1.5C?

I think that the negotiators in Paris are pretty close to reaching an agreement (may have already done so). There’s a draft version here. Maybe the most interesting aspect of the agreement is the paragraph below:

Emphasizing with serious concern the urgent need to address the significant gap between the aggregate effect of Parties’ mitigation pledges global annual emissions of greenhouse gases by 2020 [and aggregate emission pathways] consistent with holding the increase in the global average temperature to well below 2oC above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5oC, recognizing that this would significantly reduce risks and impacts of climate change,

The holding the increase in the global average temperature to well below 2oC is itself quite strong, but pursuing efforts to limit the temperature increase to 1.5oC is quite remarkable.

In a sense, it’s impressive that they’re making such strong statements, but there is a concern that they could be meaningless. At 400ppm, the equilibrium temperature change is probably close to 1.5oC. Unless we can reduce emissions substantially, concentrations will continue to rise and we will likely exceed 1.5oC. Also, if we think that negative emissions are potentially extremely difficult, or even impossible, then the best we can do is halt all emissions, which would then stablisise temperatures.

Given the above, it would seem that limiting the temperature increase to 1.5oC would require getting emissions to zero within the next few decades, and there’s little I could find that indicates that this is recognised. The closest seems to be the paragraph below

In order to achieve the long-term global temperature goal set in Article 2 of this Agreement, Parties aim to reach the peaking of greenhouse house gas emissions as soon as possible, recognizing that peaking will take longer for developing country Parties, and to undertake rapid reductions thereafter towards reaching greenhouse gas emissions neutrality in the second half of the century on the basis of equity and guided by science in the context of sustainable development and poverty eradication.

If we think in terms of a carbon budget, then the carbon budget that will give us a 66% chance of staying below 2oC is around 300GtC. To stay below 1.5oC would require emitting – in total – considerably less than this. At current rates, we’d use it up in a couple of decades. If climate sensitivity is low, then we could emit more, but we’ll only know if that is the case, once we’ve done so.

Therefore, if we’re serious about limiting warming to 1.5oC, that would seem to require drastic emission reductions starting now, and there’s little to suggest that this is likely, even with this agreement. In a sense I’m reluctant to be too critical, given that it may well be the case that limiting warming to 2oC will be insufficient to avoid some of the more serious impacts. On the other hand, aspiring to something that you don’t actually try to achieve, seems meaningless.

Of course, maybe we’ll be lucky and we’ll develop alternatives that can replace fossil fuels very rapidly; maybe we’ll develop carbon capture and storage and/or negative emission technologies; maybe climate sensitivity will be low enough that can can overshoot the carbon budget without overshooting the warming target. However, as it stands right now, it seems that giving ourselves a reasonable chance of limiting warming to 1.5oC would require drastic emission cuts starting now.

Accepting such a target without also accepting this reality seems potentially counter-productive, especially as some people will be looking for any reason to find fault with this agreement. Of course, maybe I’m missing something, so I wrote this partly to see what other people think. Feel free to let me know via the comments.

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56 Responses to 1.5C?

  1. The final draft now appears to be available.

    Also, in case it wasn’t clear in the post, my issue is not with choosing to try and limit warming to 1.5oC, it’s with saying this without recognising what is probably required if we want to have a reasonable chance of actually doing so.

  2. EOttawa says:

    I tend to agree with you and got into a bit of a twitter ‘discussion’ with the Canadian Youth Delegation. If countries don’t take immediate action immediately following signing onto the agreement, I would have to join with those who describe these COPs as a farce. Here in Canada, Alberta’s premier has stated that with their recently climate plan, they have done enough. The problem is that the plan allows for further growth in GHG emissions from the oil sands.

  3. Let’s see what happens when the carbon bubble collapses and the political power of the fossil fuel companies is broken. Might go very fast suddenly. Creative destruction.

    More importantly, Paris is a political conference, not a scientific one. When we knew about climate change limiting the warming to 1.5°C was still possible with firm action. The countries that suffer most from crossing this limit will want to be compensated for damages and help with adaptation. A treaty that talks about 1.5°C helps them with this.

    There will likely be a special IPCC report on the 1.5°C limit.

    Whatever happens, in the middle of this weird fake-science debate with the Anglo-American mitigation sceptical movement, it is refreshing that the entire world was present in Paris, see climate change as a problem and something we should and can solve.

  4. EOttawa says: “Here in Canada, Alberta’s premier has stated that with their recently climate plan, they have done enough.”

    Here in Germany, a state minister of environment just said on radio that this treaty means that we have to do more. If the others are cooperative, that makes it easier to be cooperative yourself.

  5. Here in Germany, a state minister of environment just said on radio that this treaty means that we have to do more.

    Agreed. If we really want to have a chance of limiting warming to 1.5oC, then we have to do more than we are now.

    If the others are cooperative, that makes it easier to be cooperative yourself.

    Of course, but this may be the stumbling block 🙂

  6. When I was an undergrad, there were regular forecasting contests.

    They were very simple – for a given station, predict minimum & maximum temperatures and precipitation amount.

    The climatology professor looked on ( forecasting not being a climatological thing ) but ran some statistics, and pointed out digital bias ( unfounded psychology creeping into forecasts ).

    The last digit of both temperatures & precipitation tended most to be 0 and second most to be 5.

    Seems to me that 2.0 and 1.5 are more made up from psychology than scientifically defensible.

    That’s not surprising from a political convention, but let’s not confuse it with science.

  7. TE,

    Seems to me that 2.0 and 1.5 are more made up from psychology than scientifically defensible.

    As many have probably already pointed out, science cannot tell us what to target to choose. Science can only tell us something of what will happen given certain assumptions about possible future pathways. The decision as to what target to have – or if we want to actually have one – can only be a political decision.

    That’s not surprising from a political convention, but let’s not confuse it with science.

    Apart from you, I don’t think anyone actually has.

  8. They must have some sort of super secret French technology to limit the temperature increase to 0.6 degrees C above today’s temperature. I was wondering if they have something to drop gravity a bit? I need to lose weight without losing mass.

  9. Sam taylor says:

    “I hold in my hand a piece of paper”

  10. Sam,
    I’m trying to be positive, but that is my concern. This has to translate into some kind of action soon or else it will all simply be rhetoric.

  11. Sam taylor says:

    Absent a mechanism for punishing defection I don’t really see how anything gets done, to be honest, and I’ve not seen anything like that mentioned anywhere.

  12. This Carbon Brief article by Myles Allen is pretty good as it lays out the number pretty clearly.

  13. Zeke Hausfather says:

    “At current rates, we’d use it up in a couple of decades.”

    Nope, at current rates we’d use it up in a couple of years (6 to be precise). You need massive scale deployment of negative carbon BECCs to get 1.5 C to work, and even then you need net zero global emissions by 2050 or so. Why its physically possible (as are many things), it certainly doesn’t seem very plausible.

  14. Zeke,

    Nope, at current rates we’d use it up in a couple of years (6 to be precise).

    I thought that even a couple of decades was a bit extreme, but 6 years is even more so.

    Why its physically possible (as are many things), it certainly doesn’t seem very plausible.

    I agree.

    It seems to me that if there is a general sense that 2C might lead to severe impacts and that we should be aiming to stay well below 2C, and possible try to limit it to 1.5C, then the obvious conclusion seems to be that we cut emissions as fast as is plausible. It’s presumably hard to define precisely what this would be, but if the general view really is that staying well below 2C is important, then I can’t see how they can accept this without also accepting that rapid emission reductions is a priority.

  15. Andrew dodds says:

    Given a finite amount of negotiating energy, it does seem strange to spend it on something that just won’t happen. A mechanism for fully retiring coal whilst still allowing development might have been a better goal..

  16. Zeke Hausfather says:

    Or, as Gavin Schmidt put it the other day,

    “If you are driving in completely the wrong direction, arguing about where you’ll park if you arrive isn’t your highest priority.”

  17. I tend to agree. What would be very useful is a concrete way to actually start reducing emissions. While it seems likely that they will continue to rise, it does seem a little strange to be making a big deal out of a target the budget for which we may have passed before we even get to a point where emissions are actually reducing. Could this be a stocks and flows issue? Is it possible that some think that all we need to do is get emissions to zero at some point in the future, without realising that the trajectory that we follow to get there is crucial?

  18. Nope, at current rates we’d use it up in a couple of years (6 to be precise). You need massive scale deployment of negative carbon BECCs to get 1.5 C to work, and even then you need net zero global emissions by 2050 or so. Why its physically possible (as are many things), it certainly doesn’t seem very plausible.

    The trend in ten year radiative forcing rates peaked in 1989 and have fallen by about a third since then.

    During that time, the rates of temperature increase have also fallen to less than 1C per century.

    Exaggeration still persists.

  19. Absent a mechanism for punishing defection I don’t really see how anything gets done, to be honest, and I’ve not seen anything like that mentioned anywhere.

    Weight watchers seems to work. You commit yourself to a goal and there is a weekly (?) meeting to evaluate progress.

    Even now without a treaty there is already a lot happening. Solar and wind are growing spectacularly.

    Sanctions in the Kyoto protocol did not really work well against rogue states. A treaty with sanctions would need to be approved by the US congress, which would mean that nothing would happen because the US congress is in the hands of Big Carbon. That should change, that would make this marathon a lot easier.

  20. TE,
    Did you read it?

    “It is unlikely that emissions have peaked for good. This is because energy needs for growing economies still rely primarily on coal, and emissions decreases in some industrial countries are still modest at best,” Professor Le Quéré said.

  21. I think that Hansen, as much as I respect him, has been outrageous in calling COP21 a fraud. What would have happened if he had chaired the meeting? Hitting everyone over the head until they agree with a carbon tax, which he sets? I suspect the meeting would have ended in acrimony and the world would be in despair at no agreement.

    Is the current agreement flawed? Yes, in many ways, but it is a framework on which to take us forward with 5 years reviews, and things that many developing countries had requested, like loss and damage.

    I marvel at the ability to bring 190 countries all with very different histories and current needs, to knit something together. French diplomacy tonight deserves our gratitude, not our scorn.

    Is 1.5C achievable? The science suggests almost certainly not. So why include it? Because low lying and vulnerable countries demanded it. It is a recognition of their plight. Is that a sop to them, a fraud? No, its called diplomacy and of course not an easy thing for scientists like Hansen to accept.

    There is a joke about the visitor to Ireland who asks a local old man for directions to a place he needs to get to … and the old man says … “If I were going where you are heading, I wouldn’t have started from here!”.

    We cannot change where we are starting from.

    We can all help, individually, in our towns, in our communities, as voters, etc. to help turn aspiration into reality. e.g. like (two examples at random) representatives of US states writing to the President

    and my local town …
    http://www.stroudnewsandjournal.co.uk/news/14137096.___World_Leaders_could_learn_from_Stroud_on_fighting_climate_change_____says_Green_councillor_Simon_Pickering/

    and my local football team …
    http://www.stroudnewsandjournal.co.uk/news/14122235.Premier_of_South_Australia_meets_Ecotricity_s_Dale_Vince_to_discuss_plans_to_make_Adelaide_the_world_s_first_carbon_neutral_city/?ref=mr&lp=6

    I think we all need to stop whinging about how hard it is and JFDI …

  22. Richard,
    Yes, I agree. I couldn’t bring myself to RT Hansen’s article. I applaud his passion and respect him, but I think that calling it a fraud is too much. It must be frustrating to believe that they really aren’t doing enough (and this may well be true) but that kind of terminology is counter productive and not wilding different to those who would dismiss this for different reasons.

  23. John Paul says:

    there is absolutely zero chance our elected GOP officials are going to support significant changes and cuts to domestic fossil fuel extraction. obama has said repeatedly even he supports an all-of-the-above approach. and even if there was support for ending fossil fuels, absolutely nobody wants americans to change their lifestyles and not travel as much or turn off their air conditions, which would also be necessary to reduce our carbon footprint.

    we have the best government that money can buy, and i don’t think it’s only the u.s. that’s suffers this misfortune. we consume like 17 tons of carbon per capita of carbon a year and probably have to get that under 3 if we were serious–yeah right.

  24. Magma says:

    NOTE: As I post this, media reports from Paris are that a legally-binding climate agreement has been unanimously adopted with a nonbinding but aimed-for target of 1.5°C(!)

    I was surprised to see 1.5°C make an appearance, let alone garner the level of support it did. I think it’s unrealistic, but (technically) feasible if ECS is on the lower side of the IPCC range and if countries genuinely turn a focus on decarbonizing energy and transport systems, starting with such obvious targets as carbon taxes, retiring aging coal plants, controlling fugitive methane, continuing with increased energy efficiency in vehicles, lighting, HVAC and ongoing improvements to solar and wind generation, and maybe a new look at nuclear power, with standardized plants built on time and on budget. The snowballing effect of technological progress and changing social standards must be taken into account as well – as an analogy I can’t remember the last time I saw someone wearing a fur coat in an urban area. (Even Arctic Inuit are moving to commercially made down-filled parkas, though for a variety of reasons.)

    The most important thing to remember is that this is a political agreement that will help drive policies around the world. It is better to aim for an unrealistically low target and miss on the high side than to agree on a high target (3°C) and miss that on the high side too, human nature being what it is.

    As far as coal goes, coal miners are in a panic from North America through Europe and Australia, with major energy and mining companies dumping coal assets as soon as they can find buyers and publicly traded companies losing money by the bucketful and trading at a fraction of their recent values. Apart from South Africa (3% of global production) and Colombia (1% of global production) South America and Africa have no significant coal production to speak of. This is an industry with a fraction of the power and health of oil and gas companies, and may be the first to shrink.

    Outside of non-market driven construction (as we’re learning about China’s many mothballed new coal plants) or ones in which the short-term cost and local employment trumps all other considerations, who in their right mind would fund a new coal-fired power plant today?

  25. Vinny Burgoo says:

    Has it finished, then? Is that it?

    Ho hum. No nudity.

    A first?

    I enjoy performance art as much the next pervy old man but there’s got to be proper nudity somewhere for it to be proper performance art. Did anyone spot any?

  26. “On the other hand, aspiring to something that you don’t actually try to achieve, seems meaningless.”

    but its symbolic and makes you feel good

  27. “Given a finite amount of negotiating energy, it does seem strange to spend it on something that just won’t happen. A mechanism for fully retiring coal whilst still allowing development might have been a better goal..”

    Wins the thread.

    Lets see you could use 60B to build a fast train in california

    OR

    http://mwfrost.com/coal_retirement_plan/

  28. EOttawa says:

    Victor:

    I agree when you say “If the others are cooperative, that makes it easier to be cooperative yourself.”

    I think our federal Environment Minister is a quite a good negotiator, so I do have some level of optimism. Canada’s governments will be negotiating amongst themselves over the next 3 months and hopefully we can keep the pressure on.

  29. No paradigms seem to have been harmed for the making of this paper.

  30. I’ll believe the ‘legally binding’ means something when George Osborne reinstates the CCS research grant, and the FITS for solar + wind, and removes the tax breaks on squeezing every last drop of oil and gas out of UK rock strata.

  31. rustneversleeps says:

    I think the most interesting thing is that we went from a stated goal of “avoiding” 2C, to “well below” 2C with ambitions for 1.5C.

    Say what you will about feasibility – dog knows I have – but this leaves far, far less wiggle room for the INDCs to be credible/coherent/compliant in a post-Paris world.

    I would expect the lukewarmer brigade to double-down on the “low sensitivity” gambit, and the fossil fuel industry to continue the recent PR campaign promising their (BE)CCS-to-come-promised-land.

    Time to keep the sunshine shining on those two claims.

    Other than that, how do they stay relevant/credible post-Paris?

  32. rustneversleeps says:

    edit add: i.e. that was a very asymmetric shift in ambition/targets… and implications thereof

  33. bill shockley says:

    Richard Erskine,

    JFDI doesn’t make sense if you think governments can play a key and possibly essential role in cutting global emissions at the rate required. JFDI means if governments won’t do their sworn, NECESSARY duty, then OK, we’ll do the best we can without them even if there’s no chance it will be enough and in time.

    The danger that Paris may mimic Kyoto is heightened by the “guard rail” concept, which allows governments to promise future emission reductions rather than set up a framework that fosters rapid emissions reductions. Climate science does not define a safe guard rail; instead science indicates that atmospheric CO2 is already into the dangerous range, as shown by a group including world experts in the carbon cycle, paleoclimate and other relevant areas. [10]

    I do not suggest that Obama would get prompt agreement from the U.S. Senate for a Paris accord with a carbon fee. Acceptance likely would take a number of years, but if an international framework for common domestic carbon fees is set up (with border duties on products from nonparticipating nations), pressure to join would mount as climate impacts grow.
    http://www.huffingtonpost.com/dr-james-hansen/title-tk_1_b_8665400.html

    My guess is he is right to call a fraud a fraud. He is saying don’t imagine for a second that anything was done. Keep your foot on the gas. Bad metaphor. I’ll bet McKibben is listening.

  34. Leto says:

    Richard Erskine wrote…

    “I think that Hansen, as much as I respect him, has been outrageous in calling COP21 a fraud. . What would have happened if he had chaired the meeting? Hitting everyone over the head until they agree with a carbon tax, which he sets? I suspect the meeting would have ended in acrimony and the world would be in despair at no agreement.”

    But he didn’t chair the meeting, so judging his comment in that context is not appropriate.

    He is pricking people’s consciences from the sidelines, and I am glad someone is. Even if he is mistaken, and his judgement of COP21 is unfair, his voice at one end of the spectrum will help shift people’s sense of where the centre lies… That shift would appear to be in an appropriate direction as far as I can see. For too long the “moderate” position has been to move slowly towards soft painless emission reductions, deferring the hard work for future decades. The denialists have been able to frame the debate so that we are overly impressed when a politician simply acknowledges reality.

    And is he even wrong? The decisions and actions of the world’s governments on this issue have not been in proportion to the threat faced, and are still not, despite the improved rhetoric. The Australian government engaged in the all-round backslapping in Paris but pretty much intends to continue in a policy direction chosen by a denialist.

    My own view is that COP21 has been a fraud, but a much better fraud than I expected, and introducing 1.5 degrees as the new headline target is a fantastic development, because it will also shift people’s sense of where the centre lies, and remove wiggle room from politicians more interested in votes (and funding) now than coastlines and climate refugees in some distant future.

  35. Leto says:

    PS, I read Bill’s link to Hanson… I found Hansen’s comments quite calm and reasonable.

  36. Ethan Allen says:

    Oh, I don’t know, I kind of like a moving target.

    So just to keep people like Nic Lewis happy 😉 I’ll take the lowest bound of the lowest ECS estimate, even if it’s a negative number and even if it takes Earth’s surface temperature below 😦 absolute zero.

    In other words … doing nothing is not an option. 🙂

  37. izen says:

    The Draft treaty has the following features…
    It may be scientifically fraudulent because;=

    It contains enough aspirational caveats to provide loopholes. For the reluctant or completely insincere it has enough latitude for them to sign on as involved parties on the understanding that this is a token action, BAU can be continued with only a little action or change.
    (They may be correct about that. It is entirely possible this IS a token gesture)

    Instead of following the science and making emissions targets directly constrained by the cumulative carbon budget, it is an arbitrary collection of pledges by individual nation states ov varying sincerity, feasibility and plausibility. The result is ambiguous, total of emission reductions that have no relationship to the scientific constraint because nation-states have been allowed to retain their autonomy of choice about emission reductions.
    No scientifically credible limits, or penalties for exceeding them, have been implemented.

    The adoption of a 1.5degC goal for temperature rise looks farcical.
    In the total absence of any planned process to control emissions to meet such a target, and the obvious inadequacy of the pledges made to achieve a 2degC limit, never mind constraining the rise to 1.5degC, the aspirational goal looks dellusional AT BEST AND CYNICALLY DECEPTIVE AT WORST.

    It may be politically effective because;-

    It contains enough asperational caveats to provide loopholes. for the reluctant or completelty insincere it has enough latitude for them to sign on as involved parties on the understanding that this is a token action, BAU can be continued with only a little action or change.
    (They may be INcorrect about that. It is entierl7y possible that political pressure and the impact of events will make them move faster from BAU than they envisaged)

    Instead of following the science and making emissions atrgets directly constrained by the cumlative carbon budget, it is an arbitary collection of plaedges by individual nation states ov varying sicerity, frasability and plausability. The result is anambiguous total of emission reductions that have no relationship to the scientific constraint because nation-states have been allowed to retain their autonomy of choice about emission reductions.
    This avoids the existential impossibility of any nation-state having to surerender its sovereignty, its autonomy to make indepndent local decisions that is the sin qua non of the existence of such governance systems. Thereforts it engages political entities in an agreement with the potential to effect concerted action without the overt abdication of state autonomy.

    The adoption of a 1.5degC goal for temperature rise looks farcical.
    But in politicvs fictive aims are a long tried and tested stratergy. Often a goal or mission is declared where there is tacit aknowledgement that it is unrealistic. But the adoption of a goal beyiond reach can be used to spur greater effort to reach what IS achievable.

    There is one element of the adoption of the 1.5degC limit that illustrates this. With a 2 deg limit we are already half way there at ~1degC. But that leaves delayists the option of pointing out that it took a century for that rise, so it will be another century before we have to worry about another degree. this argument is prevalent over the issue of sea level rise. Because it has been less than a foot in the last 100 years, the attitude is that as we have coped with that, another foot or so in the next 100 years is no more problem…
    But a 1.5degC limit puts that line much closer. Anyone over 40 will have already experienced the amount of climate change that would put us over that limit. That magnitude of further change is within the time-scale of subjective imagination. It may be scientifically deceptive, but it is politically energising!

  38. pete,best says:

    I cant really see how 1.5c is possible when the thermal log of the oceans indicates that we are presently experiencing warming from the accumulated emissions of 30 years ago and at a rate of 0.2c increase per decade that means another 0.6c is already in the pipeline making 1.5c a done deal I thought.

  39. OPatrick says:

    Did anyone spot any?

    Your naked attempt to trivialise this process?

  40. bill shockley says:

    pete, I don’t know how well accepted your .2C per decade is, but assuming that’s what we’ll see, we will still be lowering global temps slowly once we get to zero emissions.

    Plus, there is the realistic scenario of CO2 drawdown economically through reforestation and agricultural soil management techniques that Hansen has estimated can be as large as 100GtC in the years 2030 – 2080.

    Hansen, a few years ago was saying 1C was possible this century after a modest overshoot. He’s since backed off to 1.5C.

  41. OPatrick says:

    I think that calling it a fraud is too much. It must be frustrating to believe that they really aren’t doing enough (and this may well be true) but that kind of terminology is counter productive and not wilding different to those who would dismiss this for different reasons.

    There seems to be a clear tactic, from people who clearly, and desperately, want this process to fail, to undermine any sense of positivity about the agreement by talking it down in any way they can. Whilst people like Hansen may be being consistent in their views, I don’t see that the negativity being expressed is either justified or constructive and feels to me like it is playing into the hands of people who are expressing this same negativity for polar opposite reasons. I don’t see any problem with keeping on reiterating that this is not enough or that there is a very real risk that some at least will not abide by their pledges, after all this is clearly stated in the document itself, but surely this can be done whilst recognising the genuine change in tone and ambition.

  42. bill shockley says:

    Here’s his scenarios which include the assumption of 100GtC drawdown from 2031 to 2080.

  43. Pete,
    I think that if atmospheric concentrations stay at 400ppm, or higher, then we will probably warm beyond 1.5C (or be close). However, if we can get net emissions to zero (or close to zero) before temperatures reach 1.5C, then we would probably stabilise temperatures. Also, as Bill is pointing out, some form of negative emissions (either through technology or land management) could help to further draw down atmospheric CO2. So, I think it is technically. However, as Zeke points out, the carbon budget that gives us a reasonable chance of limiting warming to 1.5C is low enough that we could use it within a decade. So, in reality, it may – almost certainly will – prove difficult, but it isn’t impossible.

  44. bill shockley says:

    Most people don’t realize how simple and effective a carbon fee/dividend can be. We got here because FF weren’t priced to include their externalities. Pricing for their externalities is how we get out of here.

    — Immediate results: where it’s been tried, emissions decline in the first year, even at modest tax rates.

    — Wealth redistributive.

    — Creates its own political will/staying power by being popular.

    — Easily and cheaply administered.

    — MUST be 100% (or more) revenue neutral

  45. pete,best says:

    And if a significant portion of the first world go vegetarian then we would resolve the issue a lot quicker but what’s the chance of that, not much, much like the no more than 400 ppmv co2 eqv.

    Meat is,responsible for 14% of co2 emissions. Buy an electro car wont solve the issue, its all a matter of lifestyle changes, we wont do it.

  46. Pete,
    Yes, I think that is a fair point and is – I think – what Kevin Anderson regularly highlights.

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  48. rustneversleeps says:

    ATTP, I don’t think that is the point (meat) that Kevin Anderson makes regarding agriculture.

    I think he is saying that since we are going to need agriculture, and there is nothing on the horizon that is going to plausibly eliminate all emissions at scale from basic things like all tilling or nitrogen fertilizer. Yes, there is also some unavoidable emissions from livestock too, but if we switched primarily to poultry and pork, say, (and switched from rice as a crop where feasible) we could eliminate a lot of methane emissions (but again not all).

    Given all the (not-really-so) radical changes that Anderson advocates for and has personally adopted (no flying, no car, small fridge, daily shopping for groceries, on and on), I find it very unlikely that his “unavoidable emissions from agriculture” includes “insatiable human need for Big Macs”. Nor have I ever heard him say anything like that.

    Also, you say “I think that if atmospheric concentrations stay at 400ppm, or higher, then we will probably warm beyond 1.5C (or be close).”

    Not that we *are* going to stay at 400ppm, but I think we would expect to get under 1.5C if that were to occur, particularly if the second part to what you said – “if we can get net emissions to zero (or close to zero) before temperatures reach 1.5C, then we would probably stabilise temperatures.” – were to occur. See, for example, the key takeaway chart from Matthews and Solomon, 2013. Irreversible Does Not Mean Unavoidable http://www.sciencemag.org/content/340/6131/438
    chart – http://www.skepticalscience.com//pics/29-Mar-139-35-18PM.jpg

    And, further, as you yourself have noted, Ricke and Caldeira, 2014, “Maximum warming occurs about one decade after a carbon dioxide emission”, suggests that were we to actually get emissions to net zero and stabilize (or even begin to drop) concentrations, we would see a peak warming in the near future, which at current rates would probably be well below 1.5C. Here was your write-up on that: https://andthentheresphysics.wordpress.com/2015/01/04/maximum-warming/

    Maybe I am missing something, but those are my understandings.

    Anyway, pretty theoretical stuff, because not likely going to happen that quickly or comprehensively.

  49. Pete Best says:

    Meat uses a lot more land than arable alone and needs water and there is a lot of waste, far more than humans produce. Its a very energy and resource intensive activity and co2 heavy

  50. rust,

    I don’t think that is the point (meat) that Kevin Anderson makes regarding agriculture.

    Thanks. My response to Pete wasn’t as clear as it should have been. I was simply referring to Kevin Anderson highlighting how we will probably need to change our lifestyles, not to the meat aspect specifically.

    Maybe I am missing something, but those are my understandings.

    What you describe is my understanding too. If we can get net emissions to zero (or close) before temperatures reach 1.5C, then we could stabilise below 1.5C.

  51. bill shockley says:

    I didn’t do a very good job with Hansen’s RCP-equivalent scenario images. In fact, I left out the money-shot image with temps. To correct that, here they are again, with some extra shading bars to make them more readable.

    In Fig. 9A he showed how the world could get back below 1C this century if we peaked emissions right away, starting in 2012, which is a realisitic scenario with a globally-adopted rising carbon fee beginning in that year plus 2 GtC/year drawdown in 2031 – 2080.

    Fig 9B shows what can be accomplished if we peak emissions starting in 2020 or 2030. If we get our shit together by 2020, then we can stay below 1.5C with relatively modest emissions reductions of 2%/year. If we wait 10 more years then we will require 5%/year reductions.

    All scenarios assume 2 GtC/year CO2 drawdown in the years 2031 – 2080. It would have been helpful if he had shown the same scenarios without the drawdown to emphasize what a tremendous advantage it is in keeping CO2 at safe levels this century. Pretty much a necessity, I believe.

    Assessing Dangerous Climate Change

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