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How much CO2 emission is too much?

Filed under: — david @ 6 November 2006 - (Slovenčina)

This week, representatives from around the world will gather in Nairobi, Kenya for the latest Conference of Parties (COP) meeting of the Framework Convention of Climate Change (FCCC) which brought us the Kyoto Protocol. The Kyoto Protocol expires in 2012, and the task facing the current delegates is to negotiate a further 5-year extension. This is a gradual, negotiated, no doubt frustrating process. By way of getting our bearings, a reader asks the question, what should the ultimate goal be? How much CO2 emissions cutting would it take to truly avoid “dangerous human interference in the climate system”?

On the short term of the next few decades, the line between success and excess can be diagnosed from carbon fluxes on Earth today. Humankind is releasing CO2 at a rate of about 7 Gton C per year from fossil fuel combustion, with a further 2 Gton C per year from deforestation. Because the atmospheric CO2 concentration is higher than normal, the natural world is absorbing CO2 at a rate of about 2 or 2.5 Gton C per year into the land biosphere and into the oceans, for a total of about 5 Gton C per year. The CO2 concentration of the atmosphere is rising because of the 4 Gton C imbalance. If we were to cut emissions by about half, from a total of 9 down to about 4 Gton C per year, the CO2 concentration of the atmosphere would stop rising for awhile. That would be a stunning success, but the emission cuts contemplated by Kyoto were only a small step in this direction.

Eventually, the chemistry of the ocean would equilibrate with this new atmospheric pCO2 concentration of about 380 ppm (the current concentration), and its absorption of new CO2 would tail off. Presumably the land biosphere would also inhale its fill and stop absorbing more. How long can we expect to be able to continue our lessened emissions of 4 Gton C per year? The answer can be diagnosed from carbon cycle models. A range of carbon cycle models have been run for longer than the single-century timescale that is the focus of the IPCC and the FCCC negotiation process. The models include an ocean and often a terrestrial biosphere to absorb CO2, and sometimes chemical weathering (dissolution of rocks) on land and deposition of sediments in the ocean. The models tend to predict a maximum atmospheric CO2 inventory of about 50-70% of the total fossil fuel emission slug. Let’s call this quantity the peak airborne fraction, and assume it to be 60%.

The next piece of the equation is to define “dangerous climate change”. This is a bit of a guessing game, but 2°C has been proposed as a reasonable danger limit. This would be decidedly warmer than the Earth has been in millions of years, and warm enough to eventually raise sea level by tens of meters. A warming of 2° C could be accomplished by raising CO2 to 450 ppm and waiting a century or so, assuming a climate sensitivity of 3 °C for doubling CO2, a typical value from models and diagnosed from paleo-data. Of the 450 ppm, 170 ppm would be from fossil fuels (given an original natural pCO2 of 280 ppm). 170 ppm equals 340 Gton C, which divided by the peak airborne fraction of 60% yields a total emission slug of about 570 Gton C.

How much is 570 Gton C? We have already released about 300 Gton C, and the business-as-usual scenario projects 1600 Gton C total release by the year 2100. Avoiding dangerous climate change requires very deep cuts in CO2 emissions in the long term, something like 85% of business-as-usual averaged over the coming century. Put it this way and it sounds impossible. Another way to look at it, which doesn’t seem quite as intractable, is to say that the 200 Gton C that can still be “safely” emitted is roughly equivalent to the remaining traditional reserves of oil and natural gas. We could burn those until they’re gone, but declare an immediate moratorium on coal, and that would be OK, according to our defined danger limit of 2°C. A third perspective is that if we could limit emissions to 5 Gton C per year starting now, we could continue doing that for 250/5 = 50 years.

One final note: most of the climate change community, steered by Kyoto and IPCC, limit the scope of their consideration to the year 2100. By setting up the problem in this way, the calculation of a safe CO2 emission goes up by about 40%, because it takes about a century for the climate to fully respond to rising CO2. If CO2 emission continues up to the year 2100, then the warming in the year 2100 would only be about 60% of the “committed warming” from the CO2 concentration in 2100. This calculation seems rather callous, almost sneaky, given the inevitability of warming once the CO2 is released. I suspect that many in the community are not aware of this sneaky implication of restricting our attention to a relatively short time horizon.

Note: responding to suggestions in the comments, some of the numbers in the text above have been revised. November 7, 2:31 pm. David

232 Responses to “How much CO2 emission is too much?”

  1. 201
    William Astley says:

    Re: “The next piece of the equation is to define dangerous climate change. This is a bit of a guessing game, but 2C has been proposed as a reasonable danger limit.”

    What is the danger? Warmer by 2C or colder than 2C? Does the earth’s climate stabilize when it is warmer? Is the macroclimate unstable when the earth’s temperature drops?

    Refer to figure 3 in the attached paper. As the planet cools the glacial cycle intensives. There is an obvious long term cooling trend. See figure 2 in the same paper, which shows the decline in ocean bottom water temperatures in the Atlantic. The bottom Atlantic Ocean temperature is currently 2C. Salty water freezes at -1.8C. This is an unstable system. The heat stored in the deep ocean water previously protected the planet from temperature oscillations.

    The next paper shows the change in Antarctic ice core temperatures over the last 420,000 yrs. Note the increase in dust (figure 2) in the last glacial cycle the “Wisconsin Glacial Period” as compared to past glacial cycles. When the earth is colder it is drier. The increase in dust is due to colder conditions and very low CO2 levels. Photosynthesis efficiency for C3 plants (all plants except for grasses) decreases linearly with CO2 level. Photosynthesis, stops for C3 plants when the CO2 level reaches 150 ppm to 50 ppm (depending on the plant in question.)

    Note the change in ice sheet temperature during the glacial cycles is 8C (temperature drops).

    How dangerous is sudden rapid cooling? Is the planet at the end of the warm interglacial period? What causes the drop in CO2 in the glacial cycles?

    Separate energy and material conservation from dangerous climate change.

  2. 202
    David B. Benson says:

    Re #201: William Astley, even without AGW, there is no possibility of the onset of another ice age for at least 50,000 years, according to orbital forcing theory. This is treated more extensively on a previous thread, as is the question regarding carbon dioxide changes throughout the glacial cycles.

  3. 203
    L. David Cooke says:

    RE: #200

    Hey Dick;

    1. As for coming up with unique ideas to save energy you are so far from the truth that it really is scarry. Simply put, the recent “Cost” of gasoline has doubled in the US along with the cost of plastic. As the US is trying to climb out of the economic slump it found itself in since 2001 there simply has not been enough increase in salary to cover even the simple cost of living increases caused by the increased energy prices. So the money is coming out of savings and the budgets for variable costs have been cut to the bone. Most middle class families look at expenses that used to be variable costs as emergency only. If there were any reliable effective ways to reduce the higher costs of petroleum believe me the US population would be leading the way. To put it simple the energy systems are so specialised, in order to squeeze the greatest amount of energy for a given dollar that an alternative is not necessarily possible with the given infrastructure.

    The cost to forklift out the current infrastructure and to adapt to another temporary solution is not viable. The goal is to stop with the bandaid approach and move away from the evolutionary changes in the energy structure to move towards a revolutionary change. The problem with all of the chooices you have mentioned is that they are unreliable. I cannot simply hook up a Solar Panel to my house and expect it to power the house 7×24. The cost just to store the demand to supply 14-16 winter hours of power would exceed the cost of the house in 10 years if you live above 36 Deg, much less 24 to 72 hours. And yes there would be the need to supply power that long as an low front in Autumn can result in thick cloud cover for 5-7 days on the US NE and NW coasts.

    2. Again most of the grocery bags in the US are plastic and if you look into the cloth bags you take to the Grocery store you should see that they are likely made of 98% Polyester (plastic). Hence, your Tax is not helping even if you take you own bags, it will only increase the chance that someone would see them as valuable and try to steal them…

    3. As to your idea of dumping your excess to the grid, where did you get the idea that the grid was some form of giant storage system? The energy there has to come from within 100 miles or the losses are so great that the 1000 MW generated comes out the end of the “pipe” as 50 MW only 200 miles away. Do you think that the Power companies can meet your demand for power on an as needed basis? Do you actually believe they can simply turn up the “Juice” if they notice you decide to turn on the outdoor light to let the cat out? What are you going to do for power if every home or Solar Panel within 200 miles are socked in or snowed under?

    Believe me I am not saying it is not a good idea to invest in renewables; however, you have to consider their limitations. Even if the US fully embraced the use of renewables and included additional low head water power or estuary tidal power it would not meet more then 20% of demand. Add in even the best energy conservation program you might be able to trim out another 15-20%. What do you do to replace the 60% you cannot meet by this method?

    I love the idealism you are sharing; but, the pragmatic reality will not magically go away just because you think it should. The Laws of Physics are immutable just because you think something should be possible does not make it so.

    Dave Cooke

  4. 204
    Hank Roberts says:

    I pray you, consider the possibility that you may be wrong:

  5. 205

    From C. W. Magee’s comment 198,

    You can’t use quicklime to capture CO2 because quicklime (CaO) is produced by decomposing calcium carbonate in the reaction CaCO3 + heat -> CaO + CO2. If you then scrub the atmosphere with the reaction CaO + CO2 -> CaCO3, then you only get back where you started.

    Would C. W. Magee please be good enough to acknowledge my already-given explanation why I think that’s incorrect. Otherwise it looks as if he’s trying to give lurkers the impression I never addressed that point when in fact I did.

  6. 206
    Dick Veldkamp says:

    Re: #203

    Dave, frankly I do not understand your first sentence, but never mind, let me answer the rest of your post.

    1. It seems to me that in the situation you describe people would definitely consider cars with more mpg next time they buy one. I am not denying that there are practical problems in creating a fair energy tax; one obvious thing to look at would be to (partly) replace VAT or income tax with energy tax.

    2. My point was that if you have your own shopping bag you do not need to have a new plastic (or paper) one each time you go to the supermarket.

    3. No, of course the grid is not a storage system. But a dense grid (like we have in Europe) ACTS like one in the sense that I can dump my excess power into it (for the power company this is the same as reduced demand). And yes, the power company is actually adjusting electricity production all the time to make it fit demand. This is done in a somewhat indirect way, by controlling voltage and frequency in the grid. [My line of work is wind energy, I do know what I am talking about here.]

    Renewables are not the total answer, but they can make an important contribution. Most estimates are 20% of electricity by wind alone, not a number to be sneezed at. Some current numbers: Denmark 20%, Spain and Germany: 6%.

  7. 207
    William Astley says:

    Re: Comment 202 “… even without AGW, there is no possibility for at least 50,000 years, according to orbital theory [of another ice age.]”

    The above belief my not be correct based on recent work by new people who have entered the field of Paleoclimatology. They entered the field to solve the problem, of what is causing the observed periodic massive rapid climate change events (cooling and warming), in the climatic proxy data.

    The rapid warming and cooling events, they hypothesis is caused by changes in the galactic cosmic rays (GCR) flux. The galactic cosmic rays create ions which are the nucleus for clouds. Higher GCR results in more clouds and hence lower temperatures. The GCR is modulated by the earth’s magnetic field and the solar wind. A high geomagnetic field and/or a high solar magnetic field results in lower GCR, hence less clouds and a warmer planet.

    In the 1990’s it was found that the earth’s magnetic field reaches a maximum on a 100,000 year cycle. The sun is currently at its highest level in 8000 years. These two factors reduce the GCR and hence make the planet warmer. The earth’s magnetic field has, suddenly (2003), started change. Some believe the sudden change and the Atlantic anomaly is indication that the geomagnetic field is starting to reverse. Based on Paleoclimatic records, the sun will move from a its current maximum to a minimum.

    If the GCR hypothesis is correct and these two changes, occur simultaneously, there will be a sudden and sever drop in the planet’s temperature.

    The following paper is discusses the science behind the GCR hypothesis.

    The paper “The Glacial Cycles and Cosmic Rays” by J.Kirkby, A. Mangini, and R. Muller (2004) examines changes in the geomagnetic field, that are concurrent with major planetary temperature changes. Due to GCR modulation effects on clouds, it is hypothesized that a stronger geomagnetic field results in warmer temperatures and a weaker field colder temperatures. The authors examine deep sea sediments and find as have others that the geomagnetic field peaks at 100 kyr intervals. Further the authors find at termination II (Warming that led to the Eemien interglacial) that the records show that the warming started when insolation was at a minimum. They also find that the termination II warming and other warming events coincide with periodic geomagnetic field maximums.

    “Bond et al. (17,18 see paper references) have shown a strong correlation between ice-rafted-debris (IRD) events in the North Atlantic and increased GCR fluxes (measured by both BE10 and C14) during the last 12 kyr. … The Little Ice Age around the 17th century appears to be the most recent of the about 10 such centennial-scale events during the Holecene, when North Atlantic sea surface temperatures fell by around 2C in association with … high GCR flux. Remarkably, the IRD events extend beyond the Holecene… This argues against a primary internal trigger such as ice sheet dynamics since the climate conditions varied a great deal over this interval.”

    “In this paper we propose the glacial cycles, rather than being driven by insolation cycles as in the present standard model, are initially driven by cosmic ray changes, probably through their effects on clouds.”

    “Recent measurements suggest that long-term records of variation of Earth’s magnetic field – in both strength and magnetic inclination – show orbital frequencies -… The 800 kyr record known as Sint-800 is reported to show no such cycles; however we will present a new analysis here that shows such cycles are in fact present in this record.”

    “We present a new spectral analysis of cosmic ray flux recorded in the BE10 content of deep ocean sediments, which shows the present of orbital cycles. Further we present additional results based on the BE10 record and on precisely-dated speleothems that reinforce the causality problem with the Milankovitch model and support our conclusion that cosmic rays appear to be driving the glacial cycles.”

    Attached is the Antarctica data which I referred to in my previos comment. Based on that data, why would you expect this interglacial to last 50,000 years?

  8. 208
    John L. McCormick says:

    Hank, if your link in #204 was intended to prove Dave wrong, I miised it.

    Dave, the truth of your comment;

    [Most middle class families look at expenses that used to be variable costs as emergency only.]

    is amplified by the several cash flow facts most working Americans are struggling to overcome.

    In the US there is about $9 trillion we owe for our homes; $2.2 trillion of plastic card payments due, college loans???, equity lines of credit??? and high monthly energy and health care costs….all shared by about 100 million tax payers. That is roughly about $130,000 of private debt per taxpayer. Then, add the nearly $28,000 each and every American owes to US government debt holders.

    Now, that is a lot of outgoing we are coping with and definely limiting consumer choices for storm window retrofits, efficient appliance replacement and solar water heater installations or that 40 mpg+ car we should be driving.

    Hank, there is a large dose of reality in Dave’s comments (including the limited reach of renewables in the US electricity sector).

  9. 209
    L. David Cooke says:

    RE: #204

    Hey Hank;

    I wish that the pessimestic view were inaccurate. However, it is unlikely that efficiency of the current processes will improve.

    Think about this, First, imagine all species populations were expanded to the point that they did not intrude on any other species ability to thrive. Second, That the amount of energy, necessary to maintain the species with access to the total solar energy covering the area in which the species is thriving would be insufficient to sustain the species. This seems to mean that to achieve maximum population you either have to remove the solar resource from another species or find a separate source to increase the amount of energy available to sustain the species population.

    Now let’s say you have the ability to define the distribution of the incoming solar energy. So if you were to attempt to take the 1370 Watts/m^2 of incoming energy and reduce it in the atmosphere by 500 Watts/m^2 at the equator with levels being reduced to 300 Watts/M^2 at 45 Deg. N/S and 80 Watts/m^2 at 67 Deg N/S (Averaged across the year the values should be approximate 1/2 for areas above 24 Deg. N/S) You have to determine how that energy is to be distributed.

    The energy has to go to many things, from warming the atmosphere and the land and waters of the planet to providing the energy necessary for plants to grow. So what happens when you start removing energy from plants for photo volatic cells or some other anthropogenic project?

    The basis of the food chain relies on plants and the ability of plants to convert sunlight to sugar. From there the plant that forms from the conversion of sunlight and earth minerals becomes biomass. Harvested biomass begins to supply the rest of the food chain with resources. That which is not harvested feeds microbes that breakdown the Biomass resources and becomes some form of trapped solar energy in some form of storage or the energy is released to the atmosphere and eventually escapes into space.

    Obviously with even the best of technology today we cannot achieve a high enough efficiency to convert the incoming solar energy to support the human populations of the planet at the current levels with the energy demands of current technology. To that end we are extracting “stored” solar energy to meet the demand. The other problem is getting the necessary energy in the correct form to support the various current technologies. This will reduce the efficiency of the stored solar energy. Is this a good idea?

    Where do we go from here? Do we destroy anything that cannot be used by a member of a desired species population? Do we begin to place limitations on all species and define the correct sustainable mix and levels to ensure that the various species continue to thrive? Is there surface area and resoures sufficient on the planet that this discussion is unnecessary and all energy and environmental discussions are simply philosophic musings? How far is man going to go trying to play at being some form of God?

    Dave Cooke

  10. 210
    David B. Benson says:

    Re #207: William Astley, the orbital forcings are easily and correctly computable for millions of years to come. This also has been discussed on a previous thread as also have GCRs and solar fluxes. Neither of the latter appear to agree with the data anywhere near as well as orbital forcing, according to the orginal posts and comments on those previous threads.

  11. 211
    Hank Roberts says:

    >what happens when you start removing energy from plants for photo volatic cells or some other anthropogenic project?

    Why start there? There’s ample surface area available that has sunlight but not enough soil or moisture. Rooftops, for example, are quite good locations. The area available is enormous.

  12. 212
    L. David Cooke says:

    Hey Hank;

    I concur, start with the UHI sources, at least that way the heating from these sources are able to do some good. The point I was making was what became of the trees and the arable land that was covered over by buildings and roads. The point is we have already removed a great deal of the land available as resources necessary to support the human population.

    We need to remove as many of those buildings as possible and return them to cultivation of some form if we are to begin to raise the renewable resource levels above 40% on average. By the same token there are the deserts in some areas with large cities close by…

    Dave Cooke

  13. 213
    Denis Estublier says:

    Thank you for all the good information and discussions compiled in “real climate”.
    This is a question that has since long annoyed me and that I have never seen discussed anywhere:
    We are talking of Gigatons of release of CO2 in the admosphere. Since this is occuring through burning and oxidizing carbon, what is happening to O2. For each released ton of CO2, there are 727 kg of oxygen lost from the atmosphere. Therefore, if the CO2 content of the admosphere is climbing, the O2 content must be declining.
    Isn’t that also a matter of concern for human health?
    Is anyone traking the history of oxygen concentration in the atmosphere?
    Every single combustion process on Earth is using oxygen …….

    Kind regards,

  14. 214

    Re “For each released ton of CO2, there are 727 kg of oxygen lost from the atmosphere. Therefore, if the CO2 content of the admosphere is climbing, the O2 content must be declining.
    Isn’t that also a matter of concern for human health?”

    It is, and qualitatively you’re quite right. But consider that CO2 is 0.00038 of the atmosphere by volume, whereas oxygen is 0.20948. The level of oxygen is indeed decreasing, but the decrease is almost too small to measure. We could burn all the available fossil fuel and the decrease in oxygen would be less than 1%. (I think that’s right, maybe the vast coal reserves would give a higher figure.) So the immediate danger is more of global warming than of suffocation.

  15. 215
    yartrebo says:

    Re: 213, 214:

    My understanding is that the situation is somewhat in the middle. Oxygen is indeed very abundant, but well before we run too low on oxygen (12% concentration at sea level perhaps), we will poison ourselves with CO2.

    Here is what Wikipedia has to say about CO2 poisoning.

    “When inhaled in high concentrations (greater than 5% by volume), it is immediately dangerous to the life and health of plants, humans and other animals. The current threshold limit value (TLV) or maximum level that is considered safe for healthy adults for an 8-hour work day is 0.5% (5000 ppm). The maximum safe level for infants, children, the elderly and individuals with cardio-pulmonary health issues would be significantly less.”

  16. 216
    James says:

    Re #208: “In the US there is about $9 trillion we owe for our homes; $2.2 trillion of plastic card payments due…”

    Yet all that is in large part a lifestyle choice, or the consequence of such choices. How much of it is really necessary for either survival or happiness? In my experience, at least, not much.

    “Now, that is a lot of outgoing we are coping with and definely limiting consumer choices for storm window retrofits, efficient appliance replacement and solar water heater installations or that 40 mpg+ car we should be driving.”

    I don’t quite follow that line of reasoning. You’re claiming that you (the generic consumer, not you personally), can’t afford a 40 mpg car (much less a 60-70 mpg one), but you _can_ afford to spend at least half again as much on a new SUV? Oh, but you say you need it to haul around your jet skis, snowmobiles, dirt bikes, quads, and other gasoline-powered toys? Sure you do :-) Likewise, you can’t afford storm window refits, but you _can_ afford to install decorative outdoor lighting and leave it burning all night? You can’t afford an efficient refrigerator, but you _can_ afford the twice-as-expensive model with automatic icemaker, drinking water taps, and all the other bells & whistles? And have it installed along with your new granite countertops?

    Sorry, but the “can’t afford it” argument just doesn’t hold water when applied to the average American consumer.

  17. 217
    John L. McCormick says:

    RE # 216

    James, would that life was a simply as yours seems to be.

    Reading between the lines on the post at #208 is likely a challenge unless one imagines the generic consumer is, in a CO2 mitigation world, being targetted to borrow more money than ( for some debt burdened souls ) the bank is likely willing to loan.

    The houses in need of window retrofit are not the newer, grander ones. Likely they are owned by less fortunates and elderly. But, what the heck, they made their lifestyle choice so let them live with the consequences. And, just maybe, people of limited cash flow are driving fuel inefficient cars that have little trade in value so the clunker will have to last a few more paychecks. Am I making myself a bit more down to earth here?

    People are hurting despite their lifestyle choices and your off the cuff summerization of their own darned fault are ships passing in the night.

    I say all of this as an avowed climate change alarmist who sees no reason to believe generic customers will haul their inefficient cars, appliances, windows, etc. to the town dump without some financial assistance. Are you ready to pay more taxes to subsidize the lower income and fixed income Americans to live the lifestyle you do? I am.

  18. 218
    L. David Cooke says:

    Hey James;

    All I can say is you watch far too much TV or at least the wrong shows. The average American consumer doesn’t have time for half the activities or the toys you mentioned as they work two jobs and send their children off to day care to be raised by someone else so that the sppouse can go to work to pay for it and the little left over for household expenses.

    Now maybe the more affluent do; however, they make up less then 15% of the American consumer base. Get out a little, the average home in NC runs between 100 and 150K, the average income runs between 20 and 40 K. The greatest number of homes on the market exceed 300K all because there is no longer the income base to support these homes, not because they were over built by greedy developers (Though there are possibly those as well…)

    Those that can afford a multiputpose vehicle will choose a SUV because it is more economical to operate a single vehicle that can perform multiple functions then it is to purchase multiple vehicles. Hey, it is even better for the environment as only half the resources and the wastes are necessary to accomplish the task. Plus manufactures have pushed the false idea that they are safer then the average passenger car. Most SUVs are based on the small truck standard of safety and were never meant for the general consumer. That they have been pushed as the replacement for the old car pool moms station wagon is lost on most consumers. That they are not as effective at converting the BTU in gasoline to motive energy is beyond the ability of the consumer to control. However, when looking to choose a vehicle the most cost effective choice is the preferred choice. All the flash that the baby boomer generation used to flaunt was eaten up by corporate failures, the subsiquent pension failures and the stock market crash. At one point in 2001 the American people had nearly 4 trillion dollars in M1 and now only 5 years later that value is down to around 1.2 trillion sorry; but, the days of wanton spending by most Americans is long gone and the costs for their excesses will end up being born by their young for nearly a generation.

    I can say that based on you comments it is clear you have a very jaundiced view of the formerly decadent civilization you portray. Your view is far from the truth, matter of fact, it is not unlike the “popular” view that certain reactionary political organizations wish to suggest which makes the US a target for the envious. Get a grip, most Americans are far from the model you have represented.

    Dave Cooke

  19. 219
    James says:

    Re #218: You say “All I can say is you watch far too much TV or at least the wrong shows” – to which I can only respond by saying that you ought to check facts before making statements like that :-) In point of fact, I’ve never owned a TV in my life, and don’t watch it except when constrained to do so by courtesy.

    My ideas of what the American (or FTM European, as I’ve lived there at times), are derived from observation of the people I see around me. I don’t live in a wealthy neighborhood, nor yet an ‘upscale’ one of McMansions, yet the folks next door have a 40-ft RV in their driveway, across the way there are jet skis and dirt bikes, the high school kid down the road hauls his quad behind a Suburban that his folks bought him… Now maybe things are different where you live, but around here such is fairly normal. The wealthier people may buy new Hummers or Escalades instead of used Fords and Chevys, but they’re much the same underneath :-)

  20. 220
    L. David Cooke says:

    Hey James;

    So of the total population of your neighborhood what percent have the toys you are concerned about? So far it looks like three families out of how many in your neighborhood 20? So that makes your deviation around what, 15% of the whole neighborhood? Hmm…, that looks about average…

    Yes, it is much different here. Of the 20 families in my area there are no RV’s, nor children driving around in Suburbans. There are not jet skis or dirt bikes. There are a few road hog motorcycles and a “Dukes of Hazard Wanabe”; but, overall none of the types of “toys” you are seeing. There are several newer vehicles, yes, but most are 20-30 mpg family vehicles. The worst choice maybe the new little red 4×2 the fellow uses for his lawn care business.

    Of course if you are trying to determine what is actually the average you cannot rely on what is in your neighborhood can you? Looking at the data for the numbers and types of vehicles with their ages in the states tax records might be a reasonable place to start. Then you could always total up the lower 48 states and see if maybe your vision of “average” can be tracked against reality. Again, I would say that you have a very skewed vision of “average”.

    Dave Cooke

  21. 221
    Hank Roberts says:

    And in our local news: November 14, 2006
    [California] Attorney General Bill Lockyer today announced an agreement under which the federal Department of Energy (DOE) will set new standards to sharply increase the energy efficiency of many types of household appliances, such as home ranges and ovens, air conditioners and dishwashers.

    The agreement settles a federal lawsuit filed by California and a coalition of states and public interest groups against DOE for stalling energy-saving standards for appliances that use large amounts of electricity, natural gas and oil.

    According to DOEâ��s own estimates, the standards covered by the agreement may reduce energy use by as much as 35 quadrillion BTUs over an approximately 30-year period. By comparison, all US households combined consumed 21 quadrillion BTUs of energy in 2004. ….annual carbon dioxide emissions could be reduced by as much as 103 million metric tons a year.

  22. 222
    garhane says:

    The sheer volume and intellectual level of output at RC continues to amaze. Nothing else in the blogosphere compares. But more and more I see in the comments little teasers about how you ought to be doing more in the way of economics. Of course, in general that is not the plan. But also, economicis is heavily contaminated with ideology. Just look at the weird arguments surroundilng the discount rate chosen in the Stern report by those who would attack it. Your task it would seem is difficult enough with quite a raft of deniers still staging attacks on the rear. So it is this writer’s hope that you will ignore such ecomic grumbles. That way lies the Slough of Dispair.

  23. 223
    Gary Braasch says:

    ADMINISTRATIVE Question, please: Do you know why the comments do not print with the articles, and how I can access the comments on a separate page for printing or selective copying for reference purposes?

    Many thanks to all.

    Gary B.

    [Response: This was due to complaints that each article printed out with a hundred pages of comments! However, if you click on the comments link on the front page (for any particular article), the comments will come up in a pop-up window with a ‘Print this page’ link. That will just print the comments. I’ll put this information on the ‘About’ page for future reference. Thanks. – gavin]

  24. 224
    Jan Lindstrom says:

    Being a skeptic I would like to have some help on three issues:

    1. Can someone direct me to an article actually showing and proving the mechanisms behind the CO2 forcing figures commonly used.

    2. Why can not the IPCC models be used in retrospective? (Thats what my fellow skeptics tell me anyway). To my knowledge there is not enough fossil resources known to fulfill ANY of the IPCC predictions. (This is according to the Uppsala Hydrocarbon Depletion Group at the Uppsala University, 2003 and a master thesis 2006)

    3. What is the mainstream explanation for the retreating polar ice at Mars?

    Here is my view:

    There are 1000’s of reasons why fossil fuel burning should be restricted. (Anthropogenic) Climate change is not one of them.

  25. 225
    Hank Roberts says:

    #2, Jan, to avoid retyping, you or someone with a similar name asked about that Uppsala study last month. You have responses:

  26. 226
    David donovan says:

    Re 224

    Here I saved you a bit of searching…..

    1. Please see.
    as a starting point.

    This should help, unless your definitions of “proof” is so strict that you still think that cancer smoking link has not been “proven”.

    2. Very stange assertion regarding the models (If I understand you correctly). Please see. . See Fig 4 and follow the links for more info.

    Regarding the emission scenerios. Even if believe we have hit “peak oil” there is lots and lots and lots of coal left.

    3. See

  27. 227
    Chris Fellows says:

    Greetings- my apologies if I am in the wrong spot, but the relevant FAQ’s seemed to be closed to comments.

    I was just wondering if you could direct me to any climate modelling work done c.1990-1995 that has done a better job of predicting any climate metrics for the last decade than a naive chemist like myself might have done with y = mx + c?

    I used to work with a wise old physical chemist who said (about once a fortnight, on average): “Just because the model fits the data doesn’t mean the model is true.”


  28. 228
    Martin Ponsford says:

    Simple. Too much excessive “self enforced deafness”

  29. 229
    John McCormick says:

    RE # 224

    Jan Lindstrom, you said:

    [There are 1000’s of reasons why fossil fuel burning should be restricted.]

    Are you ready to list maybe 20 or 30 reasons why burning fossil fuels should be restricted? I will be satisfied with one reason, frankly.

    Then you said one of the reasons would not be [(Anthropogenic) Climate change].

    OK. How about restricting fossil fuel burning to diminish atmospheric carbon dioxide to abate GLOBAL WARMING. I see a difference. Can you?

  30. 230
    Alan says:

    #227 wrote – “I was just wondering if you could direct me to any climate modelling work done c.1990-1995 that has done a better job of predicting any climate metrics for the last decade than a naive chemist like myself might have done with y = mx + c?”

    Here is one that is a bit older than the ’90s, but still amazingly accurate.

  31. 231
    Eli Rabett says:

    #229 NOx emissions. You really can’t avoid it at high temperatures characteristic of combustion.

  32. 232
    Eli Rabett says:

    The short answer to 227 is that you need to learn more about climate models. #230 is the snarky one. Climate models are not one dimensional (well they were about 1970 but that was before Moore’s Law), but rather make predictions about many things. Moreover, coming from a chemist who uses Lewis structures the question is presumptuous. Essentially all models used in chemistry are useful but not correct in any formal sense and you can find places where they are simply wrong (chemists call them exceptions, bunnies call them wrong).

    I presume that you are thinking that all that climate models predict is the recent overall trend in global temperature. That would be very wrong. For example, hidden in that graph is the response of the global temperature to a large volcanic eruption, that was pretty much right on. Climate models predict that greenhouse gas forcing will warm the arctic a lot more than the tropics, again, right on to observations. Climate models predict that while the surface and troposphere warm, the stratosphere will cool. Again, this is what is observed. And so it goes.

    It might be interesting to complile a list of what climate models (all scales) get right and put it on the FAQ