Stabilization wedges

Here is yet another plan of action:

Stabilization wedges

by Stephen Pacala and Robert Socolow.

We need critiques of this plan. I can add a bit of critique from Joseph Romm and others...

«13

Comments

  • 1.

    I dumped a bunch of stuff from the blog into Stabilization wedges. I would love if anyone cared to take comments on the blog entry and use them to add information about the wedges discussed so far - wedges 1 through 4.

    My plan, you see, is to use blog discussions about Plans of action to build up critiques and commentary on these plans. I can do this all myself using my herculean powers, but I'd still enjoy help.

    Comment Source:I dumped a bunch of stuff from the blog into [[Stabilization wedges]]. I would love if anyone cared to take [comments on the blog entry](http://johncarlosbaez.wordpress.com/2010/11/16/stabilization-wedges/#comments) and use them to add information about the wedges discussed so far - wedges 1 through 4. My plan, you see, is to use blog discussions about [[Plans of action]] to build up critiques and commentary on these plans. I can do this all myself using my herculean powers, but I'd still enjoy help.
  • 2.
    I've added a little bit about the efficiency of coal power plants.
    (btw, I wanted to write H system*, because the * is in the name, but then the link broke)
    Comment Source:I've added a little bit about the efficiency of coal power plants. (btw, I wanted to write H system*, because the * is in the name, but then the link broke)
  • 3.

    Thanks. Yes, there are limitations on the characters that can appear in links; annoying.

    Comment Source:Thanks. Yes, there are limitations on the characters that can appear in links; annoying.
  • 4.
    edited November 2010

    My plan, you see, is to use blog discussions about Plans of action to build up critiques and commentary on these plans. I can do this all myself using my herculean powers, but I'd still enjoy help.

    I can make a draft for a summary of the relevant comments on Part 1. But should I write "X pointed out that" or write it without reference to whom said it (rather like "on the blog...")?

    I'd also prefer to post the draft first on the forum, because I guess it's not unlikely to be discussed again.

    Comment Source:> My plan, you see, is to use blog discussions about Plans of action to build up critiques and commentary on these plans. I can do this all myself using my herculean powers, but I'd still enjoy help. I can make a draft for a summary of the relevant comments on Part 1. But should I write "X pointed out that" or write it without reference to whom said it (rather like "on the blog...")? I'd also prefer to post the draft first on the forum, because I guess it's not unlikely to be discussed again.
  • 5.
    edited November 2010

    When I read your comment above, Frederick, I see "This comment is invalid XHTML+MathML+SVG; displaying source." You can preview your comments to make sure they look good, and I believe you can edit them afterwards too. I'm constantly editing mine after the fact.

    It would be great for you to summarize the comments on part 1! Please distill them down to something clear and simple. I wouldn't cite individual people who were talking on the blog: I would cite scholarly literature, websites with statistics, and/or Wikipedia (especially for general concepts like the "Jevons paradox" - though now we have our own page Jevons paradox, so you can just link to that).

    It would however be nice to include a link to the blog discussion as a whole.

    Comment Source:When I read your comment above, Frederick, I see "This comment is invalid XHTML+MathML+SVG; displaying source." You can preview your comments to make sure they look good, and I believe you can edit them afterwards too. I'm constantly editing mine after the fact. It would be great for you to summarize the comments on part 1! Please distill them down to something clear and simple. I wouldn't cite individual people who were talking on the blog: I would cite scholarly literature, websites with statistics, and/or Wikipedia (especially for general concepts like the "Jevons paradox" - though now we have our own page [[Jevons paradox]], so you can just link to that). It would however be nice to include a link to the blog discussion as a whole.
  • 6.

    (1) OK - but the articles and statistics may take some time to find.

    (2) About Stabilization wedges:

    Perhaps I misunderstand their paper (I haven't read their whole paper yet - I just picked out a few sentences) but the way I understood the first two wedges was as follows:

    Their aim is:

    Very roughly, stabilization at 500 ppm requires that emissions be held near the present level of 7 billion tons of carbon per year (GtC/year) for the next 50 years

    They assume there will be four times more cars in 2050. Thus to keep emissions the same, they propose: two times more efficient cars (wedge 1) and two times less distance traveled (wedge 2). So I guess implicitly they use:

    $ Car emissions \propto fuel efficiency (l/km) * distance traveled (km/car) * number of cars $

    (and averaging all rhs quantities over the next 50 yrs: the number of cars will rise gradually, and the efficiency and distance traveled will drop)

    How well-founded is their supposition of a fourfold increase of cars? It seems a bit ad hoc... If it's larger, distance traveled and fuel efficiency should drop more.

    Do I make a silly mistake? I fear I'm doing something wrong - on Azimuth I read:

    Clearly this wedge and the previous one are not additive: if we do them both, we don’t save 2 gigatons of carbon per year.

    But doesn't this (implicitly) depend on the expected rate of increase in cars too? Because the expected rise of $CO_2$ emissions is partly due to the projected rising number of cars?

    Comment Source:(1) OK - but the articles and statistics may take some time to find. (2) About [[Stabilization wedges]]: Perhaps I misunderstand their paper (I haven't read their whole paper yet - I just picked out a few sentences) but the way I understood the first two wedges was as follows: Their aim is: > Very roughly, stabilization at 500 ppm requires that emissions be held near the present level of 7 billion tons of carbon per year (GtC/year) for the next 50 years They assume there will be *four times more cars* in 2050. Thus to keep emissions the same, they propose: two times more efficient cars (wedge 1) and two times less distance traveled (wedge 2). So I guess implicitly they use: $ Car emissions \propto fuel efficiency (l/km) * distance traveled (km/car) * number of cars $ (and averaging all rhs quantities over the next 50 yrs: the number of cars will rise gradually, and the efficiency and distance traveled will drop) How well-founded is their supposition of a fourfold increase of cars? It seems a bit ad hoc... If it's larger, distance traveled and fuel efficiency should drop more. Do I make a silly mistake? I fear I'm doing something wrong - on Azimuth I read: > Clearly this wedge and the previous one are not additive: if we do them both, we don’t save 2 gigatons of carbon per year. But doesn't this (implicitly) depend on the expected rate of increase in cars too? Because the expected rise of $CO_2$ emissions is partly due to the projected rising number of cars?
  • 7.

    Clearly this wedge and the previous one are not additive: if we do them both, we don’t save 2 gigatons of carbon per year.

    Of course... there's no disagreement. Say, car traffic caused in 2004 about 0,5 Gton/yr, so four times more cars leads to 2 Gton/yr in 2054. Applying wedge 1 or 2 leads to 1 Gton/yr less, both to 1,5 Gton/yr less, so the same level as today.

    Still, is the fourfold increase of cars a reasonable estimate or just a guess?

    Comment Source:> Clearly this wedge and the previous one are not additive: if we do them both, we don’t save 2 gigatons of carbon per year. Of course... there's no disagreement. Say, car traffic caused in 2004 about 0,5 Gton/yr, so four times more cars leads to 2 Gton/yr in 2054. Applying wedge 1 or 2 leads to 1 Gton/yr less, both to 1,5 Gton/yr less, so the same level as today. Still, is the fourfold increase of cars a reasonable estimate or just a guess?
  • 8.
    edited November 2010

    I don't know about detailed projections, but it seems a plausible back of the envelope value. Firstly, from here it suggests China and India have lots of "capacity" if they end up with the income:

    China became the world’s third-largest car market in 2006, as car sales in China soared by nearly 40% to 4.1 million units. China should become the world’s second-largest car market by 2010, as low vehicle penetration, rising incomes, greater credit availability and falling car prices lift sales past those of Japan. Furthermore, vehicle penetration in China stands at only 24 vehicles per 1,000 people, compared with 749 vehicles per 1,000 people in the mature markets of the G7.

    Secondly 4 times increase in 50 years is about 2.8 percent net increase (ie new cars being added minus old cars being removed) per year.

    The big unknown is how many cars were taken off the roads: I can't find any reference about that.

    EDIT: The secondly point here used to have me being confused: a 4 percent change in the no of new cars is not related to the no of new cars as a percentage of existing cars, which if it was 2.8 per cent is would give a four-fold increase.

    Comment Source:I don't know about detailed projections, but it seems a plausible back of the envelope value. Firstly, from [here](http://www.worldometers.info/cars/) it suggests China and India have lots of "capacity" if they end up with the income: > China became the world’s third-largest car market in 2006, as car sales in China soared by nearly 40% to 4.1 million units. China should become the world’s second-largest car market by 2010, as low vehicle penetration, rising incomes, greater credit availability and falling car prices lift sales past those of Japan. Furthermore, vehicle penetration in China stands at only 24 vehicles per 1,000 people, compared with 749 vehicles per 1,000 people in the mature markets of the G7. Secondly 4 times increase in 50 years is about 2.8 percent net increase (ie new cars being added minus old cars being removed) per year. The big unknown is how many cars were taken off the roads: I can't find any reference about that. EDIT: The secondly point here used to have me being confused: a 4 percent change in the no of new cars is not related to the no of new cars as a percentage of existing cars, which if it was 2.8 per cent is would give a four-fold increase.
  • 9.
    edited November 2010

    I'm really glad you're tackling this stuff, Frederik!

    How well-founded is their supposition of a fourfold increase of cars?

    If you want to get into this issue, you should either get the "supporting online material" for their paper, or have someone with access to Science magazine get it for you. That should contain more details.

    I don't have this supporting online material yet. I believe there's a link to it on the Stabilization wedges page.

    By the way: see how I fixed your comment? What you wrote doesn't work, since we're not using HTML here, but XML, which requires a line of space after <blockquote> and before </blockquote>. But it's infinitely easier to use Markdown:

    > stuff
    

    produces this effect:

    stuff

    Comment Source:I'm really glad you're tackling this stuff, Frederik! > How well-founded is their supposition of a fourfold increase of cars? If you want to get into this issue, you should either get the "supporting online material" for their paper, or have someone with access to _Science_ magazine get it for you. That should contain more details. I don't have this supporting online material yet. I believe there's a link to it on the [[Stabilization wedges]] page. By the way: see how I fixed [your comment](http://www.math.ntnu.no/~stacey/Mathforge/Azimuth/comments.php?DiscussionID=122&Focus=983#Comment_983)? What you wrote doesn't work, since we're not using HTML here, but XML, which requires a line of space after `<blockquote>` and before `</blockquote>`. But it's infinitely easier to use Markdown: ~~~~ > stuff ~~~~ produces this effect: > stuff
  • 10.

    thanks for the link

    but about the back of the envelope, if I split the world's production into two groups: one producing few cars now, but at a high increasing percentage, and another group producing many cars now, but at a low increasing percentage, I can get a much higher increase in cars than just using the current average percentage for the sum of the two groups. But I only used some test values, I should still substitute the values of the link to see if this would be relevant.

    Comment Source:thanks for the [link](http://www.worldometers.info/cars/) but about the back of the envelope, if I split the world's production into two groups: one producing few cars now, but at a high increasing percentage, and another group producing many cars now, but at a low increasing percentage, I can get a much higher increase in cars than just using the current average percentage for the sum of the two groups. But I only used some test values, I should still substitute the values of the [link](http://www.worldometers.info/cars/) to see if this would be relevant.
  • 11.

    Thanks!

    one producing few cars now, but at a high increasing percentage

    I think that group is called "China and India", so you should try to look up some estimates of future car demand for these countries.

    Comment Source:Thanks! > one producing few cars now, but at a high increasing percentage I think that group is called "China and India", so you should try to look up some estimates of future car demand for these countries.
  • 12.

    John said:

    I think that group is called "China and India", so you should try to look up some estimates of future car demand for these countries.

    That would be interesting, a quick search for the sale numbers for German premium cars (you know, I'm sitting in an office building of a particular company right now) reveals that they have grown between 20% and 60% during the last years (4000% in India in 2006), so you won't get any reliable estimates from that.

    It's obviously just a horsepipe spilling into a desert, with the gardener cranking the pressure up as fast as possible.

    Comment Source:John said: <blockquote> <p> I think that group is called "China and India", so you should try to look up some estimates of future car demand for these countries. </p> </blockquote> That would be interesting, a quick search for the sale numbers for German premium cars (you know, I'm sitting in an office building of a particular company right now) reveals that they have grown between 20% and 60% during the last years (4000% in India in 2006), so you won't get any reliable estimates from that. It's obviously just a horsepipe spilling into a desert, with the gardener cranking the pressure up as fast as possible.
  • 13.

    I agree with Tim: it's not possible to use reliable estimates for India and China. In the link above there is an increase of 25% for China and India which is way too much to extrapolate. Perhaps the most reasonable estimate would be to assume that everyone in 2050 would like to have cars according to the Western car penetration today (maybe untrue, as fuel prices probably go up)

    But then, shouldn't these numbers be implicitly included in the "business as usual" (or rather, business growth as usual) scenario? Unfortunately I haven't got access to Science magazine.

    Pacala and Sokolow assume that the number of cars will rise by four. But, as David said:

    Furthermore, vehicle penetration in China stands at only 24 vehicles per 1,000 people, compared with 749 vehicles per 1,000 people in the mature markets of the G7.

    That would be significantly more than a fourfold increase (for China).

    So if the number of cars rises much more than fourfold, the solutions to wedges 1 and 2 need to be constrained much more severely.

    Comment Source:I agree with Tim: it's not possible to use reliable estimates for India and China. In the link above there is an increase of 25% for China and India which is way too much to extrapolate. Perhaps the most reasonable estimate would be to assume that everyone in 2050 would like to have cars according to the Western car penetration today (maybe untrue, as fuel prices probably go up) But then, shouldn't these numbers be implicitly included in the "business as usual" (or rather, business growth as usual) scenario? Unfortunately I haven't got access to Science magazine. Pacala and Sokolow assume that the number of cars will rise by four. But, as David said: > Furthermore, vehicle penetration in China stands at only 24 vehicles per 1,000 people, compared with 749 vehicles per 1,000 people in the mature markets of the G7. That would be significantly more than a fourfold increase (for China). So if the number of cars rises much more than fourfold, the solutions to wedges 1 and 2 need to be constrained much more severely.
  • 14.

    I will later discuss work after the original Pacala-Socolow paper which says it could be incorrect due to more rapid than expected growth in China and India.

    I was hoping that online there'd be some current projections of medium- or long-term car sales in these countries. I agree, extrapolating from 25% growth this year makes little sense.

    Comment Source:I will later discuss work after the original Pacala-Socolow paper which says it could be incorrect due to more rapid than expected growth in China and India. I was hoping that online there'd be some current projections of medium- or long-term car sales in these countries. I agree, extrapolating from 25% growth this year makes little sense.
  • 15.

    On Azimuth, Streamfortyseven linked to the wikipedia article of Fuel efficiency in transportation, for which one of the sources is Transportation energy data book Ed. 29

    There are some averaged percentages here (China gets 13%), but I didn't find projections yet.

    Comment Source:On Azimuth, Streamfortyseven linked to the wikipedia article of [Fuel efficiency in transportation](http://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation#cite_note-brianmac-2), for which one of the sources is [Transportation energy data book Ed. 29](http://cta.ornl.gov/data/tedb29/Edition29_Full_Doc.pdf) There are some averaged percentages here (China gets 13%), but I didn't find projections yet.
  • 16.

    Hi John,

    could you give some comments on the following?

    I would like to add references to scholarly articles/websites with statistics - but I haven't found them yet.

    1.

    More fuel efficient vehicles already exist. See, e.g. Most and least fuel efficient cars. The main question is how to urge the consumer to use these cars? The proposed solution on Azimuth is higher taxation: both a tax on gasoline, and a motorvehicle tax on inefficient cars. Related to taxation is the "natural" rise of oil product prices when oil becomes more scarce.

    Nevertheless, there is a problem of attitude, that is that large cars are often a status symbol and drivers may be willing to pay more for driving these cars, to promote their social status.

    In addition, the Jevons paradox may come into play: that is, simply making cars more energy efficient might lead to more distance traveled. However, because cars are a status symbol, people voluntarily buying energy efficient cars probably also voluntarily try to reduce, or keep equal, their distance traveled. People buying energy efficient cars only because of less taxation, may use the saves in their budget to travel more.

    Another danger of taxation may be that when the tax becomes an income for the government, the government may become less determined to use the tax for what its purpose is for: to reduce the number of inefficient cars.

    Another option is to impose stronger emission norms for cars. In this case, energy inefficient cars cannot be produced nor bought.

    2.

    Less distance traveled. Perhaps taxation is also the main solution to reduce the distance traveled. In addition, for large distances (<20 km) other means of transportation are more energy-efficient than cars. For small distances, transportation by foot and bicycle is also more environmentally friendly. I'm still looking for references better than wikipedia

    Comment Source:Hi John, could you give some comments on the following? I would like to add references to scholarly articles/websites with statistics - but I haven't found them yet. 1. More fuel efficient vehicles already exist. See, e.g. [Most and least fuel efficient cars](http://www.fueleconomy.gov/feg/bestworst.shtml). The main question is how to urge the consumer to use these cars? The proposed solution on [Azimuth](http://johncarlosbaez.wordpress.com/2010/11/16/stabilization-wedges/) is higher taxation: both a tax on gasoline, and a motorvehicle tax on inefficient cars. Related to taxation is the "natural" rise of oil product prices when oil becomes more scarce. Nevertheless, there is a problem of attitude, that is that large cars are often a status symbol and drivers may be willing to pay more for driving these cars, to promote their social status. In addition, the [[Jevons paradox]] may come into play: that is, simply making cars more energy efficient might lead to more distance traveled. However, because cars are a status symbol, people voluntarily buying energy efficient cars probably also voluntarily try to reduce, or keep equal, their distance traveled. People buying energy efficient cars only because of less taxation, may use the saves in their budget to travel more. Another danger of taxation may be that when the tax becomes an income for the government, the government may become less determined to use the tax for what its purpose is for: to reduce the number of inefficient cars. Another option is to impose stronger emission norms for cars. In this case, energy inefficient cars cannot be produced nor bought. 2. Less distance traveled. Perhaps taxation is also the main solution to reduce the distance traveled. In addition, for large distances (<20 km) other means of transportation are more energy-efficient than cars. For small distances, transportation by foot and bicycle is also more environmentally friendly. *I'm still looking for references better than wikipedia*
  • 17.

    Frederik said:

    Another option is to impose stronger emission norms for cars. In this case, energy inefficient cars cannot be produced nor bought.

    That's actually a policy that the EU already pursues, see e.g. european emission standards.

    Frederik said:

    In addition, the Jevons paradox may come into play: that is, simply making cars more energy efficient might lead to more distance traveled.

    The problem is that this is hard to measure, I'd expect that many people would use their better conscience and money saved to travel more by plane. And e.g. the German government does not tax kerosene, because that would harm the indigenous aviation industry :-)

    Frederik said:

    Nevertheless, there is a problem of attitude, that is that large cars are often a status symbol and drivers may be willing to pay more for driving these cars, to promote their social status.

    I think this was the main reason for the death of the Lupo, the 3-liter-car that was built by Volkswagen in 1999, (not a prototype, but in serial production). It's sad, but true: If you are a manager or a politician in Germany, you have to drive a Mercedes, a BMW or an Audi, a big model. The only way to change this is to change the public opinion, on a big scale.

    Comment Source:Frederik said: <blockquote> <p> Another option is to impose stronger emission norms for cars. In this case, energy inefficient cars cannot be produced nor bought. </p> </blockquote> That's actually a policy that the EU already pursues, see e.g. <a href="http://en.wikipedia.org/wiki/Emission_standard#European_Union">european emission standards</a>. Frederik said: <blockquote> <p> In addition, the Jevons paradox may come into play: that is, simply making cars more energy efficient might lead to more distance traveled. </p> </blockquote> The problem is that this is hard to measure, I'd expect that many people would use their better conscience and money saved to travel more by plane. And e.g. the German government does not tax kerosene, because that would harm the indigenous aviation industry :-) Frederik said: <blockquote> <p> Nevertheless, there is a problem of attitude, that is that large cars are often a status symbol and drivers may be willing to pay more for driving these cars, to promote their social status. </p> </blockquote> I think this was the main reason for the death of the Lupo, the 3-liter-car that was built by Volkswagen in 1999, (not a prototype, but in serial production). It's sad, but true: If you are a manager or a politician in Germany, you have to drive a Mercedes, a BMW or an Audi, a big model. The only way to change this is to change the public opinion, on a big scale.
  • 18.

    Frederik - I suggest the following slight modifications:

    The proposed solution on Azimuth is higher taxation: both a tax on gasoline, and a motorvehicle tax on inefficient cars.

    This may be an issue of English usage, but to me this sentence suggests that "Azimuth" has officially proposed a solution to this problem. We certainly don't want to give that impression! I think it's good to take a very distanced, neutral attitude. So I suggest:

    One possible solution is higher taxation: both a tax on gasoline, and a tax on inefficient cars.

    (No need for "motor vehicle".)

    cannot be produced nor bought.

    This should be "can neither be produced nor bought", or "cannot be produced or bought." Don't blame me: English is complicated and illogical.

    (I should make these small changes on the wiki instead of bothering you, but the wiki is down...)

    Perhaps taxation is also the main solution to reduce the distance traveled.

    I would say:

    "Taxation could also be useful for reducing the distance traveled."

    to avoid deciding whether this could be the "main" solution, or just a small part.

    Anyway, these are all small changes! I'm very happy that you're doing this, and I'm happy with the results too. I like how you're summarizing things in a very simple, crisp way.

    Since my suggested changes are so small, in the future it may be easier if you just put your information on the wiki (when it's running) and let us know you've done it. Then I can make changes there.

    Thanks again! It will really make life easier for me if I can focus on going through the 15 stabilization wedges on the blog, letting you take the discussion and transfer the most useful parts to the wiki.

    Comment Source:Frederik - I suggest the following slight modifications: >The proposed solution on [Azimuth](http://johncarlosbaez.wordpress.com/2010/11/16/stabilization-wedges/) is higher taxation: both a tax on gasoline, and a motorvehicle tax on inefficient cars. This may be an issue of English usage, but to me this sentence suggests that "Azimuth" has officially proposed a solution to this problem. We certainly don't want to give that impression! I think it's good to take a very distanced, neutral attitude. So I suggest: >One possible solution is higher taxation: both a tax on gasoline, and a tax on inefficient cars. (No need for "motor vehicle".) >cannot be produced nor bought. This should be "can neither be produced nor bought", or "cannot be produced or bought." Don't blame me: English is complicated and illogical. (I should make these small changes on the wiki instead of bothering you, but the wiki is down...) >Perhaps taxation is also the main solution to reduce the distance traveled. I would say: "Taxation could also be useful for reducing the distance traveled." to avoid deciding whether this could be the "main" solution, or just a small part. Anyway, these are all small changes! I'm very happy that you're doing this, and I'm happy with the results too. I like how you're summarizing things in a very simple, crisp way. Since my suggested changes are so small, in the future it may be easier if you just put your information on the wiki (when it's running) and let us know you've done it. Then I can make changes there. Thanks again! It will really make life easier for me if I can focus on going through the 15 stabilization wedges on the blog, letting you take the discussion and transfer the most useful parts to the wiki.
  • 19.

    Hi John (& Tim)

    thanks for the comments & also for the English corrections ;-)

    I'll put it on the wiki when it's online again.

    Comment Source:Hi John (& Tim) thanks for the comments & also for the English corrections ;-) I'll put it on the wiki when it's online again.
  • 20.

    I added it to the wiki.

    Tim said:

    It's sad, but true: If you are a manager or a politician in Germany, you have to drive a Mercedes, a BMW or an Audi, a big model. The only way to change this is to change the public opinion, on a big scale.

    could it be that it is partly related to the fact that these cars are capable of driving at the high speeds allowed on German highways? If the maximum speed limit were, say, 90 km/h it would matter less whether you're driving a Lupo or BMW.

    Comment Source:I added it to the wiki. Tim said: > It's sad, but true: If you are a manager or a politician in Germany, you have to drive a Mercedes, a BMW or an Audi, a big model. The only way to change this is to change the public opinion, on a big scale. could it be that it is partly related to the fact that these cars are capable of driving at the high speeds allowed on German highways? If the maximum speed limit were, say, 90 km/h it would matter less whether you're driving a Lupo or BMW.
  • 21.
    edited November 2010

    Hi Frederik,

    Many thanks for moving this discussion over onto the wiki proper. As a contributor one point is that you'll learn is to be suspicous of less than and greater than signs anywhere in the text :-). No matter what one seems to do they'll always get screwed up, so one pretty much always has to go through and fix them up. I've replaced (along with changing less than to greater than as this seems to fit with the surrounding text) the

    $<20$ km
    

    that had the wiki confused with an

    &gt;$20$ km
    

    (You can see how it was by looking through the page history.)

    Comment Source:Hi Frederik, Many thanks for moving this discussion over onto the wiki proper. As a contributor one point is that you'll learn is to be suspicous of less than and greater than signs anywhere in the text :-). No matter what one seems to do they'll always get screwed up, so one pretty much always has to go through and fix them up. I've replaced (along with changing less than to greater than as this seems to fit with the surrounding text) the $<20$ km that had the wiki confused with an &gt;$20$ km (You can see how it was by looking through the page history.)
  • 22.
    edited November 2010

    I've added some discussion of wedges 5-8 to Stabilization wedges.

    I've written a blog entry on these wedges, but I'll wait a day or two to post that.

    I added a mention of the fact that car sales grew at 3.3% annually from 1999-2009, faster than the 2.8% envisaged by Pacala and Socolow for 2004-2054.

    Comment Source:I've added some discussion of wedges 5-8 to [[Stabilization wedges]]. I've written a blog entry on these wedges, but I'll wait a day or two to post that. I added a mention of the fact that car sales grew at 3.3% annually from 1999-2009, faster than the 2.8% envisaged by Pacala and Socolow for 2004-2054.
  • 23.
    edited November 2010

    I added a mention of the fact that car sales grew at 3.3% annually from 1999-2009, faster than the 2.8% envisaged by Pacala and Socolow for 2004-2054.

    I got myself confused about this earlier in the thread: I now don't think you can conclude that from those figures. (I edited past forum posts to my current understanding). The number of new cars being built is $\Delta($no of cars$)$, so a change in it is $\Delta(\Delta($no of cars$)=3.3$percent, wheras what we want to know is $\Delta$(no of cars$)$> 2.8 percent or not. Also, this only references the "births" side of the process, we'd still need estimates of the "deaths" (cars taken off the road, maybe replaced with a new car).

    That's not to say Pacala and Socolow might have an underestimate, but I thinkit needs more figures. As a first pass, making around 52 million new cars when the are currently around 600 million cars in the world is about an 8.5 percent change (again, ignoring cars being taken off the road).

    Comment Source:> I added a mention of the fact that car sales grew at 3.3% annually from 1999-2009, faster than the 2.8% envisaged by Pacala and Socolow for 2004-2054. I got myself confused about this earlier in the thread: I now don't think you can conclude that from those figures. (I edited past forum posts to my current understanding). The number of new cars being built is $\Delta($no of cars$)$, so a change in it is $\Delta(\Delta($no of cars$)=3.3$percent, wheras what we want to know is $\Delta$(no of cars$)$&gt; 2.8 percent or not. Also, this only references the "births" side of the process, we'd still need estimates of the "deaths" (cars taken off the road, maybe replaced with a new car). That's not to say Pacala and Socolow might have an underestimate, but I thinkit needs more figures. As a first pass, making around 52 million new cars when the are currently around 600 million cars in the world is about an 8.5 percent change (again, ignoring cars being taken off the road).
  • 24.
    edited November 2010

    Whoops! Really dumb of me. I'll fix what I wrote.

    Hmm - I actually didn't write anything false, but maybe it was misleading, because I was sure confused. So, I've tried to make it less so.

    Comment Source:Whoops! Really dumb of me. I'll fix what I wrote. Hmm - I actually didn't write anything false, but maybe it was misleading, because I was sure confused. So, I've tried to make it less so.
  • 25.

    @ David: yes, I'm sorry, it's "greater than", of course...

    About the births: are all produced cars also used? (I vaguely remember to have heard that some companies assemble on demand, but is this widespread?)

    Comment Source:@ David: yes, I'm sorry, it's "greater than", of course... About the births: are all produced cars also used? (I vaguely remember to have heard that some companies assemble on demand, but is this widespread?)
  • 26.

    About the births: are all produced cars also used?

    In the US, Jeffrey Luers was sentenced to 22 years in prison for preventing all produced cars from being used.

    But this was statistically insignificant....

    Comment Source:>About the births: are all produced cars also used? In the US, Jeffrey Luers was [sentenced to 22 years in prison](http://en.wikipedia.org/wiki/Jeff_Luers#Arson_and_sentencing) for preventing all produced cars from being used. But this was statistically insignificant....
  • 27.

    Frederik asked:

    ...could it be that it is partly related to the fact that these cars are capable of driving at the high speeds allowed on German highways?

    Partially yes, but people in other countries buy cars that can go faster than any speed limit, so I don't think that this is the most important factor. You take your BMW or Mercedes to go to your business meetings, and take your Porsche to have fun on the highway, there is no direct overlap of the target group. (A manager at Daimler explained this to me, after I had wondered why he had model cars from Prosche on his office desk).

    (I vaguely remember to have heard that some companies assemble on demand, but is this widespread?

    The companies I know have only a small storing facility and shut down their plants if there is no demand for their cars rather quickly. Usually the customer chooses the car he would like to buy, this information is passed on to a plant that has free capacities, and is used on the assembly line to customize a car in a free slot on the assembly line. So, all cars sufficiently advanced on the assembly line are actually already sold.

    Comment Source:Frederik asked: <blockquote> <p> ...could it be that it is partly related to the fact that these cars are capable of driving at the high speeds allowed on German highways? </p> </blockquote> Partially yes, but people in other countries buy cars that can go faster than any speed limit, so I don't think that this is the most important factor. You take your BMW or Mercedes to go to your business meetings, and take your Porsche to have fun on the highway, there is no direct overlap of the target group. (A manager at Daimler explained this to me, after I had wondered why he had model cars from Prosche on his office desk). <blockquote> <p> (I vaguely remember to have heard that some companies assemble on demand, but is this widespread? </p> </blockquote> The companies I know have only a small storing facility and shut down their plants if there is no demand for their cars rather quickly. Usually the customer chooses the car he would like to buy, this information is passed on to a plant that has free capacities, and is used on the assembly line to customize a car in a free slot on the assembly line. So, all cars sufficiently advanced on the assembly line are actually already sold.
  • 28.

    I wanted to add the new information of the blog (the Small and Van Dender article) but it appears John already did that. Less work for me :)

    Btw, the wordpress format is not very customer-friendly to search for an old blog post (or worse, a comment).

    Comment Source:I wanted to add the new information of the blog (the Small and Van Dender article) but it appears John already did that. Less work for me :) Btw, the wordpress format is not very customer-friendly to search for an old blog post (or worse, a comment).
  • 29.

    Yeah, Wordpress is a bit suboptimal in many ways.

    Comment Source:Yeah, Wordpress is a bit suboptimal in many ways.
  • 30.

    I'm sure Frederik knows this, but I tend to do a general web search with a "site:johncarlosbaez.wordpress.com" which works a bit better.

    Comment Source:I'm sure Frederik knows this, but I tend to do a general web search with a "site:johncarlosbaez.wordpress.com" which works a bit better.
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