quote:Originally posted by twinky: It depends on the throughput. It doesn't take long to do the conversion, sure, but how much can it convert per unit time?
engines don't use that much fuel per unit time though... much more air.
I wonder, too about the ability to design an engine with, say, one converter per cylinder as part of a multipoint fuel injection system... there's got to be a way to do that.
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There's no advantage to generating biodiesel in-situ. The article was actually pointing out that the small size is a bit of a disadvantage, but that the reactors could be stacked to build up the capacity.
Of course, it seems to me that the real advantage of biodiesel is in recycled vegetable oil. Use it for frying first, then run it through your car. Or even better, don't make biodiesel at all, just burn the waste vegetable oil to heat your home. Adding methanol kind of takes away the environmental advantages, and makes it economically unsound.
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Incidentally, it's been in the 40s for most of May here in Chicago. I think we could use a bit of global warming. Brr...
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Cool article, Dagonee. What's weird is that I worked with Goran Jovanovic's daughter a few years back. I've been to his lab, and there was some pretty cool stuff going on there.
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I really wish I knew how to get access to original research and figures about changes in ice loads, temperature recordings, sea level changes, etc ... Both sides cite their own studies that (surprise, surprise) say what they need them to say. Is there a good way for me to get a look at the data myself?
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I was reading the new issue of Men's Health, and came across a brief interview with Al Gore.
Here is what he had to say about Michael Chriton, and others who have suggested the environmental movement is too "hype" driven:
quote:The first thing to remember about Michael is that he's a science-fiction writer. And the second thing is, he's often been attracted to contrarian plotlines. Such as the female boss who's the epitome of sexual harassment in America, instead of the more common situation. I wouldn't be surprised if he came out with a book in which the bad guys are the ones who think the earth is round and orbits the sun. He got [President] Bush's ear because Bush wanted that message in his ear.
Wow. I can't believe he went there. No discussion of facts, just a big wink-wink, elbow-elbow that, "This guy wrote about women harrasing men, and we all know that's not really how it works."
(For those interested, here's one of Chrichton's presentations on the topic.)
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Why not? Would it have been better to react as if Crichton had a legitimate, well-researched, and unbiased viewpoint?
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quote:I really wish I knew how to get access to original research and figures about changes in ice loads, temperature recordings, sea level changes, etc ... Both sides cite their own studies that (surprise, surprise) say what they need them to say. Is there a good way for me to get a look at the data myself?
If you know any university students or instructors, they almost certainly have access to geoscience journals through their university.
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Tom, if you accept his story at face value, he was researching a completely separate idea when he started to discover the statistics weren't as shocking as he felt he'd been led to believe. There actually is research going on here.
As for legitamite, you're right. He seems to have written his essays all by himself. But we don't like to think of such things as "illegitimate," so much as "growing up in single parent families."
Or is there some other way you feel his arguements are illegitimate?
As for bias--well, we're arguing biases here. The whole point of the arguement, and this thread, to a large degree, is that everybody can pull out statistics that back up their viewpoint, whatever that is.
At that point, it all just becomes religion. We all cling to whichever evidence we choose to believe.
And accuse our "enemies" of being not just misinformed, but illegitamate, poorly researched, and biased.
And fiction writers.
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I don't worship global climate change, but I do believe in it.
I don't really blame him for taking a little swipe at Crichton. It's sensationalized science-fiction and pseudo-science alarmists that are giving global climate change and anything related to it a bad name.
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quote:Originally posted by docmagik: I was reading the new issue of Men's Health, and came across a brief interview with Al Gore.
Here is what he had to say about Michael Chriton, and others who have suggested the environmental movement is too "hype" driven:
quote:The first thing to remember about Michael is that he's a science-fiction writer. And the second thing is, he's often been attracted to contrarian plotlines. Such as the female boss who's the epitome of sexual harassment in America, instead of the more common situation. I wouldn't be surprised if he came out with a book in which the bad guys are the ones who think the earth is round and orbits the sun. He got [President] Bush's ear because Bush wanted that message in his ear.
Wow. I can't believe he went there. No discussion of facts, just a big wink-wink, elbow-elbow that, "This guy wrote about women harrasing men, and we all know that's not really how it works."
(For those interested, here's one of Chrichton's presentations on the topic.)
I enjoyed reading the lecture and the book, "State of Fear." immensily. If you need good airplane reading, it did the job splendidly for me. I have always enjoyed reading Crichton's books, I think this is the first time where he has really tried to write with an obvious agenda. At least his agenda is, "Ask questions," rather then, "Here is the answer!"
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It would be a good idea to remember that the present is verifiable, while the future is not.
Discussions about the present should be supported by facts and observations about the real world.
Discussions about the future should be given more leeway because facts and observations are impossible, everything is built out of contingenices, and especially with complex systems like climate, it is extraordinarily difficult to take every possibility into account.
In other words, people should be allowed to present different opinions about the future, because after all, that's all anyone has.
Presenting an opinion that the earth is hollow and is the center of the universe could be called "illegitimate" because that opinion is verifiably false.
Presenting an opinion that you don't believe the available evidence justifies a certain prediction about the future is much harder to legitimately call "illegitimate" because no opinion about the future can be verified as true or false, except by waiting.
I think that this is Crichton's main point, global warming aside. People are acting as though we have "discovered" the future in some factually-verifiable way. Unfortunately, the evidence of this claim can only present itself slowly, one day at a time.
I think that Crichton fears we will begin to behave as though we understand the world's climate sufficiently to predict its behavior and our impact on it, when we don't ... and that our blind faith in this regard will lead us to make bad decisions down the road in the face of evidence that contradicts us.
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quote: Presenting an opinion that the earth is hollow and is the center of the universe could be called "illegitimate" because that opinion is verifiably false.
But are you saying that if someone says "the center of the Earth will become hollow tomorrow when it's eaten by space dragons," we have to consider the possibility that it's a legitimate scientific opinion?
quote: I think that this is Crichton's main point, global warming aside.
Having read State of Fear myself, it seemed to ME like his main point was that environmentalists were pawns of greedy multinational corporations intending to blackmail the planet, and that even people who've worked in the industry are still stunned and surprised when the "truth" that's been suppressed for so long is revealed to them. It's like the Da Vinci Code of global warming. Posts: 37449 | Registered: May 1999
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Tom, I agree completely with that assesment of the book.
See, he took his main point--that over-hype is the only way to sell crises--and twisted it around into over-hype, because over-hype is the only way to sell books.
There's still some valid points in the essays and the book, though.
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quote:But are you saying that if someone says "the center of the Earth will become hollow tomorrow when it's eaten by space dragons," we have to consider the possibility that it's a legitimate scientific opinion?
Obviously, there's a spectrum of plausibility. If the center of the earth were a chaotic system in which that was clearly one of the potential possibilities, then yes.
Similarly, it IS entirely possible that there are factors in climate change that we do not fully understand, and that the expected warming trend will not go off as predicted.
I mean, this warming trend was not predicted by the sophisticated climate-studying tools and techniques we had 30 years ago, which were incredibly advanced by any past standard. Yes, our current techniques are superior, and they are being used in good faith by many people to predict global warming over the next hundred years, with a certain set of potential consequences (droughts, freezes, rises in sea level, etc) ...
But isn't it possible that as we live through the next 30 years, we will see similar advances in our understanding that reverse the current predictions about global warming, or revise the predictions about what the consequences of global warming will be? Absolutely.
You can't hang a specific strategy or policy on doubt, but seriously, in a case like this, if nobody were raising any doubts or protests in the face of the absolute certainty that some are expressing about the future, I'd think our claim to rationality as a species would be tenuous at best.
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If humanity had ever, at any time in the past, accurately predicted a global trend in climate and its consequences, then I think people would be raising fewer doubts. The problem is, it's never been done before. We're trying something new here, and we've got no track record for success.
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"If humanity had ever, at any time in the past, accurately predicted a global trend in climate and its consequences, then I think people would be raising fewer doubts. The problem is, it's never been done before."
"Next, and slightly more troubling, we have some rather misleading and selective recollection regarding Jim Hansen's testimony to congress in 1988. "Dr. Hansen overestimated [global warming] by 300 percent" (p247). Hansen's testimony did indeed lead to a big increase in awareness of global warming as a issue, but not because he exaggerated the problem by 300%. In a paper published soon after that testimony, Hansen et al, 1988 presented three model simulations for different scenarios for the growth in trace gases and other forcings (see figure). Scenario A had exponentially increasing CO2, Scenario B had a more modest Business-as-usual assumption, and Scenario C had no further increases in CO2 after the year 2000. Both scenarios B and C assumed a large volcanic eruption in 1995. Rightly, the authors did not assume that they knew what path the carbon dioxide emissions would take, and so presented a spectrum of results. The scenario that ended up being closest to the real path of forcings growth was scenario B, with the difference that Mt. Pinatubo erupted in 1991, not 1995. The temperature change for the decade under this scenario was very close to the actual 0.11 C/decade observed (as can be seen in the figure). So given a good estimate of the forcings, the model did a reasonable job. In fact in his testimony, Hansen ONLY showed results from scenario B, and stated clearly that it was the most probable scenario. The '300 percent' error claim comes from noted climate skeptic Patrick Michaels who in testimony in congress in 1998 deleted the bottom two curves in order to give the impression that the models were unreliable.
Dr Hansen is further quoted (a little out-of-context) saying: "The forcings that drive long term climate change are not known with an accuracy sufficient to define future climate change". Given the discussion above it is clear that without good estimates of the actual forcings, the differences in the model projections can be large. It is widely accepted that exact prediction of what will happen to climate in 50 or 100 years is impossible. Much of the future is of course unknowable. A new energy source could replace fossil fuels, governments could control emissions, or maybe a series of huge volcanoes will erupt. Therefore it is much more sensible to ask, what would climate be like if you doubled CO2? or if this or that scenario occured. These are much better defined questions. Hansen's quote is often taken to imply that models are so unreliable they are useless in helping assess the issue. In fact it is the opposite - Hansen is actually claiming that the uncertainty in models (for instance, in the climate sensitivity) is now less than the uncertainty in the emissions scenarios (i.e. it is the uncertainty in the forcings, that drives the uncertainty in the projections)."
There have been others, too. This is the most commonly known example of a successful model, though. And note what happened to it: The success got deleted by people who didn't want anyone to know that climate-change was occuring.
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quote:Originally posted by Paul Goldner: "If humanity had ever, at any time in the past, accurately predicted a global trend in climate and its consequences, then I think people would be raising fewer doubts. The problem is, it's never been done before."
There have been others, too. This is the most commonly known example of a successful model, though. And note what happened to it: The success got deleted by people who didn't want anyone to know that climate-change was occuring.
What isn't clear from the excerpt is, did the model predict anything besides temperature change that also came to pass? If it made accurate, specific predictions in different areas of climate change, and consequences of the climate change, then it would be more significant. But merely predicting the rise in temperature when there already was a rising trend in temperature doesn't tell us a lot.
As for people not wanting people to know that climate change is occurring... there are those on every side of this issue (and there are more than two sides) who use manipulative political techniques to squash other points of view. If someone deliberately distorted Hansen's views, as the above excerpt asserts, that's wrong.
quote:What isn't clear from the excerpt is, did the model predict anything besides temperature change that also came to pass?
*blink* What are you saying -- that even if the global temperature is actually rising to a known level, we can't accurately predict what would happen and therefore shouldn't worry about it?
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quote:What isn't clear from the excerpt is, did the model predict anything besides temperature change that also came to pass?
*blink* What are you saying -- that even if the global temperature is actually rising to a known level, we can't accurately predict what would happen and therefore shouldn't worry about it?
That's not quite what I'm saying.
As far as I understand it, it's not a number on a global temperature chart per se that anyone's really worried about. It's a concern of possible resulting changes in sea levels, rainfall patterns, lengths of growing seasons et al affecting human and other life in adverse ways.
So if the only significant prediction of a particular model is, average measured global temperatures will increase by 0.11C in the next 10 years, and that comes true, that model doesn't tell us a lot. It could be a fine starting point to build on though.
However, I honestly don't know what else Hansen's model predicted. My question "did the model predict anything besides temperature change that also came to pass?" should be taken literally. That would have some effect on how significant it is. In my opinion.
(Edit add: I suppose I should disclose that I have a default sense of skepticism towards predictions of doom. And I'm not sure what to make of the global warming issue.)
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