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Comments 25951 to 26000:

25951. Big Oil at 13:31 PM on 9 January 2016
       Carbon Brief’s 15 numbers for 2015
       

       Too late. CO2 at 415 ppm causes 3 to 4 C increase in temperature.

       
       https://scripps.ucsd.edu/programs/keelingcurve/2013/12/03/what-does-400-ppm-look-like/

25952. Big Oil at 13:27 PM on 9 January 2016
       Why we need the next-to-impossible 1.5°C temperature target
       

       Actually, back in the Pliocene CO2 reached 415 ppm and caused 3 to 4 C higher temperature.

       https://scripps.ucsd.edu/programs/keelingcurve/2013/12/03/what-does-400-ppm-look-like/

25953. Big Oil at 13:26 PM on 9 January 2016
       Why we need the next-to-impossible 1.5°C temperature target
       

       Too late. Already passed 400 ppm. 3 C is locked in.

25954. Big Oil at 13:19 PM on 9 January 2016
       Carbon Brief’s 15 numbers for 2015
       

       Not a single signed the Paris agreement. It is a paper tiger.

25955. Tom Curtis at 12:54 PM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       angusmac @17:

       2a)   The simplest climate effect of warm periods is to expand the Hadley Cells that exist on either side of the intertropical convergence zone.  That has the effect of causing tropical wet conditions to expand poleward, but also for the arid regions on either side of the tropical region to also expand poleward.  In European longitudes, that means nations bordering the mediterrainian become more arid.  Much of the middle east including Peria/Iran would also become more arid.  For Australia it means the southern states become more arid while the northern states become wetter.  This is not a beneficial change.

       Secondary effects can be more complicated.  The MWP was associated with megadroughts In eastern Africa (around Kenya), the South Western United States, Peru, and Northern Europe:

       

       The Northern European drought was complicated in that it was primarilly a reduction in summer rainfall, and was compensated for regions close to the Atlantic by increased winter rainfall.  That may explain why slavic populations (far from the Atlantic, and therefore significantly impacted) were less able to resist germanic invaders, who durring the time of the MWP pushed into formerly slavic areas in what is now Poland.  In either event, while the MWP was beneficial for germanic people in general, it was not beneficial for slavs.

       In short, there is solid evidence that the MWP was not beneficial for a large number of people, across the world, while being beneficial for others.  What does not exist is evidence tying together the sum of the effects.  We don't know whether or not the gains of the germanic people outweighed the losses of the slavs and italians.  Nor do we know whether gains by american plains indians compensated or exceeded the losses by the pueblo dwelling indians of what is now the SW USA.  And nobody has integrated the effect globally.  I doubt the information to do so exists.

       In short, your insistence that we know the MWP was beneficial amounts to an insistence either that only germanic people and their descendants matter (they being the only ones of which we can say this with confidence) or a fairly blind faith beneficial effects for those germanic peoples were universal.

       2b)  With regard to the CO2 fertilization effect, logically if it is beneficial (as seems likely), then the temperature which is most beneficial from Global Mean Surface Temperature alone will be less than the temperature which is most beneficial given GMST plus the CO2 fertilization effect.  The later is probably somewhere between 0.8 and 1.1 C above the preindustrial average for our current civilization.  The figure will differ with different technologies and population distributions.  If the CO2 fertilization effect is significant, that implies the ideal temperature for current populations and technologies absent the CO2 fertilization effect has already been exceeded, and my have been exceeded early in the 20th century.

       1)  First, choosing as a baseline the most recent period prior to major rapid human climate influence is not arbitrary.  It is certainly not a cherry pick.  It fixes a useful baseline without the question of the absolute peak of benefit from warming needing to be determined.

       In contrast, your baseline requires the unproven assumption that MWP warmth was net beneficial for humans, and the dubious assumption that without anthropogenic influence current temperatures would be equivalent to MWP temperatures (the mid-century solar maximum has gone, which together with recent volcanism suggests natural forcings would be back at early 20th century values) to justify it.  Of course, you give away the real justification when you write "this does not sound nearly as bad as 2 °C".

       In response to your final question, we are 1.095 C above the baseline used above, and probabily 1.3 C above the preindustrial baseline.  That puts us 0.905 C below the guideline used above, but probably 0.7 C below the 2 C above preindustrial guideline.  Adopting your convention, we would be 0.764 C above the baseline, and 0.905 C below the guideline used above, but probably 0.7 C below the preindustrial guideline.  The current twelve month running average is more than 1 C over the baseline used above.

25956. denisaf at 11:26 AM on 9 January 2016
       Why we need the next-to-impossible 1.5°C temperature target
       

       Reducing the rate of greenhouse gas emissions means closing down many of the current high emitters and providing sound alternatives.  This can only be a slow process for practical reasons regardless of the policies adopted by governments. And carbon capture and storage systems can, at best, only slow down the global rate of emissions slightly.

       There should be more focus on measures to cope with the irreversible rapid climate change and ocean acidification and warming that is under way. Proposed amelioration measures can only slow down the unintended deleterious consequences of using fossil fuels to provide energy to power technolgical systesm.

25957. angusmac at 08:17 AM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       Tom@12
       3) Thank you for supplying the reference. I only looked at the references at the end of the Huang et al paper, not in-text. I also agree that land-only temperatures have greater variation than land-ocean but this does not change the logic of my post.

       
       2) I disagree that MWP was beneficial is a "statement of faith" – it is my perception that it is well-documented history.

       
       I am an avid reader of history and this shows that, since the last ice age, warm periods have usually been beneficial to the human race and cold periods are usually accompanied by crop failures and famine. Indeed, civilization occurred during the Climatic Optimum shown in Figure 2 (Kaufman et al, 2013) in my response to the Moderator@13.

       
       I make no comment on post-1980 CO2 fertilisation effects, I neither mentioned this subject nor alluded to it.

       
       1) Regarding pedantry, if people wish to use a pre-industrial temperature of 1750 and thus ignore warmer times in the past then they are entitled to their opinion. However, this ignores the fact that temperatures similar to the 1961-1990 mean did occur in the past without any documented dangerous effects on humanity. Consequently, “dangerous” should be measured from this or a similar baseline and not a very low period in the temperature history.

       
       My opinion is that the 1750 baseline is arbitrary and is akin to cherry picking as stated in my response to Eclectic@14 regarding the Dark Ages temperature minimum.

       Referring to your adjustment to the guideline of “1.669 °C” above the 1961-1990 mean, this does not sound nearly as bad as 2 °C. Additionally, does this adjustment mean that we are currently ≈ 0.67 °C above the guideline and not ≈ 1 °C ?

25958. Rob Honeycutt at 08:08 AM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       Angusmac... I think the faulty point of your thinking is assuming that current global mean temperature today would be similar to the MWP without the assistance of man-made CO2. But when researchers have attempted to estimate what would have happened without human forcings they come up with results that show the climate would likely have slightly cooled.

       

25959. Rob Honeycutt at 08:02 AM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       Angusmac @14...  But the peak of the last glacial period was also "preindustrial" so why not use that?

25960. mancan18 at 07:43 AM on 9 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Perhaps the tax arrangements that Exxon uses to sponsor the AGU are to their advantage. Considering that such contributions would be listed as a cost in their accounts and would reduce their reported profits for tax purposes, then this means that the tax payer is actually subsidising such contributions at the current company tax rate. Exxon are not doing it out of goodwill.

       Exxon, like many companies, employ some very highly paid accountancy firms, law firms and marketing firms to protect their corporate interests. It must be to their financial advantage to pay huge amounts of money to these people to minimise tax, make litigation difficult when they've done the wrong thing, and to continually spin their corporate image, otherwise they wouldn't spend so much. It is not likely that they do such things because they are moral corporate citizens motivated to protect the environment, improve society and to make the world a better place. They do it to protect the huge salaries of their top executives, and to maximise their profits, dividends and share price.

25961. angusmac at 07:32 AM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       Eclectic@11
       I suggest that we should compare similar temperatures cycle, namely, warm periods with warm periods and cold periods with cold periods.

       If we use the lowest temperatures of the LIA or the Dark Ages as the baseline we could be guilty of cherry picking – in a similar manner to some web sites comparing current warming with the 1998 El Nino peak to state that no warming has occurred since 1998.

       Regarding hard evidence of the modern warm period, it is not the purpose of my post to discuss the efficacy of modern temperature measurements. I am only questioning the baseline from which “dangerous” is measured.

25962. angusmac at 07:29 AM on 9 January 2016
       Tracking the 2°C Limit - November 2015
       

       Moderator@10
       I enclose documentation that casts doubt on your assertion that I was using “factually incorrect statements.”

       Regarding the MWP and the LIA not being “globally synchronized events”, it is evident that temperatures did not fluctuate uniformly among all regions. However, the PAGES 2k summary presented by Kaufman et al (2013) does show a distinct global MWP and LIA as shown in Figure 2.

       

        

       Figure 2 (Kaufman et al, 2013)

       Additionally, Section 5.3.5.1 of AR5 also states that, “The timing and spatial structure of the MCA [MWP] and LIA are complex…with different reconstructions exhibiting warm and cold conditions at different times for different regions and seasons.” However, Figure 5.7(c) of AR5 shows that the MWP was global and (a) and (b) show overlapping periods of warmth during the MWP and cold during LIA for the NH and SH.

       

       Figure 5.7 WG1 AR5

       Perhaps you may wish to consider updating your SkS references to include the AR5 information on the global extent of the MWP.

25963. One Planet Only Forever at 07:07 AM on 9 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       cs41y,

       Popularity, profitability, perceptions of prosperity and any other side-benefits thought to be obtained like tax revenue ...

       None of that excuses any group of people who actually try to keep others from fully better understanding what is going on.

       The fact that an organization as big as Exxon has developed and allowed its leadership to be controlled by such attitudes and resulting actions is unacceptable and damaging. There is no 'kind non-passionate' way to refer to what my better understanding of what is going on has made me aware of.

       And the belief that this type of group should be 'negotiated with or have its selfish interests balanced with the advancement of humanity' would be laughable if it wasn't for the tragic consequences of any success obtained by these type of people through their efforts to get away with what they can understand is unacceptable.

       The real trouble-makers in every organization or society are fairly well known by powerful wealthy people (because they illigitimately got away with becoming part of the powerful and wealthy). Too many people like that succeeding is a serious detriment to the advancement of humanity (and advancement of humanity to a lasting better future through better understandinga nd awareness has to be the objective of science, not temporarily unsustainably increasing profits, employment or taxes)

       That understanding is the best explanation of the damaging developments that have kept humanity from advancing to a lasting better future for all. I do not care what major global problem you choose to look into, that understanding explains it as well or better than beliefs that something else like 'religion' or 'race' is the root cause (because in almost every one of those cases callous greedy people have chosen to allow, support or promote intolerance to gain more undeserved advantage).

       So the 'science issue' of Exxon is not 'just science' and should not be considered without passion. There is too much at stake to prolong the success of callous greed and intolerance defying and fighting against the developing better understanding of who they are and how unacceptable their attitudes and actions are.

       The focus needs to be kept on the important matters being investigated and better understood. That is what scientists, engineers, any other professionals and all other 'responsible adults' are supposed to responsibly and conscientiously do. That is the only path to a better future for humanity (it is actually the only viable path to any future for humanity).

       So what has been done by people through Exxon has to be called out for what it is, regardless of any other interests. The advancement of humanity to a lasting better future for all life on this or any other amazing planet has to trump any other considerations.

25964. wili at 06:16 AM on 9 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Readers should be aware that there is no guarantee that some posters here are not in the pay of Exxon.

25965. cs41y at 05:03 AM on 9 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       I have a separate opinion that I think is perfectly on topic but feel free to not agree with me on that. The more emotional and passionate anyone appears to be when it comes to a science issue that is highly polarized the more they can be erroneously accused of being the "liberal left". That whole conspiracy nonsense used to turn the issue into college elitists versus the working class. I am not saying it is wrong to have emotion or passion. It is an issue with very disturbing consequences for not taking action. But we should not take actions or include language in articles which would make us appear to no longer be impartial scientists (which most of us are impartial and approach this appropriately). So unless there's a valid reason to reject funding, such as being required to withhold any unfavorable conclusions, then it does more harm to exclude them. 

25966. cs41y at 04:45 AM on 9 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       I understand the initial emotional reaction some might have when they see or are told something like this. There are no compelling reasons to exclude funding from Exxon. The AGU has been by upfront about its position on climate change which is in direct opposition to some of Exxon's interests and claims. Take away those funds from Exxon and the only thing that will change is the budget has now been reduced for scientists which support measures to combat climate changes caused by people. So Exxon will attempt the same strategy of disinformation only it may be more successful as scientists who are in direct opposition to Exxon's disinformation now have less funds to get their own findings out there. I would say it's puzzling why Exxon would fund it as there appears to be no benefit to them for it. 

       But if you look up the organizational structure of Exxon Mobil it is an incredibly huge corporation. Somewhere in the ballpark of 75000-100000 employees. Dozens of departments or affiliate companies. Most don't interact with each other. They only seem to tie in through the corporate headquarters itself. So there are very legitimate sciences going on within Exxon. Unfortunately the corporate level is the face and brains of the company with respect policies and the need to squeeze out every drop of revenue possible. So they simply ignore their scientists or even worse try to think of ways to discredit their own scientists findings. 

       So take into account all that. Also take into account how difficult and competitive it can be to getting any type of funding in science programs/research or even a job and it quickly becomes clear why someone would accept a job with them or accept funds from them. The scientist is typically not doing anything unethical, although some could do so at times. But if you can get funded and there are no restrictions on what you can publish. You can't control what the marketing, accounting, lawyers, etc do with it at the corporate level. You only know they will do the same thing to the science of climates no matter how you get your funding. You may potentially make a positive impact at the company or within the energy production industries, even if it's only very small. Then why reject those funds. There are no logical or ethical reasons to reject it. The only argument against it would be fairly weak and mostly ideological reasoning. But rejecting it based on those ideological reasons will not actually achieve very much (if anything) towards those ideals.

25967. davidsanger at 04:34 AM on 9 January 2016
       Latest data shows cooling Sun, warming Earth
       

       please correct to: "note the text does not say that at all"

25968. davidsanger at 04:33 AM on 9 January 2016
       Latest data shows cooling Sun, warming Earth
       

       Although the text of this posts is fine I believe the way the graph is presented can be misleading. The choice of the Y-axis units for total solar irradiance (1360-1363) give the impression that until roughly the 1970's changes in irradiance led ot temperature changes, and that after that there was "divergence." (note the text does say that at all).
       
       If TSI were plotted with Y-axis units from 1350 to 1375 it woudl give a different visual impression. 1300-1400 would be different again.
       
       I know you have to make some choice of units, and making both graphs fill the visual space makes some sort of sense, but it can lead people to make the wrong conclusion about how the two sets of values are related.
       
       Here's another version (scaled to show actual contribution) from a Bloomberg animated graphic :
       
       
       
       
       

25969. tmbtx at 17:48 PM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Regarding plastics, of course they have their own problems although mass extinction is probably not one them. Plastic has revolutionized many industries. Has it been a net positive? I don't know. That's not a question I can answer really. There are days I regret industrialization, not that dwelling on it accomplishes anything. It's done.

       I would like to see society in general stop externalizing all its costs. This would include, for example, companies being responsible for the disposal of their products when they are used/broken etc. If Sony had to take back all their TV's once they were obselete I imagine we'd see a lot less planned obselescence. Some of that is accomplished by recycling now, but it seems pretty marginal compared to the size of the problem. But I digress.

       Back on topic, I think they are correct overall to push AGU to reconsider its sponsorship policies. I would just ask the people pushing it to also allow the organization to be deliberate about it and take the time to mitigate any financial consequences. Maybe they can afford to quit cold turkey with the corporate funding, but I kind of doubt it. Then again if they decided to just drop them and let the chips fall where they may I'd support that too.

25970. ryland at 17:21 PM on 8 January 2016
       95% consensus of expert economists: cut carbon pollution
       

        DB  I have read the comments policy and cannot see where my post @4 contravenes.  I didn't make anything up or post graphs or make offensive comments and thought the emissions from agriculture could have been considered by the economists. Is that off topic? I understand that moderation is not open to discussion but if a commenter does not understand why a post is considered unacceptable then it woiuld be most helpful if  the reasons for this are made clear.   

       Moderator Response:

       [DB] This claim of yours is unsupported sloganeering and off-topic on this post:

       "livestock are responsible for a bigger share of total global GHG emissions than is the whole of global transport"

       If you wish to pursue that topic, bring credible evidence for your claims and present them on this thread.

25971. SirCharles at 15:04 PM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       "No more than one third"? We have to leave 75% of all known fossil fuel reserves in the ground if we want to have a chance to stay under 2°C warming by the end of this century, not just 67%.

       => Scientists warn 75% of known fossil fuel reserves must stay in the ground

25972. cs41y at 10:48 AM on 8 January 2016
       Climate is chaotic and cannot be predicted
       

       I study physics and statistical analysis. An easy analogy to explain concepts like chaos would be the random processes involved by individual atoms or molecules in an object. That would be like weather. Much more complex then weather. Weather is at least predictable with confidence. It tends to normalize fairly quickly so a butterfly flapping its wings in China does not have any effect on a weather event in the future. That's a part of chaos theory. You have to show that the dynamic system is actually sensitive to minor changes in initial conditions. I would not consider weather let alone climate to be that sensitive to minor fluctuations.

       Statistical mechanics makes use of all the individual random probabilities associated with each particle (a very crude definition but the best one in simple terms I can think up). When you include all the probabilities everything normalizes so you can't do a good job of describing the individual particles but you can define the entire object, region, whatever your calculating. That could be kind of like climate. 

       I believe this was attempted to be explained earlier. In physics and statistics stochastic processes have been validated in great depth and high degree of confidence. I am not a climatologist but the concept applies to a broad range of sciences so when they use some of these methods I generally accept the results if there were no errors in their calculations. I am not sure what the relevance of a lot of the statements on chaos being made so I did not get the best impression that chaos theory and statistical mechanics was well understood by some of the commenters. I'm not naming anyone and some people do grasp it here. But in the future a good guideline to use is if you understand something you then you can generally explain it without having to take the explanations straight out of a book. You also would not take a small part of a science theory in this case statistics or thermodynamics and try to make it sound more important to the overall results then it really would be. 

       I have an undergraduate degree in physics and mathematics. And I'm currently studying to be a statistician. So I am only commenting on specific instances here. I won't pretend to know climate models very well but I can assure you the methods being applied as far as the physics and math is not in question. if anyone would wish to argue against anthropogenic climate change these are not the areas you want to try and dispute.

25973. wili at 06:33 AM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Sooo, plastics are not an evironmental problem???

25974. PhilippeChantreau at 04:05 AM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       tmbtx, I assume you are talking about plastics. If so that is indeed a pertinent remark. I would add that, in fact, we should be concerned about preserving oil reserves for that very purpose instead of burning them. Plastics have innumerable applications that have become vital in medecine/surgery as well as countless other areas. We're not as close as replacing oil as a primary material for these as we are to produce electricity by other means than burning fossil carbon.

       I'd say it is also not a problem to use petroleum for plastic production, so long as the energy for the processes comes from something else than burning carbon. The medical field has yet to solve the problem of single use item that are bio contaminated since, as of now, disposal is mostly by incineration. So, not only the material is lost, but the fossil carbon is released in the atmosphere as well. I'm sure it is a small contribution compared to coal and oil burning, which should be addressed in priority, especially coal.

25975. wili at 02:18 AM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Exxon gets huge benefits of international legitimacy from sponsoring this high-profile event. We have to make it clear to the world that the basic 'business model' of Exxon and its ilk--profiting from baking the planet--is not only illegitimate, but morally repugnant.

       Their sponsorship of AGU is like medical conferences being sponsered by tobacco companies--not only does it legitimize the sponsor, but it tends to delegitimize the good work of conference itself.

25976. Yvan Dutil at 01:39 AM on 8 January 2016
       Latest data shows cooling Sun, warming Earth
       

       Note that the sunspot number and group sunspot number have been completely revised recentely. Accordingly, the XXth century solar maximum is now inexistant.

25977. One Planet Only Forever at 00:55 AM on 8 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       I disagree with suggestions that the actions of Exxon that delayed the development of global better understanding of what is going on regarding the impacts of burning fosil fuels can be excused because of 'other things Exxon does'. Exxon's actions are particularly unaccepable becasue 'they actually did know better'.

       The actions of Exxon regarding the development and acceptance of climayte science were clearly contrary to proper science. That needs to be understood and acted upon, or there is little hope for humanity to have a better future on this or any other planet.

       If the power players in control of what Exxon did were (does are) willing to try to delay or discredit the developing better understanding of climate science because of interests in maximizing 'profit, employment, tax revenue' or any other temporary regional 'perception of benefit for a portion of humanity', what other developing better understanding regarding the potential unacceptability of their pursuits would they also be 'interested in carefully but deliberately fighting against'?

       The advancement of humanity can only occur through the constant improvement of the understanding of what is going on with the objective of sustainably improving the conditions for all life on this amazing planet (the only viable future for humanity is a robust diversity living in a diversity of ways that are a sustainable and locally adapted appropriate parts of the robust diversity of life on this or any other amazing planet). Any 'effort to understand how to temporarily profit more in ways contrary to the true advancement of humanity' need to simply be understood to be unacceptable.

       Advancement requires efforts to effectively and rapidly undo damaging developments regardless of the perceptions of prosperity that have regionally temporarily been created through the deliberate efforts to generate poular support for activity and attitudes that can be understood to be unacceptable and unsustainable.

       It is irrational and unacceptable to pursue a 'balance' between the 'benefits obtained by a portion of the totality of humanity through time' with 'the reduced opportunity and consequences faced by others (particularly the reduction of opportunity and the increasing of challenges for future global generations)'.

25978. Tom Curtis at 23:08 PM on 7 January 2016
       Tracking the 2°C Limit - November 2015
       

       Angusmac @10:

       1)  Even if it would be convenient to state the increase in global temperature relative to the 1961-1990 average, the 2 C guideline for dangerous global warming is currently stated relative to preindustrial (approx 1750) temperatures.  If you adjust the baseline for this series to 1961-1960, you ought also to adjust the guideline for dangerous global warming to the same baseline.  Adopting the convention that preindustrial temperatures equal the 1880-1809 mean, that means adjusting the guideline down from 2 C to 1.669 C.  Similarly adjusting the figure in the OP, we obtain 0.764 C above the 1961-1990 mean.  Importantly, the result is that there is no change in the 0.905 C estimate remaining relative to the guideline.

       In sum, even if we allow that your pedantry has a reasonable basis, it makes not substantive difference.

       2)   It is far from clear that MWP temperatures were globally beneficial.  Yes, anecdotal evidence suggests they were beneficial in Greenland, and Western Europe but the data to claim it was globally beneficial does not exist, despite your statement of faith.

       What we can be fairly confident about is that the warming to 1980 plus the accompanying CO2 fertilization effect was economically beneficial in the global average.  Since 1980 the combined effect has possibly continued to be beneficial in Western nations, but has likely been harmful in poorer, particularly tropical nations.  From the relevant community of experts, 41% think the global gains to 1980 have already been wiped out.  A further 22% think it will be wiped out within the next 10 years, with a further 26% thinking it will be wiped out within 35 years.  In all, that makes 89% of relevant experts who think impacts will be net negative by approximately 2 C above preindustrial temperatures

       3)

       "...but Huang et al do not state explicitly in the paper if they are comparing their land-only proxies with land-only instrumental temperatures"

       Huang et al (2008):

       "The variance-adjusted version of the global land only surface air temperature anomaly time series we used was retrieved from the University of East Anglia Climate Research Unit web site on November 1, 2007 (CRU, http://www.cru.uea.ac.uk/cru/data/temperature/crutem3vgl.txt, 2007)"

       (My emphasis)

       Note, as a land only temperature series, temperature variations will be overstated relative to global (land plus ocean) temperature variations in both the instrumental and reconstructed temperature histories.

25979. tmbtx at 21:31 PM on 7 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Oh I forgot my only technical disagreement - as for careers, oil and gas are used for more than just burning. There will be demand for hydrocarbons even after the eventual shift to renewables for energy. Not as much demand as now, obviously, but it's not zero.

25980. tmbtx at 21:30 PM on 7 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       I have a very mixed reaction to this article, probably because I have ties to AGU, find the evidence for AGW blindingly obvious, and I also work in oil and gas as a geophysicist. The sentiment I understand completely, but it seems a bit naive and black and white. Big Oil supports a substantial number of earth science programs (not just petroleum programs) around the world with lots of money. I personally benefitted from their scholarship funding while doing research that had nothing to do with oil and gas. On the other hand, it would be fascinating (and admittedly fun in a way) to watch it play out if organizations like AGU and GSA started refusing industry funding as a matter of principle. They can certainly justify it to some extent given the behavior they've cited. Although I do wonder how big of a funding hole that would leave.

25981. Eclectic at 20:06 PM on 7 January 2016
       Tracking the 2°C Limit - November 2015
       

       Unfortunately, Angusmac, the Huang paper is currently off-line at the link you gave.

       My memory is sketchy, since it is some 2 years since I was reading on the NOAA website that the Medieval Warm Period . . . was more a North Atlantic phenomenon ~ during which, the Andean and West-Canadian glaciers were still advancing (plus some other Southern Hemispheric evidence).   The gist of it was that the MWP was greatly overrated as an event of global importance.

       Whether the (so-called) MWP should be discounted 50% or 75% (or not at all! ) in the discourse about "climate baseline" . . . there still remains the question of why you yourself should not equally favour the use of the Dark Ages Cold Period as the criterion baseline for AGW consequences.    And like the MWP, the DACP is also susceptible to criticism !

       In reality, neither Period is worthy of much consideration, because the vast amount of hard evidence we have about the Modern Period, is entirely superior as a basis for making important decisions (about climate).

25982. angusmac at 17:37 PM on 7 January 2016
       Tracking the 2°C Limit - November 2015
       

       Tom, Rob, Eclectic & Glenn

       The point I was trying to make was that the MWP is certainly preindustrial and not affected by anthropogenic CO2. Furthermore, paleo reconstructions show that the MWP was significantly warmer than 18-19th century temperatures and that this period was not dangerous. Consequently, it would be logical to use the MWP temperature as a baseline to decide what temperature is and isn’t dangerous as we progress into the 21st century.

       For example, Huang et al (2008) state that, “The reconstructed peak temperatures in the MWP appear comparable to the AD 1961–1990 mean reference level”. Therefore, if we were to use Huang et al (2008), it would be logical to compare dangerous temperatures with those that are comparable to the 1961-1990 baseline. Interestingly, Ljungqvist (2010) also shows the MWP mean to be similar to the 1961-1990 mean, albeit (as Glenn points out) for the NH.

       I now respond to individual comments.

       Eclectic, the MWP was global and there are several papers that confirm this, e.g., Huang et al (2008) above.

       Glenn, it was not my intention to infer that we should compare NH proxy temperatures with global instrumental. This is why I stated that we should use a reasonable paleo reconstruction. You could choose your own to compare apples with apples.

       Additionally, the reference level for Huang et al (2008) paper is the 1961-1990 global mean instrumental record. This appears to be CRU but Huang et al do not state explicitly in the paper if they are comparing their land-only proxies with land-only instrumental temperatures

       Moderator Response:

       [DB] "paleo reconstructions show that the MWP was significantly warmer than 18-19th century temperatures"

       And

       "the MWP was global"

       Not only is that claim NOT established, the bulk of the credible evidence attests to quite the opposite.

       Per the PAGES 2000 reconstruction, current global surface temperatures are hotter than at ANY time in the past 1,400 years, and that while the Medieval Warm Period and Little Ice Age are clearly visible events in their reconstruction, they were not globally synchronized events.
       
       
       
       Source SkS Post

       Source Paper
       
       Ancillary Source

       Please ensure that future comments do not contain such outright factually incorrect statements.

25983. ryland at 16:14 PM on 7 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Perhaps Exxon are accepted as sponsors as they have spent millions  on research into renewables, predominantly and predictably biofuels from algae, as well as millions on campaigns against climate change.  I guess like many massive companies Exxon is happy to walk both sides of the street as in that way it reduces risk to profits.  

25984. uncletimrob at 15:35 PM on 7 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Good article, but I'm not convinced that it is completely out of line for Exxon to be sponsoring an avent such as this.  Afterall the procedues they use to discover new reserves and then extract them are based on geophysical knowledge.  I agree that what they have not said publicly about climate change is concerning by the way.

25985. TonyW at 14:09 PM on 7 January 2016
       Latest data shows cooling Sun, warming Earth
       

       Thanks, Mark. Is there any research which validates the sunspot calculation by comparing those calculations, after 1978, with the sattelite measurements?

       By the way, there are other "data" which contrarians pin their hopes on - the UAH and RSS data, not just the data sets you mentioned. I fully realise that the calculations from those measurements are questionable, but how do they fair in the comparison of solar irradiance and lower troposphere estimated temperatures?

25986. Eclectic at 13:08 PM on 7 January 2016
       95% consensus of expert economists: cut carbon pollution
       

       Sorry, Ryland, but I can't speak for what the economists were considering . . . other than that they foresaw major economic damage from our ongoing Global Warming.

       If they had considered your concern about "fossil-oil" carbon pollution from food production/transport, versus CO2/methane output from livestock . . . then probably they would have expressed it in this way :-

       ~ Petroleum-oil liquid fuels produce a semi-permanent (and therefore cumulative) increase in carbon pollution, but livestock's CO2 output is not cumulative (because it's merely recycling organic carbon already "in the system").   Yes, more cattle [compared with 50 or 100 years ago] has caused a higher output of the GHG methane . . . but that methane is in itself rather short-lived and has nearly reached a plateau (compared with cattle numbers from 20 years ago ~ and cattle numbers are not likely to be very much higher in 20 or 40 years' time) . . . so we have reached a "steady state" with livestock methane.   [The increasing arctic release of methane from arctic warming, is of course a separate issue from the livestock one.]

       So there's no real comparison between steady-state livestock GHG's, and the cumulative carbon pollution from fossil fuels.   I reckon it will be very much easier to phase out carbon pollution from transport & agricultural machinery over coming decades, than it would be to change human dietary desires into the (almost) purely Vegan vegetarian.

25987. MA Rodger at 08:44 AM on 7 January 2016
       2016 SkS Weekly Digest #1
       

       criskoz @1,

       Those annual MLO CO2 growth rates from NOAA are a simple subtraction of the 1st January level from the 31st December for the year in question. Using a couple of single day readings in this manner does add a bit of extra noise which an annual average increase would even out.

       That said, with the increase in emissions since 1997/98, you would expect a significantly higher annual rise today, assuming El Nino behaves in an equivalent manner. It would be about +0.5ppm/year.

       The wobbles in CO2 growth rates are graphed here in red (usually 2 clicks to 'download your attachment'). Note the wobble in 1997/98 was far in excess of 0.5ppm, approaching 1.5ppm above the long term growth rate.

25988. keithpickering at 05:42 AM on 7 January 2016
       Latest data shows cooling Sun, warming Earth
       

       Just to be clear: The SATIRE model of Krivova et al. actually measures magnetograms (records of the Sun's magnetic field) to determine solar irradiance, rather than a direct count of sunspots. It can be (and has been) applied to raw sunspot numbers in older epochs, but is less accurate beyond the late 19th century.

25989. bbrowett at 04:05 AM on 7 January 2016
       Why is the largest Earth science conference still sponsored by Exxon?
       

       Great article.   It is wonderful that you have been so direct.  There have been attempts to create a "Hippocratic Oath for scientists".  Certainly ethical standards for industrial scientists are a challenging subject.   At the heart of the challenge for industrial scientists is the "Non-disclosure Agreement" that we must sign to gain employment.   Although, often, I was able to speak openly within a company, outside the company all communication had to have prior approval, i.e., only positive comments/reports about the company, its science, and products were allowed.  Of course there is no real protection for transgressions of the "Non-disclosure Agreement".   For industrial scientists to be taken seriously, we will need to be able to discuss industrial science without fear or favour.  

25990. Joel_Huberman at 01:03 AM on 7 January 2016
       Latest data shows cooling Sun, warming Earth
       

       Thanks, Mark. A very clear summary!

25991. chriskoz at 20:21 PM on 6 January 2016
       2016 SkS Weekly Digest #1
       

       NOAA has added 2015 to the CO2 annual growth rate records. 2015 turns the highest ever rate of 3.17ppm/a, beating the current reigning 1998 (2.93) by a considerable margin. The exact 2015 number is preliminary but there is no doubt it'll beat 1998 regardeless potential correction.

       I remember Indonesian massive pit fires (with estimated 2Pg of carbon burned) have been blamed for the 1998 spike. A now famous super ElNino was listed as a secondary cause.

       So, it's interesting how we are going to explain current unprecedented spike, esp. considering that emissions have stalled (peaked?) in 2014. I don't have any preliminary 2015 data. So such large departure from mean growth rate (which recently have been around 2.1) demands explanation. The blame on current ElNino is insufficient.

25992. ryland at 19:43 PM on 6 January 2016
       95% consensus of expert economists: cut carbon pollution
       

       Eclectic I didn't make myself clear, irrespective of the GHG emissions from  transport/industrial food processes,  livestock are responsible for a bigger share of total global GHG emissions than is the whole of global transport.  That's a very significant amount and I found it surprising that this and the emissions from agriculture in general, appeared not to have been comsidered by the ecomomists.  

       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, 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.

25993. Glenn Tamblyn at 16:32 PM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       angusmac
       
       From  Ljungqvist - "A new temperature reconstruction with decadal resolution, covering the last two millennia, is presented for the extratropical Northern Hemisphere (90–30°N)"
       
       So your comment "I suggest that the MWP mean from Ljungqvist (or any other reasonable paleo reconstruction) would be an appropriate baseline for preindustrial temperature." isn't a very good idea.

       Comparing an old record taken from 25% of the earths surface with a modern record for 100% of the surface is comparing apples and oranges.
       
       In contrast, here are the zonal graphs from GISS instead of the global graph Rob used. The top one is Northern extra-tropics. They aren't using 30N as the cutoff but 23.6N but it is still closer than using the entire globe.
       
       For the period around 1900 to the present that is a temperature rise of around 1.4 C
       
       Superimpose 1.4 C on the graph from Ljungqvist starting around 1900 and what do you get?
       
       

        

       Next, the graph you show isn't directly from Ljungqvist which can be found here. Ljungqvist does have some modern temperatures shown. They use CRUTEM3 & HaddSST2. So a land and ocean dataset, and a slightly older one at that. Yet when you look at their paper virtually if not all their proxies are land based. So are the trying to compare a land-only proxy record with a recent land and ocean dataset? If so, since land temperatures vary more than ocean there is a good chance an apples with apples comparison would show results similar to GISS. And the GISS graphs is land and ocean as well.
       
       So all in all, using Ljungqvist as a baseline doesn't seem like a very good idea.

25994. wili at 14:33 PM on 6 January 2016
       2016 SkS Weekly News Roundup #1
       

       Nice shout out to SkS from Dr. Jeff Masters toward the end of this good interview at www.voanews.com/media/video/hashtagvoa/3132077.html?z=1433&zp=1

25995. Eclectic at 14:13 PM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       Why indeed not use for comparison the Medieval Warm Period ?

       Or indeed, Angusmac, why not use the Dark Ages Cold Period, instead, as the baseline for comparison ?

       Then also, for the MWP, we have the little problem ~ that the Southern Hemisphere did not have a comparable "MWP" .   So, to avoid fruitless bickering . . . best if we stick with the much-better documented temperature information that we have for the latest couple of centuries.  Clearly the best choice, by far.

25996. Rob Honeycutt at 13:30 PM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       One more thing... Why would you think it appropriate to use a "previous warm period" as a baseline instead of the most recent preindustrial temperature?

25997. Rob Honeycutt at 13:28 PM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       I would also note, angusmac, that Ljundqvist is "extratropical Northern Hemisphere (90–30°N)," thus not only is it not global, it's not even inclusive of the entire northern hemisphere. (Stated right there is the abstract you link to.)

25998. Rob Honeycutt at 13:25 PM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       angusmac...  What I've done is limit myself to the GISS data. 1880-1909 is the earliest 30 year period in that that set.

       Going back to the MWP would be inappropriate since (a) itsn't not inclusive of the data I'm using, and (b) it's several hundred years prior to the industrial revolution.

       As Tom states, my preindustrial baseline likely underestimates actual preindustrial temperature, but it's as close as I can get with GISS.

25999. Tom Curtis at 10:39 AM on 6 January 2016
       Tracking the 2°C Limit - November 2015
       

       angusmac @3, fairly obviously, the forcings in operation in 1000 AD did not have the same strengths as the forcings in operation in 1750, or 1890.  Therefore the value of the forcing in operation in 2015 are not the value of the forcings in 1000 AD plus the anthropogenic forcings.  Rather, they are the values of the forcings in 1750 plus any changes to natural forcings, plus the anthropogenic forcings.  It follows that the temperature comparison needed to determine the impact of forcings is that between 1750 and 2015 - not 1000 and 2015.  By best estimate, Rob's baseline underestimates the temperature rise since 1750 by about 0.2 C.

       More fundamentally, the reason for tracking the temperature is the widespread concern that temperature increases of 2 C above preindustrial temperatures (defined as those in 1750) will cause significant harm to the global economy, and catastrophic effects to some individuals.  For tracking progress towards that target, again obviously the 1750 temperature is the appropriate temperature.

       Where you not more keen on making a silly rhetorical point than in understanding the debate, I doubt you would have missed these nuances.

26000. denisaf at 10:16 AM on 6 January 2016
       2015 SkS Weekly Digest #52
       

       I had a career as an aeronautical research scientist. Imagine my surprise in eventually learning that science at large did not accept until recently that the combustion of fossil fuels to supply energy had the unintended consequences of producuing the vast amounts of greenhouse gases that have contibuted to climate disruption and ocean acidification and warming.

       This type of failing of scientists has been common for centuries but the lack of understanding of the deleterious consequences of using fossil fuels must go down as the most influential to date. However, the current failure to understand that that technological systems are irreversibly using up limited natural material resoures, including the fossil fuels, will hit hard in the future, as it is an unsustainable process.

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