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Irreversible Does Not Mean Unstoppable

Filed under: — david @ 1 February 2009 - (Italian) (Finnish) (Chinese (simplified)) (Español)

Susan Solomon, ozone hole luminary and chair of the Nobel Prize winning IPCC, and her colleagues, have just published a paper entitled “Irreversible climate change because of carbon dioxide emissions” in the Proceedings of the National Academy of Sciences. We at realclimate have been getting a lot of calls from journalists about this paper, and some of them seem to have gone all doomsday on us. Dennis Avery and Fred Singer used the word Unstoppable as a battle flag a few years ago, over the argument that the observed warming is natural and therefore there is nothing that humanity can do to alter its course. So in terms of its intended rhetorical association, Unstoppable = Burn Baby Burn. But let’s not confuse Irreversible with Unstoppable. One means no turning back, while the other means no slowing down. They are very different words. Despair not!

Solomon et al point out that continued, unabated CO2 emissions to the atmosphere would have climatic consequences that would persist for a thousand years, which they define operationally as “forever”, as in the sense of “Irreversible”. It is not really news scientifically that atmospheric CO2 concentration stays higher than natural for thousands of years after emission of new CO2 to the carbon cycle from fossil fuels. The atmospheric CO2 concentration has a sharp peak toward the end of the fossil fuel era, then after humankind has gone carbon neutral (imagine!) the CO2 concentration starts to subside, quickly at first but after a few centuries settling in a “long tail” which persists for hundreds of thousands of years.

The long tail was first predicted by a carbon cycle model in 1992 by Walker and Kasting. My very first post on realclimate was called “How long will global warming last?”, all about the long tail. Here’s a review paper from Climatic Change of carbon cycle models in the literature, which all show the long tail. A number of us “long tailers” got together (electronically) to do a Long Tail Model Intercomparison Project, LTMIP, just like the big guys PMIP and OCMIP (preliminary results of LTMIP to be appearing soon in Annual Reviews of Earth and Planetary Sciences). I even wrote you guys a book on the topic.

The actual carbon-containing molecules from the fossil fuel spread out into the other carbon reservoirs in the fast parts of the carbon cycle, dissolving in the oceans and getting snapped up by photosynthetic land plants. The spreading of the carbon is analogous to water poured into one part of a lake, it quickly spreads out into the rest of the lake, rather than remaining in a pile where you poured it, and the lake level rises a bit everywhere. In the carbon cycle, translated out of this tortured analogy, the atmospheric carbon dioxide content rises along with the contents of the other carbon reservoirs.

Ultimately the airborne fraction of a CO2 release is determined largely by the buffer chemistry of the ocean, and you can get a pretty good answer with a simple calculation based on a well-mixed ocean, ignoring all the complicated stuff like temperature differences, circulation, and biology. The ocean decides that the airborne fraction of a CO2 release, after it spreads out into the other fast parts of the carbon cycle, will be in the neighborhood of 10-30%. The only long-term way to accelerate the CO2 drawdown in the long tail would be to actively remove CO2 from the air, which I personally believe will ultimately be necessary. But the buffering effect of the ocean would work against us here, releasing CO2 to compensate for our efforts.

As a result of the long tail, any climate impact from more CO2 in the air will be essentially irreversible. Then the question is, what are the climate impacts of CO2? It gets warmer, that’s pretty clear, and sea level rises. Sea level rise is a profound consequence of the long tail of global warming because the response in the past, over geologic time scales, is tens of meters per °C change in global mean temperature, about 100 times stronger than the IPCC forecast for 2100 (about 0.2 meters per °C). The third impact which gains immortality from the long tail is precipitation. Here the conventional story has been that climate models are not very consistent in the regional precipitation changes they predict in response to rising CO2. Apparently this is changing with the AR4 suite of model runs, as Solomon et al demonstrated in their Figure 3. Also, there is a consistent picture of drought impact with warming in some places, for example the American Southwest, both over the past few decades and in medieval time. The specifics of a global warming drought forecast are beginning to come into focus.

Perhaps the despair we heard in our interviewers’ questions arose from the observation in the paper that the temperature will continue to rise, even if CO2 emissions are stopped today. But you have to remember that the climate changes so far, both observed and committed to, are minor compared with the business-as-usual forecast for the end of the century. It’s further emissions we need to worry about. Climate change is like a ratchet, which we wind up by releasing CO2. Once we turn the crank, there’s no easy turning back to the natural climate. But we can still decide to stop turning the crank, and the sooner the better.

Walker JCG, Kasting JF. 1992. Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide. Palaeogeogr. Palaeoclimatol. Palaeoecol. (Glob. Planet. Change Sect.) 97:151–89

210 Responses to “Irreversible Does Not Mean Unstoppable”

  1. 151
    Brian Dodge says:

    When did the National Weather Service decide that the base reference for “normal” temperatures is the period from 1971 to 2000? Doesn’t having recent warmer years included in the average to which comparison is made skew the comparison towards making it seem cooler than it would be if the reference period were, say, 1960-1980?

    [Response: The NWS has many constituencies to serve. Many of them need statistics that are as up-to-date as possible, thus they move their ‘climate normal’ period up every ten years. This can confuse people looking at anomalies, so one should be careful what any baseline is, but looking at trends is independent of that. – gavin]

  2. 152
    Harold Brooks says:

    Re: 151

    The standard period for climatological normals is 30 years, so that’s a starting point. WMO procedure is to update every 30 years, so that they would use 1961-1990, until 2020.

    It’s my understanding that the US has chosen to use the last 30 years ending with a year ending in 0, so that the departures from normal represent something as close to current as possible. In large part, this is driven by a perceived need from users of things like the Climate Prediction Center’s seasonal forecasts. In a warming climate, almost the forecasts all become “warmer than normal”, which provides little information for users of the seasonal forecast.

  3. 153

    Chris, actually no, I didn’t. I suggested he publish his “results,” making some oblique comment or other with “Nobel” in it. If only–!

    I hope the sarcasm was a harmless indulgence; I did post some links to actual science for readers with fewer loose screws.

  4. 154

    Re the responses to my #3

    David,

    Where we disagree is that you think we have plenty of time – 1,000 years (and Gavin seems to think we have 82 years. :-)
    My problem is the tone of your post was reassuring, as is evident from the other replies, but the situation is catastrophic.

    No doubt you have been brought up to believe that in the world of geology and climate any changes happen slowly over long periods of time. That is the paradigm of uniformitarianism” described by Charles Lyell and accepted by Charles Darwin. But now we know that catastrophes such as the Great Ice Age and the extinction of the dinosaurs do happen. But more importantly, climatic catastrophes of rapid warming can also happen such as the Dansgaard-Oeschger events. Because they cannot be explained, the scientists (some would say wisely), tend not to discuss those.

    It is obvious that the only thing that could cause these rapid warmings, without leaving any evidence, is the disappearance of a sea ice sheet. And we know that the Arctic sea ice is melting. We do not have time. The time for reassurance is over. We should press the panic button now!

    It is not just me who is saying that. Simon Chu is saying something similar. Obama’s energy secretary outlines dire climate change scenario. But it is you scientists who should be leading the calls for action, not wasting your time debating with a bunch of pseudo-scientists with their heads buried in the sand.

    Cheers, Alastair.

    [Response: With all due respect, you are completely totally misreading my meaning. I do not disagree with anything that you write here. I think that CO2 emissions should be cut immediately, it’s an emergency, I don’t believe or say that we have plenty of time. I’m with you on abrupt climate change, I warn in both my books about how IPCC projections are a best-case scenario because they show no surprises such as the abrupt climate changes we infer from climate records in the past. David]

  5. 155
    Lawrence McLean says:

    Re #150
    Pat,
    The Australian Bureau of Meteorology seems to be on the ball with this issue. They have issued a report dealing with the current heatwave in South and South Eastern Australia. It makes interesting reading, check it out:
    http://www.bom.gov.au/climate/current/statements/scs17.pdf

  6. 156

    In re #134 (and how do I create links for posts?)

    In reality, no, it wouldn’t happen that way. The entire point of explaining that $0.60 is two months of fuel cost inflation is to demonstrate that solar will moderate fuel cost inflation effects. I don’t know the total demand within the Austin Energy region, but as something like solar became a larger portion of that production, the savings over time due to solar power remaining flat (except for increases in labor costs) would eventually dominate. I saw the proof of that last summer when fuel cost inflation smacked my neighbors good and hard and my bills were still quite reasonable.

    In re #135 —

    Sorry, but that’s the sort of political conspiracy thinking that is a major obstacle to getting more distributed generation on the ground. Increasing bulk power transmission is an absolute requirement to make up for the nature of renewable energy — different regions, including different regions in a stat, have different sources of renewable energy. The mountain passes of California have wind, parts have solar, and parts have wave. It’s the intermittent nature of these resources that require they be interconnected in some fashion, and those interconnections need to be able to either import all of the demands, or export all of the surplus capacity.

    There are also various laws, such as Kirchoff’s, which work against some spider web of low power distribution lines. The are technical problems that will need to be solved, and they require upgrading the “smarts” of the grid (dealing with positive voltage gradients is going to be a huge one), but the basic trunk-branches-twigs-leaves model of distribution cannot be abandoned for some “no more coal!”-based policy.

    Let’s prevent coal plants from being built by educating the public and passing legislation. Let’s don’t do what Austin did with it’s traffic policy and refuse to build highways hoping that no one would move here from California (and Austin is full-up again, so we don’t need any more people from California or Colorado moving here.)

  7. 157
    Rod B says:

    It’s OT but, FurryCH, Austin did build some major roads. But they (and TexDOT) had/have this curious habit of building only 90% of the arterial needed.

  8. 158
    Pat Neuman says:

    Re 151

    Brian, I agree. NWS use of 1970-2000 average temperatures as “normal” tends to underestimate recent warming, in the mind of the public. Many people think normal is based on conditions further back in time when it was colder. Temperature records at all climate stations in the Upper Midwest show warming trends well in progress, especially recent decades. The people aren’t getting the message that warming trends exist in the temperature records because NWS is not providing that information to the public. I think that wrong, regardless of the “many constituencies to serve” which gavin referred to in his response.

  9. 159
    Pat Neuman says:

    Lawrence, thank you for providing the link on your heat wave (#155).

    Today, NOAA is alerting residents in the Red River Valley (separates North Dakota and Minnesota) on their assesment of a potential for significant flooding in their communities this spring. Their assessment is based on the amount of rain and snowfall in the Red River Basin over the past few months, … forecasting a 50 to 75 percent chance of major flooding there this spring.

    How can NOAA NWS forecast a 50 to 75 percent chance of major flooding for this spring … when their procedures fail to account for climate change trends in the data (temperatures, snowmelt rates and precipitation)?

    Is NOAA just now beginning to do research on climate change trends in hydrology?

    “NOAA Says Prepare for Major Spring Flooding on Red River”
    http://www.noaanews.noaa.gov/stories2009/20090205_redriver.html

    Related: “Earlier in the Year Snowmelt Runoff and Increasing Dewpoints for Rivers in Minnesota, Wisconsin and North Dakota”
    http://www.mnforsustain.org/climate_snowmelt_dewpoints_minnesota_neuman.htm

  10. 160

    There is no Chinese link?

    [Response: yes – there is now! – gavin]

  11. 161
    Alex Tolley says:

    Ultimately the airborne fraction of a CO2 release is determined largely by the buffer chemistry of the ocean, and you can get a pretty good answer with a simple calculation based on a well-mixed ocean, ignoring all the complicated stuff like temperature differences, circulation, and biology. The ocean decides that the airborne fraction of a CO2 release, after it spreads out into the other fast parts of the carbon cycle, will be in the neighborhood of 10-30%. The only long-term way to accelerate the CO2 drawdown in the long tail would be to actively remove CO2 from the air, which I personally believe will ultimately be necessary.

    Can you explain why you can ignore biology? Plants are a huge carbon sink, so why won’t biology suffice to absorb the oceanic buffering? Where can I look at the numbers on this to get a handle on how the biology will affect the CO2 levels under the no-emission scenario?

    [Response: Uptake of CO2 by the terrestrial biosphere is an important part of the carbon budget today, but ultimately the 500 Gton C terrestrial biosphere carbon reservoir will be swamped if we burn enough of the 5000 Gton C fossil fuel reserves. Also, there is a potential for a large decrease in the 1500 Gton C soil carbon reservoir with increasing temperatures. David]

  12. 162

    Furry, to create links, start by clicking on the timestamp of the comment you want to link to, then copying the comment number from the address window of your browser (start with the #.)

    Then start your comment by typing a “less-than symbol” into the comment box. (I won’t type these symbols here because I don’t recall how to tag them as text rather than HTML instructions, but hopefully you know what I mean.) This will signal HTML code to follow. After that comes:

    a/ href=”

    Then paste in the comment ID, followed by the close quote.

    Next is:

    rel=”nofollow”[Greater-than]

    Type the text you want to show–“Furry”, “Rod B”, “Regarding solar vs. nuclear,” whatever–then signal the end of the link with:

    [Less-than]/a[greater-than]

    The whole thing should look like this (subbing out the less-thans & greater-thans, of course):

    [LT]a/href=”comment ID” rel=”nofollow”[GT] text [LT]/a[GT]

    Explained like this, it sounds cumbersome, but it’s not too bad to do–though I do mean to set up an automator for it sometime when I’ve nothing better to do.

    BTW, the HTML will be effective in preview mode–the link will even work, so you can verify that all the fiddly details are correct before you post. Hope this helps!

  13. 163

    To tag something as “text, not HTML”, you use the “<pre>” HTML tag.

    And for Rod B, yes, we did eventually build more roads, but we continue to suffer from the “don’t build roads or else people will move here from California” problem. Likewise, if we fail to build more bulk transmission lines, those people who couldn’t become fully self-sufficient will suffer as an undersized electric grid tries to transport power from parts of the control region which have current renewable generation to parts of the control region which don’t.

    A giant spider web of lower voltage lines simply cannot work because current takes all possible paths from “A” to “B”, not just the path of least resistance, and that will make a complete mess of electric transmission.

    (reCaptcha sez “with learning” …)

  14. 164
    James says:

    OK, experiment time:

    “A giant spider web of lower voltage lines simply cannot work because current takes all possible paths from “A” to “B”, not just the path of least resistance…”

    Though of course there are ways to get the current to prefer certain paths over others, as is done with the high-voltage transmission grid now. However, it’s a complicated control problem even there: with the low-voltage spiderweb it’d get considerably more difficult to control.

  15. 165
    Hank Roberts says:

    Good starting point (read the citing articles published since) — it’s not just the grid, it’s the deregulation:

    What’s wrong with the electric grid? – The Industrial Physicist
    Aug 14, 2003 … Eric J. Lerner. IEEE Spectrum 1999, 36 (6), 34–39. National Transmission Grid Study Report
    http://www.aip.org/tip/INPHFA/vol-9/iss-5/p8.html

  16. 166

    Thanks for the post, Hank. Very–dare I say–illuminating.

  17. 167
    Alex Tolley says:

    @david: “but ultimately the 500 Gton C terrestrial biosphere carbon reservoir will be swamped if we burn enough of the 5000 Gton C fossil fuel reserves”

    Thank you for the response. However, the article assumes we stop burning fossil fuels today, which means that most of the 5000 Gton C in fossil fuels will not be burned. Therefore it is the biology response to CO2 levels and the relative response rates of biology vs oceanic-atmosphere gas exchange that counts, both in the short and long term. Do we have data for those rates, or can make educated guesses?

  18. 168

    Hank wrote in 165:

    Good starting point (read the citing articles published since) — it’s not just the grid, it’s the deregulation:

    Well … if you want to blame deregulation, sure. Deregulation took away the utilities’ free money and that caused them to compete on cost. Do you really want to buy a parachute from the lowest bidder?

    The solution to a deregulated energy market is regulations that don’t prevent free-market competition, but which also don’t permit operating a generator at wide-open, full-throttle. N-1 redundancy is no good if the N-1th generator is at its limits.

    James writes in 164:

    Though of course there are ways to get the current to prefer certain paths over others, as is done with the high-voltage transmission grid now. However, it’s a complicated control problem even there: with the low-voltage spiderweb it’d get considerably more difficult to control.

    How do you get precisely the right amount of power to follow precisely the correct path? When you start breaking down grid, you break what makes the grid work — it’s all connected. The grid is able to function as a unit because one generator affects the other, no matter how far removed the other is. Start separating the generators and the system breaks down — one loses track of the other and when you go to put them back together again, they might not be in phase anymore.

  19. 169
    Mark says:

    Alex 167, David was talking about burning all the fossil fuels. This means that your request is irrelevant. Ask someone else or check it yourself.

  20. 170
    Hank Roberts says:

    OK, Peter Ward’s presentation from a year ago at TED is finally available.
    http://scienceblogs.com/gregladen/2009/02/peter_ward_earths_mass_extinct.php

    As he says, this is fundamentally anti-Gaian.
    The bacteria are capable of taking their planet back, if we help them along by increasing CO2 as we’re doing, making the same result as has happened before.

    Thin dark lines in the strata each time.

    And well worth watching, reading up on and thinking about:

    http://scienceblogs.com/gregladen/2009/02/peter_ward_earths_mass_extinct.php

  21. 171
    Hank Roberts says:

    FCH, you’re way oversimplifying that IEEE article; read the articles that cite it. This has long been a big serious and well studied field and the physics was utterly ignored by the last administration.

    Look at it — the dereg. legislation assumed breaking the existing grid would cause the ‘free market’ to replace it with something magic: Fail. Gaming. Same what happened in finance happened a bit earlier in energy markets. We _know_ how people really behave.

    Now the magical thinkers are assuming we won’t have another solar cycle peak — so they can ignore the need to improve both hardware and regulation to anticipate the associated breakdowns with solar flares.

    It’s utter magical thinking. Let’s hope they’re out of office a while.

  22. 172
    Alex Tolley says:

    Both the Solomon and Archer papers exclude the effects of biology on CO2 uptake. Assuming the oceans continue to emit carbon at historic recent rates, that is about 2GTon C/yr. However the Keeling curve clearly shows that mature boreal ecosystems can sink perhaps 5 GTon C /yr during summer before re-emitting that as respiration during the winter. This is about 1% of the standing mass of forests.

    It is not a great stretch to consider that managing forests on a global scale could sink enough carbon to more than compensate for ocean emissions, stabilizing or even reducing atmospheric carbon levels on the scale of 100 years, rather than 1000. What unmanaged ecosystems could do needs more work.

    This is not to decry the results of the two papers, but to point out that unless we stupidly release all fossil carbon and overwhelm the biosphere, biological processes might be more stabilizing of GW than the purely geochemical-physical models would indicate, and possibly that biological carbon sequestration might well be a viable “geo-engineering” approach to mitigation and even reversal.

  23. 173
    Mark says:

    FCH says:”The grid is able to function as a unit because one generator affects the other, no matter how far removed the other is.”

    Ever heard of a brown-out?

    And that reduces the mains frequency and, since the energy transfer across load is a harmonic system, the notional power needs go up.

    And this is a GOOD thing???

  24. 174
    Hank Roberts says:

    > assuming the oceans continue to emit carbon

    Cite please? (“mymeemz.com” is not helpful, it’s behind your name)

    Why start with a counterfactual assumption to make your case?

    We know the oceans are absorbing some of the excess CO2; that’s what’s causing the very rapid pH change.

    Where are you getting your assumptions? Why do you rely on that source?

  25. 175
    Hank Roberts says:

    Alex, you asked where you can get the numbers on biogeochemical cycling. You can look them up; here are examples of coursework:

    http://www.colorado.edu/GeolSci/courses/GEOL1070/chap04/chapter4.html
    http://www.geo.arizona.edu/geo4xx/geos478/

  26. 176
    Hank Roberts says:

    One more — reminded by the Peter Ward video from TED last year that there is serious and increasing concern about failure of the Antarctic ice; these are tidbits from an old thread at Prometheus from before the US Supreme Court ruled on the Massachusetts sea level rise issue, which is due to be revisited at some point there.

    http://www.physorg.com/news85844283.html

    —- quoting —-

    “… This unexpected result shows that the Rutford Ice stream (larger than Holland) varies its speed by as much as 20% every two weeks. Ice streams – and the speed at which they flow – influence global sea level. Understanding their behaviour has been a priority for some time. On average the Rutford Ice Stream moves forward by one metre every day….

    … British Antarctic Survey (BAS) glaciologist Hilmar Gudmundsson says,

    ‘We’ve never seen anything like this before. The discovery that the spring-neap tidal cycle exerts such a strong influence on an ice stream tens of kilometres away is a total surprise. For such a large mass of ice to respond to ocean tides like this illustrates how sensitively the Antarctic Ice Sheet reacts to environmental changes. Glaciologists need now to rethink how the Antarctic Ice Sheets reacts to external forces. ‘

    The variations in flow of the Rutford Ice Stream are related to the vertical motion of the ocean caused by the gravitational effects of the sun and moon. Every two weeks sees large tides, the so-called spring tides which are followed by small tides, the neap tides. Scientists expect movement of the floating ice shelves, but the Rutford Ice Stream is grounded in the shallow waters of the Antarctic continental shelf.
    —- end quote—-

    Fracture initiation, but not fracture propagation, is limited by the strength of the ice:

    http://www.agu.org/pubs/crossref/2007/2006GL028385.shtml

  27. 177
    William says:

    With regard to ocean acidification at higher CO2 concentrations, a couple of comments have mentioned bad effects on shells etc. But presumably these shellfish and corals (or relatives at least) were able to survive previous episodes of high CO2. How did that happen? And does that suggest there is some limit or counter-response to increasing acidification when CO2 increases further?

  28. 178
    Dennis Baker says:

    What is stoppable and what is reversable should be the question.

    Will the planet shift in its rotation to achieve a new position of dynamic balance when the polar Ice Caps melt,as a result of a redistribution of mass?

    Is this stoppable? Is this reversable?

    Dennis Baker
    PS the boxing day tsuami successfully shifted the planets rotation

  29. 179
    Mark says:

    #117. They had millions of years to find a way to solve that problem by natural selection.

    When it takes 100,000 generations to change to a high acidity ocean, having the change in 1,000 generations is bad news.

    How did you think they did it? Acid Repellent Bat-Spray???

  30. 180
    Mark says:

    Alex 172, how much land is needed to reduce carbon in the manner you stated?

    Now, remember that

    a) people gotta eat
    b) people gotta live
    c) warmer land means bigger desserts
    d) ocean sea level rises means less land

    where do we fit these trees?

  31. 181
    Alex Tolley says:

    Hank@174 “assuming the oceans continue to emit carbon”

    This is the point of the 2 papers. The accumulated reservoir of carbon in teh oceans due to CO2 absorption will provide a source to replenish the atmospheric CO2, thus maintaining a high CO2 level even if we stop using fossil fuels. No counterfactual assumption AFAIK.

    Thank you for the links – much appreciated.

  32. 182
    Alex Tolley says:

    Mark@180 I’m merely throwing out some numbers that exist. The boreal forests are assumed to be the source of the seasonal carbon dioxide sinks during the northern summers in papers noting this effect.

    The point is that these biological sinks, albeit temporary each year are large and appear to be of the magnitude needed to absorb the accumulated carbon reservoir in the ocean. This suggests that biological systems might be able to handle the CO2 in a shorter time than the 2 cited papers predict that geochemical models will require.

    Of course we would need to make each summer’s sink permanent each year, with suggests that we need to harvest the production of wood and sequester it. Since the 5 GTon C/yr sink is ~ 1% of the standing global biota, this suggests that given tree life cycles, that the numbers are of the correct order if we managed forests rather than destroyed them. Harvesting trees, sequestering their carbon permanently and replanting seedlings might be a possible strategy, if we don’t carry on with “business as usual”. At least we wouldn’t need exotic new technology to scrub the air.

  33. 183
    Rod B says:

    Hank (171), et al: I’m pretty much with you on the deregulation of the power generation industry. It was a pipe dream from pols who had little concept of the workings — other than being able to spell competition. (Though I don’t think FCH is arguing for deregulation per se…)

    But, your (and countless others) Pavlov response to blast George W. for any and every ill that crosses your path is getting tiresome, at least to me. The deregulation was his fault because???

  34. 184
    Hank Roberts says:

    FAQ from Bob Grumbine
    http://www.radix.net/~bobg/faqs/scq.CO2rise.html
    SEE:
    “2. Carbon fluxes and reservoirs

    First we look at natural carbon fluxes, next at fluxes of anthropogenic
    carbon, and finally at carbon reservoirs. Carbon enters and leaves the
    atmosphere largely as CO2. The remaining carbon fluxes involve various
    organic and inorganic carbon compounds…..”

    Copying more here would be pointless, likely losing formatting. See the original.
    See also http://moregrumbinescience.blogspot.com/
    Look through the existing topics, you’ll likely find a place to ask.

  35. 185
    Hank Roberts says:

    By the way, I’ll wait for one of the scientists on this question — but I think the lag time for the ocean uptake of CO2 is barely started, and if we do stop increasing CO2 in the atmosphere, it will continue to go into the oceans for quite a while, slowly.

    We’re not facing a “can’t help the problem because the ocean will bubble out CO2 if we remove it from the air” situation.

    Transfer to and from the ocean is slow — that’s time available for increasing the rate of removal from the atmosphere into other sinks (whether algae or plankton or bales of plastic or biochar sunk into some longterm repository, or fracturing or opening up some of the mineral material that can take CO2 out of the air). I don’t think there’s a huge amount of CO2 already _in_ the ocean, simply because it takes so much longer to go from atmosphere to ocean than from coal mine to atmosphere. We’re pumping CO2 into the air far faster than anything has done in the past.

  36. 186

    Mark writes in 173:

    FCH says:”The grid is able to function as a unit because one generator affects the other, no matter how far removed the other is.”

    Ever heard of a brown-out?

    And that reduces the mains frequency and, since the energy transfer across load is a harmonic system, the notional power needs go up.

    And this is a GOOD thing???

    Yes, I’ve heard of brown-outs. They occur when system voltage is allowed to sag in order to prevent frequency from falling below the permissible value. Frequency cannot be allowed to deviate from nominal for reasons I suspect would bore most people to tears. For SOME loads this results in increases in current requirements, but for purely resistive loads, it results in reduced POWER.

    I’m not sure what this has to do with anything — fragmenting the grid results in an inability to regulate frequency, and without frequency regulation the entire system fails or cannot be defragmented easily. That’s the big risk to positive voltage gradients from distributed generation — resynchronizing large islands when it’s time to reconnect to the grid. What you’re proposing would lead to exactly that problem, and it’s a real doozy. The only solution to that problem I know is to isolate all the distributed generation, force a blackout in the isolated region, repower from the grid, then allow the distributed generation to resynchronize itself. With turbine power generation resynching is fairly easy — the frequency is first matched, then the phase angle slowly changed to match, and finally the turbine connected to the grid, where it should stay in synch fairly easily due to some pretty slick physics.

  37. 187
    Mike G says:

    William (177)
    The history of reef building, most of which doesn’t include corals at all, is a discontinuous one. It’s full of periods where the dominant reef building groups go extinct (including two whole previous orders of corals) as well as periods where there is no reef building to speak of for several million years. There’s also the case of the Corallimorpharians which are modern non-calcifying corals that seem to have evolved from calcifying ancestors.

    While it’s hard to say with certainty that the changes in ocean chemistry were the chief cause of extinction of any reef building groups, many of the reefless periods do coincide with periods of altered seawater chemistry as does the appearance of the Corallimorpharians.

    Among calcifiers we also see switches between deposition of aragonite and calcite as the dominant polymorphs of CaCO3 at various periods in the planet’s history. The protection afforded by this switch is fairly limited though and while some species can switch back and forth between the two polymorphs depending on prevailing chemistry, many (most?) animals don’t seem to be able to do so except on evolutionary timescales.

  38. 188
    Mark says:

    186: Not what the engineer in charge of an electricity generating power station said. It was when the load on the system was more than the power possible to generate. A higher load then caused a slowing of the generator flywheel by both extraction of rotational energy and from the EMF being reduced causing the rotation of the electromagnets to be retarded.

  39. 189

    Mark writes in 188:

    186: Not what the engineer in charge of an electricity generating power station said. It was when the load on the system was more than the power possible to generate. A higher load then caused a slowing of the generator flywheel by both extraction of rotational energy and from the EMF being reduced causing the rotation of the electromagnets to be retarded.

    That’s a nice explanation for someone who doesn’t understand how the electric grid actually operates.

    What I can tell you is that if the grid frequency falls outside a very, very narrow permissible value, generators will either automatically trip off-line or destroy themselves. All AC generators must also remain in very near perfect sync, both as to frequency and phase angle, so it’s also not the case that “Generator A” gets to run a little slow and “Generator B” gets to keep on running. I’d be happy to bore you to tears, but a brownout isn’t as simple as “too much load, too little power.” Brownouts happen when voltage regulation is altered so that system voltage drops. That’s the $0.02 explanation. Frequency regulation — that rotational speed of the generator turbines and other parts — cannot be given up on, even if system voltage drops outside the -5% limit set by standards. At a -10% drop, which I think is about the limit of brownout voltages (108VAC in a 120VAC nominal system — higher voltages apply in distribution and transmission lines, or are reduced via tap selectors on transformers), frequency must still be +/- less than 0.1% of nominal throughout the entire interconnect.

    There’s also another way in which brownouts occur, and that’s when transmission congestion exceeds the capacity of those transmission lines, causing excess voltage drop along the way (our dear friend Ohm and his law), and that increases along the negative gradient from generator to consumer, as voltages are stepped down. A “spider web” of lower voltage distribution lines — what you’re suggesting — is going to have a devil of a time dealing with congestion, loop currents, and all the other problems with your suggestion.

  40. 190
    James says:

    FurryCatHerder Says (8 February 2009 at 1:42 AM):

    “How do you get precisely the right amount of power to follow precisely the correct path?”

    If you want details, find an electric power systems engineer. It involves things like reactive power control and phase shifters, that I used to know something about 20 years ago. Then you run computer programs that calculate system powerflow & stability under sets of operating parameters, ’til you find a way to get the power to go where you want it to without breaking the sustem.

  41. 191
    Hank Roberts says:

    Look at that IEEE article and follow citing articles forward in time. Education awaits.

  42. 192
    Hank Roberts says:

    See also:
    http://scholar.google.com/scholar?&q=IEEE+deregulation+electric+grid

    and use the ‘recent’ setting to cover the time span you want to look at.

  43. 193
    Alan Kohn says:

    Can geoengineered technolgies that will reduce the sun’s light/heat energy by a few percent before it penetrates our atmosphere buy us the time to go green gradually? These technolgies include solar-shades, solar-reflecting, and solar-scattering devices both on the Earth’s surface and in space. These devices would have to be replaced periodically, but any adverse effects caused by these devices could be mitigated by shutting them down as necessary. In any event, no adverse effects would be as bad as the \irreversible\ disasters the above posts have predicted for us.

  44. 194

    Re #94 Cowan,
    Why do we have a problem if the “abundant” silicate minerals will capture CO2?

    There is no doubt of their abundance. Peter B. Kelemen’s “The Origin of the Land under the Sea”, Scientific American February 2009, has on p. 56 these words: “The only way to fully appreciate the Oman ophiolite is from the air. This massive formation constitutes a nearly continuous band of rock 500 kilometers long and up to 100 kilometers wide.” And on p. 57 there is a photo.

    This rock, if pulverized, could take down all the CO2 man has ever emitted and tuck it inconspicuously into that terrain as magnesium carbonate and silica. Other outcroppings elsewhere are similarly ample; the Twin Peaks massif in, IIRC, Washington State is one. I linked some photos in the Air Capture thread. One shows how dunite terrain is desert even if well watered: a dunite massif in New Zealand adjoins another mountain, and at the joint, the other mountain is green, the dunite is orange.

    The problem, such as it is, is that the stuff isn’t pulverizing itself. The energy required to do so is small enough that dedicated coal-fired electric power plants set up on the massifs, although offensive in coal power’s usual non-atmosphere-related ways, would take down net CO2. Each would, in fact, take down enough to cancel its own emissions and those of at least seven similar plants elsewhere.

    Governments’ fossil fuel incomes are enough to pay for a large, possibly more than unit, fraction of the necessary garbage-collecting.

    (How fire can be domesticated)

  45. 195
    Hank Roberts says:

    > reduce the sun’s light/heat energy

    Useless. The fast problem is ocean pH change, and stopping the increase of CO2 is the fix needed.
    http://scholar.google.com/scholar?sourceid=Mozilla-search&q=ocean+ph+change

    See also Peter Ward.

  46. 196
    Jim Eager says:

    Re industrial-scale projects to pulverize olivine deposits (194), there’s also the Table Lands peridotite in Newfoundland, but since they are in Gros Morne National Park, I’d expect stiff, even insurmountable resistance to dismantling and pulverizing them.

  47. 197
    Jim Eager says:

    Re Alan Kohn @193, partially blocking sunlight will not force ocean acidification to proceed more slowly.

    And I suspect reducing incoming sunlight just might have negative repercussions on agricultural productivity, too.

  48. 198

    James writes:

    If you want details, find an electric power systems engineer. It involves things like reactive power control and phase shifters, that I used to know something about 20 years ago. Then you run computer programs that calculate system powerflow & stability under sets of operating parameters, ’til you find a way to get the power to go where you want it to without breaking the sustem.

    And you have to do that continually for every control point in a spider web of interconnections.

    Remember — this started with someones comments that what was needed wasn’t more high voltage transmission lines, but lots of lower voltage ones.

  49. 199
    Douglas Wise says:

    I am grateful to David Archer for his response to my comment (#132) relating to ocean iron fertilisation. I regret that I am somewhat late in picking it up. David suggests that, if one models for the likely effects of such fertilisation, the CO2 drawdown effects are likely to be trivial. I have absolutely no reason to doubt this. However, I recently learned of the existence of salps, a swarm of which can purportedly consume sufficient phytoplankton to sequester 4000 tonnes of carbon per night. This amount does not appear to be trivial. While I can see that creating more phytoplankton blooms without an existing mechanism of “taking them down” is unlikely to be helpful, I wondered whether David’s model had considered the possible contribution of salps to sequestration. Obviously, the difficulties of widespread salp culture, in part by encouraging phytoplanton blooms with fertilisation, might well prove insuperable. I am merely seeking enlightenment, not advocating salp culture.

    David mentions offsets and his fear that they may be used with respect to ocean fertilisation. This tempts me into another question. Given that many, including James Hansen, believe that we must reduce atmospheric CO2 levels rather than stabilising them, what geoengineering sequestration methods would David advocate? Would, for example, he favour offsets for biochar or accelerated mineralisation? If we really need atmospheric CO2 drawdown, we should now be considering how to do it and how to pay for it. Could we have a follow up thread to the original one devoted to air capture?

  50. 200
    Hank Roberts says:

    > salps
    The idea’s been promoted a lot recently by a company called ‘Atmocean’ — here are a few stories.
    http://www.google.com/search?q=salps+“climate+change”+CO2+atmocean

    My general comment on such is to quote this:

    “Biologically rational decisions
    may not be politically possible
    once investment has occurred.”

    http://www.sciencemag.org/cgi/content/summary/315/5808/45
    Science 5 January 2007: Vol. 315. no. 5808, p. 45
    DOI: 10.1126/science.1135767

    SUSTAINABILITY: Anchovy Fishery Threat to Patagonian Ecosystem
    — Skewgar, Boersma, Harris, Caille