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Comments 15001 to 15050:

15001. michael sweet at 23:17 PM on 5 April 2018
       Sea level rise predictions are exaggerated
       

       Yesterday a post here (since deleted as spam) claimed that I had not produced a citation to support my claims aout nuclear power.  I cited Abbott 2011 to support my nuclear claims.

       Moderator Response:

       [JH] Your post was deleted because it responded to a deleted post. 

       [DB] Further, the person to which you were responding has permanently recused themselves from further participation in this venue.

15002. libertador at 16:59 PM on 5 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       The graphic embedded here for 2° warming seems to be completely identical to the graphic in the paper for 1981–2010 climate and to the 1.5° warming graphic in the paper.What is the source of the here embedded 2° warming graphic? It is not included in the linked paper.Are the changes to small to be seen on the choosen colour scale or is there another issue?
15003. oak1971 at 12:39 PM on 5 April 2018
       Explainer: The polar vortex, climate change and the ‘Beast from the East’
       

       Not sure what planet the author lives on, record cold and snow with crop losses on this one.

       Moderator Response:

       [PS]

       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  This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online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, 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.
        
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       Note. Sloganeering, argumentive tone, offtopic, gish gallop. (Not to mention monumentally uninformed nonsense).

15004. scaddenp at 09:03 AM on 5 April 2018
       Water vapor is the most powerful greenhouse gas
       

       It is actually rather more consistent with rising global temperature. Evaporation from irrigation can only make local, short term change to water vapour in atmosphere. Change in tropospheric specific humidity over past 40 years is about 3.5%, consistant with 0.5C increase in temperature. See Fig 2.30 and accompanying text in AR5 WG1 for the list of peer-reviewed papers discussing this.

15005. One Planet Only Forever at 06:56 AM on 5 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       

       nigelj@3,

       Food exporting places like Australia would not be considered to be at risk because they can 'reduce how much they export'.

15006. One Planet Only Forever at 06:54 AM on 5 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       

       Policy makers should already understand what needs to be corrected and why, or at least they can't claim that the required information was not available yet.

       The Sustainable Development Goals were published in 2015. The fundamental understanding of what is wrong and needs to be corrected was pretty clear in the 1972 Stockholm Conference. It has been reinforced by every subsequent increased understanding, especially in the 1987 UN report “Our Common Future” and the 2012 UN report “Back to Our Common Future”.

       The reasons for the resistance to the understood corrections is also well understood. Naomi Klein's “No is not Enough” is one of many presentations of understanding regarding the developed Private Interests that are harmful to achieving the sustainably better future for humanity.

       The obvious losers of climate change impacts are the entire future generations that have to 'adapt to the rapidly changed climate' (even the biggest winners among them will suffer to a degree), thta is created by the lack of responsible correction/restriction of behaviour of the richest and most influential in the previous generations.

       The trouble-makers identified by the likes of Klein try to claim it is reasonable to do unsustainable things and create costs and challenges for others, especially future generations. They like to compare the perceived benefit or opportunity that they have to give up if creating those impacts on Others was rapidly curtailed (careful not to point out that it is mainly the sub-set of trouble-makers who would have to give things up), to the current generation's perceptions (the trouble-makers claimed perception) of the created future costs or challenges.

       In engineering design the future risk of negative consequences is to be minimized to make the built item a sustainable benefit rather than a future problem or burden. Creating problems others have to deal with in the future is understood to be unacceptable. When uncertainty is involved, the potential for negative future consequences is conservatively mitigated by over-estimating the impact and under-estimating the ability of what is built to adequately deal with those impacts.

       However, in some business thinking, the future risks of negative results are often considered to be mitigated by having someone else suffer the negative consequences, or gambling that the ones benefiting in the near term will not be penalized by any negative result that occurs in the longer term.

       Clearly policy makers need to follow the engineering approach (the application of science approach), not the business approach (the gambling to get rich quick approach). Don't get me wrong. A policy maker with business experience could be a very effective applier of science through the engineering approach. The key is to be willing to identify and effectively address the other types if they should get away with temporarily Winning anywhere.

       Focusing on properly identifying who deserves recognition and reward and who deserves to be disappointed and discouraged is what all policy makers understand they need to develop, but some of them are motivated by other Private Interests.

       Those other Private Interests are not interested in minimizing the negative impacts on future generations. Regarding food production, they would not like to see the development of responsible limits to long distance transportation of food. They would not like local agricultural Coops developed to maximize the local benefit of what can be locally grown for local consumption (rather than multinational investor operations). They would also not like to see trade limited to emergency food aid and the importing of produce that cannot responsibly be grown locally in an area (but still obtained with limited transportation).

       Working towards those types of corrections do not need improved understanding of the regional level of climate change impact. Those corrections are required, along with the requirement to most rapidly reduce the impacts causing increased climate change challenges.

15007. nigelj at 06:23 AM on 5 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       

       It mystifies me why Australia is not particularly at risk. This country has a considerable history of droughts already. 

15008. Riduna at 04:50 AM on 5 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       

       Interesting map – but no surprises. Countries of Europe, North America and Australasia have no reason to feel complacent. It is likely that most will be affected by sea level rise reducing fertile coastal land now producing food crops and destroying infrastructure essential for its distribution.

       The article asks: ‘is there a tipping point for ice sheet loss from Greenland or Antarctica? A certain temperature threshold that once passed cannot be reversed?’ I would have thought the answer was indicated by Arctic amplification, sea ice depletion and increasing mass loss from polar ice sheets.

       Is it likely that these indicators are going to reverse?

15009. Eclectic at 23:01 PM on 4 April 2018
       Humans survived past climate changes
       

       Ping34 , you should read the article [posted on 3 April 2018] titled "Scientists examine threats to food security if we meet the Paris climate targets".  Also read the linked article ("how bad will it be") mentioned in the second sentence of the 3 April 2018 article.

       Also read "Most Used Climate Myths : Number 3" which is listed in the upper left region of the Home Page.  You may read it at the Basic level or Intermediate level or the Advanced level.

       In very brief summary — a one or two degree rise (from now) in surface temperature will produce a significant reduction of cereal crops [rice, wheat and maize, and other foods as well].  More heat-waves, droughts, floods, and storms, will reduce the total food production (there are very few food crops which will benefit from the new conditions).  Maize is especially damaged by droughts and prolonged heat-waves.

       Increased ocean acidity [from CO2] will reduce the supply of fish and other marine foodstuffs.   Rising sea level will gradually affect farming in the rich soil of the river deltas.

       Less food supply, rising food prices . . .  and so more political unrest & instability . . . and increasingly big numbers of "climate refugees" (on top of political refugees) . . . yes, the world will be a tougher place to live in.

15010. Cedders at 20:50 PM on 4 April 2018
       It's cosmic rays
       

       This seems to be the main SkS page on galactic cosmic rays, reachable via sks.to/cosmic. I like the way the advanced version highlights the slim chance of new particles reaching the necessary size (about 50nm?) to become cloud condensation nuclei (and that the basic version just reiterates that there's no historical connection).  There are other rather outdated pages that could be linked here:

       • What do the CERN experiments tell us about global warming?
       • CERN - Saying Nothing About Cosmic Ray Effects on Climate
       • Galactic cosmic rays: Backing the wrong horse

       It does look like the CERN CLOUD experiments are producing unexpected and useful results, possibly finally reducing the uncertainty range in the effect of anthropogenic aerosols, but are pretty conclusive that cosmic rays have a very small effect.

       One of the most recent CERN results (Gordon et al, 2017) concludes 'Our model suggests that the effect of changes in cosmic ray intensity on CCN is small and unlikely to be comparable to the effect of large variations in natural primary aerosol emissions.' and this seems consistent with other methods finding <1% of cloud condensation nuclei are related to cosmic rays.

       However, there is some good news I've seen contrarians pick up from CLOUD studies: although present cloud effects are dominated by anthropogenic sulphates (potentiated by ammonia?), in the pre-industrial atmosphere, terpenes and pinenes and other natural VOCs had a role seeding cooling clouds.  This potential constraint on aerosol effects could reduce upper limits on ECS - one of the researchers is quoted as saying "the highest values become improbable".  I'm not clear if this is ECS > 4°C, say, or whether a reduced uncertainty has fed into recent attempts at 'quantifying our Faustian bargain' of reducing sulphate pollution.

15011. Ping34 at 18:46 PM on 4 April 2018
       Humans survived past climate changes
       

       It's not the case that we would survive or not, but in the sense that the world would be a much tougher place to live. I am curious about this. Are there any reliable prediction on the things that climate change will change our way of living in the next few decades?

15012. One Planet Only Forever at 13:58 PM on 4 April 2018
       On climate change, zero-sum thinking doesn't work
       

       A deliberately under-represented consideration/motivation in the currently developed socioeconomic-political systems is the need to only assign positive value to things that can withstand deep investigation into being sustainable benefits for all of humanity, especially the future generations, actions that would pass being evaluated to ensure they are not contrary to any of the Sustainable Development Goals (SDGs).

       Zero-sum thinking has a history of developing unsustainable harmful results, not just the current climate science exposed over-development in unacceptable directions. The clear evidence of those damaging developments resulted in the international collaboration that has produced the Sustainable Development Goals, efforts that started before the 1972 Stockholm Conference, efforts that have faced constant resistance.

       My MBA education in the 1980s helped me be aware that zero-sum thinking can develop negative-sum results, especially the power of deceptive emotion triggering marketing (deliberate disinformation campaigns) to create unjustifiable temporary (unsustainable) perceptions of winning relative to others.

       Negative-sum developments are tragically common today. Perceived winners create a future that could have been better 'overall' than it ended up being. But those 'competitors' would need to change their minds about what to value, change their mind about how to play the game, change their Private Interests in order to help develop a better potential future (the Global Public Interest).

       Aspects of systems that develop damaging 'learning to compete to appear to be the winner relative to others' (the zero-sum approach to things that leads to negative-sum results), must be 'corrected' to sustainably correct the resulting damaging developments and reduce the chances of other unsustainable damaging winning.

       Systems that develop unsustainable activities that are harmful to others can also be seen to develop resistance to being corrected. The portion of the population pushing to expand or prolong such systems, and resisting correction of such systems, are undeniably the 'problems to be corrected'. The correction requires education efforts potentially including restrictions on influence and freedom until clear changes of attitude and actions toward positive-sum ways have developed'.

       Sean Carroll's “The Big Picture” provides a comprehensive understanding of the total system of Reality and its variety of inter-related and integrated sub-systems. It is a good explanation of the fundamentals of the entire system that humanity is developing in, is a part of, including the future results in the system. It helps understand how the actions of individuals influence the future that develops. The final chapter “Caring”, is particularly enlightening. It includes the following statement “The personal desires and cares we start with may be simple and self-regarding. But we can build on them to create values that look beyond ourselves, to the wider world.”. That relates to one of my favourite quotes from John Stuart Mill's “On Liberty” - “If society lets a considerable number of its members grow up mere children, incapable of being acted on by rational consideration of distant motives, society has itself to blame for the consequences.”. And that understanding is related to the importance of developing more positive-sum thinkers, particularly among the wealthy and influential.

       Naomi Klein's “No is not Enough” provides a comprehensive presentation of the harmful unsustainable developments that have been occurring and how those Winners try to increase their undeserved winning in pursuit of more of their harmful developed Private Interests.

       People all have their Private Interests. They develop those interests as a result of the influence of the environment they experience. Aligning those developed Private Interests with the Public Good of developing sustainable improvements for the future of humanity is what is required.
       The SDGs, curiously not mentioned in “No is not Enough”, are a robustly developed understanding of the collective of Private Interests that need to be encouraged to develop (similar to what Sean Carroll says of robustly developed scientific understanding, the SDGs are open to improvement but are unlikely to be significantly altered by new learning).

       A good way for systems to develop positive-sum results would be to have the highest expectation and requirement for helpfulness apply to the biggest winners, the richest and most influential/powerful. That basis for correcting/penalizing someone who chose not to behave more helpfully/correctly would mean less hope of winning in ways that 'are understandably unhelpful but are hoped to not be able to be legally proven to have been contrary to an interpretation of whatever the written rules of the moment are'. Less freedom for the 'more popular, more profitable, more successful, bigger winners' to be excused for believing what they want and doing as they please would be a good thing. It would help limit the development of damaging zero-sum thinking.

       Efforts to educate the entire population, increasing awareness and improving understanding in the pursuit of positive-sum helpful developments, are undeniably essential to the future of humanity. The alternative is strengthening resistance to correction of regionally popular and profitable damaging ultimately unsustainable activity resulting in more harm done before it is effectively curtailed. The efforts to oppose or delay development of the corrections that climate science has exposed are required, particularly through the past 30 years, are undeniable and undeniably harmful in spite of being popular and profitable. This is undeniable proof that popularity and profitability can only be 'measures of success' in a system where nobody attempts to 'compete to appear to be the winner relative to others'. Popularity and profitability only indicate justified success in systems where everyone strives to be more aware of what is really going on in pursuit of sustainable helpful developments for the future of humanity.

       The evolving systems of human interaction with others and the environment can actually develop a less beneficial future for humanity. More freedom for people to believe whatever they wish and do as they please can actually be understood to develop more damaging and less sustainable behaviour. Education/learning that is focused on helping others be more aware and better understanding of what is really going on and the essential objective of sustainably improving life for all of humanity into the distant future is essential for humanity to have a future on this, or any other, amazing planet.

15013. scaddenp at 12:43 PM on 4 April 2018
       Water vapor is the most powerful greenhouse gas
       

       You cannot really make any long-term change to the water vapour content in the atmosphere by injecting water vapour by any means. Water just condenses out. What the atmosphere will hold is function of air temperature (Clausius-Clapeyron relation) and the oceans provide the main source.

15014. Digby Scorgie at 12:30 PM on 4 April 2018
       Scientists examine threats to food security if we meet the Paris climate targets
       

       Please fix the first sentence: "now can no longer can"?

15015. Eclectic at 12:03 PM on 4 April 2018
       Water vapor is the most powerful greenhouse gas
       

       Ruzena @308 , I have not seen scientific figures for the amount of water vapor emitted from composting or from the burning of wet organic matter (or from dry organic matter, too).   But the planet has over 300 million square kilometres of ocean to produce water vapor by evaporation — so presumably the amount of vapor from composting/burning, would be negligibly small in comparison.

       There would be a difference in the timing of release (of vapor) from human-caused composting/burning versus the release by natural composting/burning from organic materials [which would have occurred eventually, producing H2O and CO2].   But over the course of a decade or two, the end result would be about the same.   This is all part of the natural cycle of organic carbon [unlike the CO2 from fossil fuels].

15016. Ruzena Svedelius at 10:37 AM on 4 April 2018
       Water vapor is the most powerful greenhouse gas
       

       What effect does the vapor emit at
       a) burning of wet organic matter
       b) composting
       compared with the fact that the wet organic material is used as a raw material for the production of biogas and biofertilizers and the biogas is subsequently burned and thus converted into electricity and heat.

15017. Alchemyst at 10:00 AM on 4 April 2018
       Study: wind and solar can power most of the United States
       

       Wind turbines operate under great turbulence, with consequences for grid stability(Phys.org) —While previous research has shown that wind turbulence causes the power output of wind turbines to be intermittent, a new study has found that wind turbulence may have an even greater impact on power output than previously thought. The researchers modeled the conversion of wind speed to power output using data from a rural wind farm. The results showed that the intermittent properties of wind persist on the scale of an entire wind farm, and that wind turbines do not only transfer w…

       https://phys.org/news/2013-04-turbines-great-turbulence-consequences-grid.html

15018. nigelj at 08:07 AM on 4 April 2018
       On climate change, zero-sum thinking doesn't work
       

       Related reading: "How do people or companies with vested interests spread ignorance and obfuscate knowledge? Georgina Kenyon finds there is a term which defines this phenomenon."

       Agnotology (formerly agnatology) is the study of culturally induced ignorance or doubt, particularly the publication of inaccurate or misleading scientific data.

15019. swampfoxh at 01:57 AM on 4 April 2018
       On climate change, zero-sum thinking doesn't work
       

       I would like to get the scientific community to feed back on the impact of Animal Agriculture on the emerging climate crisis.  A recent UN study seemed to fault Animal Agriculture for nearly 50% of global emissions because Animal Ag contributed to desertification, deforestation, eutrophication and acidification of the oceans, wild animal habitat loss, inefficient land use, excessive water usage and health issues affecting over-utilization of medical resources.  While the list didn't end there, it would be good to know what subscribers to this site have to say.  If my request is off topic, please offer a re-direct.  Thank You.

       Moderator Response:

       [DB] This post by Dana addresses that.  Please place any concerns or questions you may have on it, after reading it and the comments below it.  Thanks!

15020. ewinsberg at 01:05 AM on 4 April 2018
       Sea level rise due to floating ice?
       

       @eclectic  cool. thanks.   Someone should tell that to the people that drew the diagram in that guardian piece.

15021. Eclectic at 00:30 AM on 4 April 2018
       Sea level rise due to floating ice?
       

       Ewinsberg @63 ,for grounded ice, as the bottom ice melts, the upper ice sags downwards.

15022. ewinsberg at 23:45 PM on 3 April 2018
       Sea level rise due to floating ice?
       

       What about ice that is trapped below sea level as in this:
       
       https://www.theguardian.com/environment/2018/apr/02/underwater-melting-of-antarctic-ice-far-greater-than-thought-study-finds?CMP=Share_AndroidApp_Facebook
       
       since that ice is not bobbing above the surface, doesn't its melting actually create more space, and hence actually lower sea level?  if not, why not?

       Moderator Response:

       [JH] Fill a glass with ice cubes and water. Let it melt and see what happens. (Hint: When a given volume of ice melts, it turns into an equivalent amount of water.)

15023. scaddenp at 11:23 AM on 3 April 2018
       How do we know CO2 is causing warming?
       

       billev - read the main article? If you want a really direct measurement, then this article explains a 2015 method. However, you have to be a disbeliever in Planck's Law if dont think that increasing the radiative flux on a surface will not increase its temperature. Doubling CO2 directly increases surface temperature by about 1.1C - the calculation is pretty straightforward. The difficulty with climate sensitivity determination however is that increasing temperature causes other feedbacks to cut in as well notably decreasing albedo and water vapour. As to teasing out of the various influences on surface temperature, then this is known as attribution studies. The IPCC AR5 summaries the published science on this in Chpter 10.

15024. nigelj at 10:35 AM on 3 April 2018
       On climate change, zero-sum thinking doesn't work
       

       Very well said. Imo there's far too much zero sum game thinking, and short term knee jerk reaction thinking coming out of the White House, and not enough calm wisdom and longer term science based  thinking.

       However "Such corrosive behaviors have undermined the competitiveness of polluting industries," surely means non polluting industries?

       Regarding the plunging costs of renewable energy and battery storage this is interesting :

       reneweconomy.com.au/plunging-costs-make-solar-wind-and-battery-storage-cheaper-than-coal-83151/

       "The plunging cost of storage, along with that of wind and solar power, appears to have crossed a new threshold after a tender conducted by a major US energy utility suggests “firm and dispatchable” renewables are now cheaper than existing coal plants."

       "The stunning revelation came from Xcel Energy in Colorado, and quietly released over the Christmas/New Year break, although some outlets like Vox and Carbon Tracker were quick to pick up on the significance."

       The original article stated "Market forces will eventually stop rewarding ever more costly carbon-intensive practices that put irreplaceable natural life-supports at risk."

       Yes, but this should not be interpreted to mean market forces will solve the climate problem alone. It's going to take some legislation, like the EPA legislation on CO2, some subsidies and a carbon tax and dividend, because market forces alone are well known to be far too slow and inadequate to deal with environmental problems, due to the tragedy of the commons problem.

       In fact I personally think it needs a combined approach of more personal initiative, better corporate behaviour without always having to be pushed, and government legislation in the background to give things a push and help where market forces don't provide sufficient answers.

       However one would hope Trump could see the obvious fact that market forces do show that coal is no longer economic. Perhaps he doesn't believe in market forces, and just wants to run the economy by command from the whitehouse on his gut instincts. Isn't that communism or even worse?

15025. DPiepgrass at 10:12 AM on 3 April 2018
       The sun is getting hotter
       

       Chanut, the ozone hole does not cause global warming. Why did you say that?

15026. DPiepgrass at 09:06 AM on 3 April 2018
       Arctic sea ice has recovered
       

       bearling, that's right. No, the thickness of sea ice doesn't affect its ability to reflect heat very much, it affects its ability to melt.

15027. Philippe Chantreau at 05:46 AM on 3 April 2018
       Sea level rise predictions are exaggerated
       

       Meanwhile, our knowledge about what is really happening is increasing:

       www.nature.com/articles/s41561-018-0082-z

       From the abstract: "Between 2010 and 2016, 22%, 3% and 10% of surveyed grounding lines in West Antarctica, East Antarctica and at the Antarctic Peninsula retreated at rates faster than 25 m yr−1 (the typical pace since the Last Glacial Maximum) and the continent has lost 1,463 km2 ± 791 km2 of grounded-ice area."

       This is from Nature Geosciences, so unfortunately behind paywall.

15028. michael sweet at 04:14 AM on 3 April 2018
       Sea level rise predictions are exaggerated
       

       Norrism:

       We can discuss the Nerem paper by comparing it to earlier papers, discussing the methods and reliablity of the authors and reviewing the new data they have discovered.  For important papers (like Nerem) other experts will comment on new papers so that the rest of us can get an idea of what is going on.  Sometimes we have to wait for more papers to come out to decide what is correct.  It took about 5 years for scientists to agree that the "pause" was denier bunk.  Curries claims that it was real have been long proven incorrect.

       This contrasts to your approach.  You said that you had read the IPCC and the 2017 US Climate Change reports as your source of information.  Then you said that you think that everything in those reports is bunk and calculated your own value denovo.  Thus your "estimate" had no relation to either of the reports you claimed to cite.  It is only the wild, unsupported idea of an oil investor. 

       It may be allowed for lawyers to make up any old story they want, but it is not allowed in scientific discussions.  You must support your claims by referring to papers that actually support your position.  Merely reading the IPCC report does not make you an expert comparable to those who have devoted decades of their lives studing the issue. 

       Your inability to discern how the Climate Report reached its new expected values demonstrates that you have little comprehension of what you are reading.  How can you calculate a new value when you have no idea how the existing value was determined?  I could find that information on my own.

       You are welcome to give our opinion in some areas, but it has no place discussing facts on a scientific blog.  You must support your claims with something besides "this is what I thought up on my own after reading a few scientific papers".  Some of the posts are on more subective issues and then all can promote their opinion, athough you still should be able to support your claims with some sort of reference.

       When you have little understanding of a subect you are much better off asking for help on some of the issues you do not uderstand.  People  here are happy to help you undersatnd why scientists are worried that sea level might rise 8 feet when you think 8 inches is a better estimate. A group of top experts recently published a paper warning about the possibility of 17 feet of sea level rise by 2100.

       Making your own novel calculations is a waste of everyones time.  I have a Masters in Chemistry, I have followed AGW closely for 20 years and I have decades of scientific experience. I rely on my personal knowledge less than once a year (and only on chemical behaviour).  If challenged I produce references.   In a scientiic discussion you must find papers that support your claims.  If you cannot find papers to support your claims that tells you that the claim is incorrect. 

       Your claim of 8-10 inches is 50% of the lowest estimate of the IPCC which they say is very likely to be exceeded.  The IPCC is well known to be extremely conservative (low) on sea level rise.  Would a judge allow such a wild claim by a novice to be allowed as evidence in court to argue against expert opinion?

15029. gws at 03:27 AM on 3 April 2018
       How could global warming accelerate if CO2 is 'logarithmic'?
       

       Alchemyst @6 and nigelj @5: The Lambert-Beer Law shows an exponential rise of Absorption with increasing concentration. So Alchemyst's statement is incorrect.

       In the atmosphere, though, the law applies only to infinitesimally small slabs because neither temperature nor pressure are constant with height, thus the results have to be integrated over the whole atmospheric column. Individual absorption lines of GHGs that are "saturated" (e.g. all "strong" GHGs such as CO₂), thus absorb less per concentration change, than lines of "weak" GHGs (e.g. CFCs) that are not "saturated". This is discussed in detail in most atmospheric chemistry textbooks.

       The scientific community worked through the math decades ago and found that weak absorbers produce approximate linear increases in radiative forcing in response to their concentration increases, while those for strong absorbers increase logarithmically. These relationships are empirical, aka they apply to our Earth's atmosphere. The numbers for radiative forcing enter the calculation of Global Warming Potentials.

15030. Philippe Chantreau at 02:46 AM on 3 April 2018
       Arctic sea ice has recovered
       

       Bearling, the sea ice extent has not recovered at all. Although your remark about volume does have some validity, anyone attempting to argue that see ice extent has "recovered" is taking you for a ride. See NSIDC for the latest news.

15031. bearling at 02:18 AM on 3 April 2018
       Arctic sea ice has recovered
       

             So, many people think that the ice has recovered because of the extent of the ice without considering about the volume. The point is that we need to look at the volume to measure how much there really is. According to the thick ice graph, it is great concern that thick ice takes a lot more heat to melt and it is disappearing so fast.
             “Although a thin layer of ice doesn’t tell us much about the overall state of ice loss at the Arctic, it does tell us a great deal about Albedo, the property of ice to reflect heat back into space. When the sea ice diminishes, more heat passes into the oceans. That heat melts the thick ice and speeds up the melting of thinner sea ice, which in turns allows more heat to accumulate in the oceans.” My question is that, does the thickness of the ice really matter to how well it can reflect the heat? If it is thicker will it be better to reflect the heat or not so much difference?

15032. NorrisM at 02:17 AM on 3 April 2018
       Sea level rise predictions are exaggerated
       

       michael sweet @ 62

       There is much to reply to in the responses to date but do not interpret my comments that I do not think AGW is something we have to deal with which will require a move from fossil fuels.  What I am trying to determine is how much time we have to deal with the issue.  There are many potential effects of AGW but obviously one of the most critical is sea level rise.  What I am trying to sort out is how much can we expect and, to a certain extent, how much can be mitigated by a reduction in fossil fuel use.

       But I would like to address one philopsophical point about making contributions to this website.  If your position is that all we can do is exchange academic papers, you would slow any discussion on this blog to a snail's pace.  For example, there could be no references of criticism of the Nerem 2018 paper by other persons until other papers had been published which perhaps disagreed with it.  As you know full well, this could take a year given the process of first writing the paper and then having it go through the peer review process and finally having it published.

       The other philosophical problem I have with your approach is that you then limit any discussion or questions on this website to persons with a technical background.  I highly doubt that the sponsors of this website intend to limit discussion to those persons.  

       If you cannot adequately communicate and discuss these issues with the non-technical public then I have no idea how you expect to get the public onside except on faith.  "Trust me, we know better".  This is obviously a rhetorical statement on my part.

       As promised, I have supported most of my statements in my reply with citations from either the IPCC or peer-reviewed papers. 

       Obviously, my point is that there is more uncertainty in many of these positions than I am fully comfortable with in order to fully accept the projections of the IPCC or the US Climate Report based upon the levels of uncertainty acknowledged, especially when the projection is based upon a statement of "Medium Confidence".  On this point, the US Climate Report was much more "up front" about these uncertainty levels than the IPCC.  I actually did not locate the measurements of Confidence Levels in the early chapter of the Fifth Assessment (I found the probability levels relatively easily but not the Confidence level definitions).

       Glenn Tamblyn has provided me with a paper on the reasons for the increase in the upper level of the sea level rise in the US Climate Report and I intend to read it.

       Moderator Response:

       [DB] Off-topic and argumentative snipped.

15033. NorrisM at 01:51 AM on 3 April 2018
       Sea level rise predictions are exaggerated
       

       Glenn Tamblyn @ 65

       Thanks.  I have printed it and will read it today.  

       One issue which I did not get into in my post given its length already is the cause of ocean warming in the Amundsen Sea which is obviously impacting the melting and calving of the WAIS, or at least parts of it.

       My understanding is that there is geothermal activity at the bottom of the Amundsen sea caused by about 200 fissures of some sort of which some 90 have only recently been discovered.

       If this is a major cause of the warming of the ocean then it obviously is relevant, not as to how much sea level rise we be caused by the melting of the WAIS but how much of that melting can be laid at the doorstep of AGW.

       Have there been any academic papers that have discussed the geothermal warming and its effect on the Amundsen Sea? Either positive or negative.  

       Moderator Response:

       [DB] Off-topic and sloganeering snipped.

       No more.  Period.

15034. billev at 00:11 AM on 3 April 2018
       How do we know CO2 is causing warming?
       

       Is there any measured evidence that the heat energy retention by CO2 and methane has had any measureable effect on the  temperatures shown on the official graphs of yearly global air temperature?

15035. CBDunkerson at 21:50 PM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       The 'we only just recently figured it out' defence seems to fail both on the grounds that A: it is false and B: several of the denier groups they fund filed amicus briefs insisting it is all a big fraud with the court on this case... so even if it were true that we only figured global warming out a few years ago, the judge is literally holding proof in his hands that they are still funding misinformation to the contrary.

       On the 'shareholder value' front... there is more to it than that. Lying to your shareholders, even if doing so will make them more money, prevents them from making properly informed decisions. It is illegal regardless of the financial outcome... and again, the admission of the truths of climate science in this case does not match well with some dismissive statements these companies have made just in the last year.

15036. Tminus at 20:11 PM on 2 April 2018
       How could global warming accelerate if CO2 is 'logarithmic'?
       

       Though methane‘s direct contribution to sea level rise is small compared to potentional ice melting on Greenland and Antarctica, the point is that the thermal expansion of the sea caused by methane represents stored heat that lasts much longer than the life cycle of methane in the atmosphere that warmed the water. Such methane is like a blow torch heating rocks for only 5 minutes but the rocks then stay hot then warm for 50 minutes. Methane‘s heating of oceans, therefore, contributes to melting ice plugs around Greenland and Anarctica plus on top by contributing to heating the air. Dismissing methane seems misguided.

15037. Glenn Tamblyn at 19:33 PM on 2 April 2018
       Sea level rise predictions are exaggerated
       

       NorrisM
       
       "The US Climate Report increases the upper level of the very likely range from 98 cm to 130 cm but does not explain its reasons for its difference with the very likely range of the Fifth Assessment."
       
       The updated sea level estimate from the most recent reports, since AR5, is primarily due to some key studies that have identified additional mechanisms, poorly considered up till now, that can see ice shelves and marine glacial fronts break up more rapidly than previously considered due to mechanical failures. This could lead for example to 1 meter of sea level rise, just from Antarctica, by centuries end.
       
       Perhaps the key paper is DeConto & Pollard 2016.

15038. Postkey at 18:28 PM on 2 April 2018
       It's global brightening
       

       I presume that 'you' have seen this?

       http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml
       A BBC documentary about how unintentional increased reflectance due to man made pollution has actually hidden the affects of increased carbon dioxide in the atmosphere.

15039. nigelj at 10:53 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming Digest #13
       

       John Hartz, my comments basically do apply to America, but I think China affects other countries in a similar way, and the trump issue is similar to other authoritarian leaders. 

       I should have been clearer. I got the more global story of the week and the editorial on america confused in my head. 

15040. Bob Loblaw at 10:27 AM on 2 April 2018
       It's global brightening
       

       Dpiepgrass et al:

       The aerosol property of interest is the "single scattering albedo". Overall, any reduction in radiation is referred to as "attenuation". What was travelling in a direct line is no longer travelling along that direct line. It can be absorbed, or it can be scattered (now travelling in a different direction).

       Scattering occurs in all directions, For scattering, some is back-scattered (the vector is at least partially opposite to the original direction of travel) and some is forward-scattered  (the vector is at least partially in the same direction as the original direction of travel).

       Things like soot are strongly absorbing. Things like dust are strongly scattering.

       Atmospheric attentuation is easily measured by instruments pointed at the sun (sun photometers). Figuring out how much is absorbed and how much is scattered is a little trickier, but done routinely by international networks such as AeroNet.

15041. Bob Loblaw at 10:16 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       nigelj:

       Well, that's the conundrum. Their strongest defence agains a lawsuit that claims they failed to preserve shareholder value is to show how their actions preserved shareholder value. But that same defence is pretty much an admission of guilt that they preserved shareholder value at the expense of everyone else, even though they knew the damage it would cause.

       Location[self]= insert[between(rock,hard place)]

15042. John Hartz at 09:16 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming Digest #13
       

       nigelj: Fuch's opines about "three threats that could fundamentally endanger American national security". Your comment seems to address more global issues.

15043. DPiepgrass at 09:14 AM on 2 April 2018
       It's global brightening
       

       Correction: some aerosols do absorb solar radiation (which in fact warms up the atmosphere, and I don't know whether this causes more/less warming at ground level than sunlight hitting the ground. "Global brightening" is not a useful concept w.r.t. climate change; it creates a distinction between sunlight warming the ground and solar-induced infrared/warm air warming the ground, which is not an important distinction.)

15044. DPiepgrass at 09:02 AM on 2 April 2018
       It's global brightening
       

       Thanapat, clouds and aerosols do not absorb solar radiation, they reflect it.

       Cloud behavior is complex, and clouds have both warming and cooling effects: clouds traps heat beneath them, but they also reflect light back to space. The main effect of thick, low clouds is cooling; the main effect of high, thin clouds is warming.

       Here, the important thing about clouds is that scientists have determined (after many years of study) that clouds will not change very much as the climate changes. So their effect on climate change will be small (though clouds will most likely act as an amplifying feedback).

       Fossil fuels cause global warming via CO₂ (and NO₂), but fossil fuels also cause aerosols (via SO₂). If humans stop burning fossil fuels, the aerosols will dissipate immediately, but the CO₂ will not. Unfortunately, this may cause global temperatures to increase slightly after we stop burning fossil fuels.

       Infrared radiation is normal. Almost everything on earth emits infrared. The important thing to understand is that greenhouse gases glow in infrared—they send down infrared light from the sky. Reducing greenhouse gases is like removing a blanket, it lets heat escape to space more easily. To reduce greenhouse gases, we can:

       • Use less energy (within reason)
       • Build clean power plants (solar, wind, and nuclear plants such as MSRs).
       • Regrow forests (trees store carbon)
       • Look at drawdown.org for more ideas.
15045. nigelj at 07:47 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming Digest #13
       

       The largest threat to humanity is indeed climate change, because of the level of damage, the range of different effects, and the millenia level time scales and impacts on multiple generations. In comparison, difficult authoritarian leaders are more temporary aberrations although still very troubling.

       Trump has indeed badly handled climate change along with almost everything else, and is distracting attention from the three real existential level threats. The english language simply doesn't have adequate words to describe the situation.

       Surely we also need to be considering other environmental threats, resource scarcity issues and growing inequality and job insecurity in western nations.

       I'm not sure about the alleged existential level threat of China. While China is a dictatorship and this is not ideal, it is relatively benign, and imho the economic threats can be contained with sensible responses by the world more forcefully pushing fair free trade rules in China, etcetera, but this absolutely shouldn't include punative tariffs like Trump is doing. There have to be smarter and less mutually destructive ways than that. But the world cant do nothing either, because China is simply developing in ways that do pose some threats, well analysed on the economist.com.

       I agree threats to democracy are existential, although the issue is not so much democracy itself as a means of electing governments. It is more the threat posed by democratically elected authoritarian leaders, and the mindset that is doing this.

       Many of the current authoritarian leaders seem to currently share the following attributes. They  denigrate scientists and public servants in government, denigrate minority groups and scapegoat them for no good reason, they spread  unfounded fears of immigration and free trade. Some of these authoritarian leaders promote reckless corporate and personal economic behaviour that is short sighted, and pushes costs onto future generations.

       Unfortunately this combination of factors with many of these authoritarian leaders is by its nature toxic to efforts to deal with climate change, so reinforces this existential threat. So the existential threat against democracy posed by excessive authoritarianism and anti science thinking is a huge problem.

15046. nigelj at 06:52 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       Bob Loblow,  well they might try anything, but if the dissinformation campaigns are shown to be fraudulent, I dont think you can use law breaking as a defence.

15047. michael sweet at 06:50 AM on 2 April 2018
       Sea level rise predictions are exaggerated
       

       Norrismm

       Here is the most up to date sea level graph:

       

       I may have misread the graph and the 90% interval for RCP4.5 may be 5.2 instead of 7 feet.   My argument remains unchanged.  Your estimate of 8-10 inches is in contradiction to your sources.

15048. michael sweet at 06:38 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       Bob Loblaw,

       You propose an interesting defense.  I do not know the answer. It seems to me that they could argue they preserved value for shareholders 10 years ago but current shareholders will be left holding the bag.  Those left holding the bag get to sue.

15049. nigelj at 06:30 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       NorrisM @6

       I would have expected the oil companies to be open with the public about what their own internal science was saying, and so also agree with the IPCC findings. This is hard I know, but the oil companies allegedly knew the risks and so had an established  legal duty to acknowledge them unequivocally. The law doesn't make exceptions for products that have benefits, to my knowledge.

       Instead they hid things from the public and got caught, and funded deniers like the Heartland Institute. You pay a price for this sort of corporate behaviour.

       Damages will be based on the fact that politicians and the public 'may' have made completely different choices regarding climate change if oil companies had made proper disclosure, and with potentially robust and full mitigation. The plaintiffs do not have to prove they 'would' have made different choices, or what level of mitigation they would have used, because such a thing is impossible to prove either way. Tobacco litigation has shown us these same principles in that it only had to show the smoker may have chosen to give up.

       Damages will be quantified on physical damage caused on the basis of how much damage full mitigation would have prevented. Its complicated to work out but the causative link is there. There may also be punative damages. Again the same principles as tobacco litigation are likely to apply.

       What the IPCC said is irrelevant. Again tobacco litigation showed that what counted was what tobacco companies didn't say, regardless of what the surgeon general said.

       If the oil companies had made full disclosure, the entire denialist movement and influence of fossil fuel companies on politicians would all have probably been much weaker. 

       I also reinforce the point that OPOF makes we cannot assume that oil was the only alternative humanity ever had. Without oil, better progress may have been made with natural forms of energy or nuclear or fission power.

15050. Bob Loblaw at 06:07 AM on 2 April 2018
       2018 SkS Weekly Climate Change & Global Warming News Roundup #13
       

       michael:

       "Additional cases are being investigated because they lied to their stockholders about the likely future value of their fossil holdings in the ground. "

       I wonder if the oil companies would have the nerve to defend themselves against such a lawsuit by arguing that their disinformation campaigns were so successful that they actually preserved shareholder value far above what would have been realized if action to reduce climate change had begun in earnest 30 years ago.

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