other WWS resources. The energy to make and liquify the hydrogen is included in the calculation. Some pipelines may be needed for hydrogen but the hydrogen might be made where it is needed with power from transmission lines. If the electricity was used to make liquid fuel (as described by KR at 56), the fuel could be shipped in existing pipelines. Liquid fuel releases more pollution when it is burned but no changes in current airplane technology are required.
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mancan18 at 09:46 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
@ PluviAL 57, 58.
The value of this article is that it shows that the world can move to WWS to replace FF, if it wants to, and I think most of us do want to despite the powerful vested economic interests against doing so. Also, we will have to do so within a little over 100 years anyway due to the depletion of FF resources, even if the economic forces against doing so triumph at Paris like they did in Copenhagen on the back of the GFC. Perhaps, what is happening economically in China at the moment will impact the world to the extent that Paris also ends in failure. Acting now rather than waiting till FF resources are depleted will mean the difference between restricting CO2 to "manageable" levels to putting CO2 levels up to over 800 ppm with all the projected climate calamity and uncertainty that this means. Based on the mainstream acceptance of technology in the past, like cars, aircraft and computers, it will take around 30 years anyway, and these technologies were driven by the very wealthy taking up the new technology. Transitioning from FF technology to WWS technology is not being driven by the very wealthy because, unfortunately, this time it is not seen as some trendy plaything but just an extra short term expense, even though the long term cost is much larger if nothing is done. It does mean that Governments do need to act in the interest of us all so that the huge long term negative externalities of not acting are avoided. Sadly, those who matter, the very wealthy, wield far more politcal influence than their numbers suggest. I hate to be pessimistic but until they get on board, very little will be done except for some token policy or effort. I guess something is better than nothing, but it is unlikely to be to at the levels that are needed to avoid the worst IPCC projections. I still try to remain optimistic, because it is all you can be.
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denisaf at 09:10 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
The discussion about using hydrogen fuel cells for airliners does not consider the overall feasibility. Producing vast amounts of hydrogen by electrolysis of water woul use up electrical energy. What would be the source of that energy? Also, the hydrogen would have to be liquified (by a cooling system) for transportation and for storage on the airliners.
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PluviAL at 08:57 AM on 25 August 2015World Bank rejects energy industry notion that coal can cure poverty
The arguments for renewable energy for developing countries are valid, but the cost factors must be considered. A carbon tax could go a long way balnce the cost difference. Another factor is compensating developing nations for using the more expensive option of renewables.
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PluviAL at 08:40 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Mancan18, I don't even know what is not my opinion, still your assertion is a big one. So, let me approach it from your concluding argument. CFCs could be controlled because they are inconsequential, replaceable, and there are not huge economic interests behind them. FF are all the opposite. The article, and this wonderful 107 page paper behind it argue that they are replaceable, and rather easily if 150 years of infrastructure is to be replaced in 35. I argue the same as this paper in my book, but on the basis of much cheaper technology with overwhelming benefits.
Fossil fuels without tax are far better than most renewable technologies; my opinion from similar study as yours. The paper proposes a road map to give policymakers a sense that there are alternatives.
So, if a carbon tax is imposed, we know there are viable alternatives.There are many points of contention, of course, but its a good starting point. I would allow that FF will not be easily replaced but its a duable task.
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Jonas at 07:56 AM on 25 August 2015Adapting to air pollution with clean air stands in China
I am searching for words far beyond "despair".
Is this what homo sapiens calls a "solution"?
The situation must be way out of any control. -
scaddenp at 07:38 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Stranger - to be honest, I didnt see the date on that article. However, the description of their current technology says they are still based around same slow speed direct drive annular generator, but I also note comments that their technology is considered expensive compared to neodymium-based systems. Still, as 4th largest player world wide and with 40%+ of German market, they are not exactly a bit player.
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ronald myers at 06:13 AM on 25 August 2015Adapting to air pollution with clean air stands in China
Based on the reports of the pollution composition and level in China prior to the Olympics, I doubt that these shelters reduce pollutant levels to the US standard for Particulate, SO2, NOx, Ozone and Lead. At 70% reduction it would be marginal. However, the technology to reduce all of these pollutants would require three different technologies. Particulate (and Lead) would likely be the easiest by using a fabric filter. By adding an alkaline material to coat the inside of the fabric filter, the SO2 might be reduced. At great expense a paladium catalyst may address the NOx and Ozone. However, I would have to see a substantial amount of data to beleve any high reduction in the pollutant concentrations. That still does not address the hazardous organic vapors (benzene, toluene, etc.) which would require the addition of activated charcoal for removal.
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New paper shows that renewables can supply 100% of all energy (not just electricity)
I'll note that current analyses indicate that overbuilding capacity in wind and solar is more cost-effective than building energy storage into the grid. If that continues to be the case, excess power when available could be used for additional synthetic fuel production, effectively becoming energy storage for a large sector of the economy.
Whether or not that diversion methodology makes overall economic sense will depend on whether syn-fuel production facilities can afford to operate part-time, though, and I don't have numbers on that aspect. But syn-fuels from renewable power do appear workable and economic. The US Navy has considered this for fueling their carrier aircraft, producing syn-fuel kerosene from reactor power on the move to extend carrier mission duration, at a cost of ~$6-7/gal. - apparently the amount of fuel for the aircraft becomes a limiting factor.
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New paper shows that renewables can supply 100% of all energy (not just electricity)
Regarding hydrogen fuels - aircraft (and transport in general) have certain needs, among them sufficient energy density in the fuel to pack in enough for a reasonable trip while still having room for occupants and cargo.
Considering the issues with hydrogen storage density, I suspect synthetic fuels created with renewable energy (Jensen et al 2007 published in the "International Journal of Hydrogen Energy", for but one example) will be a more viable path for transport.
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MA Rodger at 04:27 AM on 25 August 2015Medieval Warm Period was warmer
Steven Sullivan @233.
The 2012 comment by realscience @148 referred to Oppo, DW, Y Rosenthal, BK Linsley, 2000-year-long temperature and hydrology reconstructions from the Indo-Pacific Warm Pool, Nature, 460 1113-1116, doi:10.1038/nature08233, 2009. You are referring to a more recent paper - Rosenthal, Y., BK Linsley, Oppo, DW, Pacific Ocean Heat Content during the past 10,000 years, Science, 342 617-621, 2013.
The quote you make from this later paper has been bandied about by contrarians, mainly because they rather enjoyed the paper saying "The inferred similarity in temperature anomalies at both hemispheres is consistent with recent evidence from Antarctica (30), thereby supporting the idea that the Holocene Thermal Maximum, MWP, and LIA were global events," but felt the sentence you quoted needed a bit of trashing as it spoiled their interpretation of what the paper was saying. So some branded your quote "a single sentence of genuflection to CAGW." Reading this contrarian blather, I think it's fair to say that the contrarians inabilities in understanding 'CAGW' are also persent in their understanding of the relationship between OHC & surface temperatures.
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MA Rodger at 04:13 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
PhilippeChantreau @48.
My appologies. When I posted the link it was fully readable. A 737 was to be filled with a hydrogen fuel tank so this was not a commercially viable machine being built. However the link does demonstrate that Beoing are looking at hydrogen fuel cells which was the contended issue.
Further, CRYOPLANE did not involve hardware but again, demonstrated that Airbus were not of the opinion that "hydrogen fuel cells for airliners were found to be impractical over forty years ago," again a point of issue.
I don't recall weight being a hinderance to hydrogen fuel. Rather it reduces the weight of fuel which is an enabling situation. However it is correct to say that the aviation industry are not rushing to embrace this technology. As I remember, the CRYOPLANE report was suggesting 2015 as the timing for hardware to begin working for a living but that conventional feuls would retain a price advantage for some period.
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Rob Honeycutt at 04:00 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
No problem. Honest mistake.
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Stranger8170 at 03:59 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Sorry Rob. I always tell my wife I'm the king of l faux pas. And it's embarrising after I said I come here everyday.
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Rob Honeycutt at 03:54 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Stranger... Around here, we prefer to use the abbreviation "SkS" instead of "SS" for obvious reasons.
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Stranger8170 at 03:46 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
Thanks KR. That's really informaive stuff.
I've make it here everyday since this website was created but rarely post. Real Climate use to be my main read but I've found SS to be more helpful for the non science majors.
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Rob Honeycutt at 03:00 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
It's worth noting that there is a large ARPA-E project to develop permanent magnets that are free of rare earth elements called Rare Earth Alternatives in Critical Technologies (REACT).
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PhilippeChantreau at 02:50 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
MA Rodger, your link to the Boeing fuel cell demonstrator leads to a paywall. The cryoplane assessment project was an entirely theoretical study that concluded that using hydrogen as fuel for transport aircraft was technically feasible. However the extra weight leads to hiher operating costs. Furthermore, it has, to my knowledge, not led to the development of any flying prototype. It also did not seem to consider all the infrastructure and operating procedures modifications, which would be significant.
There may be more medium term future for aviation in generalizing jet fuel from algae, which has a chance to be carbon neutral if processes use renewable energy or their own product. This would have the inconvenient of not alleviating the release of turbine exhaust gases at high altitude but at least would prevent further injection of previously stored carbon. These fuels are also easier to deal with when spilled.
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PhilippeChantreau at 02:27 AM on 25 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
johnkg, the article you reference discusses research to replace airliners' auxiliary power units (APUs) by hydrogen fuel cells. APUs are used to generate power for the aircraft needs when parked on the ground with the engines shut off. APUs are small gas turbines but pack a lot of power and have even been used occasionally as a powerplant for smaller aircrafts. However, it is a far cry from powering an ariliner for flight with hydrogen fuel cells, and the article does not mention any intention or researching in that direction.
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New paper shows that renewables can supply 100% of all energy (not just electricity)
Stranger - Rare earth magnets are among the most powerful permanent magnets, making very efficient windmills cheaper and more effective. As such, their availibility is a potential limiting factor in wind energy.
However, in addition to the current supplies from China, there are mines being developed in Austrailia, Brazil, Canada, and Vietnam that may be online in a few years, and there are potential replacements in the works such as iron nitride magnets with no rare earth components and twice the magnetic energy of present rare earth magnets.
Rare earth availability doesn't represent a ceiling on potential wind energy.
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Steven Sullivan at 01:55 AM on 25 August 2015Medieval Warm Period was warmer
realiscience wrote (in 2012): "Did you look at Oppo's data points. Some are clearly at this level, meaning that it is within the margin of error that sea surface temperatures could have been higher. ?"
I read the paper. Did you see this part? " The modern rate of Pacific OHC change is, however, the highest in the past 10,000 years (Fig. 4 and table S3)." OHC = ocean heat content
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Stranger8170 at 23:49 PM on 24 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
scaddenp, to be honest I've barely scratched the surface in understanding the dymanics of rare earth metals in the construction of things like gearless wind turbines and thin solar panels. I figured that by bringing my concerns to Skeptical Science I'd gain futher insights to what was only recently pointed out to me as a problem. You've enlightend me on the fact that thin solar pannels are used less often than normal PV instalations which don't use rare earth metals.
Concerning wind turbans, what little bit I've learned is that the reason they've gone to rare earth mineals was to make the wind turbines gearless which means they have far fewer mechanical problems which had plagued them in the past.
I noticed the link you posted was 4 years old. That seems like a long time in todays high tech world. Do you know if the turbines built by Enercon have panned out well since 2011?
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MA Rodger at 22:33 PM on 24 August 2015New paper shows that renewables can supply 100% of all energy (not just electricity)
denisaf @42.
If anybody needs to present "a reference" then that is yourself. You make bold claims here but without a single shred of evidence to back up your foolhardy assertions. So who were these "reputable researchers" you mentioned @25, the ones who have "thrown out over forty years ago ... the suggestion that airliners could be powered by hydrogen" and presumably the same ones who found, as you asserted @42, "hydrogen fuel cells for airliners ... to be impractical over forty years ago." All this with not a whiff of a reference.
Airbus were a big part of the Cryoplane project that, much more recently than 1975, concluded it was technically feasible to power air transport with hydrogen fuel cells except that the supply hydrogen wasn't available. And given that finding, we should not be so surprised to see Beoing continuing with their own researches.
And denisaf, if you want to have a bish-bash-bosh over a session at an AIAA conference, do pause a while. The AIAA hold many events that could be described as 'conference' and so this session you refer to will not be evident to someone reading your words. Thus without a reference to it you will appear as just another know-it-all mouthing off on the internet.
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