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Can we fix global warming?

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Scientific studies have determined that current technology is sufficient to reduce greenhouse gas emissions enough to avoid dangerous climate change.

Climate Myth...

It's too hard

"The fact is that there is no one in the world who can explain how we could cut our emissions by four fifths without shutting down virtually all our existing economy. What carries this even further into the higher realms of lunacy is that such a Quixotic gesture would do nothing to halt the world’s fast-rising CO2 emissions, already up 40 per cent since 1990. There is no way for us to prevent the world’s CO2 emissions from doubling by 2100" (Christopher Booker)

In order to avoid dangerous global warming, we need to reduce global greenhouse gas (GHG) emissions by about 50% by the year 2050.  Skeptics often make the argument that we simply don't have the technology necessary to reduce emissions this much, this quickly.

Pacala and Socolow (2004) investigated this claim by examining the various technologies available to reduce GHG emissions.  Every technology they examined "has passed beyond the laboratory bench and demonstration project; many are already implemented somewhere at full industrial scale."  The study used the concept of a "stabilization wedge", in which "a wedge represents an activity that reduces emissions to the atmosphere by a certain amount. The study identifies 15 current options which could be scaled up to produce at least one wedge:

  1. Improved fuel economy

  2. Reduced reliance on cars

  3. More efficient buildings

  4. Improved power plant efficiency

  5. Substituting natural gas for coal

  6. Storage of carbon captured in power plants

  7. Storage of carbon captured in hydrogen plants

  8. Storage of carbon captured in synthetic fuels plants

  9. Nuclear power

  10. Wind power

  11. Solar photovoltaic power

  12. Renewable hydrogen

  13. Biofuels

  14. Forest management

  15. Agricultural soils management

This is not an exhaustive list, and there are other possible wedges, such as other renewable energy technologies they did not consider.   The study notes that "Every one of these options is already implemented at an industrial scale and could be scaled up further over 50 years to provide at least one wedge."  Implementing somewhere between 7 and 14 wedges would be necessary to avoid dangerous climate change.

The bottom line is that while achieving the necessary GHG emissions reductions and stabilization wedges will be difficult, it is possible.  And there are many solutions and combinations of wedges to choose from.

Last updated on 8 November 2010 by dana1981.

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Comments 26 to 50 out of 73:

  1. I've just read two articles about humanity's future problems. Now they aren't journal articles, but the author (1) Albert Bartlett has written many peer reviewed articles on over population and (2) Andrew Charlton, is an academic

    To a first approximation Bartlett states that 'the magnitude of the effect of humans in producing global climate change is proportional to the product of the size of the global population P and the average percapita annual consumption of resources, A
    the total annual consumption of resources (tons per year). 

    He argues that we must reduce both P and A simultaneously and rapidly throughout the world, and that there is no such thing as sustainable growth (the way we generally define it that is).

    The second author I just read, was a quartily essary by Andrew Charlton (2), an advisor to the Australian Government at the Copenhagen Summit. He basically makes the case that as there are 1 billion rich people and 6 billion poor people. He quotes Saul Griffith, who in his study found that in order to reach the 2 degree mark would require the roll out of 13 Terrawatts globally over the nest 25 years.

    To put that in perspective 2 terawatts of solar PVs, he calculates would reuire installing 100 square metres of solar cells every second for the next 25 years or 77,700km² of mirrors. (Tasmania is 68,401km²).

    Basically, current technology cannot cut it. 

    Forgive my long post, but the question is, shouldn't the issue of population be looked at as cause in part of emissions? I have met my fair share of 'Libertarian' people who actually don't even believe there is such a thing as overpopulation. 

    And, am I correct in assuming we need a WW2 scale change in economies to actually achieve any emission reductions?

    Is this something SkS could look out?

    The only way I see the way across the line is engaging with developing nations more than ever helping them get access to cheap clean energy.


    (2)   (*)

    (*) a free sample can be found on Google Books



  2. yocta @26:

    1)  Bartlett's equation excludes an important variable, I, or the Emissions Intensity of production.  Total emissions are equal to Population times per capita production times the emissions for a given level of production (P x A x I).  Given suitable changes in these values, the product can fall even though some values continue to rise.  In particular, if I falls towards zero, P x A can increase arbitrarilly consistent with a net decline in emissions. There are other constraints on population and productivity such that it is likely that we need to limit population growth and growth in per capita productivity (and hence consumption) cannot be very large; but a determination to reduce GHG emissions in no way commits us to reducing either.

    2) Charlton's argument simply tries to impress you with large numbers without context.  In context, 77 thousand km2 of solar panels, or 77 billion square meters of solar panels can be installed by each member of the current population installing 77.7 square meters of solar panels over a period of 25 years.  Frankly, I could knock of my 77.7 square meters in a week.

    To put that into more context, PV installation per annum is more than doubling world wide every year.  Lets assume that falls of to an average effective growth of installations to 30% over 25 years.  In that case, in the 25th year, 22.6 terrawatts will be installed per annum.

    3)  On current evidence it will not require a WW2 change in economies to combat climate change.  In fact, if we get serious about it, the cost is likely to be about 1% of GDP, ie, significantly less than the US' peace time military budget.  

  3. Tom Curtis @27:
    Thanks for the reply.

    A lot to think about. I would agree that looking more into the numbers of things is important, however the 77.7 square metres per week I feel is quite significant. Also that will only account for 2tW. There would be another 13tW to go.

    According to the International Energy Outlook [1] the future of energy has it growing by ~50% by the year 2035. Projected oil use increases. Projected fracking from natural gas reservoirs also increases.

    More of a comment really, but I don't share your optimism that it would only cost 1% of the US GDP. There are so many countries with their own competing interests, and, if history shows Economy always beats the Environment.  Coal usage [2] shows absolutely no sign of slowing down, especially in the developing world.

    If the effects from Cook et al., (2013)  recent study still shows from the usual crowds is denial, denial, denial. The often misquoted Daniel Botkin on how it will take a natural disaster or two to get people really talking, Results from the Yale Climate Change Communication Project [3] showing that a cold season is enough for people to think Climate Change is not happening, again reinforces this view.

    World population and energy use per person I think will be the elephant in the room. I would agree that Bartlett's equation does exclude the Emissions Intensity. Thankyou for that. 

    I am still staggered by the level of denial I meet on any news article, blog, or YouTube video of people still not understanding anything. 

    This reads more of a rant than anything constructive. I wish I could share your optimism. Myself I work in the energy sector trying to green things (or at least light brown) them up but at times I feel like Sisyphus. If you or anyone could direct me to any readiing material that can show a more optimisic world view I would be very appreciative.




  4. I would like to get you guys' opinions on this: It seems it is going to spawn a new meme that goes something like, "NAS says renewable subsidies don't work!"

  5. Well I am not a fan of any kind of subsidy. Forget subsidies renewable whatever, but more importantly stop subsidizing FF. However, seeing as the link is Fox News and headline looks like it meant to be attack on government, I'd say read the actual report instead. The substantial conclusion of that report was that "Finally, many studies have found that the most reliable and efficient way to achieve given climate-change objectives is to use direct tax or regulatory policies that create a market price for CO2 and other greenhouse gas emissions" . Maybe I missed that bit in the Fox take on that? I would strongly agree and I hope after reading the report that Fox readers would urge your president to implement that final recommendation.

  6. davidnewell at 13:13 PM on 29 May, 2014
    As more and more evidence accumulates in regard to the looming catastrophe, more serious consideration may be given to ways to counter at least the rate of increase, so that more time is available to employ other methods, and educate "the masses".

    Somewhere here someone took some "shots" at the technique found at


    mumbling a dismissive comment relating to the amount of CO2 dissolved in the Gulf Stream, or something.. Totally non-bearing on the proposal.


    I propose to defend the matter, thru simplicity.l. Many here may find "fault",

    but it's hard to argue against this..


    I propose a "new measurement" of alkalinity.
    Maybe it's NOT new, but it's new to me, and facile for raising my point.

    Total Alkalinity, volume, (vs. CO2) = volume of pure CO2 adsorbed / volume of solid substrate

    Abbreviated TA(sub)v or TAv, it can be in any dimensional system,
    as long as they are "in common". ( of course)

    My laboratory measurements were in CC.

    Ranges of TAv for surface alkali soils ranged between about 2 1/2 to over 3.

    (there are speculative reasons to think that lower levels will be more reactive..)

    I presently cannot find this (following) calculation, so anyone of interest can do so.

    Given the elongated inverted pyramid approximation of (say) the Black Lake Desert,

    which is about 25 miles long by 10 miles wide..

    Assume that it is a rectangular box 1 mile deep.

    Given a conservative TAv of 2.5, what is the weight of CO2 in tonnes possible if all the material was reacted.???????

    After that is derived, then we can see if further consideration of the other objections may be warranted.


    Lets see: 22.4 liters^ of CO2 = 1 mole wt of CO2, in grams, at STP.

    formula wt = 44.grams/ mole


    According to my trusty HP-55, which is still running after all these years,

    under consideration is 25X10X1, which is 250 cu miles of "dirt",

    which can ultimately sequester (with a TAv of 2.5), 625 cu miles of CO2.

    1 cubic mile =4.16818183 × 10^15 cubic centimeters
    625 " = 2.605113641 x 10 ^18 "
    or 2.605113641 x 10 ^15 liters.

    or (changing decimal pt) 26.05113641 x 10 ^17 liters,
    which, when divided by 22.4 liters, = 1.2 X 10^17 moles of CO2,
    or, multiplying by the mole weight of CO2, 44,
    equals ~5 X 10 ^ 18 grams ,
    or 5 X 10^12 tonnes.

    Anyone who used an HP55 in college is old as the hills,
    OVER the hill,
    and probably missing a screw, as well..

    Please point out my errors, other than those which are simple approximations.


    All that is needed, urgently, is to employ a technique
    which reduces the rate of increase in circulating CO2,
    while "other measures" take effect. If we can take 5 billion tonnes
    OUT of the air, per year, we "MIGHT" have a chance.

    Pumping costs be damned!
    AT the very LEAST civilization is "under threat" by our combined ignorance.
    (This "rant" is more "refined" at, so I'l discontinue it,

    For far less than Gov Moonbeam's favorite projects of continuing stupidity,
    ie the "twin tunnels" under the Delta, and/or the "Train to Nowhere",
    we could implement this plan,
    (side issue)
    produce a hell of a lot of clouds going dowwind.

    It may be noted that many of the playas (the above is just an example, although one of the larger playas, to be sure..) are "saline" in nature, and are "wet" at some depth under the surface. Maintaining conditions for bicarbonate stability (dampness) is not difficult.
    Thank you for your time.

    David Newell


  7. Perhaps someone would deign to advise my questing mind as to why it is that discourse about this possible (at least partial) answer to the CO2 problem cannot be elicited?

    Yes, pumping ocean water over a 6,000 foot "head" is far from trivial: but "It's all downhill from there.." 

    thank you.

  8. Interesting idea. The size of the deep ocean reservoir is big enough that it could buy us a few decades.

    Probably the cheapest method of doing it would be by heating deep ocean water to make it rise rather than pumping e.g. by dumping thousands of unshielded breeder reactor cores off the side of a ship.

    How many would it take? No idea, but my first wild-assed guess is that it is going to be at least thousands of times the power output of the human race.

  9. David Newell, response here.

  10. Kevin C @33, pumping deep ocean water to the surface will in fact draw down excess CO2, but only by limiting the extent to which the ocean will further draw down CO2 once we stop pumping CO2 into the atmosphere.  It does rapidly now what the ocean will do gradually over the next several hundred years.  That may be a net gain overall.  However, equilibriating the deep ocean will only draw CO2 concentrations down to 25-30% of total emissions (Archer), or to 45 to 55% of the net increase to a given date.  I have severe doubts as to how economical this method of "carbon sequestration" would be.  Essentially you need to produce enough waste heat to generate current flows several times larger than that of the overturning circulation to be effective.

  11. As a general observation about sequestration technologies, it is important to ensure that the perfect doesn't become the enemy of the good. Sequestration techniques don't need to provide 'permanent' storage. Just storage for long enough to blunt the sharp edge of the impacts and allow slower natural sequestration methods to work.

    As with all these things it comes down to scale and energy. What scale of infrastructure do we need and how much energy will it take?

    Storing carbon as CO2 in something like Carbon Capture & Storage schemes requires huge infrastructure and some energy but at least we don't need the energy involved in changing the chemistry of what we are storing.

    Other approaches might convert CO2 into some more inert form such as carbonate rocks or something giving potentially better sequestration but essentially there is a huge energy cost for the chemistry involved. This would be at least partially reversing the energetics of the original combustion of the fossil fuels.

    As a general principal we should strive to harness the natural energy flows available within the climate system itself to aid us in this.

    One area that I have always thought was ripe for some 'bright spark in a white lab coat' was how to kill two birds with one stone.

    A major form of geoengineering being considered is injecting aerosols into the atmosphere to provide artificial cooling - there are companies looking at how to do this injection right now.

    This opens up a possibility. Vast quantities of extremely small particles of 'something' injected into the air. So an absolutely enormous surface area available for a potential chemical reaction 'of some sort'. The CO2 we want to remove is located right next-door to these particles.

    And some really nifty other resources that could contribute to some clever chemical reactions - Hydrogen, Oxygen, Nitrogen.

    And the secret ingredient - energy - to drive any reactions. Its called sunlight. Really there is a wonderful chemical factory up there waiting for us to employ it.

    This chemistry needs to do several things:

    • Capture carbon in a form that can be returned to the surface, probably in precipitation and ultimately drained to the ocean.
    • Be sufficiently chemically stable that it doesn't re-enter the short-term carbon-cycle and just get outgassed from the ocean again. It needs to stay sequestered from the carbon cycle for many decades if not a  century or two.
    • It cannot be (unduly) damaging to the environment, including contributing to Ocean Acidification. No point sequestering carbon if it kills off forests, pteropods or moles for example.
    • It cannot be (unduly) damaging to human health. A carbon sequestration technique that increased deaths from Asthma 100 fold for example is probably a non-starter.

    The basic chemistry of CO2/H2O -> Carbonic Acid -> Weathering cycle -> Carbonates seems a simplistic approach to this that probably doesn't work or someone would have thought of it already.

    But surely there is some other answer in the chemists toolbox. After all this is carbon we are talking about. I.e, Organic Chemistry, i.e. gazillions of compounds and reactions.

    The surface area of any volume of aerosols that we inject into the atmosphere constitutes a vast and precious resource.

    But I'm no chemist so I have no idea what this chemistry might be. :-(

  12. I don't know how mods have not yet lost patience with Jetfuel. I read only the first few lines of this last post and already found "an article that I read" without reference to said article. That's followed by rethoric so pityful it's normally found in electoral bullsh&$t fests: "sequestration killing jobs by the thousands." Really? Where is the evidence that carbon sequestration (a method not widely implemented on an industrial scale) is "killing" jobs by the thousands? I did not even bother reading the rest, the value to be expected of it was clearly announced by the opening statements. I'm underwhelmed.


    [PS] Indeed. jetfuel continues with sloganeering, posting misinformation and continuing to state conclusion based on cherry-pciking despite this being pointed out. Jetfuel has shown no interest in engaging with science when commentators have pointed out issues out. Continued violations of comments policy have been noted.

  13. jetfuel.

    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 or off-topic posts. 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.


  14. It may be noted that the dialogue in regard to the premise I have advanced above has been moved to


    Perhaps I will become facile at making shorter hyperlink  tags, as Tom Curtis has mastered.  But we do what we can, right?


    [JH] Your lenghty post addressed to Tom Curtis was deleted because it was argumentative and nothing more than a thinly disguised infomerical for your website. In the past you have made similar posts and they have been deleted. If you continue to make posts of this nature, they too will be deleted. You will also forefeit your privilege of posting on this site.   


    Chart from

    From Scientific American: "The researchers found that previous cost and efficiency estimates for air capture from entrepreneurs and scientists were far too optimistic. Extracting carbon dioxide from the air would likely cost more than $1,000 per ton, compared to $50 to $100 per ton from a system installed in a chimney. "We're not saying it's infeasible to take CO2 out of the air; we're asking if this is an economic way to mitigate climate change, and here we're very clear it's not," said Herzog."



    [PS] Chart removed as it was breaking page-formatting. Please post a link to a chart and not a data url. This helps people see it's context as well. See the instructions on embedding images at the bottom of the comments policy.

    Furthermore, air-capture is something of a wild idea, and the CO2 sequestration referred to in the article is in-chimney type (cost $50-100 per tonne - expensive but then so is climate change) so your posting is close to offtopic.

  16. With the avg American causing 19.3 tonnes CO2 per capita in 2007. Even $100 per ton is likely to cause huge negative consequences.


    [PS] The article posits 15 possible wedges with varying degrees of feasibility for that could be explored to reduce carbon. You seemed to zeroed on just one of them and ignored any interactions as well as naive economic model. (All spending one sector is total loss to all other sectors). If you are not interested in serious discussion, then please find somewhere else for your entertainment.

  17. Or, jetfuel... It might likely cause huge positive consequenses. Like, we might start taking a critical issue seriously, as we should be.

    I would note that, here in California, it only took a 10 cent fee on disposable bags to get everyone (as in nearly 100%) to switch to reusable grocery bags. I think it will take far less than $100/ton to substantially change consumer behaviour.

  18. I saw the chart that had to be removed. It was a mere time series of CO2 emissions for the US, from the EPA. It had no relation whatsoever with the Scientific American blurb cited below it. Neither that chart nor the Scientific American piece comes anywhere close to be evidence that carbon capture is "killing jobs" by the thousands; the killing jobs cite (in the present tense) is from Jetfuel. First he tried to argue that carbon was capture was currently adversely impacting the economy, probably based on his mistaken assumption that capture out of the air was doing that. Then he realized that neither was applicable and now is trying to argue that, if implemented, at the cost mentioned above, on site capture will have "huge negative consequences." Jetfuel's discussion techniques are duly noted.

    People's perception of risks, benefit, effort are way too removed from reality and colored by their emotional attachment to ideology or other things. Economics doesn't help much. Few economists warned against the huge negative consequences of bad financial risk management in 2006 and 2007 and they were ignored anyway. Will the consequences of increasing the price of a ton of carbon by $50 or 100 be as bad as the financial fiasco of these years? Would the negative consequences of capturing carbon be as bad as having the New York metro flooded by seawater again? On a somewhat regular basis? How about all the other negative consequences of sea level rise? And that's just one aspect of warming. <Snip>

    If one wants to argue about carbon capture, he should look at the thermodynamics of it, that's where one can make the point that it makes little sense. Considering the level of Jeftuel's posting so far, I doubt there will be a cogent argument on that terrain.

    This thread is about the "it's too hard" argument. That argument is by nature completely stupid. One way or another, there is no long term future whatsoever for humanity that does not involve the complete eradication of widespread, industrial scale, use of fossil fuels. It's really that simple. That fact is inescapable. 

    It's much more comfortable for many to imagine that, somehow, that eradication is not something that will concern them in their lifetime. Anyone below the age of 40 is very likely to be concerned by that transition, however, whether they like it or not. It will start with oil, of which there will not be enough to have all of the Western World, China and India fly around and play with automobiles as we currently know them. This realization will not take half a century. Wake up and smell the Jetfuel while there is still plenty to go around. It won't last forever. It may not even last your lifetime.


    [PS] please avoid personal attacks.

  19. Jet Fuel @40 cites figures showing costs for carbon capture and storage at site of emission of $50 to $100 per tonne.  In 2011, US carbon intensity was 0.413 Tonnes of Carbon Dioxide per $1000 GDP.  It has likely fallen further since.  However, using this figure we can calculate that eliminating all emissions by at site carbon capture and storage (CCS) would cost 2.065 to 4.13% of GDP.  That is, it would be the equivalent of losing 1 to 2 years of average economic growth.  Phased in over 20 years, the cost would not be detectable against normal annual fluctuations in economic growth.

    In some respects, this is an upper bound on the cost of the complete elimination of emissions from the US.  That is because there are many cheaper ways of eliminating CO2 emissions, including switching to lower emitting fuels (coal -> gas), switching to renewable or nuclear power, and more deliberate steps to improve energy efficiency and reduce power usage.

    Of course this calculation falsely assumes that transport emissions can be eliminated at the same cost as power emissions.  There would be an additional cost to eliminate transport emissions either by converting to electric vehicles, biofuels, or by the reliance on the less efficient CCS from the open air.  As transport only represents 28% of US emissions, more efficient means of reducing emissions in other sectors should more than compensate for the difference.

    These figures clearly show that jet fuels claims of "huge negative consequences" are overblown.

  20. New estimate of electricity generated if every roof and parking lot were covered with solar panels:  100 times consumption in the U.S.

  21. "You need to start citing peer reviewed articles, not Koch propaganda," someone wrote above.

    I fail to see any reason to trust 'peer reviewed articles.' I know from my own experience (in another discipline) that the peer review process is just a way of screening out dissent. When a reviewer agrees with a point of view advanced in an article, they don't even care if many of the 'facts' that support it are adequately referenced. Peer review is a bad joke.

  22. James P @46, your claim indicts your discipline as not being scientific, rather than calling into question peer review in other disciplines.  Or (a more conservative hypothesis), perhaps it merely indicts you as not being able to distinguish peer review based on quality of paper from peer review as viewpoint discrimination.

  23. Tom Curtis (#47) the human tendency is towards double standards, where someone whose opinions differ from one's own are held to a much higher (sometimes impossible) standard while opinions one likes are regarded with benevolence and the expectation that these opinions should be backed up by hard evidence is much lower. Given the passion generated by the subject of climate change, it is fairly obvious to the non-scientist like myself that the general atmosphere in which the discussion is unfolding is not sufficiently dispassionate to bring us anywhere near the conditions in which peer review could be carried on in an appropriate manner. (That your comment ended with an ad hominem comment - a slur on my intellectual capacity - is, itself, proof of this contention.) 

  24. Tom Curtis (#47) referred to a distinction between 'peer review based on quality of paper from peer review as viewpoint discrimination' What I'm suggesting is that such a distinction cannot be made in the real world. Overwhelmingly, people discriminate against viewpoints they do not like by dismissing such viewpoints as 'not quality.'

  25. Well, at least James P has made it clear what he wants to be true about peer review in climate science.  Unfortunately he fails to provide any evidence the peer review in climate science is broken.  He also shows that he considers entertaining about him the hypothesis that he entertains about climate scientists is, in his opinion, ad hominen.  Personally, I don't think so - but if that is his opinion, he indicts himself.

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