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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 1 to 50:

  1. Is Nuclear Energy the Answer?

    Recommended supplemental reading: 

    Regulators have approved designs for 12 small reactors to be built in Idaho, but opponents say the project is dangerous and too late to fight climate change.

    Small Nuclear Reactors Would Provide Carbon-Free Energy, but Would They Be Safe? by Jonathan Moens, InsideClimate News, Oct 21, 2020

  2. Climate's changed before

    Eclectic @834,

    Do be aware that London's frozen River Thames was a very rare event and if anything provides evidence against the Little Ice Age being something exceptional with reported freeze-ups occurring even during the Medieval Warm Period. There were perhaps only a half dozen Frost Fairs listed in the records and they stopped appearing, not because of warmer winters but because the old London Bridge was demolished and the river embanked.

    Given such reasons for the absence of  Frost Fairs since 1813, perhaps a better river to look for evidence of a Little Ice Age (or lack ofevidence) is the Rhine which is recorded freezing 14 times since 1784, the last time in 1963. Of those 14 freezes, most occurred well after any Little Ice Age with seven during the 20th century.

  3. Is Nuclear Energy the Answer?

    Philippe Chantreau,

    When I was young I believed the promises of nuclear engineers.  After 45 years of following nuclear power I no longer trust their paper designs and promises of safe reactors.  If they ever build a pilot plant we will see if their scheme actually works as they claim.  Upthread I cite the French Nuclear Regulatory Agency which does not see safety improvements in these new designs and the Union of Concerned Scientists who fear that false claims of inherent safety will lead to removal of expensive safety features in reactors.  There are reasons that they have not yet built even a test reactor or pilot plant after 13 years of work.

    I note that NuScale is losing customers now that they are actually trying to build their reactors.  The cost is too great.  It is not clear to me if their reactor price has increased or if renewable energy is now so cheap that they cannot compete.  Probably both.

    Nuclear power is uneconomic.  It takes too long to build.  Even if they achieve their goals it will be 2050 before TRW reactors are ready for a large scale buildout.  I see no reason to believe that reactors with complicated double cooling systems can control the problems of using liquid sodium in a cost effective manner.  They have not addressed the problems of Abbott 2012.  I am especially concerned about the extensive use of rare materials.

    In a renewable energy world baseload power is very low value.  Peak power on windless nights is most valuable.  Current baseload plants are dinosaurs.

  4. All Renewable Energy Plan for Europe

    A $20 billion plan (Guardian article) to build a giant solar farm in the Australian outback has been announced.  Much of the electricity will be transmitted to Singapore to replace expensive gas generated electricity.  I recently saw a description of a scheme to manufacture hydrogen using electricity from a giant solar array in Australia.

    The price of solar power is now so much lower than fossil energy that this type of plan can make money.  Hopefully more giant farms will replace current fossil generators.  The Southwest USA has a large area perfect  for this type of farm.  Usable deserts exist in many locations worldwide.  Existing gas generators can supply backup power at night while storage solutions are developed.

  5. One Planet Only Forever at 15:03 PM on 21 October 2020
    What does the global shift in diets mean for climate change?

    wayne,

    Thankyou for re-presenting the rice example as a part of your thinking regarding this issue.

    My comment is that the sustainability of all food production needs to be the objective. From a climate impact perspective the status quo plant and animal growth activity, not its expansion or other impacting things humans do to grow the food, is not an issue in the planet's surface/atmospheric cycle. The issue is human activity that is harmfully changing things like increasing ghg's in the atmosphere.

    There have been many study reports regarding the ghg impacts of different types of agriculture. The general, and consistent or common, conclusion of those investigations appears to be as presented in this OP - reduced meat consumption and changes of how the reduced amount of meat is produced or obtained would be beneficial from a climate impact perspective.

    My concern is the broader Sustainable Development Goals which include biodiversity loss and other harmful unsustainable impacts of human activity. Expansion of food production that negatively impacts biodiversity is also harmful and needs to be reduced.

    It may be that rice and meat consumption need to be reduced, and for more reasons than the climate impacts. Rice has less nutrient value than potato. And over-consumpton of meat has serious health implications.

  6. What does the global shift in diets mean for climate change?

    Hi Rob @23 that's why I said it was a start :) and was just adressing the impact of rice cultivation. Do we not think that 22% and 11% methane contributions compare unfavourably with those of cattle?

    Organisms vary in their efficiency of feed conversion. Ruminants or foregut fermentation is one of the greatest developments in evolution since it's arrival some 50 million years ago. The benefit and efficiency of this system can be seen in their almost complete dominance of the herbivorous meso/megafauna. Virtually all non-ruminants or complete hindgut fermenters have since that time faced extinction. Out of some 450 ungulates today only about 25 non ruminants survive.

    See (Demment MW, Van Soest PJ (1985) A nutritional explanation for body-size patterns of ruminant and nonruminant herbivores. Am Nat 125: 641–672) for an explanation on the distribution and relative efficiencies of these different fermentation systems. Notice that non-ruminants are fermenters as well, just that one of the fermentation products ie., methane comes out the back instead of the front.

    This does not just apply to different digestive/fermentation systems but the inputs and outputs themselves.

    Feeding high nutrient/digestable feed to ruminants may result in lower enteric methane outputs (Boadi, D. A., Wittenberg, K. M., Scott, S. L., Burton, D., Buckley, K., Small, J. A. and Ominski, K. H. 2004. Effect of low and high forage diet on enteric and manure pack greenhouse gas emissions from a feedlot. Can. J. Anim. Sci. 84: 445–453.), but see their qualification and comparison to IPCC estimates

    A concern when evaluating animal feeding and management strategies to determine greenhouse gas mitigation potential is that significant emission reduction in one part of the production system may be negated if emissions are increased in another part of the production system. Table 6 demonstrates that inclusion of whole sunflower seed in general resulted in significantly lower (P < 0.05) total daily emissions of CH4 and NO2 expressed as CO2 equivalents. The observed reduction in total emissions is attributed to a significant reduction in enteric CH4, which contributed 95 to 96% of the total non-CO2 emissions from the feedlot. Enteric emissions by feedlot cattle fed a typical barley-based finishing ration were 72% of that estimated by IPCC (Tier 1). Use of whole sunflower seeds in the high forage:grain diet resulted in even lower emissions relative to estimates. Similarly, manure pack emissions in the current study were approximately 50% of that estimated using IPCC (Tier 1) coefficients.

    Indeed over 7.5 times more CH4 kg–1 dung (DM basis) was emitted from grain-fed compared to their hay-fed counterparts.

    Jarvis, S. C., Lovell, R. D. and Panayides, R. 1995. Patterns of methane emissions from excreta of grazing animals. Soil Biol. Biochem. 27: 1581–1588

    Thus the "thermodynamically impossible" comment, but it goes much further than that.

    People do realise that sheep and goats are just small ruminants and cattle are just large ruminants. You can even have cattle and sheep that approach each other very closely on a size basis. On the basis of size alone one of the biggest thermodynamic constraints will be the surface area to volume ratio, smaller organism will be energetically less efficient than larger ones, "having to run all day just to stay in one place". This is literally highschool physics and biology.

    Monogut organisms like ourselves and for simplicity sake chickens and pigs cannot handle the feed inputs that hindgut and forgut fermenters can, generally requiring higher quality feed from both a nutrient and digestive quality standpoint. But those feed inputs didn't arrive out of the blue, they required huge (relative) inputs and resulting outputs. By focussing on enteric emissions we are missing the forest for the trees. 

    I can deal with monogut efficiency and energy inputs/outputs of cash crops later as I am running out of time, but these conversations always remind me of how little people understand about their food whether it be wheat, corn, chicken or cows

  7. What does the global shift in diets mean for climate change?

    Wayne... As far as I can tell, your statement "the math is wrong, that it is thermodynamically impossible" isn't supported by your references at comment #22. 

    Can you be a little more specific?

  8. Climate's changed before

    Hal Kantrud, the planetary "wobbles" are much too slow to cause any brief effect such as the Little Ice Age [LIA].

    Have a look at the PAGES 2K study.  

    Many people hear the name "Little Ice Age" ~ and combine it in their mind with old illustrations of Dickensian snow and London "Ice Fairs" on the frozen Thames, and suchlike Christmassy freezes.

    But in reality, the LIA was very minor.  Less than 0.5 degreesC colder than the usual background for the Northern Hemisphere, and more like 0.3 degreesC cooler for the global whole.

    Even the Medieval Warm Period [MWP] was only around 0.3 degreesC warmer than the global historic background.  Despite some of the trumpet-blowing about the MWP and the LIA, they were both pretty minor events overall.  Their names do greatly exaggerate their size.  And they are insignificant compared with the level of warmth of the Holocene Maximum (about 8000 years ago) and the even higher temperature levels of recent decades (which are around 0.5 degreesC hotter than the Holocene Maximum).

  9. A Skeptical Science member's path to an experiment on carbon sequestration

    Hi RedBaron

    I doubt they would have the time, need,or inclination to do what you are doing as it would be a distraction to their primary endeavour. There is another 20 years of articles going forward and the SFJ has another 20 years going back.

    How many acres are you looking at converting to no-till?

  10. What does the global shift in diets mean for climate change?

    ok moderator let's start with rice cultivation, which literally doesn't pass the smell test. Rice cultivation is responsible for 22% of global agricultural methane emissions and 11% of total anthropogenic methane emissions.

    Smith P, Martino D, Cai Z, Gwary D, Janzen H, Kumar P, McCarl B, Ogle S, O’Mara F, Rice C, Scholes B, Sirotenko O. Agriculture. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL, editors. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press; 2007. pp. 498–540.

    United States Environmental Protection Agency. Global Anthropogenic Non-CO2 Greenhouse Gas Emissions: 1990–2020 [Internet]. 2006. Available from: http://nepis.epa.gov/ Adobe/PDF/2000ZL5G.PDF 

    Then there's the N2O

    https://www.pnas.org/content/115/39/9720

  11. Climate's changed before

    Hal Kantrud: The "Little Ice Age" (LIA) was not a glaciation in any sense. It was a brief period within which some particular regions got colder for a little while before getting warmer again, but not all of them at the same time. From the PAGES 2K study:

    "Our regional temperature reconstructions also show little evidence for globally synchronized multi-decadal shifts that would mark well-defined worldwide MWP and LIA intervals. Instead, the specific timing of peak warm and cold intervals varies regionally, with multi-decadal variability resulting in regionally specific temperature departures from an underlying global cooling trend."

  12. Climate's changed before

    Thanks.  So if the "wobble" that triggered the Pleistocene glaciation, and less extensive glaciations occur during the interglacial, I guess the proper name would be Interglacial Subglaciations.  These must be what misinformed laypersons like myself have termed "Little Ice Ages".  How many have there been during the last 12,000 years and could they have dampened atmospheric CO2 levels? Did the extent of polar ice increase during these lesser glaciations?  

  13. What does the global shift in diets mean for climate change?

    one planet, no I'm saying that the math is wrong, that it is thermodynamically impossible and using it to justify your life decisions or as a template for behaviour change is probably a mistake

    Moderator Response:

    [DB] "the math is wrong, that it is thermodynamically impossible"

    In the same manner that stating that a dog's tail is a 5th leg does not make it so, stating that "the math is wrong, that it is thermodynamically impossible" without citing a credible source or showing your calculated analysis does not make it so. 

    You'll need to substantiate your position in order to be taken seriously.

  14. One Planet Only Forever at 15:03 PM on 20 October 2020
    What does the global shift in diets mean for climate change?

    wayne,

    I am referring to much more that needs to be corrected than the climate impacts.

    But just focusing on the climate impacts, climate impacts need to be ended - all of them. And reduced impacts are reduced impacts - steps in the right direction.

    You seem to be arguing that there can be math done that says that some climate impacts are OK because of comparison to other climate impacts. It is not about which ones are OK or better or worse. None of them are OK.

  15. A Skeptical Science member's path to an experiment on carbon sequestration

    @Wayne 8,

    Well I did notice this from your link Wayne, 

    Cultivating Questions: Evolution of a Permanent Bed System
    by: Lou Johns
    from issue: 27-3
    Crops & Soil • Cultivating Questions • Farming Systems & Approaches
    Planting Beds
    After three or four years we could see that the nature of our farming practices would continue to have detrimental effects on our soils. We were looking for a new approach, a routine that would be sustainable, rather than a rescue treatment for an ongoing problem. We decided to convert our fields to permanent planting beds with grassy strips in between where all tractor, foot and irrigation pipe traffic would be concentrated.

    It's pretty similar to what I am testing. But I don't see any soil tests, much less a rigorous trial. So it is interesting, and could even be tested to see what rate that sequesters carbon. 

    Interesting because they saw that they still had the ongoing problem with soil degradation. (requiring amendments to maintain fertility) And decided to make a change. I might encourage them to test it at experiment.com too. If they are legends, it shouldn't be too difficult to raise the expense money by crowdfunding it for a token donation from their followers. 

    I can assure you though, that isn't a standard biodynamic approach. They even say it themselves.

  16. A Skeptical Science member's path to an experiment on carbon sequestration

    RedBaron, I'll think you'll find that the Nordell's and a few others have done quite a bit of experimentation with no-till, which is quite amazing as they are farming with horses. We're talking about real working, succesful, profitable farms. I've never met them but know some very impressive people that have, and quite frankly they are legends

  17. A Skeptical Science member's path to an experiment on carbon sequestration

    At Wayne #6,

    Yes Wayne, Biodynamic is a way to grow good crops. But it is not no-till and it has quite limited use as a method to increase soil sequestration of carbon. This produces biomass that decomposes in the labile carbon cycle rather than the non-labile carbon cycle. (fixed carbon that decomposes and returns to the atmosphere as CO2, rather than sequestered carbon that forms stabile humic polymers tightly bound to the mineral substrate)

  18. A Skeptical Science member's path to an experiment on carbon sequestration

    Hi RedBaron

    I'm not sure how relevant it would be to your work, but for gardening techniques there is probably no better source than Anne and Eric Nordell

    https://smallfarmersjournal.com/category/cultivating-questions/

  19. What does the global shift in diets mean for climate change?

    One planet, I'm afraid I don't undertand what you're saying in this response either

  20. One Planet Only Forever at 07:18 AM on 20 October 2020
    What does the global shift in diets mean for climate change?

    wayne @ 17,

    What you state needs a more detailed presentation. I do not understand how your comment applies to what I presented, not even the part where you appear to agree with what I presented.

  21. A Skeptical Science member's path to an experiment on carbon sequestration

    Vertical gardening is a niche method, intended to resuse otherwise wasted space.  Within its boundaries, it's a fine idea.

    A brief excercise with arithmetic will demostrate how the method is unsuited to making a sufficently substantial contribution to adequately feeding 9-12 billion people for it to be a substitute for more conventional methods.

    Meanwhile, hydroponics don't feature carbon capture, which is a key feature here.

    We need to sequester carbon and eat.  Both things have to happen. 

    Economics follow reality, in the long term. And "long term" here means "forever." Our systems have to work forever

  22. Philippe Chantreau at 05:53 AM on 20 October 2020
    Is Nuclear Energy the Answer?

    I was not under the impression that the 2 designs were similar, perhaps I should have conveyed that better. To my defense I can say that at least I mentioned the 2 different types in 2 different paragraphs... :-)

    I had not realized that quite a bit of tension seems to have developed in this thread over time, but had no intention to strike any nerve.

    I am quite familiar with Terra Power; the article I linked, however, is of a much more detailed and informative nature than the basic info available through the Terra Power website. Especially interesting is the the radiation induced swelling issue, which does require special alloys, but the paper claims to have a workable solution with the HT9 alloy.

    I understand that the classic objections to "new" nuclear designs (there isn't one working, economics have not been demonstrated, time to be online, etc) do apply to this one as well. Nonetheless, the advantages of being able to use spent fuel, leaving depleted uranium as a by-product, and the safety features inherent to the design deserve consideration. Not to mention that a 600 MW plant operating as baseload is nothing to sneeze at. If it can be scaled up, as projected, to 1200 MW, I'm imagining how many coal fired power plants can be replaced by carbon free operations (free beyond, of course, material production, initial construction etc), and I find it very appealing. As far as I know, they do have a buildable prototype design, which was going to be started in China but everything fell by the wayside due to the current US administration policies. I find it shocking that a prototype had not been started in the US before 2016.

    This is not something to be discounted only on the basis of traditional objections, ideological opposition, or any other preconceived ideas. It offers tremendous advantages if it works as expected. It can produce, and deserves, a prototype and if it turns out as good as projected, it is, in my opinion, a very good solution.

  23. A Skeptical Science member's path to an experiment on carbon sequestration

    Yes, It's good to hear that his experiemnts are trying to do something about the soil and the carbon level of the environment. I wish him al lthe best. But, reducing the soil use should be a goal too. In this era we have alternate way of farming. Like as vertical gardening and using the hydroponic system.

    Trying to returning back the carbon back to the soil - I just don't think this will be economically viable. Environmentally - Yes, but think about all the people we have to feed.

  24. Is Nuclear Energy the Answer?

    Philippe:

     The TWR reactor you link is a sodium cooled reactor and not an MSR.  It is confusing when you discuss MSR's and sodium cooled reactors in the same post.  Are you aware that TWR reactors are not MSR's?  Sodium cooled reactors have their own, different, set of problems compared to MSR's.  Sodium is extremely corrosive and is flammable in both air and water.  

    The article you link is a progress statement from TerraPower LLC, a company associated with Bill Gates.  They claim they are making progress with their design but do not have a buildable design yet.  When they have a buildable design we can discuss their future prospects.

  25. Is Nuclear Energy the Answer?

    Philippe Chantreau:

    Thank you for providing a peer reviewed study to support your question.

    Your reference is a summary of current knowledge of "freeze valves".  The first paragraph states:

    "Reliable mechanical valves that can withstand the corrosive and high-temperature conditions in Molten Salt Reactors (MSRs) have not yet been demonstrated. In their place, freeze valves (sometimes called freeze plugs) represent a unique nuclear design solution for isolating salt flow during operations." my emphasis.

    As I stated above, no alloys to manufacture control valves are known that can withstand the extreme heat, corrosion and radiation fields in an MSR.  Reactor designers are looking for other ways to control liquid flow.  A freeze plug is a system of a thin pipe where a plug of solid salt is allowed to form.  This pipe has to have complicated heating and cooling systems.  It takes about 15 minutes to form the plug, during which the molten salt cannot be moving, and about 15 minutes to thaw the plug.  Most of the small amount of known data and designs about freeze plugs are from the 1960's.  Apparently recently MSR developers have started to investigate freeze plugs again because they have been unsuccessful in finding alloys to build mechanical valves.

    Freeze valves are apparently not used in any existing chemical or nuclear processes.  Therefore the knowledge of their manufacture, use and failure modes is rudimentary.  They are complicated and have many failure modes compared to normal mechanical valves.  They open and close very slowly in emergencies.  The size of pipes used is restricted.  Test valves have suffered catastrophic failure.

    The conclusion of the paper you cite says:

    "Especially because the technical maturity of all solutions to isolate salt flow is so low, it will be important for MSR stakeholders to advance the state of knowledge surrounding freeze valve systems, and other alternatives under consideration, through a combination of physical tests, computational simulations, and design-related studies." my emphasis

    I conclude that it is currently unknown how to control the flow of liquid salt in an MSR.  It may be possible to develop a solution but it will take significant research, time and testing.  Designers tried to avoid freeze plugs because they have many undesirable properties.

    Proponents of MSR's have many significant problems that they need to resolve, including the fact that they do not know how to regulate the flow of liquid through the reactor.  It will take many years of research to solve these issues, if they can be solved.  Suggestions that a design that can be built exists or will exist in the near future are deliberately false.

    Many additional problems exist for MSR's.  The designs are complicated and only the nost optimistic proponents envision that they can compete with renewable energy in the foreseeable future.  If a reactor is ever designed, there will still not be enough uranium in the world to provide more than a small amount (less than 5%) of energy to the grid.

    I think it is a waste of money to attempt to develop a reactor where a pilot plant cannot be designed in less than 10 years.  It would take at least 5 years to validate the design and then 10 years to build the first commercial reactor.  You are looking at 2050 or later for the first commercial reactor which is too late.  The uranium problem has no proposed solutions (thorium has additional problems of its own).  The money would do much more good used to build a wind or solar farm.

    Your reference is very long and technical.  I only read about half of it in detail.

  26. A Skeptical Science member's path to an experiment on carbon sequestration

    Nigel,

    As a general rule of thumb, no-till increases yields over tillage systems. There are a few exceptions though. For example organic production with reduced tillage does beat conventional no-till usually. But focusing narrowly on those two would also be misleading, because no-till organic beats both long term. There are very good long term trials proving both those controversial claims. 

    Yields from a long-term tillage compareson study

    The Farming systems trial

    Even focusing on that would be misleading though, because farming is a science and a skill too. There is a learning curve. And in both the cases above when people first switched, they generally lost yields per acre at first. Only after they became more skilled at it did they see the gains. Soil health also does not rebound immediately either. So the yield increases seen by improving the soil, even with experienced farmers, can take three years or more. A novice farmer could take decades to really gain the knowlege required.

    For those two reasons and more, it is also easy to find shorter term trials that have the opposite result.

    If you really want to be a skeptic, you need to always check your premises first. Next step is to check context.

    Trust but verify

  27. A Skeptical Science member's path to an experiment on carbon sequestration

    It may be a matter (and I have a completely superficial exposure to this topic so emphasis on "I dunno") that  this is a bit akin to other sustainable technologies: no, it's not economically optimal according to some framings, but economics as they're understood from our history don't predict economics we may expect in the future, economics that are dominated by "we've filled the space available and we now need. a plan for how to occupy the available space in perpetuity."

    Our history and experience of economics is very short and very warped by circumstances.   

    One thing I _know_ (and yeah, I have my thumb heavily on the scale here I freely admit) is that more understanding of capacities is what we need, and Scott is offering a means to expand that understanding, help to set brackets on what we can expect.

  28. A Skeptical Science member's path to an experiment on carbon sequestration

    I think this experiment sounds very useful, so good luck. I also think some form of regenerative agriculture has merit, and is the way of the future. I haven't always agreed with RB (aka Scott Strough), possibly because I'm a born sceptic (I drove my parents crazy) but I agree on many of the basics.

    I came across the following discussion some time ago. No till farming is good for soils, but it reduces productivity and this is apparently why farmers are a little bit reluctant to use it. However  reduced till farming hits a sweet spot of significant soil benefits and improved productivity according to this research. 

    www.no-tillfarmer.com/articles/9378-reducing-tillage-improves-soil-yields

  29. What does the global shift in diets mean for climate change?

    one planet @ 15 much of what you said may be true, but is irrelevant if people are going to continue to promote these energy/methane/CO2eq numbers that are beyond questionable. But I guess it makes people feel better when they are eating their "organic" baby carrots and rice, and that's all that matters right!?!

  30. Climate's changed before

    Hal Kantrud, you wrote that you thinks you read that changes in Earth's axis of rotation may be involved in the Little Ice Age. You might well have read that, because misunderstanding is widespread. But the "Little Ice Age" was not actually an ice age. Indeed, what popularly are called "ice ages" actually are glacial periods nested within actual "ice ages." Within each actual ice age there is a series of glacial periods and "interglacial periods." Currently we are in an interglacial period within an ice age. The Little Ice age in fact was merely a short period of regional cooling within the current interglacial period. See this relevant post--first the Basic, then the Intermediate, and finally the Advanced tabbed pane.

    "Wobbles" in the Earth's axis are so slow that they operate on the time scale of triggering the glacial and interglacial periods.  See this post about Milankovich cycles.

  31. Philippe Chantreau at 05:52 AM on 19 October 2020
    Is Nuclear Energy the Answer?

    MIchael,

    I searched valve issues for MSR and found mostly publications centered around the freze valve problem,  but nothing specifically relating to the availability of alloys up to the task. Can you be more specific?

    As for myself, I believe that there is immense potential in the TWR model, and I find it hard to understand that a prototype would not already be underway in the US. If construction times can be kept at the necessary levels, it is the only solution that I know about with the potential to solve the energy problem of civilization at the short and medium term. If this was given the public attention it deserves, working plants could be generating commercial electricity even before ITER would start delivering useful data.

  32. Climate's changed before

    "n more depth, human activities have been modifying the climate system for far longer than most people realize. Evidence exists that humans have been doing so since the development of agriculture more than 10,000 years ago, contributing as much as 25 ppm to existing, preindustrial atmospheric CO2 levels.'"

    But even from the Antarctic ice data it looks like a gradual rise began about 7000 years ago. This could correlate with the increased use of the high-carbon content grassland soils for cultivation of annual crops such as small grains and also for pasturage.

    "During periods of previous pandemics, reforestation of formerly cultivated lands have drawn down atmospheric carbon dioxide levels enough to measurably lower global temperatures."

    I see no dips in atmospheric CO2 following any of the world's worst pandemics. "Reforestation" probably means abandonment of cropland where forests once stood, where weeds and annual grasses quickly become dominant. So this perhaps accounts for the lack of dips. I doubt if large scale abandonment of cropland occurred in fire-derived ecosystems like grasslands where forests did not originally exist as these areas would be the first to be returned to agiculture or for domestic livestock by the survivors. Unlike grasslands, forests are shallow rooted and store little carbon, other nutrients, or water underground, so I would think long-term effects of reforestation on atmospheric CO2 would be quite low.

    "Scientists understand that the so-called Little Ice Age was caused by several factors - a drop in atmospheric carbon dioxide levels, a series of large volcanic eruptions, changes in land use and a temporary decline in solar activity."

    Thought I read where regular changes in Earth's axis of rotation ("wobble") may also be involved here.

    "This new study demonstrates that the drop in CO₂ is itself partly due the settlement of the Americas and resulting collapse of the indigenous population, allowing regrowth of natural vegetation."

    Whew! Now you are saying that Amerindians had more land under cultivation and overgrazed more acreage than European man?

    "it demonstrates that human activities affected the climate well before the industrial revolution began."

    I agree with that, but believe the recent upward blip was caused as much by convesion of New World grasslands to cropland as it was by the industrial hydrocarbons used to accompish that task.

  33. One Planet Only Forever at 02:08 AM on 19 October 2020
    2020 SkS Weekly Climate Change & Global Warming News Roundup #42

    nigelj,

    I agree with your assessment and would add that a significant part of the problem is that 'Future people' will be the ones to suffer from what 'current day people' do that they can understand, but resist understanding, are causing harmful consequences for 'future people'.

    This harmful misunderstanding, or resistance to learning to be less harmful and be more helpful, is an expected result of the human made-up artificial games of competition for impressions of superiority relative to Others. Those games have boosted the tendency for humans to be selfish rather than helpful, and developed the belief that 'Harm Done is justified by Benefit Obtained or Money Made'.

    An insidious aspect of the current socioeconomic-political environment is that the more harmful someone can get away with acting the more competitive advantage they can have over more caring and considerate people - including people in the general population who do not need to care about the harm done by their purchasing or vote choices or the choices of how they will enjoy their lives.

    Adam Smith's "Invisible Hand" is only helpful if the economic-political games are Dominated or Governed by requirements to eliminate harm done, with related constant learning by everyone, especially by people in leadership roles in everything (business, politics, social institutions). Without that Helpful Governing, the "Invisible Hand of Competition" is bound to be Very Harmful.

    The solution requires systemic changes that make consideration of impacts on Others, including future generations, an essential part of the evaluation of acceptability of an activity. And the pursuers of benefit should not be the ones to determine the harm done by their actions.

    People hoping to benefit from an activity can be biased against ensuring that no harm is done. They may even try to claim that what they want to benefit from is acceptable by comparing their perception of the benefit obtained to their perception of harm done and as long as there is a Net-Positive it must be acceptable. They ignore the undeniable understanding that unsustainable harmful activity must be eliminated in order for sustainable improvements to be developed. That type of selfish evaluation insidiously makes it appear as if "Harm Done is justified by the Benefit Obtained by the people benefiting from the harm being done".

    Harmful activity will likely always have a competitive advantage, including the way it can get people to make-up evaluations that justify continuing the unsustainable harmful activity. Those incorrect justifications for actions harmful to future generations include 'discounting the underestimated costs of future impacts' and comparing that 'level of harm done to the future of humanity' to over-stated costs of eliminating the harm being done.

    The measure of acceptability needs to be "No Harm Done". And that understanding is resisted because the current developed ways of living are very unsustainably harmful. That understanding illuminates the reality that the socioeconomic-political systems that have developed need to be significantly changed in order for sustainable improvements to develop.

    Profit and popularity have failed miserably as means of developing sustainable improvements. In fact, games of popularity and profit have made it harder to limit the harm done by human activity. And being able to get away with misleading marketing, especially in politics, is the major impediment to humanity developing a sustainable improving future.

    As a final note I would add that fossil fuels should be kept in reserve for a real future emergency, like keeping people warm after something like a tragic asteroid impact, or using a little bump of CO2 to get through a future period of significant reduced solar energy input.

  34. Is Nuclear Energy the Answer?

    Apparently the NRC has approved the NuScale modular reactor design.  They are set to build a reactor on the Idaho Falls DOE site.  A pro-nuclear article in Forbes said:

    "NuScale is building its modular SMR on the DOE’s Idaho Falls site and has a contract to sell the electricity to a consortium of rural electric cooperatives, two of which recently dropped out because of spiraling cost projections. This is dampening SMR enthusiasm and attention is returning to the large reactors of 1,000 MWe and above."

    Apparently even nuclear supporters are losing enthusiasam for small modular reactors.   Nuclear supporters move the goal posts again because the current designs have failed.

    The Forbes article supports a molten salt start-up.  As I understand it, the alloys necessary to build the valves in a molten salt reactor have not been invented yet.  Perhaps they have a supply of "unobtainium".  A major cost savings was the claim that a containment structure is not needed.

    This peer reviewed article finds that countries that build out nuclear power plants do not reduce carbon pollution while countries that build out renewable power plants reduce carbon polllution.  If nuclear is built out than the amount of renewable energy is reduced.  It is only a correlation study, more research will be necessary to confirm the conclusions.

  35. Climate's changed before

    Hal Kantrud

    Atmospheric CO2 levels reached about 265 ppm about 11,000 years ago, near the end of the last glacial phase and the start of the current Holocene interglacial.  From then until just before preindustrial (1850), CO2 levels slowly increased to about 280 ppm, an increase of 15 or so ppm.  

    The last 10,000 years

    (bigger image here)

    What this doesn't take into account is that human activities starting around the development of agriculture until preindustrial times added about 25 ppm to those atmospheric levels.  This implies that, without the human impacts, atmospheric CO2 levels would have naturally dropped by some 10 ppm over the same interval.

    In more depth, human activities have been modifying the climate system for far longer than most people realize. Evidence exists that humans have been doing so since the development of agriculture more than 10,000 years ago, contributing as much as 25 ppm to existing, preindustrial atmospheric CO2 levels. During periods of previous pandemics, reforestation of formerly cultivated lands have drawn down atmospheric carbon dioxide levels enough to measurably lower global temperatures.

    "Scientists understand that the so-called Little Ice Age was caused by several factors - a drop in atmospheric carbon dioxide levels, a series of large volcanic eruptions, changes in land use and a temporary decline in solar activity.

    This new study demonstrates that the drop in CO₂ is itself partly due the settlement of the Americas and resulting collapse of the indigenous population, allowing regrowth of natural vegetation. It demonstrates that human activities affected the climate well before the industrial revolution began."

    Link1
    Link2
    Link3
    Link4
    Link5
    Link6
    Link7
    Link8
    Link9
    Link10
    Link11
    Link12

  36. 2020 SkS Weekly Climate Change & Global Warming News Roundup #42

    And it would be better to keep remaining fossil fuel reserves for use as petrochemicals. Make them spin out as long as possible and the CO2 they generate can be released at a much slower pace or buried in landfill.

  37. 2020 SkS Weekly Climate Change & Global Warming News Roundup #42

    Studies trying to evelauate the costs of climate change and  putting a price on  carbon,  like Nordhaus's study have been heavily criticised as understating the costs of climate change and the price on carbon. It looks like a very difficult exercise to be definitive about any of this.

    liu.se/en/news-item/liu-forskare-riktar-skarp-kritik-mot-ekonomipristagare

    I would look at it the whole thing a different way. What we know is the very worst case scenario includes as much as 6 degrees c of warming this century, and 12 degrees c of warming, by about the year 2200 - 2300, from the IPCC studies, which would obviously be genuinely catastrophic. Only a fool would think otherwise or need to do nit picking studies. The risk of this is probably small, but the consequences are very grave, so this should be considered. Its not worth taking the risk. Its the entire planet we are talking about.

    An immediate plan of infrastructure spending and regulations would stop the worst of this problem eventuating, without strangling the economy and in fact studies show it would create jobs.

    Doing nothing will mean being forced at some future date to suck CO2 out of the air, a technology that would cost a fortune to scale up, if its even possible. Wind and solar power along with other policies prevents the problem and provides a tangible benefit with electricity generation. Throw some nuclear power into the mix if it can become economic and built quickly enough, but right now it has to prove that.

    Doing nothing also has a huge irony. In about 50 - 100 years time we will be running out of economically recoverable fossil fuel reserves. These are absolutely finite reserves. So we will have no option but to consider things like wind and solar power, so this strengthens the case for more immediate action.

  38. Climate's changed before

    Has there been a gradual rise in atmospheric C0s during the last 10 millenia followed by a spike following the industrial revolution?  Does the gradual rise correlate with human agiculture and pastoralism?  Does the spike correlate with conversion of North American grasslands to agriculture and pastoralism with the aid of machinery powered by fossil fuels?  This makes sense to me because grassland soils contain more carbon than soils of forestland or brushland. 

  39. Climate's changed before

    As this is your first post, Skeptical Science respectfully reminds you to please follow our comments policy. Thank You!

  40. What does the global shift in diets mean for climate change?

    I concur with Philippe Chantreau @12's statement:

    I see numerous valid points from all contributors so far, suggesting that this is a complex problem and indeed it is.

    The complexity of the agriculture's contribution to manmade climate change extends beyond CO2 and methane emissions. For example. it includes the use of nitrogen fertilizer as addressed in:

    Nitrogen fertiliser use could ‘threaten global climate goals’ by Daisy Dunne, Science, Carbon Brief, Oct 7, 2020 

  41. One Planet Only Forever at 02:05 AM on 18 October 2020
    What does the global shift in diets mean for climate change?

    wayne,

    I am inclined to agree with you about non-cattle food production needing to be better understood and helpfully corrected to be more sustainable. But I am less inclined to disagree with the opportunity, and the need, to dramatically reduce cattle rearing. Correcting how cattle are reared is indeed required, along with reducing how much beef people eat and the resulting reduction of cattle reared for human eating.

    The 2015 Sustainable Development Goals always need to be kept in mind. They are based on massive amounts of research and improved understanding that, like all improved understanding, is open to further improvement (the 2030 update will incorporate those improvements and recognize the progress made toward achieving the 2015 SDGs).

    The SDGs point to the need to reduce the unsustainable harm done by all human activity, not just food consumption. And they identify the need to address the way that economic competition for popularity and profit has a history of creating harmful results, including creating Desperate Poverty as measures of wealth increase faster than the population.

    Some people may claim that the real problem is the total global population increase. I do not disagree. But it is important to remember that harm being done, including the creation of Poverty, has happened while wealth increased faster than the population. And the recent global population study published in the Lancet indicates that achieving the SDGs will reduce the peak global population. So achieving the SDGs, all of them, is the answer to almost everything humanity needs to have a lasting improving future on this one amazing planet we are certain that humanity can thrive on as a part of the robust diversity of life that had developed.

    The harm done to the robust diversity of life on this planet, including harm by actions related to rearing massive numbers of cattle for wealthier humans to eat, is harm done to the future of humanity.

    A lame but common claim that also needs to be addressed is the claims that reduction of harmful environmental impacts can only be done by having increased wealth. The counter-argument is simple. "Harm Done does not justify Money Made and is certainly not excused by a portion of the money made being applied to partially correct the harm that was done by activities that created the appearance that money was made".

    Economics are an unnatural game made up by humans. The economic game can be responsibly governed to limit the harm done and increase the helpfulness achieved by the players in the game. That results in the understanding that the Libertarian Free Market thinking that some people want to promote are actually some of the most harmful ideas humans have ever come up with. It is undeniably incorrect to believe that Good Results will be developed if there is more freedom for people to believe whatever they want and behave however they wish in competition for Superiority relative to Others. All human actions need to be governed by the need to not be harmful and the desire to be more helpful. The economic games would need to be dominated, governed, by people who think and behave that way in order for Adam Smith's "Invisible Hand" to be Helpful rather than Harmful.

    Humans have been coming up with different versions of those unjust justifications for Superiority of Some relative to Others (including those Political Nationalists), including beliefs that humans are separate from, and Superior to, the rest of life on this planet, for a very long time.

    Humanity needs to pursue expanded awareness and improved understanding and apply what is learned to develop a robust diversity of ways for the diversity of humans (more complex than the binary belief) to live as sustainable parts of the robust diversity of life.

    Advancement of humanity is not necessarily indicated by technological achievements or measures of wealth. It is measured by how sustainable global human activity is, and its harmlessness.

  42. It's not bad

    Almost any scientist looking at a new idea views it with deep skepticism and doubts it, and that skepticism is only overcome by a consistent preponderance of the evidence that keeps supporting the idea that that might be important - that global climate change driven by humans might actually be occurring. As that evidence has been accumulated, skeptic after skeptic among the scientists has decided, "Well, I'd better pay more attention to this." The physics of this is much more well understood. The models that incorporate all of our known aspects of physics and atmospheric chemistry and climatology and so on, all predict that what we're doing is going to lead to climate change. All these bits of evidence keep falling into place. They all keep saying, "Gee, we'd better pay more attention to this global climate change idea," because when we look at some data that maybe would have rejected it, it doesn't. It supports that idea. I guess what I would say is that the idea is so real now. There have been so many attempts to test it, so many attempts to reject the idea that we might be causing climate change which has not been successful, which keep supporting that hypothesis. I think it is now incumbent upon us to take it seriously and to do things to help slow the rate of climate change and hopefully stop it. If we find out in the long-term that climate change is not going to happen, we won't have done much to harm ourselves. But if we don't act now, we could have a runaway climate change that could basically greatly decrease the livability of the earth. The science is now solid enough that any reasonable person examining the scientific evidence would decide, "We have to pay attention to it. It's time to have some action."

  43. What does the global shift in diets mean for climate change?

    I find it hard to agree with the premise on a lot of this. Cattle don't need grain fed to them, only forage and maybe hay if you have a dry season or winter. Thus you only need to cut and bale the forage, and that's it no more inputs required. The cattle can even cut and bale the forage themselves if you're so inclined. It is a little harder to manage sheep(and to a lesser extent goats). But raising chickens and pigs without grain inputs is a huge amount of work. Grain cropping requires huge energy investment even with no-till. Rumination is one of the greatest evolutionary advancements, so maybe don't just pick on cattle as there a lot of ruminants walking the earth. The non ruminant/livestock methane production just comes out after digestion as their feces breaks down. And for anyone like myself who has stood in a rice paddy in Thailand, let me tell you it reeked, so I question the methane numbers there as well

  44. What does the global shift in diets mean for climate change?

    PC @12 says "A big question is: Is it possible to have the 987.5 millions cattle in the current World inventory all graze in sustainable fashion? "

    I don't think you can. I can briefly describe the scenario in New Zealand. In recent decades, intensive dairy farming has expanded to the point our soils are degrading and most of our rivers have become seriously polluted unfit for wading let alone swimming.

    Some of these problems have been mitigated by keeping stock away from rivers by fencing and planting trees near rivers to reduce runoff etcetera, and this has reduced bacteria levels significantly, but has hardly even dented nitrate levels. It appears the only way to truly control the problem is to reduce stocking density, so absolute numbers of cattle. Its hard to see why it would be different in other countries.

    It's not viable to resolve the problem by increasing areas for dairy farming to reduce stocking ratios. There are numerous competing requirements for land including massive government schemes to plant trees as carbon sinks. And its hard to get beyond the fact that meat requires vastly more resources for a given quantity of calories compared to grains and vegetables.

    Of course it depends on how one defines sustainability, another hellishly difficult problem but theres a general consensus in the country that turning our rivers into open sewers that are unfit for wading let alone swimming isnt terribly sustainable and certainly isn't acceptable. The debate is about how much pressure, rules and costs its acceptable to put on farmers to fix the issues.

    Then there is less intensive cattle farming on open grasslands where density ratios aren't so high and feedstock is primarily grass as opposed to grains. This is more sustainable, but only to a degree. To get the sort of carbon sequestration RB talks about requires rotational grazing, and quite low stocking rates, lower than presently. There was a research paper on this in one of your weekly research summary columns some months ago.

    As you rightly say its a really complicated issue. People also don't like being told what to eat. Theres a lot of conflicting advice even before you get to the climate issue. However a couple of things stand out to me. The trend in some countries like the UK seems to be just starting to move towards eating less meat, especially red meat, and towards more plants and maybe fish for a range of different reasons, not just climate issues.

    It's this range of issues that appears to be combining and leading to change. I think  looking at history, that change often seems to happen when a number of things suggest change is appropriate, not just one causative factor. It adds up. Lower meat consumption may spread to other countries eventually. But it seems unlikely to me this will be particularly quick, or lead to global vegetarianism, so that leaves a lot of space for getting grazing systems and chicken farming as sustainable as possible. I'm not sure how sustainable battery cage farming is. I doubt that the chickens would consider it particularly sustainable, if they could be consulted :)

  45. Philippe Chantreau at 01:34 AM on 17 October 2020
    What does the global shift in diets mean for climate change?

    I see numerous valid points from all contributors so far, suggesting that this is a complex problem and indeed it is.

    A big question is: Is it possible to have the 987.5 millions cattle in the current World inventory all graze in sustainable fashion? Immense areas of tropical forests have been destroyed to make room for cattle, what is the full analysis on that? Even if we can have close to a billion sustainable heads of cattle, can you then add to that all the other livestock and still have a sustainable system?

  46. What does the global shift in diets mean for climate change?

    RedBaron @8

    Thank's for the technical information. There's some good stuff there, but I have a few criticisms about a couple of things.

    Firstly I did indeed not say cattle are 'the' problem as BL points out. Clearly many things contribute to the increase in atmospheric methane in recent decades, not only cattle. Many studies have confirmed that.

    "If cattle numbers are dropping and methane levels are rising, it is a probable falsification of the hypothesis that cattle emissions were the problem."

    Cattle numbers are not dropping overall globally which is obviously what matters. Both the links provided by Alan Russel and myself showed that.

    "Cattle properly raised on grasslands restore degraded land, they do not "use" those limited resources, they are part of a system that generates those limited resources...."

    Strawman. The statement I posted was cattle use a lot of land compared to crop farming. This is a simple fact. Nothing you have said changes that. It's something we have to consider. You appear to be looking at it from quite a narrow perspective.

    But I don't disagree about the positive relationship you describe between cattle and resources. I did say I think grazing cattles on open grasslands has value. I agree cattle farming properly done can improve the land and sequester carbon, to an extent. Theres some good evidence. The trouble is so many things operate in the opposite direction. Warming causes soils to release carbon over time and also nitrogen oxides so dont get carried away with what can be achieved.

    On balance I go along with lower red meat consumption for climate and other reasons. Obviously fewer cattle equals less of a methane problem. And properly managed environmentally sustainable grasslands farming requires low cattle density so probably lower numbers than currently, assuming the same area of land is used for cattle grazing. Its certainly unlikely to increase in area. This is consistent with a lower red meat diet.

    That said, it seems to me that its really unlikely the entire world would go vegetarian, and some grasslands aren't very suitable for cropping or forestry, so we should clearly graze them in the most environmentally sustainable way possible as per your general prescription.

  47. What does the global shift in diets mean for climate change?

    Regarding Alan's remark (fling) regarding Skeptical Science promoting misunderstanding of animal husbandry and consumption of meat contributing to GHG, I feel complled to point out that we've covered this elsewhere and that the conclusions of that effort belie Alan's claim:

    How much does animal agriculture and eating meat contribute to global warming?

    This is one of our more popular debunkings (or in this case perhaps "calibration improvement"). 

  48. What does the global shift in diets mean for climate change?

    Red. Nigel did not say that cattle are the problem, he said that cattle are a problem. And that there contribution to the overall problem will be a function of how many there are. I don't see that as "nonsense".

    As you point out, not all cattle will contribute the same amount, as other factors come into play, but you've made a strawman out of Nigel's comment.

  49. What does the global shift in diets mean for climate change?

    @6 7 Nigel, 

    That's not the only nonsensical thing you said Nigel.

    "Firstly this is a tacit admission that cattles methane emissions are a problem, and less cattle equals less of a problem."

    That statement is pretty wrong too. If cattle numbers are dropping and methane levels are rising, it is a probable falsification of the hypothesis that cattle emissions were the problem. There are plenty of other sources of methane that actually are the problem, natural gas leaks are the most likely culprit. However, grain production is way up there on the list because in the overwhelming majority of cases it destroys the ecosystem function of grasslands, which are a net sink for methane. Haber process nitrogen made from natural gas, commonly used to raise grains, is also rising. Cattle raised properly on grasslands can restore ecosystem services, and do not need haber process nitrogen to do it.

    You also said, 

    "Since food, water and land are scarce in many parts of the world, this represents an inefficient use of resources."

    Also wrong. Cattle properly raised on grasslands restore degraded land, they do not "use" those limited resources, they are part of a system that generates those limited resources. We all know they generate food. But commonly misunderstood is they generate water too.

    Effect of grazing on soil-water content in semiarid rangelands of southeast Idaho

    Notice that the best result for soil moisture is properly grazed land? Even better than no grazing at all? What do you suppose would happen if we plowed that land to grow grain? In case you didn't know, Google "dust bowl images" for a graphic explanation.

    The proper use of animals, especially ruminants, generates new fertile land, food for human use, and water cycles. It does not use them up, it generates more of each.

    Feedlots are a different matter. This is why I have asked multiple times on this forum that people use their words carefully. It's not the animals that is the problem, it's the way we raise or food that matter. Actually animals are a great help in this regard.

    “As the small trickle of results grows into an avalanche — as is now happening overseas — it will soon be realized that the animal is our farming partner and no practice and no knowledge which ignores this fact will contribute anything to human welfare or indeed will have any chance either of usefulness or of survival.” Sir Albert Howard

     

  50. What does the global shift in diets mean for climate change?

    I said @6 above "It should be very obvious we could get all the calories we need from much less volume of grain and vegetables etcetera than volume of meat." This is nonsensical. I'm not sure what I was thinking. Please just ignore it.

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