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Comments 9851 to 9900:

9851. wjohnallen at 12:18 PM on 31 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      @Evan #8

      You are right that the determination of the GWP for biogenic methane accounts for the fact that it is a short lived gas (compared to CO2).  That assesses its warming impact and in terms of emissions accounting (to the IPCC), that conversion to CO2eq equates to it remaining in the atmosphere for as long as CO2 does.  We do not often see it used, but fossil methane has a GWP100 of 33 (from memory), compared to the most recent figure for biogenic methane of 28. This difference in accounting reflects the fact that fossil methane is a new-to-the-atmosphere ghg, unlike biogenic methane which is part of the short-term carbon cycle.  

      All that accounting aside, the point still remains that in terms of warming impact, once CH4 degrades (to CO2, H20,...) its warming impact also degrades but nowhere is that accounted for. Each molecule of CH4 is accounted for as if it remained in the atmosphere. So, if atmospheric biogenic CH4 concentrations are not increqsing, then biogenic CH4 sources are not adding to global warming to any significant extent.

9852. Evan at 10:25 AM on 31 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      wjohnallen@7

      But the second thing missed by many is that the IPCC report regime, counts each molecule of CH4 as if it is in the atmosphere forever.

      My understanding is that a GWP (global warming potential) of 25 for methane accounts for the fact that it does not remain in the atmosphere forever. Or am I missing something?

9853. nigelj at 08:19 AM on 31 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Human 2932847 @15, 

      "I don't think it matters whether Seager is alone in his views or his papers are ten years old, he seems a perfectly sane and competent scientist, not a fringe flake or paid shill."

      I agree Seager doesn't come across as a fringe flake or some sort of closet climate denialist, and his article you linked to seems ok, but it does matter that he is alone in his view. This doesn't mean hes wrong, but it does mean we need to be rather cautious, a point made by MAR rather clearly I would say with his example of Chen and Tung. 

      The little detail that stood out to me is western europe is much milder in climate than canada on the same latitude line, and this not well explained by the atmospheric heat transport, or oceans giving up heat in winter, but is easily explained by the gulf stream, so a slowing gulf stream would seem fairly large implications for Europe.

9854. wjohnallen at 07:50 AM on 31 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      A couple of things about meat missed by many:

      One is that the grass a ruminant eats, regrows and as it does so, CO2 is taken out of the atmosphere.  Based on the numbers used to report emissions to the IPCC (CH4 emissions factor (Kg CH4/animal/year), animal weight (Kg), feed energy requirements (MJ E/day)) and data from the dairy industry (energy content of pasture grasses (MJ/Kg DM) and feed consumed (Kg DM/day)), it turns out that a cow consumes more CO2 than it belches out as CH4 (on a CO2eq basis at a GWP of 25).

      Who knew that ruminants on grass pastures are carbon negative?  

      Further, of the global average emissions factor for beef on the plate (26.6 KG CO2e/Kg meat), other on-farm processes plus the beef supply chain adds more emissions than the animal does.  If CAFO operations were eliminated, then the average beef emissions factor would come down and beef would then be seen as a carbon neutral protein source. 

      Those who want animal agriculture to be the cause of our climate problem will rush on to say that CH4 is a more potent ghg than CO2.  They are right of course, it is.  

      But the second thing missed by many is that the IPCC report regime, counts each molecule of CH4 as if it is in the atmosphere forever.  Of course it is not - because natural processes remove it from the atmosphere over time.  Which means that if biogenic methane emissions did not exceed withdrawals, then biogenic methane makes little contribution to global warming (not none, just not as much as the ghhg accounting system makes out).

      But who cares about these facts when pointing the finger at agriculture means that we humans do not have to address the prime drivers of global warming - the mining and burning of fossil CO2 and CH4, plus, and more importantly, the harvesting of nature's carbon sinks (forests).

9855. NoctambulantJoycean at 07:24 AM on 31 August 2019
      Models are unreliable
      

      @rupisnark 1151

      Christy's offers his usual distortions that he's been giving for decades. His core argument is that climate models exaggerate bulk tropospheric warming, especially in the topics, and this results from climate models over-estimating climate sensitivity (over-estimating CO2-induced warming). His conclusion is wrong, and the discrepancies he points out are primarily not due to model error, but instead primarily due to errors in inputted forcings for the models, along with internal variability and observational uncertainty (ex: Christy showing tropospheric warming estimates contaminated by stratospheric cooling). So the models aren't greatly over-estimating climate sensitivity.

      If you want an introduction to this subject, then I recommend reading "A response to the “Data or Dogma?” hearing", "Fact sheet for “Causes of differences between model and satellite tropospheric warming rates”", along with the papers with the following DOI numbers: 10.1175/JCLI-D-16-0333.1 ; 10.1038/NGEO2973 ; 10.1002/2017GL073798

      Here is a list of some of the problems:

      1) If bulk tropospheric warming was muted relative to surface warming, especially in the tropics, then that would be a sign of a muted negative lapse rate feedback. That would increase climate sensitivity, not decrease it, contrary to what Christy claims. And there's plenty of evidence of a multi-decadal, positive water vapor feedback.
      2) If Christy's position was right, then we'd expect to see a strong model vs. observational analyses discrepancy pre-1999. But we don't. We instead see it post-1999, as one would predict if the issues were with errors in inputted forcings over that period, not over-estimated climate sensitivity.
      3) The models don't greatly exaggerate temperature responses to volcanic eruptions in the way one would expect if Christy were right about over-estimated climate sensitivity.
      4) A number of papers showed that errors in inputted forcings largely explained residual post-1999 differences between surface analyses vs. models; that would also imply a contribution to post-1999 bulk tropospheric discrepancies as well.
      5) Christy has a decades-long history of too hastily jumping to model error as an explanation, when the actual explanation was something else. This includes the notorious case in which he claimed models over-estimated satellite-based bulk tropospheric warming, when actually Christy screwed up the sign of the diurnal drift correction for his UAH satellite-based analysis.

      There are other problems with Christy's position, but I think that list should be enough to get you started.

      Moderator Response:

      [DB] Hot-linked reports and DOI's.

9856. william5331 at 07:04 AM on 31 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      Technically, these problems are pretty easy to solve.  It is the political will and the fact that Who Pays the Piper Calls the Tune which is the core problem.  Politicians will do the bidding of whoever finances them.  But leaving that aside, no solution to the food problems will succeed without affordable contraception in the hands of women.  To paraphrase Richare Dawkins,  "If ever there is an increase in food production, population will rise until the original state of misery has been re-established".  The much vaunted green revolution of the 60's is a case in point with an extimated increased population of 700m people as a result.  With every increase in population we push Gaia, with her free provision of air, water, genes, fiber etc. into an ever smaller corner.

9857. marilia16805 at 03:04 AM on 31 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      I have downloaded the summary and the controversial chart wasn't there. Nor was any mention to vegan or other (also controversial) diets. It seems to me that most dietary concerns focus on food waste rather than radical changes on macronutrient sources.

      I can't see how to reconcile concerns with poverty-derived macronutrient malnutrition and radical recommendations such as vegan diets (extremely expensive to meet protein demands). I cound't find one single economic projection of shifts to veganism (and I suspect it is impossible to model that).

      Moderator Response:

      [DB] The graphic in question is Figure 5.12 from Chapter 5 from the full report, and is found on page 766.  The full legend:

      "Figure 5.12 Technical mitigation potential of changing diets by 2050 according to a range of scenarios examined in the literature. Estimates are technical potential only, and include additional effects of carbon sequestration from land-sparing. Data without error bars are from one study only."

9858. Daniel Bailey at 01:15 AM on 31 August 2019
      It's the sun
      

      "Can 'the sun' account for as much as 10%?"

      That depends upon where you demarcate your start and end periods.

      Scientists have quantified the warming caused by human activities since preindustrial times and compared that to natural temperature forcings.

      Changes in the sun's output falling on the Earth from 1750-2011 are about 0.05 Watts/meter squared.

      By comparison, human activities from 1750-2011 warm the Earth by about 2.83 Watts/meter squared (AR5, WG1, Chapter 8, section 8.3.2, p. 676).

      What this means is that the warming driven by the GHGs coming from the human burning of fossil fuels since 1750 is over 50 times greater than the slight extra warming coming from the Sun itself over that same time interval.

      

9859. Human 2932847 at 01:05 AM on 31 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Looking at Ka-Kat Tung's stuff online, he doesn't seem to be denying AGW, and it's not obvious why he's unreliable - certainly not to a layman such as I. He might be, he might not, I don't know.

9860. Human 2932847 at 00:46 AM on 31 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Thank you again for taking the time to help me. If I may say, though, I don't think it matters whether Seager is alone in his views or his papers are ten years old, he seems a perfectly sane and competent scientist, not a fringe flake or paid shill. So his academic minority status doesn't seem a problem to me. He also seems to draw his conclusions from other's work and has several co-authors. So I don't know why you say it's only his opinion.
      Anyway, thanks for showing me the plurality of views, which may give an updated refutation of Seager's points, and you probably know what the predominant views are in the field of things AMOC so I'll stay open minded.
      If it's out of date, maybe Columbia should look at updating it's website ?

9861. Nick Palmer at 22:38 PM on 30 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      RedBaron @2
      
      While broadly sympathetic to the 'regenerative agriculture' solution to sequestrating our carbon emissions, I have to say, having a fair amount of experience interacting with exponents in the field that they really have to up their game and PROVE their beguiling assertions with properly conducted independent peer reviewed trials published in reputable journals.
      
      'Leading light' figures such as Gabe Brown, Elaine Ingham, Allan Savory, Christine Jones et al need to reduce the 'gee wiz' anecdotes and supply published hard data on request, instead of just hand waving. I look forward to these other figures doing the sort of scientific evaluation work that Dr David C Johnson of NMU is doing to establish the veracity of claims. In the meantime, there are plenty of extreme 'soil regeneration cowboys' who've just done correspondence courses out there making ridiculously overhyped unproven assertions and muddying the waters.

9862. MA Rodger at 20:30 PM on 30 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Human 2934527 @13,
      The understanding that a weaker AMOC cools lands bordering the N Atlantic is pretty-much accepted by all. There are exceptions. one being Richard Seager from a decade ago. I would suggest his position back then was fuelled by the work from a few years earlier enumerating the poleward energy fluxes. From his presentation slide 12 (linked @12) “First hint that this may all be myth comes from using observations to estimate atmosphere and ocean heat transports.“ This basically shows that above 40N only a tenth of the north-bound energy is via the oceans, a finding that has pretty-much stood the test of time. Thus from Schmitt (2018) 'The Ocean's Role in Climate'  its Fig 3:-
      
      
      Being an ocean-based account, |Schmitt (2018) splits the atmosphere fluxes into dry and wet, but the proportion of the total within the ocean is small beyond 40N, not much more than 10 percent.
      And that 'not much more than 10 percent' is almost all the AMOC which operates on a rather small bit of the planet so its influence over that bit of planet is quite large. (The number often given to the AMOC energy flux is ~0.4PW. Today's climate forcing due to AGW is [3.1Wm^-2 x 510M sq km=] 1.6PW acting over the entire world.) So I would suggest that Seager was barking up the wrong tree in his 2007 presentation & his modelling was presumably somehow flawed in concept.

      What has been of interest to the science of recent years is getting the strength of the AMOC & its present rate of decline, of interest because AGW models suggest it will decline under AGW and this will cool the N Atlantic borderlands. The science is now starting to get results on the decline. (See for instance this RealClimate post from this January.)
      
      As for the future the jury is still out as to how much the AMOC will slow, with some evidence still in play that it could actually collapse under AGW. Thus Lui et al (2017) 'Overlooked possibility of a collapsed Atlantic Meridional Overturning Circulation in warming climate'. which modelled a 2xCO2 world.
      And the overwhelming view is that slowing of the AMOC does lead to cooling of the European Atlantic coastal regions. A figure obtained for a RealClimate post from the researches of Lui et al is captioned:-
      
      Temperature change in the winter months (DJF), 300 years after CO2 doubling in the experiment. Due to the almost completely extinct Atlantic flow, the northern Atlantic region has cooled significantly. Source: Wei Liu, with permission.

      Of course, the dangers of relying on a single paper can be demonstrated by the paper Chen & Tung (2018) 'Global surface warming enhanced by weak Atlantic overturning circulation'. One of its two authors is Ka-Kat Tung who is happy to beat the denialist drum and, as I can testify, a very unreliable source of AGW research. So folk should take what Chen & Tung (2018) says with an oceanful of salt.

9863. Postkey at 17:54 PM on 30 August 2019
      It's the sun
      

      Can 'the sun' account for as much as 10%?

      “Gavin A. Schmidt, head of the Goddard Institute for Space Studies in Manhattan, a NASA division that studies climate change, said that the sun had probably accounted for no more than 10 percent of recent global warming and that greenhouse gases produced by human activity explained most of it.”

      www.nytimes.com/2015/02/22/us/ties-to-corporate-cash-for-climate-change-researcher-Wei-Hock-Soon.html

9864. Human 2932847 at 07:07 AM on 30 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      @MA Roger

      Thanks for your comments and points of order. I'm still not really seeing why the slowdown of the AMOC would be a cooling problem as everything I've read from Seager (granting the oddity you noted) indicates a continuity of warming due to AGW, doesn't it ?

      What's the crux of disagreement between people who think cooling would be a problem, and people who don't ? Is it just factoring in Greenland melt ?

9865. Evan at 01:07 AM on 30 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      Thanks for the article John.

      We live in an age of large-scale distrust of government and organizations. The IPCC is saying that we can stay below 1.5C if we all sacrifice and do herculean things to modify the way we farm, eat, produce energy, ...

      Meanwhile we've hit 415 ppm CO2 (more or less) and CO2 is accelerating upwards (just take a look at your favorite form of the Keeling curve). Using a climate sensitivity of 3C/doubling CO2, 415 ppm CO2 means we have already locked in 1.5C warming, unless we can drop atmospheric CO2 to below 400 ppm. That requires either that the optimistic science reports are all correct (unlikely), or that everyone on Earth pulls together to do the right things and that a lot of the scientific reports are correct (still unlikely).

      CO2 is not just increasing, it is accelerating upwards. Do we have a realistic chance of doing any more than stopping the upward acceleration of CO2 by 2030?

      Assuming that the responsible people of the Earth respond during the 2020's by sacrificing and doing as much as they can, how will they feel when we blow by 1.5C? Will trust in the IPCC begin to erode along with trust in all other government organizations?

      We need to do all of the things these reports say, we need to remake the energy and food system. I get that and agree.

      But perhaps we need to motivate people by simply saying that we need to stabilize climate ASAP. That there is no time to waste, because severe effects are upon us and will continue to worsen until we stabilize CO2, without citing specific levels. There is no realistic hope of staying below 1.5C, so telling people we can do that can only lead to distrust and anger when we blow by it.

9866. MA Rodger at 19:40 PM on 29 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Human 2932547 @11,

      You are mistaken by the authorship you attribute to your citation which appears to be the same article that you linked-to @6 - 'Climate mythology:The Gulf Stream, European climate and Abrupt Change' This has no multiple authorship, just Richard Seager of the Lamont-Doherty Earth Observatory, Columbia University. nigelj @7 rightly describes it as a "one person's view."
      Note the link on the webpage to a presentation by Seager which gives a better understanding of his argument and the modelling it is based on. (Both this presentation & the article appear to be over a decade old.) The presentation sets out the following conclusion:-

      "Conclusion: The climate system is so rich, complex, and still not well understood that the current emphasis on the limited impacts of the Gulf Stream and North Atlantic Ocean circulation is a serious distraction of effort and resources when many regions of theworld face a truly worrying future, even in the near-term." [original emboldening]

      Your comment @9 (& repeated @11) concerning the article linked by nigelj @7 is perhaps overhasty. You brand the article as irrelevant because we are concerned with interglacial condiditons and the article concerened glacial conditions which could be fundamentally different. But do note the final lines of that article which runs with an 'on the other hand' rider, the ending:-

      But [Jerry] McManus [of Columbia University] says that studies looking deeper into the ice ages have found that the 1500-year climate oscillations tend not to be nearly as strong during interglacial periods. “It would suggest that this kind of thing isn’t so likely to happen today,” he says. On the other hand, he adds, “In most interglacials, Greenland didn’t melt … and Greenland is currently melting.”

      The only work Seager has had published directly** concerning the AMOC appears to be Delworth et al (2008) 'The Potential for Abrupt Change in the Atlantic Meridional Overturning Circulation'. Interestingly this skates over the warmth brought to northern latitudes by the AMOC.
      Delworth et al (2008) does concur that there is measurable cooling resulting from a weaker AMOC but that the reduced strength of the AMOC will be small enough through the 21st century that this cooling will probably do no more than reduce the rate of AGW warming. "Even with the projected moderate AMOC weakening, it is still very likely that on multidecadal to century time scales a warming trend will occur over most of the European region downstream of the North Atlantic Current in response to increasing greenhouse gases, as well as over North America."
      So it is a little strange that later in considering the impact of a collapsed AMOC, they write:-

      "Although our current understanding suggests it is very unlikely that the AMOC will collapse in the 21st century, the potential consequences of such an event could be severe. These would likely include sea level rise around the North Atlantic of up to 80 centimeters (in addition to what would be expected from broad-scale warming of the global ocean and changes in land-based ice sheets due to rising CO2), changes in atmospheric circulation conditions that influence hurricane activity, a southward shift of tropical rainfall belts with resulting agricultural impacts, and disruptions to marine ecosystems."

      So not one mention of temperature effects, or importantly, no mention of there being minimal temperature effects.
      ** Seager & Battist (2007) considers abrupt climate change and its causes which includes the AMOC.

       

9867. RedBaron at 17:54 PM on 29 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      There is a huge problem with this graph, and in fact this whole article. This demand side mitigation idea presumes that we can't change agriculture to sustainable systems. 

      The report states with high confidence that balanced diets featuring plant-based and sustainably produced animal-sourced food “present major opportunities for adaptation and mitigation while generating significant co-benefits in terms of human health”. 1

      This so called "demand side mitigation" is extremely misleading. We already know how to change agriculture from a net emissions source into a net sink. That flips everything on that graph upside down and those demand side actions most beneficial become the least beneficial. More importantly though, it is impossible for that graph to actually happen in a world where all excess arable ground not needed for food production is instead used to make biofuels. Any relatively tiny changes that diet might make are immediately absorbed by increased commodity biofuel production, which has a vastly larger footprint.

      If you actually want to make any demand side impact at all, you must stop raising commodity grains for biofuels, and stop clearing forest for palm plantations. The forests need replanted, and the arable land in grains replanted into grasslands. Eliminate the over demand for these commodity crops and return agriculture to feeding people.

      It's Time to Rethink America's Corn System - Scientific American

      Only a tiny fraction of corn grown in the U.S. directly feeds the nation’s people, and much of that is from high-fructose corn syrup

      according to a recent study published in the Proceedings of the National Academy of Sciences, roughly 1.3 million acres of grassland and prairie were converted to corn and other uses in the western Corn Belt between 2006 and 2011, presenting a threat to the waterways, wetlands and species that reside there.

      Then when we do that, use regenerative practices instead of industrialised practices and in net we turn that 23% net source into a net sink potentially as much as 50-100% depending on how much degraded land we restore. But to restore that land we MUST use animal husbandry. This is why one sided reports like this are so misleading and actually harmful biased reporting making mitigation even harder.

      “The number one public enemy is the cow. But the number one tool that can save mankind is the cow. We need every cow we can get back out on the range. It is almost criminal to have them in feedlots which are inhumane, antisocial, and environmentally and economically unsound.” Allan Savory

      Just to give someone an idea of scale. The above 1.3 million acres recently cleared prairies mainly to produce biofuels is 1/2 the total acreage in the whole country in vegetable production. (2.62 million acres) and according to the USDA in 2019 the total area in corn is 91.7 million acres, up 3% from 2018. In other words, in a single year roughly equivalent to the entire acreage in vegetable production was offset by just corn and with the exception of HFCS, it did not feed anyone! About 1/2 goes into the gas tanks and about 1/2 into CAFOs.

      That land needs replanted into prairies and prairies need animals on them That's your problem and your solution. The suggested demand solution given in this article (and to be fair others too) is bordering on ridiculous and absolutely NOT what the UN climate-change report said or implied.

      "If all farmland was a net sink rather than a net source for CO2, atmospheric CO2 levels would fall at the same time as farm productivity and watershed function improved. This would solve the vast majority of our food production, environmental and human health ‘problems’." Dr. Christine Jones

9868. Human 2932847 at 16:33 PM on 29 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Hmm, well, that's Columbia university Earth Institute saying the effect of the Gulf Stream is way overestimated. If you disagree you could email and chew it over with them.

      I would have thought that ice caps over Europe (and America) affect a lot of things like wind, ocean currents, albedo etc. There would be no North Sea or Baltic. Your link says that there was huge amounts of fresh water released from the American ice cap, more than from Greenland, but that wouldn't be available now. There would be different solar insolation - what else ? It just seems like a very different context to the current one.

      They say

      The determinants of North Atlantic regional climates
      We showed that there are three processes that need to be evaluated:

      • The ocean absorbs heat in summer and releases it in winter. Regions that are downwind of oceans in winter will have mild climates. This process does not require ocean currents or ocean heat transport.
      • The atmosphere moves heat poleward and warm climates where the heat converges. In additions, the waviness in the atmospheric flow creates warm climates where the air flows poleward and cold climates where it flows equatorward.
      • The ocean moves heat poleward and will warm climates where it releases heat and the atmosphere picks it up and moves it onto land.

      I don't know anything about the middle one - but the first and third points must be affected by ice cap conditions over sea and land - of which there was more in the past.

9869. One Planet Only Forever at 14:24 PM on 29 August 2019
      2019 SkS Weekly Climate Change & Global Warming Digest #34
      

      Comments 3 through 6 on "2019 SkS Weekly Climate Change & Global Warming News Roundup #34" directly relate to this Story of the Week.

      One thing to add to  the many concerns that are presented in these two posts and their related comments (or present more directly) is the reduction of biodiversity due to human impacts reducing Rainforest extents.

      Researchers in Rainforsts are constantly discovering lifeforms that have never before been documented. That makes it likely that, unlike the likes of DoDos and Passenger Pigeons, there are almost certain to be losses of unkown biodiversity. And that could mean losses of lifeforms with potential for human benefit. Those opportunities for human benefit will never be known to have been lost forever. And that loss will have happened because a portion of current day humanity had developed powerful desires for "other interests and priorities" and allowed those interests and desires to compromise the environment and biodiversity to the detriment of the future of humanity.

      As the full Story of the Week concludes: "The fires in the Amazon remind us this is not just a crime against nature but a crime against humanity."

9870. One Planet Only Forever at 13:48 PM on 29 August 2019
      2019 SkS Weekly Climate Change & Global Warming Digest #34
      

      A question/suggestion and a correction regarding the presentation of the Story of the Week.

      I read the full article linked at the bottom of the part that was extracted and presented here. Is there a way to be clear that only an extract of the full story is being presented here? Could the link be provided at the top rather than at the end of the extract?

      I also just noticed that the Big W at the start of the full article did not get picked up at the start of the exctract.

      Moderator Response:

      [JH] Beginning with this week's edition of the Weekly Digest, I will  embed a link to the full article in the initial title of the article appearing immediately after the heading, "Story of the Week". I will also add text at the end of the article indicating that what is presented above is only an excerpt of the complete article — typically the introductory paragraphs. I'll incorporate both changes into "Editor's Choice" article of the Weekly News Roundup. Thank you for the suggestions.  

      The missing "Big W" has been inserted. Thanks for catching and pointing out this glitch.  

9871. nigelj at 13:02 PM on 29 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Human 2932847 @9, maybe there is other reseach I dont know, but plenty of research suggests the slowing gulf strean brings cool conditions to Europe, see my comment at 1 and the links.

      I dont see why it matters that the gulf stream slowdown happened during an ice age which is just a cold period. The gulf stream slowed down and the ice age deepened further, thats the point apparent in the article. If slowing cools things then, why wouldn't it do the same now? I can't see a reason. 

      In addition, its non controversial that the gulf stream originates in the warm oceans off africa where the trade winds blow this water north ultimately, influenced by the coriolis effect and the thermohaline circulation. Its hard for me to see why slowing this down wouldn't cool the northern atlantic.

      I guess its a question of how much and what other influnces there are, and I agree its all not 100% certain. The research you quote has to be right to the extent that warm air does travel north due to the basic global circulation system and global warming is affecting this pattern as well. But it looks like the conventional view is quite strong that a slowing gulf stream could cause a cooler climate in the north to some extent.

9872. John Hartz at 04:47 AM on 29 August 2019
      IPCC's land report showed we're entering an era of damage control
      

      Recommended supplemental reading:

      What Does '12 Years to Act on Climate Change' (Now 11 Years) Really Mean? by Bob Berwyn, InsideClimate News, Aug 27, 2019

9873. Human 2932847 at 19:02 PM on 28 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      The sciencemag article describes conditions during glacial times, not the interglacial in which we are now. Presumably, conditions where quite different, and Europe was already ice-bound. The climate change referenced in the article wasn't the change from an interglacial into a glacial - day after tomorrow style - but variations in an already glacial kind of environment. So I don't know how much that work tells us about our current situation, I'd like to know more.

9874. Human 2932847 at 18:51 PM on 28 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      nigelj @7

      Well, being on his own doesn't make him wrong, and he draws on several other's work so I assume there is a body of work about this.

      thanks for link

9875. Deb9714 at 14:44 PM on 28 August 2019
      2019 SkS Weekly Climate Change & Global Warming News Roundup #34
      

      nigelj @4

      Thank you for the links, and advice.

      The photos posted by celebrities and world leaders, and the Amazon is not "the lungs of the earth", are appearing on FB and websites, (see link) so I've read and shared the links you provided, and the Moderators too. 

       www.forbes.com/sites/michaelshellenberger/2019/08/26/why-everything-they-say-about-the-amazon-including-that-its-the-lungs-of-the-world-is-wrong/#51245fa25bde

      Moderator Response:

      [DB] That articles gets some things right, but it gets other things wrong and is misrepresenting the science (per this link).

9876. prove we are smart at 10:53 AM on 28 August 2019
      IPCC is alarmist
      

      M A Rodger @ 135, i think shooting from the hip is exactly what the IPCC should be doing. With CO2 levels still increasing from the last three decades, taking slow aim and firing is just missing the target. Just how unprepared / misinformed are we in Australia? Look at this,      https://www.breakthroughonline.org.au/

9877. nigelj at 08:22 AM on 28 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Human 2932847 @6

      Your link is one persons view. I dont know the answer, but periods of rapid cooling in the past in Europe coincided with the gulf stream slowing or stopping here, 

9878. Bob Loblaw at 07:49 AM on 28 August 2019
      It's satellite microwave transmissions
      

      tkaczevski:

      No one has provided an answer to you yet, so let me try. My guess is that this question has not been examined in the scientific literature, but there is likely a reason why.

      Let's first think about what your question means. Is the energy in cells phones, etc. a significant amount,, compared to other natural flows? The energy emitted by these sources of EM radiation has to come from somehwere - namely electricity. How much electricity is used to operate these devices?

      I don't know, but scientists have looked at the total contribution of human heat production, and it is only 1% of the amount of energy added to the earth-atmosphere system by the effects of added CO2. SKeptical Science has a page on that subject:

      https://skepticalscience.com/waste-heat-global-warming.htm

      The fraction of total human-consumed energy that is used for cell phones, etc. is going to be very small. A very small proportion of 1% means that these devices cannot compare to the effects of CO2. I think it is safe to say that the EM radiation emitted by these devices is not a significant source of energy to warm the atmosphere.

9879. jozef.van.giel@gmail.com at 05:10 AM on 28 August 2019
      Why German coal power is falling fast in 2019
      

      The main reason why gasemissions from electricity is falling is due to increased import of nuclear energy from France. see also: https://www.electricitymap.org

      Moderator Response:

      [PS] Can you provide data to support that assertion? It seems to be contradicted by other sources (eg here).

9880. SirCharles at 01:48 AM on 28 August 2019
      Why German coal power is falling fast in 2019
      

      Thanks for the article.

      "the German power sector’s emissions fell by 20m tonnes of CO2"

      If we break that down on a per capita base for these six months we're ending up with a reduction of 1.3kg CO2 per day per capita, equivalent to burning one Imperial pound of coal or half a litre of petrol. Does that sound much?

      Chancellor Merkel wanted to get one million EVs on the road by 2022 (2% of the fleet). But currently there are only some 140,000 registered EVs in Germany. Now picture how much more electricity is needed to feed just the 2% of the fleet.

      So the outlook is anything but rosy. Germany was sleeping for the last decade. The government's boot licking of the automobile industry (Diesellüge) is now firing back big time.

      

      Moderator Response:

      [DB] Please reduce image widths to 450 or less.

9881. Human 2932847 at 21:55 PM on 27 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Hi, what about this ?

      http://ocp.ldeo.columbia.edu/res/div/ocp/gs/

      It says,

      "The Gulf Stream and future climate change
      A slowdown of the Gulf Stream and ocean circulation in the future, induced by freshening of the waters caused by anthropogenic climate change (via melting glaciers and increased water vapor transport into high latitudes) or simply by warming, would thus introduce a modest cooling tendency. This would leave the temperature contrast across the Atlantic unchanged and not plunge Europe back into the ice age or anything like it. In fact the cooling tendency would probably be overwhelmed by the direct radiatively-driven warming by rising greenhouse gases."

       

      Is this true, and does that mean AMOC slowdown isn't a worry ?

       

      thanks in advance.

9882. MA Rodger at 21:50 PM on 27 August 2019
      IPCC is alarmist
      

      prove we are smart @134,

      With one exception, I have only read the summary of the paper Spratt & Dunlop (2018) 'What Lies Beneath: The understanding of existential climate risk' which you refer to. In short, the need for action on AGW was demonstrated by the science over a quarter of a century ago yet globally our emissions increased as though no such science existed. There is now, policy-wise, an agreement that radical action is needed to prevent a +1.5ºC increase in global temperature, radical as such a goal requires global CO2 emissions in future years to be restricted to something like 120Gt(C). The general message from the science is that such a goal will prevent the very bad AGW effects from happening. Yet in terms of policy, there is still little urgency. The enthusiasm for declaring a Climate Emergency has not yet resulted in any useful policy but let us hope that it will, soon. Spratt & Dunlop (2018) suggest the 120Gt(C) is flawed but it seems to me that its argument would need to be far better presented to be a useful contribution.

      Their main criticism is that the science includes those "fat tails" which may make a +1.5ºC world a bit too hot to handle. There has been quite a bit of criticism of the IPCC for failing to make such potential outcomes better known. Most recently, Oppenheimer et al (2019) 'Discerning Experts: The Practices of Scientific Assessment for Environmental Policy' has described well instances of the IPCC's failings (three of the authors have an account of the book HERE). But while there are systemic problems within the IPCC assessments, they do not systematically underestimate AGW. There is perhaps need for the failings of the IPCC assessments to be better understood and in addressing that, I have no criticism of Spratt & Dunlop (2018).

      But Spratt & Dunlop (2018) goes further than this. There is a feel of this in their assessment of the impacts of AGW. Their Summary begins:-

      "Human-induced climate change is an existential risk to human civilisation: an adverse outcome that will either annihilate intelligent life or permanently and drastically curtail its potential, unless carbon emissions are rapidly reduced."

      The word "existential" is usually, in my view, very poorly wielded in regard to AGW. Here, the use "an existential risk to human civilisation" is refreshing to see. But then it is followed by "annihilate intelligent life" which is something I find very difficult to envision.

      So this got me delving into one further section of Spratt & Dunlop (2018). The section Carbon Budgets makes a number of points (♣ Not working other GHGs into the budget, ♣ Not evaluating "fat tails" which would reduce carbon budgets to zero, ♣ Relying on models that potentially run cool, ♣ Not defining pre-industrial temperature adequately, ♣ Ignoring actual peak temperatures) but I only see one of these issues that is germane to setting carbon budgets (the cool models). So for me, Spratt & Dunlop (2018) seems to be 'firing from the hip' a bit too much and needs to tighten up its message if they want to make a serious contribution.

9883. prove we are smart at 20:01 PM on 27 August 2019
      IPCC is alarmist
      

      I believe the IPCC reports are probably the most used information to help set climate policy around the globe. However after reading this,

      http://climateextremes.org.au/wp-content/uploads/2018/08/What-Lies-Beneath-V3-LR-Blank5b15d.pdf

      and part of their summary :

      " Climate policymaking and the public narrative are significantly informed by the important work of the IPCC. However, IPCC reports also tend toward reticence and caution, erring on the side of “least drama”, and downplaying the more extreme and more damaging outcomes. Whilst this has been understandable historically, given the pressure exerted upon the IPCC by political and vested interests, it is now becoming dangerously misleading with the acceleration of climate impacts globally. What were lower-probability, higher-impact events are now becoming more likely. This is a particular concern with potential climatic tipping points — passing critical thresholds which result in step changes in the climate system — such as the polar ice sheets (and hence sea levels), and permafrost and other carbon stores, where the impacts of global warming are non-linear and difficult to model with current scientific knowledge.However the extreme risks to humanity, which these tipping points represent, justify strong precautionary management. Under-reporting on these issues is irresponsible, contributing to the failure of imagination that is occurring today in our understanding of, and response to, climate change. If climate policymaking is to be soundly based, a reframing of scientific research within an existential risk-management framework is now urgently required. This must be taken up not just in the work of the IPCC, but also in the UNFCCC negotiations if we are to address the real climate challenge. Current processes will not deliver either the speed or the scale of change required."

       

      So, i was wondering just how correct is this need to modify the scope of the IPCC reports. 

      " What Lies Beneath" put into words my feelings on our current  Aussie state - pretend we care but open more coal mines and do nothing..

      This video was also enlightening , a new documentary series , pt 1.

      https://www.breakthroughonline.org.au/#!

9884. MA Rodger at 18:56 PM on 27 August 2019
      There's no empirical evidence
      

      The  abstract linked @391 which is also the reference supporting the existence of those "measurements of your referral ... claimed to be the result of a 22 per million increase in CO2" which Billev @395 finds so difficult to accept: that abstract is that of Feldman et al (2015) 'Observational determination of surface radiative forcing by CO2 from 2000 to 2010' which can be read in full HERE demonstrating that the effects of the +22ppm increase of atmospheric CO2 2000-10, equal to a climate forcing of +0.26Wm^-2, is directly measureable given the right circumstances

9885. Doug_C at 17:25 PM on 27 August 2019
      2019 SkS Weekly Climate Change & Global Warming Digest #34
      

      What happens in the Amazon has impacts across the world, something the current government of Brazil is ignoring as it refuses international aid to fight the 75,000 fires in the region.

9886. scaddenp at 13:31 PM on 27 August 2019
      There's no empirical evidence
      

      So Billev are prepared to actually learn enough physics as to why increasing CO2 to 400ppm from pre-industrial levels can cause such an effect? - (you could see "its just a trace gas" myth but then you have been referred there before without apparently learning anything).  Or do you prefer to stick with your ignorance?

      Can I assume you would happily walk into a room with 400ppm of cyanide gas - you know how could such a tiny amount of gas be a problem?

9887. KR at 13:20 PM on 27 August 2019
      There's no empirical evidence
      

      billev - "This sounds nonsensical to me" is a pure Argument from incredulity, an erroneous logical fallacy. As scaddenp points out, you've been repeating this very same fallacious argument for at least 3 years. Clearly you're not learning anything from these discussions. 

      Moderators, might I point out a Comments Policy situation here, namely "Comments should avoid excessive repetition"? Also known as PRATT, a 'point refuted a thousand times'?

9888. bozzza at 12:09 PM on 27 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Yes, Brian, it is largely due to coriolis effect ... Salt and heat are simply other factors!

9889. bozzza at 12:01 PM on 27 August 2019
      The North Atlantic ocean current, which warms northern Europe, may be slowing
      

      Salt doesn't freeze!

9890. TVC15 at 11:15 AM on 27 August 2019
      Medieval Warm Period was warmer
      

      @258 scaddenp; 259 Daniel Bailey

      Thank you so much!  I love how much I learn posting here! :)

9891. billev at 11:05 AM on 27 August 2019
      There's no empirical evidence
      

      Scaddenp, the measurements of your  referral were claimed to be the result of a 22 per million increase  in CO2.  This would mean that the observed heat increase was caused by an increase of one part of CO2 per each 45,454 parts of atmosphere.  This sounds nonsensical to me. 

      Moderator Response:

      [DB]  Please note that posting comments here at SkS is a privilege, not a right.  This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

      Moderating this site is a tiresome chore, particularly when commentators repeatedly submit offensive, repetitive (even after being disproven), off-topic posts or intentionally misleading comments and graphics or simply make things up. We really appreciate people's cooperation in abiding by the Comments Policy, which is largely responsible for the quality of this site.
       
      Finally, please understand that moderation policies are not open for discussion.  If you find yourself incapable of abiding by these common set of rules that everyone else observes, then a change of venues is in the offing.

      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, as no further warnings shall be given.

9892. scaddenp at 10:38 AM on 27 August 2019
      There's no empirical evidence
      

      Just reviewed billev posting history on this site. Hmm. I think the response I gave him in 2016 here still applies. What actually is the point of asking the same thing and then running away from the answers? At this point, billev is engaging in evasive repetition and running away when evidence is posted. I am not sure I can find any evidence that he has read single paper that he has been pointed to.

9893. Bob Loblaw at 10:35 AM on 27 August 2019
      There's no empirical evidence
      

      Frankly, I don't think billev is interested in any answers you give him. He's had lots of opportunity to learn from his many ill-posed questions here. What he's really saying is that there will never be any evidence that he will accept. As long as he dismisses any and all evidence, he can conitnue in his beliefs and remain confident of his position.

      Do not feed the troll.

9894. David Kirtley at 10:03 AM on 27 August 2019
      Hockey stick is broken
      

      TVC15 @160. Denier's statement: "State with specificity what the exact average global temperature should be now".

      This is a common technique and it's a bit of a strawman argument. Scientists don't make any claims about what the "ideal" temperature "should be". There is no "perfect" temperature for the earth.

      But, there are ideal temperatures for sustaining a global human civilization. We need stable temps to grow our food, we need stable sea levels to insure that our major cities are not inundated, etc, etc.

9895. Daniel Bailey at 08:36 AM on 27 August 2019
      Medieval Warm Period was warmer
      

      Time for some updates to this thread:

      "'No doubt left' about scientific consensus on global warming, say experts"

      The Guardian article then cites 3 brand-new studies, just published, which show that:

      "there has never been a period in the last 2,000 years when temperature changes have been as fast and extensive as in recent decades"

      

      Neukom et al 2019 - No evidence for globally coherent warm and cold periods over the preindustrial Common Era

      PAGES 2K 2019 - Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era

      “This paper should finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural climate cycle. This paper shows the truly stark difference between regional and localised changes in climate of the past and the truly global effect of anthropogenic greenhouse emissions,” said Mark Maslin, professor of climatology at University College London.

      Bronnimann et al 2019 - Last phase of the Little Ice Age forced by volcanic eruptions

      "global mean annual temperatures are higher now than any time in the last 2,000 years, with the middle of the 20th century either matching or exceeding Common Era temperatures as well"

      Tardif et al 2019 - Last Millennium Reanalysis with an expanded proxy database and seasonal proxy modeling

      “But even when we push our perspective to the earliest days of the Roman Empire, we cannot discern any event that is remotely equivalent — either in degree or extent — to the warming over the last few decades.”

      St George 2019 - Aberrant synchrony of present-day warming

      Related LINK

      This skeptic meme is stone dead.  Stick a fork in it, it's done.

9896. KR at 08:35 AM on 27 August 2019
      There's no empirical evidence
      

      billev - It's unclear to me what your particular complaints are, but there are more specific Skeptical Science threads for various aspects of your complaints. If you can be more clear, I would suggest taking the discussion to the appropriate thread.

      • You don't trust the surface temp records? They are quite solid, and show considerable warming despite the statistical approaches used: skepticalscience.com/surface-temperature-measurements-advanced.htm
      • You don't believe we're the cause? Lots of attribution evidence shows that we are - natural forcings would have caused a temperature decrease over the last 50 years, and we have a statistically significant warming matching anthropogenic forcings: skepticalscience.com/a-comprehensive-review-of-the-causes-of-global-warming.html
      • You for some reason don't believe the atmospheric changes are real? Lots of empirical proof for that, including direct spectral measurements of radiative changes over the last few decades: skepticalscience.com/empirical-evidence-for-global-warming-intermediate.htm

      Now, if you don't have any reasons, supported by evidence, to disagree with those aspects of the global temp. record, it's linkage to greenhouse gas atmospheric changes, and attribution to human causes, your objections IMO come down to an Argument from incredulity, which is a logical fallacy. I'm more than willing to be proven wrong about that, but you're going to have to support your arguments. 

9897. TVC15 at 08:26 AM on 27 August 2019
      Hockey stick is broken
      

      @ 161 Daniel Bailey

      Thank you so much for that great response and all the data!

9898. Daniel Bailey at 08:20 AM on 27 August 2019
      Medieval Warm Period was warmer
      

      Specifics on proxy datasets can be found here.

9899. scaddenp at 08:10 AM on 27 August 2019
      Medieval Warm Period was warmer
      

      yes. Where no temperature measurements exist, then proxies are all you have.

      Dont let a denier take you down the path of believing that climate theory depending on paleoclimate studies. Paleoclimate studies are useful testing grounds - if our current understanding of climate cannot reproduce measurements of temperature given the uncertaintites in the temperature measurement and our understanding of the forcings operating at the time, then the theory would be in trouble. Not the case. Paleoclimate is also useful in constraining climate sensitivity. However, uncertainties in estimating solar output, aerosols, albedo and temperature all create significant limits compared to analysing the physics of the climate system today.

9900. scaddenp at 08:02 AM on 27 August 2019
      There's no empirical evidence
      

      billev - I am struggling a bit to understand your issue. The surface air temperature have gone up and that is consistant with the increased irradiation of the surface. While you ask about "reduction in outgoing longwave radiation causes any temperature change", more relevant is measured increase in irradiation of the surface (though one is simply the reflection of the other  assuming conservation of energy). More recent direct measurement of the increased irradiation due to CO2 at the surface is here.  Are you proposing Stephan-Boltzmann law does not apply? If the sun increased its radiation by 4W/m2 and you noticed the temperature increasing as it does today, would you be saying there "was no evidence that increased output from the sun was raising temperatures"? If so, then what kind of evidence are you looking for - or are you engaging in sophistry to support a belief grounded in ideology/identity rather than science?

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