Ken Fabian

I would like to believe we have that kind of battery technology in the near future and I can see it's heading in the right direction. I'm not convinced it is truly assured any time soon at the scales and relative costs needed, especially not without firm, appropriate energy policy applied with great conviction - or the absence of inappropriate energy policy applied with great conviction. Nor do I think massive growth of robotics can occur without adding it's own environmental and economic burdens; they may have some potential to tackle some difficult problems but too many of the most critical problems are not presenting themselves as profit making opportunities. The political fallout of ever greater loss of employment opportunities to automation might be ever greater support flowing to the kinds of populist political opportunism that prevents foresight and planning being applied in a thoughtful and far-sighted manner.

EdEarl, I think that without the low emissions energy technologies underpinning their production and use, robots will just add to rather than reduce the emissions problems. Automation/robotics will undoubtedly play a role in making those improved energy techologies at the scales needed but the emissions problem will only be solved by addressing the emissions problem, not by cleaning up the mess it makes afterwards.

Unless sequestering CO2 is a low cost consequence of profitable kelp farming for other reasons it's no more than one more thought bubble. There may be sound reasons for activities that increase biosequestration - increased soil carbon, re-forestation - but I can't see how they can put enough Carbon back into sinks and stores to replace what clearing and agriculture took out let alone all the extra from excessive fossil fuel burning. That we are failing to do so in a prompt and adequate manner doesn't alter the clear imperative to drastically reduce that rate of burning and if we continue to fail no amount of kelp farming or biochar will prevent serious and irreversible climate change.

Seeking to attribute short term variability to specific climate processes - and 15 years is short term - is reasonable. (The largest component of that variability has been ENSO, an ocean oscillation between warm water accumulating at and near the surface that warms the air masses over it and warm surface water being forced deeper and being displaced by upwelling colder water that cools the atmosphere). Calling it a pause in the rate of global warming is not so reasonable; ocean heat content which more directly measures the underlying changes from AGW continued to rise during that period, without any such pause. Whilst scientists may have attempted to explain what they mean by "pause" (a period of surface temperature variability) it was wrongly interpreted as some kind of admission that warming stopped during this period. With climate science so politicised it's unfortunate that choice of terminology can be so significant. Calling it a "pause" was a mistake and helped perpetuate the illusion that GHG driven AGW is something erratic, that comes and goes rather than being a persistent underlying influence which is overlayed by natural and unnatural variability. Temperatures adjusted for known influence of El Nino Southern Oscillation (with no change to long term trend) - Ocean Heat Content - Global warming didn't pause or stop at all.

I think it's a far greater problem that so many people who are educated and intelligent choose where to stand on climate and emissions according to criteria that have nothing to do with the validity of the science based advice. That so many in positions of power and influence lend respectability to denial of the problem's seriousness and to opposition appropriate policy responses to the expert advice is a more profound failure of trust and responsibility than "ordinary" people making the best of their own circumstances and opportunities in ignorance of the wider consequences. I suspect a great many of those "leaders" are aware of the importance, but that it is less immediately important to them and the organisations they lead than avoiding the burden of costs and complications of having to commit to a society wide remake of how we make and use energy.

It would be good if Patti would follow up her opinion that global warming is merely opinion with something. Preferably something more than more opinion. That she (I'm assuming she) has started with a provocative statement doesn't concern me - some good discussions start that way - but some reasons why she holds that view would go some way to directing the discussion into realms of greater relevancy. Sounds suggestive of a philosophical "how can science know what it knows" objection but I don't know.

Haven't we already had 1 degree of warming and not yet reached a doubling of CO2? And the transient response - near term change we are experiencing - is going to be short of the ultimate equilibrium response - long term change.

If fossil fuels had been scarce resources would we have had an industrial revolution? Not as it played out historically but I suspect we would still have achieved a lot. We may have valued their products - and the alternatives like steel making from charcoal - more, without the option of taking them for granted and whilst perhaps the consumer economy with it's growth in prosperity as well as extravagant wastefulness may have been harder to achieve economic growth and innovation would not have stopped. Would we truly be less capable of lifting ourselves out of poverty or would there have been earlier and greater incentives to manage our economic activities within the bounds imposed? Greater use of wind, hydro and solar seems obvious but forest farming - for timber, firewood, blacksmith's charcoal, chemical feedstocks - less obvious from our perspective, could have looked crucial and become more important. All these technologies would have been economically important and subject to ongoing innovation at a greater rate because of it. Still, the impacts would likely play out in more than just the technologies we rely on - pace and type of social change, governance, warfare, academic and ideological thinking...

The simplest and most compelling explanation for how the Egyptians moved blocks of stone I have come across is lashing crescent shaped timbers around the blocks and rolling them. The doco I saw claimed such pieces - flat on one side (chord of a circle) and a section of circle circumference on the other and with a deep slot carved around it for ropes - were found in burial chambers but their function was not recognised. 8 such pieces would effectively lash two wheels around each block which could be rolled with relatively ease and would be reusable for similar sized blocks. I think a variant of this with 4 pieces that cradle the block rather than 8 was excavated. Even going up ramps would be relatively uncomplicated - I'd hesitate to say "easy" - I'd probably wrap ropes around and have teams pull, with people with blocking wedges keeping pace behind. Even so I doubt only one method was in use - depending on what size, shape and fragility of what needed to be moved, and the terrain, other methods probably had their place.

This isn't entirely clear to me but.. It sounds like a distrust of uncertain or incomplete knowledge - with science based knowledge acknowledged to be incomplete and retaining degrees of uncertainty. Yet alternatives like religious beliefs might claim absolute certainty and completeness whilst rejecting the requirement for evidence of that being so - and may include the dogmatic rejection of contrary evidence because being contrary is taken as evidence that it is false. Whilst uncertainty allows for knowledge to be tested, changed and improved, absolute certainty resists improvement. The amount of uncertainty within science based knowledge can vary widely, from so near to certain as to be for practical purposes indistinguishable from it to very uncertain hypotheses that can exist as allowable possibilities within the bounds of what is known yet to be confirmed or rejected; what may be unique to science is embracing that uncertainty and making it into motivation to further test and refine knowledge. I'm wary of any absolute definitions of what science is or how it is undertaken; I suspect even those are subject to change in the face of changing methodologies and human needs. Even so there are some common, unifying threads including accuracy of observation, measurement and record keeping, the requirement for reasoning to be logical, the making available of data and reasoning to peers for critique, review and replication.

To what extent is "But I didn't know" acceptable when reports and advice from the leading science advisory bodies - like NAS or Royal Society - is consistent? I have begun to suspect the main value of the handful of credentialed climate scientists who reject the science of their peers isn't to persuade the public it is to provide a reasonable seeming excuse for those who should know better and hold positions of trust and responsibility to assist in avoidance of that responsibility and potential liability. Of course having elected governments - politicians being effectively immune from legal redress no matter how irresponsible - who are sympathetic to those seeking to avoid the burden of climate responsibility can short circuit any attempts to use the legal system to enforce the "acting in good faith" and other requirements.

Waitforufo - it sounds like you have a combination of exaggerated economic fear of fixing the climate problem and understated economic fear of not fixing the climate problem. The studies like Stern and Garnaut lend support to the view - supported by climate science - that there is much more to fear from the latter. Like borrowing big and living high ("being Great again"), the economic benefits of avoiding a transition to low emissions come with a heavy debt that is going to be paid; I'm not sure it's anything to be proud of that most of that will be paid by others ("putting our nation (or our generations?) first"), most of whom will have gotten little or none of the benefits. That debt is going to be paid out irreplaceable natural capital - upon which essential economic activities depend - constraining future economic potential in ways that are irreversible.

Whether it's dodging significant questions they would prefer not to answer - and on climate that's what our conservative Australian politicians do as standard - or those diverting accusations that shift the focus away, being misleading and deceptive is a significant political skill. It doesn't benefit those who lie the most, but those who lie - or fail to tell the truth - selectively and intelligently. For climate that can be building perceptions of it being of low significance, or low priority or that it is more difficult and economically damaging to address (using alarmist economic fear) than it actually is. I suppose sometimes they believe their own BS - ie they are failing the great trust and responsibility of their office by failing to be well informed and give proper consideration of expert advice. Ordinary citizen may have a kind of right to remain uninformed or misinformed but those who hold offices of trust, responsibility and power ordinarily do not. Politicians appear to have considerable immunity from being held legally accountable when harms arise that they could or should have been aware of - and they failed to give credence to in their decisions. They are not usually held legally accountable, rather, they are accountable to public opinion via election processes; but public opinion is mutable, influenced in ways that can have little relationship to the best available expert advice on any particular issue. News service are not strongly bound either and can and do present biased, misleading and deceptive information, often engaging in the influencing of public opinion in partisan rather than impartial ways. Politicians both reflect and influence public opinion; to seek to mislead and misinform the public about an ongoing issue the expert advice is consistent in saying is profoundly important to long term prosperity and security is, in my opinion, a very serious breach of trust. Whether they do so knowingly or because they have failed to - or are incapable of - comprehending the abundant advice available they are letting us all down by preventing the preventative measures the climate problem - which is effectively irreversible - from being addressed effectively.

I suspect a complex construction like a 3D manufacturing facility require a lot of components that can't be made using 3D manufacturing. As will many products such a factory might be set up to produce. And will that type of manufacturing successfully compete with other production methods for the components that it can make? Injection moulding and extrusion for example, will probably be able to deliver parts cheaper for some time yet - and those techniques are still open to innovative improvements that could still outpace improvements in 3D printing. One application that I do find promising is in some kinds of building construction in concrete - which may be able to use less of it and without steel reinforcement by employing clever, internally strong "honeycomb" structures.

The Australian experience is of politicians and political organisations making in-principle statements of acceptance of climate science and the importance of emissions reduction policy whilst their actions say they don't accept it at all. In some ways hiding opposition and obstruction behind a facade of accepting and supporting climate action - given journalists and media show little interest in calling them to account - appears to allow them to neatly sidestep closer examination of where they really stand and what their energy policy goals really are. Energy supply reliability as an unassailable priority and excuse has become the preferred angle for attacking Renewable Energy and supporting fossil fuels. Policy to make energy networks RE ready, despite the near certainty that it will continue to grow rapidly with or without policy support, is not part of that agenda. I'm not sure which is worse for holding back effective policy - overt or covert denial. Being misleading and deceptive may be an essential skill and requirement for political success - those who don't or won't are fighting with hands tied and are headed for defeat. Whilst I think truth should be valued I suspect that either way there will be political players who will be open about their climate science denial but still include being misleading and deceptive in their MO in order to achieve their goals. So I will not be surprised if there are some effectively meaningless concessions to climate action from a Trump administration finding outright denial isn't working for them. Meaningful ones? No. Even those who claim to support strong climate action appear to struggle with meaningful policy. Whilst support for RE has, in my view, tended to be done as appeasement of (Political Environmentalist led or at least framed by media that way) community concern - it's transmutation into credible low emissions option being totally unexpected - I do wonder if rhetoric about nuclear from climate action obstructive conservatives serves as a different kind of appeasement, for those conservatives who do accept the science; even if "we could fix the problem easy if only those Environmentalists would let us" statements contain no actual commitment to either climate policy or nuclear to displace fossil fuels they probably reinforce the political divide that enables successful climate action obstruction by muting such concerns within and limiting defections of climate policy "traitors".

I suspect that as President, Mr Trump can choose not to accept the advice put before him. Where I live it's a bit different but as I understand it he appoints the department heads of his choosing so those presenting unwanted advice - such as that climate change is real, serious and will increasingly have economic and global security implications - can be replaced. I'm not sure to what extent those in such positions are legally bound to present the reports and advice from their department, but there are ways and means - budgetary, administrative and legislative - to render many unwanted advisory bodies toothless. US Intelligence and Military communities may be more difficult to directly influence that way and as I understand it, they do take climate change seriously; they may prove persuasive in expressing that view in the face of reluctance of a President to accept it. It does seem like elected politicians have extraordinary immunity from the kinds of legal requirements to take expert advice into consideration in their decisions. Even so I would expect a President would have the means to order backgrounding investigations or demand reports from relevant agencies about the veracity of something like climate science; the kind of widespread conspiring that the caricature version of climate as hoax would necessitate would surely be accompanied by consistent trails of evidence and whilst absence of evidence may not be evidence of absence, the scale of such a conspiracy combined with the investigative capabilities available is very suggestive that such lack of evidence shows an absence of a climate science conspiracy. I'm not so sure it works the other way - as another commenter above suggests, climate science denial looks a lot more like a working conspiracy than climate science does and investigation of those links could be very revealing.

EdEarl, I think exploitation of space resources requires a lot, lot more than better automation with AI - and automation that can mine, refine, manufacture and replicate the most advanced technologies, including itself, in such a hostile environment are a long way off. Accessible resources are either deep in gravity wells or so far out from the sun that nuclear power is the only viable energy option. Fissionable ores in concentrations that are usable tend to arise as a consequence of hydrogeothermal processes and are going to be scarce in asteroids - the tech as well as fuel for that will be an Earth export for a long time to come. Fusion that is reliable and usable remains a significant technological challenge, let alone fusion that an automated, self assembling factory can produce fusion power plants on demand. And your faith in the enduring ability of the US military industrial complex to drive the innovation that successful, economically viable exploitation of space resources requires could well end up looking like wishful thinking if not hubris in a changing world well on the way to ecological disaster. I think if we fail to rise to the near term challenges of living sustainably within the limits of world as resource rich as our own we will fail to lay the foundations for successfully extending human civilisation beyond Earth. Rather than the resources of space being what saves civilisation on Earth, an enduring, prosperous and well managed global economy on Earth is the only thing that can realise hopes and dreams of colonising space. And I think that we are running out of time whilst collectively refusing to face our near term, Earthly problems head on with our eyes open.

That we are creating and experiencing a cumulative ecological disaster appears well documented and that will impact humanity, but humans remain tough and resourceful so it's not likely to lead to human extinction. EdEarl, I'm not convinced about Post Scarcity and even less convinced Space can provide it - not without some extraordinary technological advances. Whilst improved technologies can squeeze more from finite resources on a finite world they remain finite - and the technologies themselves rely upon can be highly dependent on availability, at reasonable cost, of those finite resources in turn, but there are high costs involved in exploiting resources that are in abundance in space. I would say extreme costs; it takes a lot of technological capital to become independent of natural systems here on Earth and space resources currently exceed the capabilities of the most technologically advanced economies on Earth to exploit even in small ways; that may change but I suspect a continuing, healthy global economy down here on Earth is essential for any serious attempts to do - and I don't think we have ever had, or are likely to achieve a healthy, sustainable global economy. Looks a lot like we are already overshooting boundaries in ways that have serious, irrevocable consequences. My own view is there is a very large - excessively large - pre-investment in hypothetical, difficult to achieve and unproven technologies needed to do anything at scale in space - unlike past colonisations that were done with existing, economically proven and widely available technologies, often using the leftover, destined for scrap stuff on shoestring budgets by the marginalised and desperate. With destinations that were rich in readily exploitable resources. Even though more food than ever is grown in controlled, technology dependent environments most global food supply is still reliant on soils made but no longer sustained by natural processes, including biological ones that are interupted by deforestation and conversion to agriculture, on water reliably falling from the sky, on climatic conditions that remain within usable bounds. Failure of those nature dependent systems will tend to destabilise nations and economies and desperate people can be less inclined to engage productively, with long range forethought in building the kinds of sustainable systems that can support those high tech solutions.

I would say it's extremely unlikely we can make this planet uninhabitable without some serious intent to do so involved. With climate change I think it's not a matter of going past the point of no return, but that there is a progression of tipping points that could be seen as points of no return, each with consequences that are effectively irreversible; a lot of change is already unstoppable but we can still make more.

I'm not convinced Mutually Assured Destruction was ever an intrinsically stable deterrence - and my understanding is there were some close calls besides the Cuban Missile Crisis. Not that it wasn't a real deterrence, but it doesn't apply so well when there is confidence that the enemy will be unable to retaliate after extreme force is used. Between well armed protagonists even a small possibility of a retaliatory strike is likely to remain as a serious doubt, but when the enemy is seen to be incapable of retaliation the confidence of a Commander in Chief that a nuclear strike can win a war without endangering his/her own forces is going to be stronger. Clearly there are other considerations that have acted as restraints or we would have seen them used before now even though I doubt there is any innate abhorrence of such extreme force by military commanders. There can be international as well as internal condemnation and retaliation - not necessarily nuclear or even 'conventional' military reprisal - to be feared and even small nukes applied with precision are going to have collateral damage; I've often wondered if the rise of Islamic terrorism is in large part a consequence of repeated interventions in their nations by outsiders employing what appeared to be overwhelming force, by superior military forces that saw themselves as beyond the reach of effective retaliation. Short of genocide there will always be survivors, most of whom had no say in the triggering events, who can be left with enduring, unreasoning and unyielding hatred - which can be exploited along with religious differences by extremist organisations.

I wonder if solar technology has been changing too rapidly for solar roofing to take off in a large way - a big commitment to a production facility when PV costs for competing "add-on" systems can halve in a few years can be risky. That the PV technology still has so much potential for improvement may see this kind of integration deferred but I think we will eventually see some form that's an enduring winner, superior enough that it becomes the standard that is emulated . Others have tried and many have fallen by the wayside but I think it's inevitable that it does get successfully integrated into building materials - roofing of course, but also, depending on how cheap the PV components and integration can get, wall cladding and paving. It's functional life expectancy is a crucial element. Musk apparently is claiming 50 years which, if this can be relied on, going to change the economics; most solar panels can be expected to last 20-30 years and aren't functional roofing. Ultimately it may become a standard 'sweetener' for roofing products. The complimentary energy storage systems are highly significant to solar fitted homes and businesses and to the whole solar PV market - what Tesla and others manage there is probably more worth watching than solar roof tiles.

I suspect that as long as some nations feel entitled and even obliged to keep them as their weapon of last resort they will be sought by others to be theirs. They do seem to be highly prized status objects for a lot of nations, even ones with well equipped "conventional" militaries. Given the prevalence of "maximum force" style of military logic - more prevalent I suspect than Sun Tzu inspired "winning without engaging the enemy in battle" style - it's difficult to believe someone won't use them. Perhaps when faced with losing a war by other means. It chills me to know that Kennedy was being advised to use them - by people who really should have known better - during the Cuban crisis; I'm not convinced some other US Presidents and Presidential hopefuls would have been able to say no. I do think it's hubris to think these things can't be developed independently, using novel pathways, by nations with a solid foundation of civilian nuclear technologies.

HB of CJ certainly ticks many of the standard boxes when it comes to rejecting what science tells us about messing with the concentrations of greenhouse gases of our atmosphere. Follow the money? I think the bedrock foundation of high level mainstream political support for climate science denial and obstruction is about avoiding the perceived economic costs that flow from acceptance of climate responsibility. To what extent politics leads or follows is probably irrelevant but I think the most politically influential sector of modern nations is commerce and industry and the larger parts of those have decided where they stand based on how it affects their bottom lines in the near term; that desire to avoid the burden of costs by rejecting responsibility flows upwards from affected businesses as political lobbying, downward to their workforce as fears about job security and further downward into the gutters of PR, advertising, tankthink and other forms of ethics deficient opinion for hire. Economic Alarmism tends to trump Environmental concerns - except that climate change is definitely a serious economic issue that will affect prosperity and international security on unprecedented scales. But the latter concerns are about timescales of multi-decades, centuries and millennia whereas the former impacts people and their choices much more immediately. It doesn't appear to much matter that solutions are within our reach and are unlikely to result in widespread economic disaster - for those sectors that are most directly affected, the burden of climate responsibility is indeed a financial disaster. Yet, unlike the more usual case for an activity that is shown to have serious harmful consequences, the opportunities for (unofficial) amnesty for past actions and an orderly transition that allows major investors to avoid major losses and liabilities are intrinsic to the policy responses proposed. Science is conducted within institutions, conventions and practices that are bound by professional ethical standards - practices that are reinforced by accurate and open record keeping that allows and encourages independent expert review and critique. And then there are institutions like the National Academy of Sciences and Royal Society that call on the very best of scientific expertise to provide independent advice to policy makers.

I suppose we should add safe deconstruction and disposal to the essential project specifications.

I think this kind of engineering needs to have large safety margins built into it - so if the currently available materials are only just sufficient for the structure to support itself that won't be nearly good enough. I doubt static charge or heat conduction are likely to be real problems. I don't know if carbon nano-tubes are tolerant of heat and cold - certainly they are good heat conductors - but whatever is proposed needs to consider the heat differences between full sun and Earth shadow which are, by ordinary standards, extreme. Exceptional heat conductivity may be an asset. Vacuum diffusion and erosion from charged particles may be issues. Weather will affect the parts in the lower atmosphere and add sideways stresses that may be severe during extreme weather events. It may be that there won't be any solid materials good enough, but perhaps some kind of chained electromagnets that achieve greater tension than a physical material? (I don't even know if that is even theoretically possible - probably not, if the electromagnets themselves get torn apart by the tension!) That then introduces a whole new set of problems, including power supply that absolutely cannot ever fail. Then there is the actual construction and installation - during which there may be additional stresses, such as if the bottom end were dropped down (flown?) from orbit and anchored. As a thought experiment it's interesting. As an engineering project it's not feasible and it may well prove to be forever unachievable - unless we see some extraordinary technological advances of course. And I suspect that technological advancement, despite the achievements I've seen in my nearing 60 years, ultimately will approach physical limits that aren't going to be amenable to techological workarounds or allow exceptions.