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Aerosol effects and climate, Part II: the role of nucleation and cosmic rays

Filed under: — group @ 15 April 2009 - (Italian)

Guest post by Bart Verheggen, Department of Air Quality and Climate Change , Energy research Institute of the Netherlands (ECN)

In Part I, I discussed how aerosols nucleate and grow. In this post I’ll discuss how changes in nucleation and ionization might impact the net effects.

Cosmic rays

Galactic cosmic rays (GCR) are energetic particles originating from space entering Earth’s atmosphere. They are an important source of ionization in the atmosphere, besides terrestrial radioactivity from e.g. radon (naturally emitted by the Earth’s surface). Over the oceans and above 5 km altitude, GCR are the dominant source. Their intensity varies over the 11 year solar cycle, with a maximum near solar minimum. Carslaw et al. give a nice overview of potential relations between cosmic rays, clouds and climate. Over the first half of the 20th century solar irradiance has slightly increased, and cosmic rays have subsequently decreased. RC has had many previous posts on the purported links between GCR and climate, e.g. here, here and here.

The role of ions

The role played by ions relative to neutral (uncharged) molecules in the nucleation process is still very much under discussion. For instance, based on the same dataset, Yu and Turco found a much higher contribution of ion induced nucleation (to the total amount of particles produced) than Laakso et al did. Evidence for a certain nucleation mechanism is often of an indirect nature, and depends on uncertain parameters. Most literature points to a potential importance of ion induced nucleation in the upper troposphere, but the general feeling is that neutral pathways for nucleation (i.e. not involving ions) are likely to be dominant overall. Most field studies, however, have been performed over land, whereas over the open ocean nucleation rates are generally lower due to lower vapor concentrations. In theory at least, this gives more opportunity for ion induced nucleation to make a difference over the ocean (even though the ion production rate is smaller).

The ion production rate (increasing with altitude from ~10 to ~50 ion pairs per cubic centimeter per second over land) sets a limit to what the particle formation rate due to ion induced nucleation can be. Based on his model for ion induced nucleation, Yu found that at low altitude, the number of particles produced is most sensitive to changes in cosmic ray intensity. At first sight, this may be a surprising result in light of the increasing cosmic ray intensity with increasing altitude. The reason is that high aloft, the limiting factor for particle formation is the availability of sulfuric acid rather than ions. Above a certain GCR intensity, increasing ionization further could even lead to a decrease in ion induced nucleation, because the lifetime of ion clusters is reduced (due to increased recombination of positive and negative ions). In contrast, at low altitude particle formation may be limited by the ionization rate (under certain circumstances), and an increase in ionization leads to an increase in nucleation.

How important is nucleation for climate?

Different modeling exercises have been performed to investigate this question. The strong dependency on input data and assumptions used, e.g. relating to primary particle emissions and nucleation parameterizations, and the different sensitivities tested, hampers an overall assessment. However, it is clear that globally, nucleation is significant for the number of cloud condensation nuclei (CCN) e.g. in the absence of boundary layer nucleation, the number of CCN would be 5% lower (Wang and Penner) or 3-20% lower (Spracklen et al.), and in a recent follow up study, they concluded that the number of cloud droplets would be 13-16% lower (in 2000 and 1850, respectively). Pierce and Adams took a different approach and looked at the variation of predicted number of CCN as a result of using different nucleation schemes. The tropospheric number of CCN varied by 17% (and the boundary layer CCN by 12%) amongst model runs using different nucleation rate parameterizations. Note that the globally averaged nucleation rates differed by a factor of a million (!).

It should be noted that the sensitivity of the number of CCN to nucleation depends greatly on the amount of primary emissions and secondary organic aerosol (SOA) formed. These are very uncertain themselves, which further limit our ability to understand the connection between nucleation and CCN. If there are more primary emissions, there will be more competition amongst aerosols to act as CCN. If more organic compounds partition to the aerosol phase (to form SOA), the growth to CCN sizes will be quicker.

Locally, particle formation has been observed to contribute significantly to the number of CCN; the second figure in Part I gives an example of freshly nucleated aerosols which grew large enough to influence cloud formation. Kerminen et al observed a similar event, followed by activation of part of the nucleated aerosols into cloud droplets, thus providing a direct link between aerosol formation and cloud droplet activation.

How important are cosmic rays for climate?

At the recent AGU meeting (Dec 2008), Jeff Pierce presented results on the potential effects of GCR on the number of CCN (their paper at GRL (sub. required)). Two different parameterizations for ion induced nucleation were used (Modgil et al and an ‘ion-limit’ assumption that all ions go on to form a new particle). They ran their model with both high and low cosmic ray flux, simulating conditions during solar maximum and minimum, respectively. This happens to be comparable to the change in cosmic ray flux over the 20th century (mostly confined to the first half), and amounts to a 20% change in tropospheric ion production. With both mechanisms of ion-induced nucleation, this leads to a 20% change in globally averaged particle nucleation, but only to a 0.05% change in globally averaged CCN. The authors concluded that this was “far too small to make noticeable changes in cloud properties based on either the decadal (solar cycle) or climatic time-scale changes in cosmic rays.” To account for some reported changes in cloud cover, a change in CCN on the order of 10% would be needed. More studies of this kind will undoubtedly come up with different numbers, but it’s perhaps less likely that the qualitative conclusion, as quoted above, will change dramatically. Time will tell, of course.

The bottom line

Freshly nucleated particles have to grow by about a factor of 100,000 in mass before they can effectively scatter solar radiation or be activated into a cloud droplet (and thus affect climate). They have about 1-2 weeks to do this (the average residence time in the atmosphere), but a large fraction will be scavenged by bigger particles beforehand. What fraction of nucleated particles survives to then interact with the radiative budget depends on many factors, notably the amount of condensable vapor (leading to growth of the new particles) and the amount of pre-existing particles (acting as a sink for the vapor as well as for the small particles). Model-based estimates of the effect of boundary layer nucleation on the concentration of cloud condensation nuclei (CCN) range between 3 and 20%. However, our knowledge of nucleation rates is still severely limited, which hampers an accurate assessment of its potential climate effects. Likewise, the potential effects of galactic cosmic rays (GCR) can only be very crudely estimated. A recent study found that a change in GCR intensity, as is typically observed over an 11 year solar cycle, could, at maximum, cause a change of 0.1% in the number of CCN. This is likely to be far too small to make noticeable changes in cloud properties.

309 Responses to “Aerosol effects and climate, Part II: the role of nucleation and cosmic rays”

  1. 151

    CCS and Obama, Part II of II

    Ike Solem wrote in 144:

    Obama’s biggest backer in the Senate was the midwestern utility Exelon, a coal based concern. You’re looking at a situation where midwestern coal cartels and tar sand developers are in the driver’s seat on energy policy, as compared to the previous administration, which had a more Mideastern oil flavor.

    Obama voted against the Clear Skies Bill:

    [0:25] I’ve already — I’ve already done it. You know — I voted against the Clear Skies bill. In fact I was the deciding vote, despite the fact that the fact that I’m a coal state and that half my state thought that I had thoroughly betrayed them because I think clean air is critical and global warming is critical.

    … my transcription in comment 397

    … which would have weakened the legal requirements imposed upon industry to retrofit existing plants to deal with their emissions.

    … or as Inhofe puts it:

    This bill has been killed by the environmental extremists, who care more about continuing the litigation-friendly status quo and making a political statement about carbon dioxide than they do about reducing air pollution.

    Senate Impasse Stops ‘Clear Skies’ Measure
    Pollution Bill’s Failure a Setback for Bush
    By Shankar Vedantam
    Washington Post Staff Writer
    Thursday, March 10, 2005; Page A04

    … and James M. Jeffords responded:

    This legislation denies plain scientific evidence of human health damage from toxic air pollution and of global warming from greenhouse gas emissions.


    Ike Solem wrote in 144:

    The current U.S. administration’s dedication to coal can be seen in this story on one of their main economic advisers: …

    Or, try Barak Obama on the campaign trail:

    … and he quotes Barack Obama saying:

    Clean coal technology is something that can make America energy independent!…We put a man on the moon in 10 years. You can’t tell me we can’t figure out a way to burn coal that we mine right here in the United States of America and make it work!

    Obama also states:

    [1:29] Let me sort of describe my overall policy. I mean what I have said is that we will put in place a cap and trade in place that is more that is as aggressive if not more aggressive than anybody’s out there. That is the first call for a 100% option on the cap and trade system. Which means that every unit of carbon or greenhouse gases that is emitted would be charged to the polluter.

    [1:56] That will create a market in which whatever technologies are out there that are being presented whatever power plants are being built that they would have to meet the rigors of that market and the ratcheted down caps that are placed that are imposed every year.

    … my transcription in comment 397

    If we take him at his word, he is more than willing to impose increasing costs upon the fossil fuel industry until they either impliment CCS or go out of business.

  2. 152
    James says:

    Mark Says (20 April 2009 at 2:51 PM):

    “Although over a country as widely spread as the US, the rather fuzzy law of large numbers will ensure that there’s plenty of wind SOMEWHERE.”

    Not so. You need to read up on meteorology. Winds aren’t random events: they’re driven by large scale processes such as weather fronts & storm systems, and by local conditions that vary by time of day & season. At Altamont Pass, for instance, the wind turbines are usually idle before noon, but turning busily in the evening, because the winds are driven by temperature differences beween the ocean/SF bay and the hot San Joaquin/Sacramento valley.

  3. 153
    Rod B says:

    Ray (110), thanks. But I’m still a bit confused (admittedly over a minor clarification). If there is a broad distribution of GCRs from throughout the galaxy, why would our Sun’s variations have any relevance?

    [Response: modulation of the magnetic field by the sun which affects the shielding. – gavin]

    Or is it the while GCRs come from throughout the galaxy, nearly all that have enough energy to impact Earth come from the Sun? [If the latter why not call them SCRs?]

    [Response: SCRs are too feeble, except possibly at the very high latitudes and very high altitudes. – gavin]

  4. 154
    Rod B says:

    G.R.L. ……… (111), Gee, I pulled the trigger too quickly. So GCRs are truly GalaticCRs and it’s the Sun that does not produce enough CRs with sufficient energy to have an impact on what this thread is about. In which case the Sun’s activities do have no relevance; if there is a correlation between the Sun’s activity and GCRs, it is purely coincidental with zero cause and effect? Correct?

    Just curious, to get sufficiently energetic, do most (all??) GCRs emanate from the center of the Galaxy?

  5. 155
    Rod B says:

    FurryCatHerder, but isn’t grid reliability inherently worsened (and geometrically – at least in a vacuum) the more geographically dispersed the sources become and the more those sources have considerable variation? I suspect it is manageable (with some of your costs – and maybe patents J ) but without some revision and mitigation, if you multiply (by a large number) the sources which are not linear and unpredictable – well it would be the first complex system in history that didn’t have its reliability (stability, really) affected. What might I be missing here?

  6. 156
    Rod B says:

    Mark (136), what oil-powered electric power stations?? What are there? Two???

  7. 157
    Rod B says:

    Gavin, Bingo! Thanks! (re GCRs and SCRs) As I see it the CRs come from high energy sources in the Galaxy but are “herded” by our Sun’s magnetic “pointer”.

  8. 158
    Mark says:

    RodB, #157, they aren’t herded. The energy of these particles is HUGE.

    The magnetosphere for the higher energy particles are “suggested” to go in a particular way.

    GCR’s are not shielded by the sun, the number you get goes down when the matgnetophsere is strong, but they still generally get where they were going to be anyway.

    To get the energy you need a HUGE field both in strength and in size (synchrotron radiation) and the best location for that is the galactic magnetic field, where there are lots and lots of stars all adding their fields. Magnetars are magnetic white dwarfs and can have a massive magnetic field too, so they could be a source outside the centre.

  9. 159
    Mark says:

    “Not so. You need to read up on meteorology. Winds aren’t random events: they’re driven by large scale processes such as weather fronts”

    And if there’s a high pressure system blocking the winds somewhere else there is a low pressure system where the winds are plentiful.

    Know of any high pressure systems that are bigger than the US???


    Then somewhere there will be a storm and low pressure systems.

    (note fronts to NOT make wind. They are where the wind changes direction. There’s no need for the wind speed to change maybe you could do with a meteorology course too).

  10. 160
    Mark says:

    “Mark (136), what oil-powered electric power stations?? What are there? Two???”

    Plenty more.

    Big ones, for the national grid in the UK, probably only one or two. They start up quickly.

    For power backup on a large business (especially one with a server farm), any backup will be a diesel engined power station on site.

  11. 161


    No, the larger and more diverse the sources are, the MORE predictable the average is, not the LESS predictable.

  12. 162
    CTG says:


    Right, so we are both saying the same thing – that Wilmot’s original statement: “The grid becomes unreliable if renewables are more than 20%” is inaccurate, because hydro does not pose this problem. It is nonsensical to pretend hydro is not a renewable just because it is more “controllable” than wind or solar.

    Hydro is still variable though. In NZ, the amount of power from renewables varies from 50% to 75% each month, and most of the variability comes not from wind, but hydro. When the inflows to the hydro lakes are low, the dams are usually shut to preserve lake levels, and so thermal generation has to go up to compensate.

    Interestingly, something that is not really used in NZ is pump storage – where off-peak electricity is used to pump water back into hydro lakes. This seems to me to be a particularly good use of wind power – if the wind blows at night, when general demand is low, then the excess power could be used to refill the hydro lakes.

  13. 163
    Ike Solem says:

    Timothy Chase:
    “If we take him at his word, he is more than willing to impose increasing costs upon the fossil fuel industry until they either impliment CCS or go out of business.”

    1) It is not possible to “implement CCS”, technically speaking. Can you yourself describe a process that would make it possible? One that doesn’t suck up 90% of the power generated by burning a ton of coal? No – and neither can anyone else.

    2) Notice that the charges in cap-and-trade go to the emitter of CO2, not to the producer of fossil fuels or to the distributor of fossil fuels – so those two entities have zero reason to slow production.

    3) There are no real offsets in cap-and-trade. The only way to remove a ton of CO2 from the air is via a biochar process – and that’s perhaps 25% effective, meaning that for every 4 tons of biochar added to soil, 1 ton stays in the soil. None of the other proposed offsets do anything to remove CO2 from the atmosphere – building a big solar PV system does nothing to atmospheric CO2.

    4) What is needed is direct support for renewable energy on a large scale – the same kind of multibillion dollar l-o-a-n guarantees and tax subsidies that are given to fossil fuels need to be eliminated and given to renewable energy, especially solar and wind.

    It’s increasingly clear that the federal governments in the U.S., Canada, Britain and Australia are all opposed to seeing an increase in renewable energy production. That can be seen in their refusal to discuss or mention the International Renewable Energy Agency, as well as in the lack of any budget for renewable energy research in the U.S.

    What’s remarkable is that even though cap-and-trade is unlikely to do anything positive for renewable energy generation, Obama advisor and fossil fuel magnate Warren Buffet opposes it:

    During his three-hour appearance on CNBC today, Warren Buffett, the world’s most famous investor, described the cap-and-trade plan to limit greenhouse gas emissions which President Barack Obama included in its recent budget proposal as a “pretty regressive” tax…

    …Buffett has said, not in so many words, that Obama would hurt the low and middle income Americans the president sees himself championing since a larger share of their incomes would go towards paying higher utility bills than would be true for the more affluent.

    This is funny stuff. Here we have an investor who backed Sarah Palin’s governor run, apparently so that his energy company, Mid-American, could get the natural gas pipeline to the tar sands contract, a deal that fell through over corruption concerns (the pipeline deal went to Transcanada, along with $18 billion in U.S. federal support).

    This same investor then put $4 billion into ConocoPhillips – but let’s be clear, this was a structured deal: Alaskan natural gas was to go to Alberta tar sands, where it would be used to convert tar to syncrude, polluting billions of tons of water in the process. From there, the oil was to be shipped to Midwestern refineries, or to West Coast refineries (Chevron and other companies have already prepared their refineries to deal with the heavier oil).

    Now, none of this will be profitable if oil remains at the present $45 level – so Warren Buffet is desperate to drive up the price of oil to the levels that existed when he bought into ConocoP. So are a whole lot of other investors, but Buffet makes for the most illustrative examples. Will this hurt the “poor consumers” that Buffet is concerned about? Of course it will. Never mind that Transcanada also got their steel for their pipeline from India, outraging local laid-off steelworkers in the U.S. Truly amazing.

    Nevertheless, cap-and-trade is a smoke-and-mirrors game. The best way to reduce emissions is to directly support the development of the renewable energy industry, and to eliminate tax subsidies and government handouts to the fossil fuel industry – which really doesn’t need it, considering the grotesquely large profits involved (or maybe that’s the reason for the grotesquely large profits).

    That’s the last thing Warren Buffet and cohort wish to see. The reason is that the rapid development of electric cars and solar and wind (or of hybrid cars and ethanol and biodiesel) will obviously push the price of oil even lower due to shrinking demand – and then, there will be zero incentive to develop Alberta’s tar sands, and you’ll see the fossil fuel sector start to shrink, dividends reduced, etc.

    So, that’s the J.D. Rockefeller end of the fossil fuel business – but Buffet makes a great example, because he is also deeply into the Samuel Insull end of the fossil fuel business, also know as the coal mine – railroad – coal-fired utility business, usually organized under the umbrella of larger holding companies (like Berkshire-Hathaway). This also means that Buffet probably has more control over the two companies that ship coal out of Montana (Burlington and Union Pacific, I think) than any other person – and likely earns more from that than anyone else.

    So, one of Obama’s top advisers is more deeply involved in tar sand oil and coal-to-electric businesses than anyone else in the world, just about, and has many billions invested in projects that will only be profitable if they do not face competition from renewables.

    That’s why I say it appears that Midwestern energy cartels are in the driver’s seat when it comes to federal energy policy. The fact that BP’s chief scientist was appointed to the #2 position at the DOE only serves to reinforce this notion (BP being one of the main developers of Alberta’s tar sand oil fields, as well as being a major owner of Alaskan North Slope gas fields). This is indeed different from the previous administration, which had more of a focus on Middle Eastern, Central Asian and African oil fields, not Alberta tar sands.

    Thus, it appears that progress on renewable development will continue to come from state-level initiatives, with technological innovation coming from foreign researchers and private firms – all against a steady drumbeat of opposition from the federal government and existing energy cartels, who will continue to promote CCS as a do-nothing greenwashing approach to the problem.

  14. 164
    steve says:

    I often read about the topics you gentlemen and ladies are discussing trying to keep up with the topic. This particular topic has led me to reading on pan evaporation rates and has confused something I have considered a given: that all watts are created equal. If photons from the sun are primarily the cause of evaporation wouldn’t that lead to a higher climate sensitivity for solar then for an equal amount of other forcing? I’m sure there is a reason why this isn’t true but have yet to be able to identify it. Thanks in advance.

  15. 165

    Makes sense, CTG–one of the pump storage issues, I suppose, is reservoirs–where do you put ’em, how do you fill ’em, and how do you finance them. None of which is a factor in the scenario you propose.

    More generally, I think that there needs to be institutional support of some kind for all kinds of hybrid energy schemes in order to create consistency & efficiency in energy supply. Wind/solar and solar/biofuel are a couple of pairings I’ve heard proposed.

  16. 166
    Mark says:

    steve, the sunlight is turned into thermal equilibrium. Temperature.

    That temperature increases the moisture capacity.

    This is already included.

  17. 167
    Rod B says:

    Mark, my only point was that in the US less than 2% of primary power generation comes from oil-fired units, and the price of imported oil would have minimal effect.

    It would be important even if small, however, as you point out, for back-up generators which are predominately diesel powered.

  18. 168
    Rod B says:

    BPL (161), if you think the average over the entire grid is what determines reliability and stability in a a distributed system, then you know little of distributed systems. I would find that hard to believe, so I’ll just write it off as a temporary lapse. ;-)

  19. 169
    steve says:

    #166 Mark perhaps I am misreading what you are saying. Are you saying that pan evaporation rates are regulated by temperature? Because pan evaporation rates have been going down despite rising temperatures and the answer that I have been able to find to this paradox is that the evaporation rate is directly related to photons from the sun. The answer I haven’t been able to find is why this would not affect the climate sensitivity of solar in ways different to other forcings. Thanks.

  20. 170
    Mark says:

    “in the US less than 2% of primary power generation comes from oil-fired units”

    And that is how much money? 2% of a huge number is still pretty darn big.

    Then add in petrol.

    You can move over to using local products to produce the electricity instead of buying petrol to put in a billion cars.

    re: 168. Please inform us of what it really is then, please. AFAIK, the voltage differential travels at the speed of light in the copper. 300 000 kps means you cover a lot of the US in one second.

  21. 171
    R Keene says:

    Richard Ordway,
    Are you confusing me with some other R. Keene? I haven’t published anything called Skywatch West or lectured to any students.

  22. 172
    SecularAnimist says:

    Re: integration of wind and solar into the grid, here’s some recommended reading (“CSP” as most of you know is Concentrating Solar Power, a.k.a. Solar Thermal):

    Why CSP Should Not Try to be Coal
    By Tom Konrad, Ph.D.


    The coal industry says that we need baseload power because our refrigerators still come on in the middle of the night. This is like saying we should have the water running constantly in the kitchen sink because we may get thirsty at any time and want a drink. Put in these terms, the assertion that we need baseload power is clearly nuts: what we need is controllable power that’s there when we need it, but is not wasted when the lights are off and the fridge is not running.

    … dispatchable generation is a truly premium power source. Dispatchable generation, like energy storage, long distance transmission, and demand response, all allow the grid to accommodate more variation in both power supplies and in demand. In a carbon-constrained world, where we want to use as much variable generation such as wind and PV as possible, zero carbon, dispatchable power from CSP can do far more to help us decarbonize the grid than CSP baseload.

    Baseload power is part of the problem; it’s not the solution. We should not denigrate CSP by pretending it is only a substitute for coal or nuclear.

    I would also note that multiple studies in Europe and the USA have shown that a diversified, regional portfolio of renewable electricity generation (wind, solar PV, CSP, geothermal, biomass) can produce 24×7 baseload power that is at least as reliable as coal or nuclear. I have linked to some of these studies in previous comments. They are also recommended reading for folks who like to discuss the potential contribution from renewable energy to our electricity supply.

  23. 173
    Martin Vermeer says:

    Rod B #168, I think it it more a matter of talking about different things.

    You appear to be referring to the stability problem that arises in an AC grid, when you start connecting power sources like wind turbines to it, the output of which can fluctuate on a time scale of seconds, and which are not centrally controlled. The existing grids, which are synchronized over large areas, are indeed not well suited for handling this kind of situation and may crash spectacularly. As you say, solutions for this can and must be worked out.

    BPL and FCH seem to be talking about the availability of power, when you need it where you need it, which is a quite different issue. The sun doesn’t always shine and the wind always blow at the same place. One approach to solving this is interconnecting AC networks using long range high voltage DC interconnects. Long range being 1000 km or so, larger than your typical weather system.

    And this issue is helped by having heterogeneous generating systems, i.e., a mix of solar, wind, hydro, geothermal and whatever.

  24. 174
    David B. Benson says:

    Ike Solem (163) — Over on Rabitt Run, several threads ago, there is a description of a CCS coal “burner” which appears to be about 50% as efficient as supercritical burners, as best as I can tell from cost estimates.

  25. 175
    Mark says:

    “Are you saying that pan evaporation rates are regulated by temperature?”

    What do you mean by pan evaporation rates?

    What I’m saying is that the effect of sunlight on the water content of the atmosphere and the warming thereby is already in the GCMs.

    Unless the sun increases its power substantially and quickly (i.e. over a timescale where water is resident and as a large percentage increase in power) then maybe (and only maybe) you could make a case for direct solar evaporation.

    Go take a look at the water cycle:

    What is that yellow thing at the top, there, making all that evaporation?

  26. 176
    James says:

    CTG Says (21 April 2009 at 8:44 AM):

    “Right, so we are both saying the same thing – that Wilmot’s original statement: “The grid becomes unreliable if renewables are more than 20%” is inaccurate, because hydro does not pose this problem. It is nonsensical to pretend hydro is not a renewable…”

    Yes, though I’m fairly sure that the original statement was shorthand for “if intermittent, uncontrollable renewable sources such as wind & solar are more than 20%”, because wind & solar are what come to mind when people start discussing renewable energy. There’s probably more than a little bit of American parochialism in there, since as a practical matter US hydro resources are fully used, but provide something under 10% of generation IIRC. Unlike New Zealand, the parts of the US that have plentiful water tend to be flat, while the mountainous parts are dry.

    Martin Vermeer Says (21 April 2009 at 12:14 PM):

    “The sun doesn’t always shine and the wind always blow at the same place. One approach to solving this is interconnecting AC networks using long range high voltage DC interconnects. Long range being 1000 km or so, larger than your typical weather system.”

    While that helps, the problem is that the sun doesn’t always shine, and the wind doesn’t always blow, period. Day & night are obvious for solar, but in many places the winds will be calm before dawn through the morning. and blow in the afternoons & evenings, so that if you graphed daily wind energy over the US, or one of the regional power interconnects, you’d find a pronounced daily variation that’s not in sync with demand.

    Then of course you have seasonal variation on top of that, plus the fact that long distance HVDC interconnects cost money to build & operate, and have losses & environmental impacts. It’s not that such systems can’t be designed & built; it’s that costs escalate non-linearly the larger the fraction of such intermittent generation you try to put on the system. It’s a much larger reflection of the cost difference between putting grid-connected PV solar on your roof, and building a complete off-the-grid house.

  27. 177
    Brian Dodge says:

    @ steve 21 April 2009 at 9:10 AM

    The important measurement is Watt-seconds, or Joules (or, for larger scales, kiloWatt-hours), and it doesn’t matter where they come from. What does matter is where the joules go; it takes about 4 joules to raise the temperature of one gram of water one degree C, but it takes about 2300 joules to evaporate one gram of water at a constant temperature. If the air above a pan of water is dry, some of the water will evaporate and give cooler, more humid air; the energy from cooling the air goes into evaporating the water(google “swamp cooler”). If its windy, some of the heat of evaporation can come from the kinetic energy of the air. If the pan is in sunshine, some of the energy required will come from photons. If it’s nightime, but there is more CO2 in the air (limiting thermal radiation) and the air is dry /windy, more heat will go into evaporating water than radiating into space. Water vapor is more complicated because of opposing effects, but going from 50% RH to 100% RH will reduce evaporation. The amount of pan evaporation is a measure of all these factors summed together over a period of time. If it’s cloudier where your pan is (because of GCRs?), or more humid because more joules are evaporating water somewhere upwind(like over the ocean), your pan evaporation rates might go down even if the temperature has gone up.

  28. 178
    Ike Solem says:

    See the following:

    Modelling grid losses and the geographic distribution of electricity generation

    Poul Alberg Østergaard
    Department of Development and Planning, Aalborg University, Denmark
    19 November 2004.


    “In Denmark more than 40% of the electricity consumption is covered by geographically scattered electricity sources namely wind power and local CHP (cogeneration of heat and power) plants. This causes problems in regard to load balancing and possible grid overloads. (A)

    The potential grid problems and methods for solving these are analysed in this article on the basis of energy systems analyses, geographic distribution of consumption and production and grid load-flow analyses. (B)

    It is concluded that by introducing scattered load balancing using local CHP plants actively and using interruptible loads such as heat pumps, requirements of the transmission grid are lowered thereby reducing or eliminating needs of grid reinforcement. (C)

    It is important that load balance is kept at local level and not just at an aggregate level.” (D)

    Now, most energy storage systems would work with solar and wind as ‘interruptible loads’ – if excess electricity was being generated, as on a clear summer day at noon, the storage system would kick in, and when demand exceeded production (evenings), the storage system would become the power source. The ideal technology for doing that might be a water hydrolyzer/ hydrogen-oxygen fuel cell: solar energy converted to electrical energy, stored in hydrogen-hydrogen bonds, and converted back to electrical energy as needed.

    Economically, this would be called arbitrage, I think. A private business would buy power from solar panel owners at noon when prices were low, and sell it to consumers in the evening at higher prices. Some would say that would create the most efficient system – but in that case, the overall grid would have to be owned, managed and repaired by the government, much as the national road system is. Imagine if all the roads in the U.S. were owned by private interests that only allowed preferred customers access – that’s how the electrical grid works today. Incidentally, that’s also how the Hostmen of Newcastle operated their coal cartel in medieval Britain… control of access to rivers & roads.

    Changing this is no easy task – we are talking about the biggest revision of the U.S. electrical grid since the 1920s and 1930s, a task somewhat bigger than the construction of the internet and its fiber-optic backbones. It will probably be accomplished via government contracting programs with private manufacturers, as is standard in the U.S. – but the government must remain the owner.

    Arguments that this represents some kind of anti-capitalist agenda are ludicrous – it will actually open up the power market to more competition, which increases efficiency, productivity and quality, right? The other option is as in France, where the government is completely responsible for the operation of the electrical system, and private firms are only involved in manufacturing reactors and fuel rods. In the U.S., the free-market model is more likely to win wide support – especially from small-scale renewable power producers.

  29. 179
    Hervé says:

    Dear Alan (#23),
    While I can understand the irritation of those who have answered or read your argument so many times, I wish Real Climate did not become as so many blogs, i.e. a place of witch hunt rather than real dialogue. The question that you raised is not devoid of interest and I would like to complement Bart’s reply (#39) by highlighting the fact that even multi-decadal (not only year-to-year) climate variability is probably not only explained by external forcings (either anthropogenic or natural like volcanic eruptions or solar activity) but also by the internal variability of the global climate system (ocean+land+atmosphere to tell it as simple as possible). This point is sometimes underestimated by climate scientists themselves (a reason why I appreciated very much Bart’s comment #11 about professional deformation) and is a key stone for understanding climate change. In particular, it can contribute to apparent discrepancies between the ensemble mean 20th century climate simulations and the instrumental record. What matters is not the detail of the simulated 20th century warming, but the long-term perspective, the fact that greenhouse gases are long-lived species in the atmosphere (while aerosols are short-lived), and their anthropogenic emissions keep on increasing while there is growing evidence that it will lead to irreversible impacts on climate, ecosystems and human societies worldwide.
    Yes, many impacts are still uncertain, but imagine you drive in the night and your headlights break down: will you increase your speed ?
    Looking forward to reading you again on Real Climate.

  30. 180
    Walt Bennett says:

    Steve is correct when he states that solar intensity at the surface is a determining factor in pan evaporation. This was a central conclusion of the NOVA documentary “Dimming The Sun”:

    GERALD STANHILL: The scientific community was obviously not ready to deal with the fact that there was a global dimming phenomenon.

    NARRATOR: Gerry claimed that, on average, the solar energy reaching Earth had fallen by two percent to four percent. That should be making the world significantly cooler, yet scientists knew the Earth was getting hotter.

    As we burn coal, oil and gas, we increase the concentration of carbon dioxide and other greenhouse gases in the atmosphere. Like a thermal blanket, they prevent the Sun’s heat from radiating back into space, causing global warming.

    BEATE LIEPERT: My friends’ reaction, actually, to Gerry’s and to my work—at the same time, too—was, “Oh my god, this is really extreme. You are contradicting global warming. Do you know how many billions of dollars was spent on global warming research? And you and this old guy are contradicting us?”

    NARRATOR: So Liepert and Stanhill’s work was widely dismissed. But global dimming was not the only phenomenon that didn’t seem to fit with global warming. In Australia, two other biologists, Michael Roderick and Graham Farquhar, were intrigued by another paradoxical result, the worldwide decline in something called the “pan evaporation rate.”

    PROFESSOR GRAHAM FARQUHAR (Australian National University): It’s called pan evaporation rate because it’s evaporation rate from a pan. Every day, all over the world, people come out in the morning and see how much water they’ve got to add to a pan to bring it back to the level it was the same time the morning before. It’s that simple.

    NARRATOR: In some places, agricultural scientists have been performing this routine daily task for more than a hundred years.

    GRAHAM FARQUHAR: The long-term measurements of pan evaporation are what gives it its real value.

    DOCTOR MICHAEL RODERICK (Australian National University): And the fact that they’re doing the same thing, day in, day out, with the same instrument.

    GRAHAM FARQUHAR: Yeah, they deserve a medal, each of them.


    NARRATOR: Nobody outside of agriculture took much notice of the pan evaporation measurements, but, in the 1990s, scientists spotted something very strange, the rate of evaporation was falling.

    GRAHAM FARQUHAR: There is a paradox here about the fact that the pan evaporation rate’s going down, an apparent paradox, but the global temperature’s going up.

    NARRATOR: This was a puzzle. Most scientists reasoned that like a pan on the stove, turning up the global temperature should increase the rate at which water evaporated. But Roderick and Farquhar did some calculations and worked out that temperature was not the most important factor in pan evaporation.

    MICHAEL RODERICK: Well, it turns out, in fact, that the key things for pan evaporation are the sunlight, the humidity and the wind. But really, the sunlight is a really dominant term there.

    NARRATOR: They found that it was the energy of the photons hitting the surface—the actual sunlight—that kicks the water molecules out of the pan and into the atmosphere. And so they, too, reached an extraordinary conclusion.

    MICHAEL RODERICK: You know, if the pan is going down, then maybe that’s the sunlight going down.

    NARRATOR: Was the falling pan evaporation, in fact, evidence of global dimming? Somewhere in the journals, they felt, must be the hard numbers that could tie the two things together.

    MICHAEL RODERICK: And then one day, just by accident, I had to go to the library to get an article out of Nature. And, as you do, I couldn’t find it, and I just glanced at a…through the thing, and there was an article called “Evaporation Losing Its Strength,” which reported a decline in pan evaporation over Russia, the United States and Eastern Europe.

    And there, in the measurements, they said that the pans had, on average, evaporated about a hundred millimeters less of water in the last 30 years.

    NARRATOR: Mike knew how much sunlight was needed to evaporate a millimeter of water, so he put the two sets of figures together, the drop in evaporation with the drop in sunlight.

    MICHAEL RODERICK: So you just do the sum in your head: a hundred millimeters of water, less a pan evaporation, two and a half mega joules, so two and a half times a hundred is two hundred and fifty mega joules. And that was, in fact, what the Russians had measured with the decline in sunlight in the last 30 years. It was quite amazing.

    NARRATOR: It was the same in Europe and the U.S.A. The drop in evaporation rate matched the decline in sunlight reported by Beate Liepert and Gerry Stanhill. Two independent sets of observations led to the same conclusion. Here, at last, was compelling evidence that global dimming was real.

  31. 181
    Brian Dodge says:

    Further info on pan evaporation. If you want to get an idea of how much irrigation water your crop uses, you can measure the temperature, humidity, windspeed, sunlight(direct and scattered), IR temperature of the atmosphere, etc, etc, at regular intervals over the day, plug these data points into a calibrated computer model and let it crank out the answer. Or you could stick a pan of water in the field and see how much evaporates. (As long as the field isn’t saturated or the plants wilting, so you’re away from highly nonlinear extremes)

  32. 182
    David B. Benson says:

    Mark (170) — The transmission lines are not impedance free, so the voltage differential is slower than the speed of light; still very fast.

    Moderators — Why is my previous comment, #174, still stuck in moderation?

  33. 183
    steve says:

    #174 Mark, pan evaporation rates are pretty much what they sound like, a pan of water where the amount that evaporates is measured. A typical use for such a device would be determining irrigation requirements. It was the decrease in the pan evaporation rates over the last few decades which led to the discovery of global dimming from aerosols or so goes my understanding. The reason why this decrease in evaporation occurred has been pinned, at least by some, on less solar irradiation directly hitting the water’s surface. To allow the scientist who determined this to say it in his own words:

    Surely, higher temperatures should evaporate water faster, like turning up the heat on a stove? Not so, says Roderick: “It turns out that the dominant force in evaporation is the energy of sunlight itself – photons hitting the surface of the water and tearing away water molecules, not the air temperature.”

    The paper supporting his position is : The Cause of Decreased Pan Evaporation Over the Past 50 Years published in 15 Nov 2002 in Science vol 298

    My question is: if water vapor is the most significant feedback mechanism then shouldn’t the forcing that causes the most water evaporation have the highest climate sensitivity.

    Thank you

  34. 184
    Greg Simpson says:

    Steve, all watts are equal in terms of driving the Earth’s surface temperature. That doesn’t mean they have to affect anything else the same, such as pan evaporation or the temperature of the stratosphere. In general, they don’t. In particular, the solar sensitivity of pan evaporation rates isn’t a good measure of climate sensitivity.

  35. 185
    truth says:

    I think it’s pretty safe to say that if John Collee had been a dissenter from the AGW ‘consensus’, you would be treating his panic with absolute disdain—you would no doubt be ridiculing him and asking what a medical doctor and movie scriptwriter would know about climate change.
    Do you believe Penny Sackett knew nothing of the facts of the Shindell paper on black carbon and its very large part in the warming of the Arctic?
    ‘Though greenhouse gases are invariably at the center of discussions about global climate change, new NASA research suggests that much of the atmospheric warming observed in the Arctic since 1976 may be due to changes in tiny airborne particles called aerosols.’
    “We will have very little leverage over climate in the next couple of decades if we’re just looking at carbon dioxide,” Shindell said. “If we want to try to stop the Arctic summer sea ice from melting completely over the next few decades, we’re much better off looking at aerosols and ozone.”
    All the rest of us in Australia remember vividly the heavy black pall of smoke that has hung over Indonesia and parts of Malaysia for months on end, year after year—-the locals in those countries being forced to wear masks to protect themselves.
    The whole world knows about the dense fog of particulates and other aerosols that have been a signature of Beijing in recent years.
    Do you think our Chief Scientist, Penny Sackett knew nothing of this, when she made her speech in Canberra?—and if not, why not?
    Would you not think that if she really believed we had only six years to do something, she would be putting much effort into doing the mitigation that scientists believe will have a much more immediate effect than CO2 mitigation?
    From the NASA comments on the research by Shindell:
    ‘Atmospheric chemists theorize that the climate system may be more responsive to changes in aerosol levels over the next few decades than to changes in greenhouse gas levels, which will have the more powerful effect in coming centuries.’
    Instead of highlighting this important factor, Professor Sackett waxed lyrical about Denmark’s windpower, but it’s not exactly as cut and dried as she claims, as described here, and in other reports:
    And yet she appears to have been silent too, while the Australian Opposition leader was derided by the AGW lobby , for his policies for reforestation initiatives and research into biochar.
    On the weekend Nicholas Stern triumphantly cited Australia as an example of a country where the AGW issue had brought a government down—that government being one that was prescient on the reforestation to restore the carbon sinks, and had funded [ with $200million], a Global Forest Initiative——even while some of the European countries cited as shining AGW true believers, had policies that encouraged the destruction of forests in Asia.
    You seem to be so admiring of the questionable and sometimes downright untrue claims made by John Collee.
    James Hansen’s actions and statements indicate that he wants to make coal-fired power a lame duck right now.
    Do you happen to know what technology he thinks would pick up the slack in the delivery of base load power—because no renewables are ready to do that.
    As Nathan Lewis of Caltech said:
    ‘No amount of saving energy ever
    turned on a light bulb or put food on someone’s
    table. We need to both save as much
    energy as we now make, and make as
    much clean energy as all the energy we
    now use, to meet a doubling or more of
    demand and drastically cut emissions of
    CO2 as well. In considering solutions to our
    energy supply problems, three “big cards”
    remain to be played: (1) technically prove
    that carbon sequestration works at scale; (2)
    create an enormous amount of nuclear
    power from plutonium; and/or (3) find a
    way to cheaply capture, convert, and store
    the energy from the sun, so that it can be
    used wherever it is supplied, and whenever
    it is demanded.’
    John Collee attributes the Murray Darling problems in Australia , and the drought of SE Australia to AGW, but that’s not exactly so either.
    The Murray-Darling has suffered from land-use changes and faulty irrigation practices, as well as El Nino—and recent research by the CSIRO and others attributes the droughts of Southern Australia , not to AGW, but to the Indian Ocean Dipole.
    The dramatic loss of rainforest was encouraged in Indonesia , by the appetite for palm oil in German and other European industry.
    And maybe the ‘defrosting of Siberia’ that he speaks of, has something to do with the black carbon that increases the Arctic warming.

  36. 186
    Alan Millar says:

    #179 Herve

    “While I can understand the irritation of those who have answered or read your argument so many times, I wish Real Climate did not become as so many blogs, i.e. a place of witch hunt rather than real dialogue. The question that you raised is not devoid of interest”

    “Looking forward to reading you again on Real Climate.


    Hi Herve

    I would post more but a lot of my posts never seem to make it past moderation.

    I did reply to Ray Ladbury on this thread.

    #44 Ray Ladbury

    “Alan Millar @23,

    Actually, Alan, you and I have something in common:

    Neither of us has a clue what the hell YOU are talking about. Where on Earth (or off, for that matter) do you get your information.”

    In reply I said something like :-


    James Hanson said :- ” Hansen said, “but the aerosol effect is complicated because aerosols are distributed inhomogeneously [unevenly] while greenhouse gases are almost uniformly spaced. So you can measure greenhouse gas abundance at one place, but aerosols require measurements at many places to understand their abundance.” and :- “Hansen suspects the relatively sudden, massive output of aerosols from industries and power plants contributed to the global cooling trend from 1940-1970. That’s my suggestion, though it’s still not proven,”

    The global temperature record in the 20th century is only in accord with the GCMs and AGW hypothesis for 25% of the time (1975 – 2000) it is in discord for 65% of the time (1910 -1975).

    The 21st century is also not looking good for the hypothesis and the models so far.

    To close the disconnect between the hypothesis and models from 1940 – 1970 a hypothesis based on aerosol production is put forward to stitch it together.

    However, nobody has been able to show a direct and consistent connection between aerosols and global temperatures. For instance areas with a high production of aerosols show a lower cooling trend in the period 1940 -1970 than other areas.

    Greenland ice cores show much higher levels of sulphur aerosols present in 1940 than in 1900, a period of significant warming.

    If the aerosol suggestion had been proven I am sure we would have heard about it by now. I am sure, Ray, that you realise that you, logically, cannot prove one unproven thing by using another unproven thing. It just doesn’t compute. So Ray if you can stitch these two hypothesis together with some level of proof then you should publish and make a name for yourself.

    Until the obvious discord between the models and observed data in the 20th and 21st century can be closed by proven hypothesis then clearly noone can say that the science is anyway settled.


  37. 187
    steve says:

    #184 Greg thank you for the response. I must admit the lack of substance leaves me hanging on what you base the response on. Perhaps this is too simple to warrant an explanation and if I were in the field it would be obvious? Or perhaps the answer is too complicated to explain within the confines of this format?

  38. 188
    Rod B says:

    I’m getting confused and perplexed with the evaporating pan discussion. What happened to the ole’ trade-off between vapor pressure, surface tension, and the Boltzmann distribution of thermal energy among the water molecules to determine evaporation? I can see a big effect from the Sun (I think…) by virtue of radiation absorption, and the resulting increase in temperature, leading to a shift in the B-distribution, yada, yada. But a photon knocking a molecule loose (presumably?) like a billiard ball??? What is the physics process of that? Back-of-the-envelope calc seems to indicate the momentum of a photon might be large enough, though the vector directions look screwy. Is this what happens?

  39. 189
    Brian Dodge says:

    re Rod B 21 April 2009 at 10:01 PM photoevaporation?
    I too agree that it sounds improbable, especially since water is pretty transparent at the wavelengths where most of the solar energy arrives. About 5% (more at shallower incident angles) will get reflected at the surface, most of the rest will transmit to the bottom of the pan. Are the pans black, white paint, shiny metal? Are they insulated? I think that some googling may be in order.

  40. 190
    Mark says:

    Aye, RodB, I’m wondering why steve is saying what he’s talking about, too.

  41. 191
    Mark says:

    “However, nobody has been able to show a direct and consistent connection between aerosols and global temperatures. ”


    Bog bada-boom.

    Loadsa soot.

    Global temps down for some months (?).

  42. 192
    Mark says:

    “#174 Mark, pan evaporation rates are pretty much what they sound like, a pan of water where the amount that evaporates is measured. A typical use for such a device would be determining irrigation requirements.”

    And evaporation from that pan depends on the temperature of the water and the dryness of the air.

    And if the air is already saturated, no water will stay out of the pan until the air is warmed and can hold more moisture.

    This is already in the water cycle. So why do you think this is not taken care of in even the most basic GCMs?

    And during the night, when there is no sun, the pan will cool, and night can get a lot colder because the night sky is at ~4Kelvin. If it weren’t for blanketing by greenhouse gasses.

  43. 193

    Alan writes:

    The global temperature record in the 20th century is only in accord with the GCMs and AGW hypothesis for 25% of the time (1975 – 2000) it is in discord for 65% of the time (1910 -1975).

    Really? When I regress temperature anomaly on ln CO2 for 1880-2008 I get 76% of variance accounted for. Looks like a pretty close match to me.

  44. 194
    steve says:

    #192 Mark you could very well be right. But a peer reviewed paper in a reputable journal has said what you and I learned in school is inaccurate. I don’t have the expertise to determine if the paper has merit and am patiently waiting to see what those who do have the expertise have to say about it.

  45. 195
    Mark says:

    “But a peer reviewed paper in a reputable journal has said what you and I learned in school is inaccurate.”

    Which paper did we learn in school that was innaccurate? And why are current GCM’s using that paper to design its physical simulation?

    I merely guard against making a mountain out of a molehill merely because “we don’t know for certain”.

  46. 196
    Miguelito says:

    Nir Shaviv is at it again with the cosmic rays: this time he’s saying there’s too much heat flux in the oceans over 11-year solar cycles to be just from the solar index and positive feedbacks, thus cosmic rays are to blame. This time it’s in the form of an article in GRL.

    His blog comment:

    The paper:

    Anybody care to dissect it to tell me what he’s done right or wrong? Or where I can be pointed to in case it’s already been done?

  47. 197
    Patrick 027 says:

    Re Ike Solem, others…

    CCS – well, that alone doesn’t solve the mercury pollution, the removal of potential wind power sites in West Virginia, other stuff in West Virginia, etc…


    It is possible. Coal might be processed differently to remove other pollutants – or maybe CO2 itelf, before combustion – COME AGAIN? – well, with significant variation, coal may have 0.8 atoms of H for each atom of C, so if there were someway to seperate the H from the C (and try it with oil and gas too)… Maybe even within the coal mine so that mines could be pumped like wells instead of dug up – but I suppose that may be very dangerous?


    1. Accelerate the natural chemical weathering process. Someone mentioned that this may be quite economical in the “Climate Change Methadone” post comments from some time ago.
    …”proper rock pulverizers. For hard rock they typically take 25 kWh(e) per tonne if 80 percent of the mass is to be in sub-100-micron particles, 50 kWh(e) per tonne for 80 percent below 25 microns.”
    …”In that previous discussion, Dr. R.D.Schuiling asserted the cost per tonne CO2 would be US$10-15. (Some discussion here has referred to the olivine dispersal idea as mine; it is not.)”

    I cannot verify those numbers for myself, but assuming they are true:

    Composition of rocks (from Encyclopedia Britannica: “Chemical Elements”):

    granite, basalt, shales, sandstones, carbonates**, metamorphic rocks
    % by mass:
    Ca: 1.00 , 7.8 , 2.2 , 3.9 , 30.2** , 2.9
    Mg: 0.23 , 4.0 , 1.5 , 0.70 , 4.7** , 1.4
    Fe: 1.36 , 7.7 , 4.7 , 0.98 , 0.38** , 3.1

    If 80% of those amounts were changed into CaCO3, MgCO3, FeCO3, kg C / metric ton rock, (it should be obvious why I put asterisks for the carbonate mineral values):
    _________ gran, basa, shal, sand, carb**, meta
    Ca only : 2.4 , 18.7 , 5.3 , 9.4 , 72.4** , 7.0
    Ca + Mg : 3.3 , 34.5 , 11.2 , 12.1 , 91.0** , 12.5
    Ca,Fe,Mg: 5.6 , 47.8 , 19.3 , 13.8 , 91.6** , 17.8

    (Molar masses, g: C 12.011, Ca 40.078, Mg 24.305, Fe 55.847)

    If 50 kWh(e) per metric ton of rock (most tons are similar to a metric ton), energy per kg C in MJ(e) (3.6 MJ = 1 kWh):

    _________ gran, basa, shal, sand, carb**, meta
    Ca only : 75.1 , 9.6 , 34.1 , 19.3 , 2.5** , 25.9
    Ca + Mg : 54.4 , 5.2 , 16.1 , 14.9 , 2.0** , 14.4
    Ca,Fe,Mg: 31.9 , 3.8 , 9.3 , 13.0 , 2.0** , 10.1

    If coal is ~ 80% C by mass with energy density of ~ 20 MJ/kg, oil is ~ 12/14 C by mass, 43 MJ/kg, and natural gas is 12/16 C by mass, 55.6 MJ/kg (PS I will have to verify the C content of coal – I’m thinking the 20 MJ/kg includes impurities that are not C,H,O,N (that it includes the ash))

    (PS that’s MJ/kg C,
    coal ~ 25 MJ/kg C (I think it can be higher than that)**,
    oil ~ 50 MJ/kg C
    natural gas ~ 74 MJ/kg C)

    and electricity production and delivery is ~ 30 % efficient, then, the energy (electric) for sequestering CO2 as a fraction of energy (electric) produced when emitting CO2 is:

    For coal (~ 7.5 MJe/kg C ?)
    _________ gran, basa, shal, sand, carb**, meta
    Ca only : 10.0 , 1.3 , 4.6 , 2.6 , 0.33** , 3.5
    Ca + Mg : 7.3 , 0.7 , 2.1 , 2.0 , 0.26** , 1.9
    Ca,Fe,Mg: 4.3 , 0.5 , 1.2 , 1.7 , 0.26** , 1.3

    For oil: (~ 15 MJe/kg C ?)
    _________ gran, basa, shal, sand, carb**, meta
    Ca only : 5.0 , 0.6 , 2.3 , 1.3 , 0.17** , 1.7
    Ca + Mg : 3.6 , 0.3 , 1.1 , 1.0 , 0.13** , 1.0
    Ca,Fe,Mg: 2.1 , 0.3 , 0.6 , 0.9 , 0.13** , 0.7

    For natural gas: (~ 22 MJe/kg C)
    _________ gran, basa, shal, sand, carb**, meta
    Ca only : 3.4 , 0.4 , 1.5 , 0.9 , 0.11** , 1.2
    Ca + Mg : 2.4 , 0.2 , 0.7 , 0.7 , 0.09** , 0.6
    Ca,Fe,Mg: 1.4 , 0.2 , 0.4 , 0.6 , 0.09** , 0.5

    The most economical in all cases would be to use carbonates**; basalt is the only other possibility with coal and it is not a great one.

    (Where energy used in sequestering is ~ 30% of energy produced with emission, if electricity costs ~ 8 cents/kWh(e) coal, and if ~ 2 kWh(e)/kg C for coal, then 16 cents/kg C for coal electricity generation, so sequestering C with 30% of the energy costs AT LEAST ~~ 4.8 cents/kg C = ~ $48/metric ton C; obviously more than the 10 to 15 $/ton mentioned above.)

    But the referenced comments above referred specifically to olivine, which is (Mg,Fe)SiO4, which could sequester a mass of C per unit mass rock similar to that for carbonates** as calculated above if the Fe can be used.

  48. 198
    William says:

    In reply to “The reason is that high aloft, the limiting factor for particle formation is the availability of sulfuric acid rather than ions. Above a certain GCR intensity, increasing ionization further could even lead to a decrease in ion induced nucleation, because the lifetime of ion clusters is reduced (due to increased recombination of positive and negative ions). In contrast, at low altitude particle formation may be limited by the ionization rate (under certain circumstances), and an increase in ionization leads to an increase in nucleation.”

    I agree with this statement. I do not understand logic of the conclusion that the solar magnetic cycle does not modulate planetary cloud cover.

    Svensmark and Palle have cloud data that shows correlation of planetary cloud cover at both low (increases in low level clouds) and high altitudes (decrease in clouds at high latitudes) at the specific latitudes as predicted by Yu for increases in GCR levels and visa versa for decreases in GCR.

    Palle in addition found evidence of Yu’s electroscavenging effect which is caused by solar wind bursts which remove cloud forming ions and hence masks correlation of cloud cover with GCR changes, for the period.

    If there are multiple observations current as well as in the paleodata that support a mechanism, how can a theoretical strawman disprove the mechanism?

    The sun appears to be entering a deep magnetic minimum. What is the predicted affect of that change on planetary temperature? I would be interested in your thoughts and others in the forum.

  49. 199
    Patrick 027 says:

    From Fig 1 of

    “Initiation of clement surface conditions on the earliest Earth”
    Sleep, Zahnle, Neuhoff

    it appears that production of carbonate minerals from silicates is most favorable for (among those relatively abundant cations from silicates) Ca, followed by Mg, then Fe, then Na. As the temperature is lowered and the partial pressure of CO2 raised, CaCO3 (calcite) forms first, then CaMg(CO3)2 (dolomite), then MgCO3 (magnesite), then FeCO3 (siderite). (CaCO3 can also form as aragonite).

    I don’t know why but my impression is that dolomite has not formed much in recent geologic times. From the graph, it seems that dolomite and calcite are thermodynamically favored (with quartz, kaolinite, etc.) at 300 ppm CO2 at sea level at temperatures colder than 50 deg C (will the reactions occur fast enough at that temperature – if the rock has been ground up fine enough?). I would think that the partial pressure of CO2 increases down into the ocean for the same concentration of CO2, … so if CO2 and mineral dust were injected at depth, more Mg and Fe could be utilized – but that defeats the economics of sequestration from the air. I have read that injection of CO2 into deep aquifers would produce carbonate minerals – I think a variety of them (even Na carbonate, I think). Of course, mineral dust could just be fed into the smokestack… for that matter, there might be energy available from the reaction (Ca,Mg,Fe)x(?,Si)y(O,etc)z + CO2 = carbonates + some other silicates… (and CO2 and other pollutants can also be used to feed algae farms…)

    And what about using carbonate minerals? Well, for example, dissolved CaCO3 can react with dissolved H2CO3 to produce dissolved Ca(HCO3)2, and buffer the pH of the ocean while giving the ocean greater capacity to take up CO2 (at least that’s my understanding). Presumably this could apply to other partly soluble carbonate minerals – so the supply of Ca and Mg cations from silicates could actually sequester (from the atmosphere, anyway) twice what was stated above, while cations from carbonates would take up just what was stated above. The energetics and economics still do not great, though, but maybe a bit better. Would this work for the cations that do not form stable carbonate minerals under given conditions? I think the Fe might not do much for the pH problem but Ca,Mg,Na,K should.


    Use CO2 to make polycarbonate plastics. (won’t bother analyzing that one – but there was an article in Scientific American a while back called something like “Turning pollution into DVDs” – or something like that.)


    pump into old salt mines, oil wells, etc… forget about chemical stability, as long as it’s physically sound for the necessary time frame (is it?)


    Make the actual electrical generation more efficient. Whatever happened to MHD generators? Something already being used to some degree is making use of the waste heat (PS could also be used with solar cells to heat water (and cool the cells)). Here’s an idea: Make H2 and CO from coal – my understanding is both can be used in fuel cells.


    I’m okay with trying it, putting some public funding into R&D for it, so long as at least similar amounts are available for anything at least as promising or more so (which I would suggest will include solar, geothermal, new biofuels).

  50. 200
    Patrick 027 says:

    “at 300 ppm CO2 at sea level at temperatures colder than 50 deg C” … actually, maybe 400 ppm (or reduce the temperature) – I just eyeballed it from the graph.


    Re Ike Solem –

    Either Cap and Trade (with 100% auction) or emissions taxes would work to increase use of clean energy and/or energy efficiency and reduce emissions by forcing the market to react to a price signal (representing the externalities).

    When someone has to pay to emit, they will either pass the cost on to consumers or reduce their profits. If they pass it on to consumers, there will be increased demand for cleaner energy, energy efficiency, valuables that do not require energy, etc, and so on with other climate emissions (deforestation, cement production, rice paddies, cows, landfills, dark aerosols – especially high-latitude black carbon (depending on season), etc…. if the emissions were priced evenly according to CO2-equivalent values (global warming potentials for some agreed time-horizon***). This increased demand will attract investment (including R&D) to increase the affordable supply of those options, and the decreased demand for the emitting options will repel investment, reducing the affordable supply. On the other hand, if the emitter absorbs the cost, the investors will be repeled and want to go to other options, etc. (for non-corporate entities, the investors would be the emitters in that case – they would pursue other business options, trying to improve efficiency or going some other route).

    A similar logic applies whether the price signal is forced at point of emission or at point of fuel sale, or at point of fuel production. I favor (this works with energy-related emissions) taxes, and favor putting them at either point of fuel sale (to power plants and natural gas/oil distributors, so there is a smaller number of larger transactions, and thus less paperwork, etc.) or at point of fuel production. I favor these options because I think they will be easier and less costly to enforce and regulate, and they present a clear price signal to the market (that can be adjusted over time in response to market reaction and scientific progress). It might be a more understandable system, and perhaps less prone to corruption or fraud (?). But a cap-and-trade system would work.

    What I would specifically not prefer is a cap-and-trade system that specifies caps for distinct sectors of the economy. The starting point should be that CO2 from cement production, CO2 for energy, CO2 from deforestation, CH4 (in CO2 equivalent terms) from cows, etc., should be treated as equal; they should not be walled off from each other. The market can decide whether it is better to reduce emissions from cement and still eat beef and cheese or the reverse or somewhere in between, etc.

    If real economic and political** conditions require some adjustments to such an idealized system, so be it, but my opinion is that such adjustments should be in the form of additional policies, so as not to muddy the clarity of the original price signals. For example, these policies may be regressive. For some period of time (allowing lifestyle/cultural adjustment), it may make sense to specifically help the poor. This shouldn’t take the form of a reduction on what they pay for emissions; it should be as aid that is not tied to individual emission quantities.

    See also references here:

    *** It is important to to cover as many significant emissions sources as possible so that the market reaction does not simply shift the mix of emissions (deforestation to grow biofuels would not be prefered) – on the other hand, there are some greater costs (overhead, bureaucracy, limited accuracy) for regulating some pollutants/emissions than for some others (aerosols because of regionality and different regional/seasonal/etc. climate effects; other emissions due to difficulty of monitoring, accounting, tracking, measuring, etc.) – and those costs have to be weighed against the benifits; differently designed policies might be better for some different types and sources of emissions).

    Found this today:
    “Will the U.S. Ever Need to Build Another Coal or Nuclear Power Plant?
    The new chairman of the Federal Energy Regulatory Commission doesn’t think so”

    Happy Earth Day!