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Comments 7851 to 7900:

7851. MA Rodger at 02:52 AM on 7 March 2020
      It's CFCs
      

      Do note that the paper discussed above Polvani et al (2020) 'Substantial twentieth-century Arctic warming caused by ozone-depleting substances' has been the subject of some corrections. And for the record, I would answer the question of EGS @17 "Would that not be evidence that climate sensitivity to CO2 must be much lower than previously modeled?" with a flat "No!"Given the comment thread since, I'm not sure that any explanation would be helpful.

7852. EGS at 02:40 AM on 7 March 2020
      It's CFCs
      

      This is clearly outdated. Polvani et al. showed that ozone depleting chemicals alone account for 1/3 of all anthropogenic global warming between 1955-2005. The papers I cited above all show that anthropogenic, CH4, N20 O3, and black carbon contribute more than previously thought. I don't understand why these far more potent anthropogenic greenhouse gasses/particles get relegated to relative insignificance, not least since CFC, HFC, SF6, tropospheric O3, N02, and black carbon have unambiguous anthropogenic sources. Increased ppm of C02 is also anthropogenic, but you can't impute the kind of radiative forcing and amplification feedbacks to it and not apply those to these even more potent greenhouse gasses, otherwise there would have been far more warming than we have been able to measure. Something has to give up some radiative forcing in oder to get anything like the warming we have been able to measure. The underappreciation of CFCs and other GHGs is likely why climate models have been running hot. Michael Mann is himself aware that there are problems with the climate forcing theories. He coauthored a paper in Nature Geophysics in 2017 (https://www.nature.com/articles/ngeo2973) that argued that the failure of climate models to align with the measured level of tropospheric warming since 2000 is unlikely to have been caused by natural variability and model error in climate sensitivity but rather in “systematic deficiencies in some of the post-2000 external forcings used in the model simulations.“

       

      Moderator Response:

      [DB]  Research shows that climate models are getting future projections right, meaning that the physics of the models are well-validated by subsequent observations.

      

      Sloganeering snipped.

7853. EGS at 01:54 AM on 7 March 2020
      It's CFCs
      

      What the science does not say:

      "CFCs contribute to global warming at a small level."

      Moderator Response:

      [DB] Per the AR5, Halocarbon (which includes CFCs) radiative forcing (RF) is small relative to that of CO2 RF.

      

7854. EGS at 01:49 AM on 7 March 2020
      It's CFCs
      

      Poorly understood and misrepresented papers? Which papers have I not understood? The paper by Unger et al. in the proceedings of the US National Academy of Sciences (citing work by the Fourth Assessment working group of the IPCC) that tropospheric O3’s direct cumulative radiative forcing when combined with fine particulates like black carbon may outweigh that of all the CO2 released since the beginning of the industrial era https://www.pnas.org/content/pnas/early/2010/02/02/0906548107.full.pdf.

      Moderator Response:

      [DB] Off-topic and moderation complaints snipped.  You are essentially arguing one of the many subsets of arguments that "It's not us".  Pick one of the most-appropriate and repost this line of reasoning there.

      Please note that posting comments here at SkS is a privilege, not a right.  This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.  One of the most important of these precepts is to stay on-topic.

      Please take the time to review the policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter.

7855. EGS at 01:42 AM on 7 March 2020
      It's CFCs
      

      Could ozone depleting chemicals and the other GHGs (with a large revision downward of CO2 radiative forcing and amplification feedbacks?) explain a modestly warming upper troposphere, higher tropopause, and a cooling stratosphere that are among the markers of anthropogenic climate change? Wouldn’t that also align with the strong empirical evidence of very little global warming since the preindustrial era until 1950 that then really accelerated after the 1950s and 1960s as CFCs, HFCs, halons, and SF6 emissions skyrocketed from their industrial use as refrigerants, solvents, propellants, and electrical insulating gasses? The spike in anthropogenic warming from N20 and CH4 could likewise be timed with the massive intensification of agriculture enabled by large-scale application of nitrate fertilizer and changes in land use patterns (deforestation) accompanying the green revolution since the 1970s. This was a time that was also accompanied by dramatically increased diesel tractor and diesel vehicle use, skyrocketing bunker fuel emissions from the expansion of container shipping, and rising heating oil emissions from a switch from coal to oil, which could account for much of the rest of the increase in N20, much of the tropospheric O3, and a large part of the fine particulate emissions increases. The timing of the acceleration of warming would also strongly imply a weaker climate sensitivity to C02 forcing and a greater cumulative forcing of these other greenhouse gasses. It was, after all, in the 1980s and 1990s that global warming really accelerated, not earlier. Would that not also align well with the much stronger warming over the poles (mostly accounted for by CFCs, HFCs, N20, tropospheric O3), strong stratospheric cooling from the depletion of/hole in the polar stratospheric 03 layer, and the much weaker than expected tropical upper tropospheric temperature anomoly and the weaker than expected deep ocean warming?

      Moderator Response:

      [DB]  In the early 20th century human activities caused about one-third of the observed warming and most of the rest was due to low volcanic activity. Since about 1950 it's all humans and their activities.
      
      https://journals.ametsoc.org/doi/10.1175/JCLI-D-18-0555.1
      https://onlinelibrary.wiley.com/doi/full/10.1002/wcc.522
      

      Off-topic and sloganeering snipped.  Arguments pertaining to Climate Sensitivity is Low must be placed on that thread, not here.

7856. EGS at 23:59 PM on 6 March 2020
      It's CFCs
      

      Eclectic,

      Are you claiming that the degree of northern hemisphere ice albedo is a trivial amplification feedback in anthropogenic radiative forcing? 

      Moderator Response:

      [DB] Your previous 2 comments were removed as being off-topic and Gish Gallops of rambling assertions lacking foundation.  Just throwing out a bunch of poorly-understood and misrepresented papers does not give you any credence in a science-based forum such as this.  Please stick to the topic of this post.  Other topics are covered by other posts here (literally thousands exist).  Use the Search function to find the most relevant post and read it and its comments and this site's CommentsPolicy  before posting further.

7857. MA Rodger at 20:31 PM on 6 March 2020
      Skeptical Science New Research for Week #9, 2020
      

      swampfoxh @1,

      Your question doesn't 'ring any bells' with me and the authors you mention don't seem to lead anywhere that I can see.

      The 1,500 year timescale is occasionally mentioned as the time it takes the ocean waters to re-appear at the surface and so reach CO2-quilibrium with the atmosphere. That is part of what Goreau (1990) 'Balancing Atmospheric Carbon Dioxide' addresses but it is not the same as timescales for temperature equilibrium under otherwise-fixed CO2 levels.

      Rohling is the lead author of Rohling et al (2009) 'Antarctic temperature and global sea level closelycoupled over the past five glacial cycles' and this does consider multi-millennial equilibrium timescales but this concerns sea level. There is a connection in that the melt-out of, say, Greenland would both impact sea level and temperature as the albedo change constitutes a slow climate feedback (see this SkS post). But over such multi-millennial timescales with Milankovitch cycles in operation, it would require more than "modest" climate forcings to be significant.

      More directly addressing your question, the ice cores do show a small increase in CO2 levels over the last 8,000 years. This would provide roughly a 0.3Wm^-2 climate forcing which (slow and fast feedbacks so perhaps a sensitivity of 6ºC) could have given a total temperature rise of +0.5ºC. Yet spread over eight milennia, any residual effect today would be now miniscule.

      

7858. Eclectic at 16:03 PM on 6 March 2020
      It's CFCs
      

      EGS :-

      Being far from expert in this area, I should be grateful if you would explain the significance or importance of that recent study by Polvani et al.

      The authors are somewhat vague in their claims, and request confirmatory studies.  AFAICT their models are based on experimental infrared spectra & calculated instantaneous radiative forcings.  They say that their results suggest that ODS [Ozone-Depleting Substances] provide about 20% of the GHG RF forcing over the Arctic.  (This fits with past information provided on the NASA website.)   Yet they state that "the precise value of ODS efficacy remains to be robustly quantified."

      By area, the polar regions are only a small portion of total planetary surface, and they have even lesser importance when given a radiative weighting.

      There may be some misinterpretation of the relative radiative importance of the halocarbons, since (like with the comparative weightings of CO2 and H2O vapor) it is difficult to un-tease the overlapping absorptive spectra of other GHGs.

7859. michael sweet at 15:13 PM on 6 March 2020
      It's CFCs
      

      EGS:

      A free copy of the paper you cite is here.  It states

      "in this paper we focus specifically on the period 1955–2005,
      during which ODS concentrations grew rapidly. Over that period
      the RF from ODS is estimated16 to be 0.31 Wm–2, which amounts
      to nearly one-third of the RF from CO2 (1.02Wm–2), making ODS,
      collectively, the second most important GHG in the latter half of
      the twentieth century, as seen in Fig. 1. These facts are well established7,17 and the important contribution of ODS to global warming has previously been noted18,19" my emphasis.

      It appears to me that your claims are not supported by your citation.

7860. michael sweet at 15:03 PM on 6 March 2020
      It's CFCs
      

      EGS,

      You appear to be arguing that Climate Science has severe flaws in calculations based on this paper.  The paper does not make that claim.  Your claim that "Nearly all the recent decline in arctic sea ice due to CFCs and tropospheric O3?" is not what the paper says.  In fact the abstract says:

      "when ODS are kept fixed, forced Arctic surface warming and forced sea-ice loss are only half as large as when ODS are allowed to increase" my emphasis.

      The response of water vapor to added greenhouse warming from CFC's would be the same as the response to CO2.   Your claims that the effect of CO2 are overestimated by the IPCC are not in the abstract of the paper, you appear to have made them up yourself.

      Much of the difference between the warming we have seen since 1989 and what Hansen modeled is due to the fact that Hansen modeled CFCs increase as more than they did.  The Montreal Protocol resulted in lower increases of CFCs than previously expected.  

      Only climate deniers claim that only CO2 affects global climate change.  Climate scientists know that other gasses (including black carbon) also affect warming and the total effect of human released gasses is much greater than the effect of 415 ppm CO2 alone.  The linked press release claims 82% of the increase in greenhouse gasses from 2007-2017 is from CO2.  CFC's were released less in that decade than before because of the Montreal protocol.

7861. One Planet Only Forever at 14:13 PM on 6 March 2020
      The potential climate consequences of China's Belt and Roads Initiative
      

      Re-reading the article leads me to strengthen my skepticism of the story being told, or at least be skeptical of the way it is being told.

      The New Silk Road will closely-integrate Asia, Europe and Africa, and help many of the poorest regions on the planet. Done with the Sustainable Development Goals in mind it would be amazing. But even if it is done that way it is likely not what the current day American Exceptionalism Empire Builders want to see happen.

      I am skeptical of Stories that make speculative claims about the behaviour of Others without including mention of their own leadership's history of actions (or inaction). Like climate science reporting, stories about the current situation and speculation about the potential future should be based on, and adequately refer to the complete current day story and the History that developed the current day.

      Many of the criticisms presented in the article are speculations about how China’s leadership will behave without mentioning that those are the ways that the current wealthy and powerful, and the European Colonizers of the past, acted to develop and maintain perceptions of their superiority relative to Others.

      People who are concerned about what China’s Leadership might be doing can be helpful by telling stories to Their Leadership about what should be done to be more helpful than the Chinese Leadership might be. In particular, Their Leadership could step in and Altruistically give the poorer nations Renewable Energy Systems rather than speculating about what China might be up to (and they should have started doing that decades ago).

      China’s introduction of coal burning electrical generation in poorer nations could and should be clarified to indicate the failure of the supposedly more advanced nations to have already helped by donating renewable energy generation to those nations. In the 1970s the UN agreed that the supposedly most advanced nations should each dedicate 0.7% of their GDP to Official Development Assistance (ODA). And the Kyoto Accord added the obligation of the supposedly more advanced nations to help the poorer nations on climate change matters (assistance on top of the 0.7% ODA).

      The USA delivers less than 0.2% ODA while expanding its military spending (and demanding that NATO nations spend at least 2% GDP on their military, without any mention of also needing to spend at least 0.7% on ODA). There is lots of capacity for the supposedly more advanced portion of the global population to be more helpful than the Chinese Leadership.

      China could be choosing to behave better. They could be improving living conditions for the poorest by the quick installation of fossil fuel systems with the intent to rapidly transition them like China has been rapidly transitioning. China does not seem to suffer from the Libertarian Capitalist mental-block of believing that the potential for profit from any capital investment must be maximized – no matter how harmful the developed activity is understood to be. The Chinese leadership have proven they are able to shut down fossil fuel operations, and are willing and able to do it without compensating the investors for missing out on future benefits from the harmful activity.

      The leadership of the supposedly most advanced nations, particularly the USA, have a history of failing to be helpful. They need to hear more stories that are justifiably critical of their history of actions, not stories overlooking their harmful past and speculating about how bad their current day opponents might be.

7862. EGS at 12:33 PM on 6 March 2020
      It's CFCs
      

      1/2 of all arctic warming between 1955 and 2005 due to CFCs & N20?

      1/3 of all global warming between 1955 and 2005 due to CFCs & N20? 

      Nearly all the recent decline in arctic sea ice due to CFCs and tropospheric O3?

      Tropospheric O3 and black carbon with as much impact on global warming as all the CO2 emitted since c. 1750? 

7863. EGS at 12:25 PM on 6 March 2020
      It's CFCs
      

      Would that not be evidence that climate sensitivity to CO2 must be much lower than previously modeled? These other GHGs would presumably have the same water vapor amplification feedbacks as CO2 (as non-condensing atmospheric gasses) and produce the expected lower adiabatic lapse rates of warmer water vapor, would they not? Or does water vapor resonate more readily with the discrete wavelengths of infrared radiation emitted by vibrating CO2 molecules? Are those wavebands already saturated so that any additional CO2 emissions can’t add much more radiative heat? In other words, if CO2 is as radiatively powerful as modeled, there should have been dramatically more global warming since the onset of industrialization, especially since the 1950s when these other GHGs really began to be emitted on a very large scale.

7864. michael sweet at 08:20 AM on 6 March 2020
      It's CFCs
      

      EGS:

      From the abstract of the paper you cited:

      "While the dominant role of carbon dioxide is undisputed"

      The IPCC knows that there are a number of other greenhouse gasses besides CO2.  Modelers have these gasses in the models.  It appears to me that Polvani et al are trying to quantitate more accurately how much warming is due to gasses besides CO2.  This is interesting but does not change the basic science of AGW.

7865. swampfoxh at 07:42 AM on 6 March 2020
      Skeptical Science New Research for Week #9, 2020
      

      Can anyone refer me to the source of the idea that it takes thousands of years for the planet to reach equilibrium from the relatively modest rising "rate" of greenhouse gas levels and that the planet is still warming from the effects of 260ppm about 1,500 years ago?  (not in just a few decades).  I have been told that a study by Goreau in 1990 and another by Rohling in 2009 addresses this "stretched" delayed effect?  

7866. EGS at 07:27 AM on 6 March 2020
      It's CFCs
      

      In my previous post I failed to mention HFCs (a.k.a. HCFCs). They replaced CFCs with the Montreal Protocol. 

      The 100 year global warming potential of HCFCs (C5H2F10) was recently re-estimated to be somewhat lower than previously thought, but at 1,410 it is still over 1000 times greater per molecule than C02. https://www.sciencedirect.com/science/article/abs/pii/S0022285217301455. According to NOAA, these chemicals have been accumulating in the atmosphere at a rapid rate since 1990, with HCFC-22 and HCFC-134a above 250 and 100 pptv respectively in 2015 and increasing linearly. https://www.esrl.noaa.gov/gmd/hats/about/hfc.html

7867. EGS at 06:46 AM on 6 March 2020
      It's CFCs
      

      Very recent work led by Lorenzo Polvani and an international team of scientists just published in January 2020 by Nature Climate Change (https://www.nature.com/articles/s41558-019-0677-4)
      argues that large amounts of global and arctic warming are actually due to ozone depleting chemicals (CFCs, HFCs, other halons, and nitrous oxide [N20]), no less than 1/2 of all warming in the arctic and no less than 1/3 of all global warming between 1955 and 2005. These ozone depleting chemicals are trace gasses measured in parts per billion but have global warming potentials 100s to many 1000s of times greater than CO2. CFC-11 and CFC-12 are 19,000 and 23,000 times more radiatively efficient than CO2 per molecule. The global warming impact of methane has apparently also been underestimated, with one new study by Hmiel et al. in Nature arguing that anthropogenic CH4 releases have been 25-40% greater then previously thought (https://www.nature.com/articles/s41586-020-1991-8). Another study by Thompson et al. in Nature Climate Change from November 2019 showed that N20 emissions have been rising far more than the IPCC had assumed since 2009 (by an estimated factor of 2.3!) (https://www.nature.com/articles/s41558-019-0613-7). According to the US EPA, the global warming potential of N20 is 265-298 times greater than CO2 over a 100 year timescale (https://www.epa.gov/ghgemissions/understanding-global-warming-potentials). Tropospheric ozone (O3) is both a potent direct greenhouse gas and plays a role in the lifetime and effectiveness of other greenhouse gasses. According to research by Jim Hansen and others published in the Journal of Geophysical Research (2006), tropospheric O3 is estimated to have caused no less than 1/3 to 1/2 of the observed recent trends in arctic warming in the winter and spring, when O3 is easily transported to polar regions from lower latitude urban centers https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2005JD006348. Tropospheric O3’s direct cumulative radiative forcing when combined with fine particulates like black carbon is believed to possibly outweigh that of all the CO2 released since the beginning of the industrial era https://www.pnas.org/content/pnas/early/2010/02/02/0906548107.full.pdf. Sulphur hexaflouride (SF6) is perhaps the most potent anthropogenic greenhouse gas, and its emissions have been rising rapidly from use as an electrical insulator. Its 100 year global warming potential per molecule is estimated at 23,000 times that of C02. Its atmospheric abundance is low at 8.60 parts per trillion volume, but it is rising at a linear rate by 0.33 pptv per year and can persist in the environment for more than 1000 years. https://www.atmos-chem-phys.net/17/883/2017/acp-17-883-2017.pdf

      Would that not be evidence that climate sensitivity to CO2 must be much lower than previously modeled? These other GHGs would presumably have the same water vapor amplification feedbacks as CO2 (as non-condensing atmospheric gasses) and produce the expected lower adiabatic lapse rates of warmer water vapor, would they not? Or does water vapor resonate more readily with the discrete wavelengths of infrared radiation emitted by vibrating CO2 molecules? Are those wavebands already saturated so that any additional CO2 emissions can’t add much more radiative heat? In other words, if CO2 is as radiatively powerful as modeled, there should have been dramatically more global warming since the onset of industrialization, especially since the 1950s when these other GHGs really began to be emitted on a very large scale.

7868. nigelj at 13:24 PM on 5 March 2020
      The potential climate consequences of China's Belt and Roads Initiative
      

      30% of the worlds metals are recycled, particularly steel and copper. Lithium can be recycled but very little is recycled, because  its not currently economic to do so. Only 9% of plastics are recycled presumably because its not economic.

      If we want more recycling of those uneconomic sorts of things, government incentives would help, so we effectively will all have to contribute. From what I've read it does not require much incentive to make recycling financially viable.

      In the future people will probably mine rubbish tips for old metals and other materials.

7869. dana1981 at 08:01 AM on 5 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      gws @13 - thanks good catch, correction made!

7870. John Hartz at 06:53 AM on 5 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      Recommended supplemntal reading:

      The Congo rainforest is losing ability to absorb carbon dioxide. That’s bad for climate change. by Daniel Grossman, Climate & Environment, Washington Post, Mar 4, 2020

7871. Eclectic at 03:09 AM on 5 March 2020
      CO2 effect is saturated
      

      Dien @585 ,

      heat rises through the atmosphere by radiation, convection, and latent heat changes (water phase-change).  Consult the famous "Trenberth cartoon" to see the proportions of these.

      The lapse rate can be viewed in the simplest term, as like the multiple layers of clothing you wear on a cold day ~ the thermodynamic heat flow across the temperature gradient, from warm innermost layer to coolest outermost layer.  You can look at the complexities of each mechanism: but the ultimate effect is a simple gradient, from planetary surface up to the effective radiation "escape" layer.

7872. dlen at 02:28 AM on 5 March 2020
      CO2 effect is saturated
      

      @ ma rodger, #584: Thx for the lengthy answer and the little lecture about heat pathways. I got the impression, before developing ad hoc heat propagation models, I should have done some reading about convective-radiative heat transfer in the atmosphere. 

      So, if I interprete your post correctly, the main transport mechanism to the effective emission height is convection, with radiation from the soil being nearly insignificant. This should be named as such in the explanation. It is not very complicated, not hard to understand.  

      The effective emission height is rising. This is sufficiently well explained in the text. What is not explained is, why it is colder in higher levels of the atmosphere. I see two aspects here: 

      1. adiabatic expansion of rising air packets. This is a general explanation for the lapse rate. The rising air packet uses up internal energy for expansion work.

      2. After the earth has been warmed sufficiently, the now higher effective emission layer will not be colder anymore. The rising air packets will start with a higher temperature = internal energy and so will be warmer even after having risen to a higher effective emission layer. 

7873. jef12506 at 01:08 AM on 5 March 2020
      The potential climate consequences of China's Belt and Roads Initiative
      

      AT the core of all our converging catastrophies is the fact that in order to live you must participate in this very destructive system. We extract finite natural resources, process and manufacture, distribute globally, buy, sell, then ultimately 90% of it is thrown away.

      Each step of this system in its self is highly destructive, put together it spells the end of life as we know it. 

      We are a highly inetlligent species and are capable of restructuring, reorganizing ourselves in a much more intelligent manner. Problem is first we need to see that this is the core issue then we must dare to imagine an alternative.

7874. One Planet Only Forever at 10:01 AM on 4 March 2020
      The potential climate consequences of China's Belt and Roads Initiative
      

      I have read a few books that mention details about the New Silk Road. And I have read some articles on News Sites.

      And the plan will develop an integration of renewable energy systems connected through the Belt network.

      I will read this article again. But my initial impression is the article is written from the perspective of someone who is immersed in a USA-centered Libertarian global domination that would be threatened by the success of the New Silk Road.

      The USA, and the undesreving among the wealthy who like to control things in their favour through its power, could participate collectively in developing a sustainably better future for humanity. But they have Other Interests.

      Jeffrey D. Sachs, a major contributor to expanded awarensss and understanding regarding the Sustainable Development Goals, makes that point clear in his book "A New Foreign Policy: Beyond American Exceptionalism" (Columbia University Press, 2018).

7875. nigelj at 06:54 AM on 4 March 2020
      The potential climate consequences of China's Belt and Roads Initiative
      

      China's BRI is very environmentally concerning, however The USA invested 5.95 trillion dollars in other countries in 2018. Not sure of the composition, but its likely much of this was in carbon intensive projects. Europe is probably similar.

      Lots of virtue signalling where countries do the right thing with emissions in their own countries (up to a point) but export their climate problems in various ways. Shame on all of them.

7876. takamura_senpai at 22:17 PM on 3 March 2020
      How much would planting 1 trillion trees slow global warming?
      

       @RedBaron   "US started planting trees in the 1920's" Rome started planting trees 2000 years ago, and What is ...? In our region started planting trees 300 years ago, becouse almost desert. and What?
      "and there are at least as many now as the pilgrim days or more." Lie. Americans killed many forests. For example wonderful sequoias.
      "Deforestation in the United States. Deforestation refers to the long-term or permanent loss of tree canopy cover and the conversion of this land for other purposes. A 10 percent loss of canopy qualifies for this term. United States deforestation has caused the destruction of virgin forests by 75% percent since 1600." Google tells. https://greenliving.lovetoknow.com/United_States_Deforestation So you just lied.
      USA export wood to China MORE than Russia, in dollars.

      Americans at first have to stop killing forests, and AFTER this we will speak about 1 trillion new trees.

7877. gws at 13:46 PM on 3 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      Dana, note the typo in US emissions: It is not 5.4 GtC, but 5.4 GtCO₂. Otherwise the US would emit more than 50% of global (=10 GtC).

      https://www.eia.gov/environment/emissions/carbon/

7878. nigelj at 06:20 AM on 3 March 2020
      Nine ‘tipping points’ that could be triggered by climate change
      

      Related research: Trajectories of the Earth System in the Anthropocene

7879. Philippe Chantreau at 03:43 AM on 3 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      Joe Z says "Forestry work is also beneficial for wildlife becaue many species prefer young forests or thinned forests. Biodiversity is not maximized by letting all the forests grow old."

      This is the kind of statement that deserves citations from science papers for substantiation. My experience of forestry was limited to the African rainforest, where, as far as I can remember, the highest biodiversity is found in old growth forests, where the canopy is continuous and so little light reaches the ground that it is easy to circulate on foot because of the lack of undergrowth. These forests are very rich in 3 dimensions, from the top of the canopy to their soil, which often can be thin (hence the buttresses shown by many tropical species) and tends to wash away without the tree cover due to the heavy rains from repeated thunderstorms (a daily occurrence in the rainy season).

      I wholheartedly agree, however, that good forest management is possible, in any environment. It is possible only if based on sound scientific evidence and free from undue influences like corruption or the maximization of profits at any cost.

7880. JoeZ at 01:54 AM on 3 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      Scanddenp,

      "what matters is how much in land is permanently allocated to forest as opposed to other land uses" You got that right!

      "There can be plenty of reasons other than CO2 sequestration to keep foresters from felling forests however. I wonder how many fights are really about that and CO2 sequestration is excuse?" Right on that too- at least, there are other not so good reasons- like, some people just can't stand the sight of a forest that has seen some silvicultural work which includes thinning and clear cutting- they consider it a rape of the land- despite their own love of their wood home, wood furniture, and paper products- like the people who think milk comes from the supermarket, not a cow. Forestry work is also beneficial for wildlife becaue many species prefer young forests or thinned forests. Biodiversity is not maximized by letting all the forests grow old.

      "in managed forest, how much carbon per hectare at point where forest is harvested compared to your "old growth" forest." I don't have the numbers in front of me- but forestry researchers have the numbers which vary depending on forest type and where it is. As I mentioned, here in New England, it might be something like a half ton per acre per year- whether it's just been logged or not. Old growth forest should be fairly stable in sequestered carbon- but the total will be substantially greater than any managed forest. But as many have noted- stopping all logging or slowly down the amount of logging isn't going to solve the problem of climate change and it will result in economic problems for some and the loss of a fine, low carbon footprint raw material. Unfortunately, as a non academic, I don't have good access to the research. Most such research is behind a paywall- especially in America from The Society of American Foresters- which have no need to join due to expense. There is literally tons of forestry research from all over the planet. I'm just a guy who has been working in the forests- not spending a great deal of time on top of the research so my knowledge is more personal- and localized to New England- which has many forests types due to elevation and geologic variations.

      Saving forests from a "land use change" is a great idea- stopping all or most logging to save the Earth from climate change is foolish. I should think a fair amount of logging even in the rain forests would be a good idea- if done right, which of course is the issue- because it probably wouldn't be.

7881. One Planet Only Forever at 13:53 PM on 2 March 2020
      Different Crises: Coronavirus & Climate Change
      

      CBC News has this article "Fallout from coronavirus outbreak triggers 25% decrease in China's carbon emissions". It is related to the BBC News item I linked to in my comment @2. And it adds some interesting thoughts regarding actions to limit the negative impacts of human burning of fossil fuels.

7882. John Hartz at 13:43 PM on 2 March 2020
      Medieval Warm Period was warmer
      

      Recommended supplemental reading:

      Current climate warming is rapid and occurring on a global scale, unlike past periods of regional climate fluctuations, Edited by Katy Dynarski, Climate Feedback, Feb 21, 2020

7883. One Planet Only Forever at 13:38 PM on 2 March 2020
      Different Crises: Coronavirus & Climate Change
      

      There is a similarity between responses to COVID-19 and 'Climate Change due to Global Warming due to Increased CO2 levels due to Human Activity'.

      Some people want to minimize the potential for negative impacts on perceptions of wealth in the economic games, especially changes that lower the perceptions of wealth and power of 'people who are perceived to be wealthy and powerful'.

      The initial comments regarding COVID-19 were along the lines of 'this is not likely to be easily transmitted'. Some perceived to be wealthy powerful people are still trying to claim it is 'Not a serious concern'.

      And as this BBC News Item shows the air in China has become rapidly cleaner, which can help people understand that the machinery of prosperity had been seriously affecting them. And NOx is just one of many harmful products of burning fossil fuels.

      Hopefully this side-effect of COVID-19 will help more people become more aware and understand that there are many more reasons to stop burning fossil fuels. The dead-end burning up of buried ancient hydrocarbons creates more harmful consequences than excess CO2. And those impacts are immediately affecting people everywhere the stuff is burned (and where it is extracted and processed into fuel for burning), no matter how convenient and popular it is or how wealthy it makes some people appear to be.

7884. scaddenp at 11:35 AM on 2 March 2020
      How much would planting 1 trillion trees slow global warming?
      

      Joez, I am not much interested in how fast land is taking up carbon (because an equilibrium will be reached), but how much carbon per hectare total. On scale of hundred years, it doesnt matter too much what state the forest is in (if you clearfell, I think regrowth will suck CO2 from air faster than timber will release it) - what matters is how much in land is permanently allocated to forest as opposed to other land uses.

      There can be plenty of reasons other than CO2 sequestration to keep foresters from felling forests however. I wonder how many fights are really about that and CO2 sequestration is excuse?

      So again question is, in managed forest, how much carbon per hectare at point where forest is harvested compared to your "old growth" forest.

      Situation here (NZ) is very different. We have large plantation forests of tightly managed exotic trees (mostly Pinus Radiata which can be ready for harvest in under 30 years in our climate) but also large areas of slow growing native forest, much of it virgin. Native forest is largely protected with very limited amounts of forestry. Plantation gets clear-felled and immediately replanted. Very selective logging (sometimes with helicopter) is norm in native forest.

      Mature native forest contain 258 tonnes carbon /hectare compared to  192 tonnes per hectare for plantation at maturity. Radiata however sucks up carbon far faster than native so much preferred for carbon farming.

7885. takamura_senpai at 07:30 AM on 29 February 2020
      Different Crises: Coronavirus & Climate Change
      

      Coronavirus has a potential drop CO2 emission on 1-10%. Coal burning in China drop approx 1.5 times, oil like the same. Soon in other countries in the stage.....

      So Don't worry, be happy
      Don't worry, be happy now

      Oh, ooh ooh ooh oo-ooh ooh oo-ooh don't worry, be happy

7886. JoeZ at 23:00 PM on 28 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      Scaddenp, it all depends. A true old growth forest (we foresters don't use the term virgin forest) might not be adding any carbon, it might be adding carbon in the soil if not in the trees (since some will be dying or decaying internally), it might be losing carbon (if old trees are dying frequently). Young forests will be sequestering carbon but it depends on the type of forest, where it is, how healthy it is. In the US northeast it might be roughly 1 ton/acre/year not counting soil carbon. From what I read in forestry literature- the forests of North American have been gaining carbon for decades faster than the carbon losses from harvesting and natural mortality and the frequent decay in living trees and conversion of forests to other uses. I don't have access to the current research. I have a lot of old text books but I'm too lazy to look up what they say. In summary, there is much less carbon in the forests now than pre-European times but despite a thriving timber industry and forests being lost to other uses the total amount of carbon in the forests is increasing. If forests are managed properly with concern for increasing carbon- we can harvest wood products while still increasing carbon. Meanwhile, there is a movement now happening (especially here in Massachusetts) to lock up all the forests so that their only purpose is sequestering carbon. No consideration is given to where we'll get wood for construction, furniture and paper producs- no consideration that using cement and steel for construction and plastic for furniture will have a higher carbon footprint. Major political wars are now occuring over how to manage or not manage forests- it's not just about  protecting the rain forests. One huge battle which I've been caught up in is over woody biomass for energy. Massachusetts is the epicenter of that battle. One last comment- there is now a movement to build very tall structures with wood and not steel. It's called cross laminated timber- https://www.thinkwood.com/products-and-systems/mass-timber/cross-laminated-timber-clt-handbook

7887. MA Rodger at 21:20 PM on 28 February 2020
      Berkeley Earth Surface Temperature Study: “The effect of urban heating on the global trends is nearly negligible”
      

      YTeddy @45,

      You are correct in that there are no satisfactory answers posted for Lassesson @2.

      I'm not sure what is being asking regarding 1865-70 but the "huge peak arond 1880" was the 1877-78 El Niño which appears in the extended MEI record, its impact on the global temperature records (both BEST & HadCRUT cover back to 1850) being excentuated by the preceding and succeeding La Niñas.

      

      The article you link-to is describing the work presented at the 2017 AGU Fall Meeting ' El-Niño Grande and the Great Famine (1876-78) '. Looking at the citations the paper gained here, I don't see any response to the paper from climatologists although it does receive attention for its analytical method.

7888. YTeddy at 16:37 PM on 28 February 2020
      Berkeley Earth Surface Temperature Study: “The effect of urban heating on the global trends is nearly negligible”
      

      Lassesson at 18:25 PM on 21 October, 2011
      What happened around 1865-1870 in figure 3 and where did the huge peak around 1880 come from?

      I don't see the answer posted.   The answer to your inquiry is almost certainly the very large, perhaps largest in recent history, El Nino Event, 1876-78.

      https://www.insidescience.org/news/historys-greatest-el-ni%C3%B1o-may-have-caused-severe-19th-century-famine 

7889. scaddenp at 10:53 AM on 28 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      Interesting info JoeZ. Do you have a source for carbon sequesteration per hectare in managed forest compared to virgin forest?

7890. JoeZ at 01:10 AM on 28 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      Scaddemp said, "Not according to US Forest Service. Current forest looks to be 75% of what pre-European coverage was." There is less acreage of forest but each acre has more trees than in pre-Euro times. In the US northeast, in pre-Europ times each acre may have had 40-100 trees per acre. Now most have several times that. The trees are much smaller and the total volume of wood is far less but it's growing fast and overall, US forests are sequestering more carbon than is being lost to harvesting, storms and fire. Trees are seldom planted in the northeast. In the US southeast, forests are intensely managed and trees are planted after most harvesting- more trees than will survive to the "final cut" due to periodic thinning.

      I  posted a comment in the new version of this thread. I'm certainly not qualified to debate climate science but I do know American forests.

      Joe Zorzin

      MA Forester License #261

7891. DantetnaD at 20:55 PM on 27 February 2020
      How deniers maintain the consensus gap
      

      @MA Rodger it was on 20min.ch, it's one of those quick news sites (lots of garbage on there). 

      I was just astounded by the numbe of people commenting stuff like "Yeah! Finally an anti-Greta, you go girl!". Sigh.

      I'm pretty sure that if Greta was a 30 year old without aspergers (I believe it's what she has, don't quote me on that though), you'd have the same people calling her out on other things to discredit her.

      @Eclectic indeed it is a form of insanity, but I wonder if the root cause isn't also to be found somewhere in the education system. I did not grow up in the US so correct me if I'm wrong, but the fact that in some states creatonism is being taught gives us a hint about this. Not that we don't have our share of negationists over here too though...

      And yes, the other issue is the way our modern society works. We are still immensly dependent on fossil fuels for pretty much everything. The reallity is that there are many powerful and rich people that benefit from this, and they don't like the idea of this getting disrupted. Reallity will hit them at some point, as fossil fuels will get depleted at some point anyway.

7892. scaddenp at 09:36 AM on 27 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      "there are at least as many now as the pilgrim days or more."

      Not according to US Forest Service. Current forest looks to be 75% of what pre-European coverage was.

7893. scaddenp at 09:14 AM on 27 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      Manwichstick - the carbon is sequestered so long as the area planted remains in forest. Undisturbed, old trees are replaced by new one and the carbon sequestered by hectare of forest approaches an approximately stable equilibrium. Even if harvested or burnt, so long as forest regrows, then it is only temporary blib in the carbon stock.

7894. JoeZ at 07:33 AM on 27 February 2020
      Planting a trillion trees will solve global warming
      

      I doubt many people think "Planting a trillion trees will solve global warming"- not even Trump. I heard his speach and I don't think he said it's going to solve the problem. He wouldn't say that because doesn't think there is a problem. Regardless, it might help. What's missing in this tree planting idea- is that existing "commercial forests" that are managed or mismanaged- could increase their carbon sequestration if managed better. I'm most familiar with the forests in the U.S. northeast- most of which were severely abused in the past half century (high graded where they took the best and left the rest). Such forests are loaded with deformed, diseased and defective trees- often of slow growing and short lived species- instead of the more vigorous species that probably dominated most forests in the region- oaks, maples, pines. Improved forestry practices (which I believe is called for in IPCC documents without explaining what it means)- could remove the unhealthy trees that are slow growing in favor of fast growing, healthy specimens. How much of an improvement this would make- I don't know- I'm not aware that any forestry researchers are working on this- but I've seen estimates that if such improved forestry practices became common- the additional carbon sequestration would be substantial.

      Joe Zorzin, Massachusetts Licensed Forester

7895. Manwichstick at 06:23 AM on 27 February 2020
      How much would planting 1 trillion trees slow global warming?
      

      Isn't the other problem with tree planting that it is only temporary carbon storage for a period of time that is equal to the length of time the tree lives?
      It falls and rots and returns all the carbon.
      
      

7896. One Planet Only Forever at 01:44 AM on 27 February 2020
      How deniers maintain the consensus gap
      

      DantetnaD @22,
      As someone who tries to expand my awareness and improve my understanding and apply what I learn to try to help develop sustainable improvements for Others including the future of humanity, I see the Anti-Greta as a young actor-activist, potentially brain-washed by a tribe that desires to maintain beliefs and perceptions of status that are understandably harmful and incorrect, unsustainable.

      And what I know is that one of the main attacks on Greta has been claiming that she has been brain-washed by adults and is just being used as an 'actor-activist'.

      And the groups that do that type of thing have a history of trying to accuse others of misleading marketing that they actually are the perpetrators of.

      And it isn't just USA Team Trump. There are the harmful likes of Hungary's Orban - claiming their harmful promotion of selfish nationalism to mask deplorable actions that harm Others is justified because 'People Should be Proud of Their Pats, Those Things they developed a Liking for that everyone can actually understand are harmful unjustified attitudes and actions needing to be corrected'.

      The real problem is indeed a system problem. The developed socioeconomic systems produce undeserving powerful and wealthy people who abuse misleading marketing to Get More Undeserved Winning and resist being corrected, resist losing their undeserved perceptions of superiority relative to Others.

      Correcting the system is required. And that is easily powerfully resisted in many regions where the corrections of the system would be easily understood to reduce undeserved developed perceptions of status and opportunity.

      I also see this where I live in Alberta. The resistance to expanded awareness and improved understanding is Strong among the Fossil Fuel Exporting Dependant portion of the population. The result has been the election of a Authoritarian, nearly police-state (more aggressive legal actions on protesters), leadership desperately doing anything it can get away with to push for more fossil fuel export. That claimed to be Conservative-Libertarian type of leadership is now expressing interest in having Their Government meddle more directly in the marketplace. They suggest that public money should be investing in business interests that investors are choosing to walk away from (a way of using public money to compensate investors for their bad bets). The Federal Government of Canada did this when they bought the Transmountain Pipeline Expansion Project, so the national system is also tainted, not just the more easily tainted Provincial level of Government.

7897. Eclectic at 23:44 PM on 26 February 2020
      How deniers maintain the consensus gap
      

      Moderators : I note that since the recent "down time" of this website, a double line spacing is appearing between paragraphs.

      Is this intended?

      Moderator Response:

      [BW] Thanks for letting us know! We'll check it.

7898. Eclectic at 23:38 PM on 26 February 2020
      How deniers maintain the consensus gap
      

      DantetnaD , you are correct that the science-denier movement is an example of what is in effect a type of intellectual insanity.  It is based on emotion & consequent Motivated Reasoning (cherry-picking, and self-deception) . . . and/or on the emotions of tribal thinking  (the sort of "them and us" division which has been so harmful to humanity through the ages).

      Interesting that this politicization tendency seems greatest in the USA and to a lesser extent the other Anglophone nations.   That may be because for the USA, the Right Wing contains many people who don't like to see any change in their current lifestyle ~ they are resentful of and fearful of the gradual sociological "erosion of privilege" (perceived, if not actual . . . and including a dollop of racism, too).   Such a group is also fertile soil for the propaganda seeds implanted by the overt & covert manipulation from the Fossil Fuel lobby, which aims to turbo-charge all such concerns.

      Not a pretty picture.  Eventually things will get bad enough that more and more voters will press for stronger climate action ~ but this voter activity will not happen fast enough to stop a lot of preventable damage.

      BTW, a few weeks ago, I did catch up with the "Anti-Greta" video by the German girl.  It is not worth seeing.  IIRC it was about 5 minutes long, and contained nothing substantive ~ no factual scientific arguments: just vague rhetoric and complaints that she didn't like being patronized or being called a denier.   Only a fond mother (or a climate denialist) could see any virtue in it.

7899. MA Rodger at 23:08 PM on 26 February 2020
      How deniers maintain the consensus gap
      

      DantetnaD @22,

      Perhaps your article on the 'anti-Greta' could be this one in yesterday's Guardian about Naomi Seibt. I note in the linked YouTube that her contribution is no more than a pantomime - "Oh no it's not!!"

      I'm not sure that her association with Heartland makes Naomi anything more than an advertising tool for that particular pack of numpties. An actual Naomi quote from the linked YouTube (which contains a lot of editing breaks suggesting Naomi can't speak fluently about numptyisms, at least not in English) runs:-

      "We at the Heartland Institute, we want to spread truth about the science behind Climate Realism [cut] which essentially is the opposite of Climate Alarmism [cut].   ...   [Cut] I don't want you to panic. I want you to think."

      Of course, if folk do as Naomi asks and engage their brains and think, then the lies set out by Heartland are all pretty obvious.

7900. DantetnaD at 20:54 PM on 26 February 2020
      How deniers maintain the consensus gap
      

      This is what scares me.

      There was an article yesterday about this new "anti-Greta" german girl which basically says climate change isn't as bad as it looks. Go in the comments and you see the sheer ignorance of a vast majority of the folks out there, even in our "first world" countries. 

      Just a whole bunch of hateful comments against Greta and a whole lot of people who have a complete lack of intellectual capacity to understand and analyse scientific evidence.

      I don't have a scientific degree per say, but my parents both had scientific degrees. I work with computers which gives me the capacity to understand complex systems. And what I do see out there, is that a lot of people don't understand how systems work in general. They don't understand that it is all about an equilibrium of a large number of factors that, when they work together, make a stable system. When you start to tinker with a parameter, the system will eventually become unstable and crash. Simple example: raise the frequency of a CPU without increasing the cooling capacity and you computer will overheat and crash.

      What annoys me most about deniers, is that they completely dismiss scientific evidence. They will go at great length to find data, studies or any piece of news (often not verified for that matter), that comforts them in their own bias. When you tell them that there is a consensus of actual scientists that do state that global warming is real and probably accelerated by humans, they will throw this "30'000 scientists say it's not true" idea in your face without even fact checking that these people are actual climate scientists.

      It honestly doesn't take a genius to read the reports. To look at the data. To look at the charts. And from their on, extrapolate to what is potentially going to happen. 

      The real problem in the end, is that human induced climate change has been politicized. Suddenly you're either pro or anti climate change. Why does everyone fail to understand that this should not be the case? How is it that we cannot understand that we all need to work together to do something about it? What's the worst that can happen? We make a better home for ourselves?

      Have we regressed so much that we are, once again, dismissing science in favor of "beliefs"?

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