It's probably rated troll because it's intentionally misleading. (Ok, I'll give you the benefit of the doubt: maybe it's just ignorantly misleading.) Or more likely, because of uninformed snide comments about "being had".
Human emissions are small compared to natural sources, but that misses the point. The point is that normally natural sinks are in close balance with natural sources, so the net flux is near zero and the net CO2 concentration is near constant. (This changes during large climate shifts like the ice age cycle.) When humans add emissions, it unbalances the system, so that the sources are slightly greater than the sinks. Over time, CO2 accumulates. Analogy: if every year natural sources put 100 units of CO2 into the air and natural sinks take 100 units out, you get no net accumulation or decrease. If in addition human sources put 1 unit in every year, then you get 101 units into the air and 100 out, so 1 extra unit stays in the air. There is a net accumulation over time.
Over the last 150 years (coinciding with the Industrial Revolution), CO2 levels have increased 35% despite being nearly constant (to within a few percent) for 10,000 years. Almost all of that excess CO2 is due to humans. This has been demonstrated by about a half dozen independent and mutually consistent lines of evidence, including records of fossil fuel extraction and use, the C13 isotopic signature of fossil fuels, the C14 signature, the corresponding O2 decrease, ecosystem flux measurements, ocean flux measurements, and ocean dissolved carbon penetration patterns. It's one of the most strongly confirmed lines of evidence in the whole debate.
If you insist on being a climate skeptic, you need to catch up with the skeptical dialogue. They don't still argue about whether the CO2 is due to humans, or whether there's warming. Or even so much whether there is warming due to humans; that's no longer a very tenable position. Mostly the argument is about how strong the climate feedbacks are, i.e. whether we're going to get weak CO2 warming that will eventually be dominated by other natural factors, or strong CO2 warming.
The point is that we should focus on reducing CO2 emissions now, because relying on geoengineering has very high costs of failure down the road if it doesn't work or we fail to maintain it for a very long time. To use the medical analogy, an ounce of prevention is worth a pound of cure. The time to use geoengineering is later, if really bad things loom near that we weren't able to prevent. Ideally, we wouldn't have to resort to geoengineering at all, because it's a risky intervention. But we should have it ready as a backup.
Exactly right. You're committed to maintaining and replacing this huge geoengineering infrastructure for as long as the excess CO2 is in the atmosphere, which could be hundreds or thousands of years.
Worst case scenario: these ships are actively harmful, so we shut them off, the water vapor precipitates in a week or so, and we've wasted the budget equivalent of 12 days in Iraq.
Depends on how quickly we learn they're harmful. If it's quickly, no problem. If we only learn that after a hundred years, then we turn them off and boom, the water precipitates out and all of a sudden we get all the global warming that those ships were suppressing. That's a VERY much worse case.
This is well known regarding the total greenhouse effect, but the relevant issue is that CO2 is responsible for most of the increase in the baseline greenhouse effect since pre-industrial times. That is, you get tens of degrees of natural warming that's already been there from water vapor and other greenhouse gases, and then our excess CO2 comes along and adds another degree on top of that (and a few more in coming centuries, if we keep emitting it).
I forgot to mention that one of the CC perspective papers does make a larger point about uncertainty, and unsurprisingly advocates a stronger role for economically induced mitigation policies. The other perspective paper argues that such mitigation will be too expensive unless accompanied by serious R&D into alternative energy — a fair point, but one which is not inconsistent with other conclusions such as the IPCC WG3 report. I don't think anybody believes that mitigation is going to work without more technology R&D, or that mitigation will eliminate the need for adaptation. Note that the perspective papers also agree that policy instruments like carbon taxes are an important component of the portfolio of solutions.
If you read the challenge paper from Lomborg's Copenhagen Consensus (CC), you will find that they conclude the optimal mitigation policy includes cutting CO2 emissions by economic force (e.g., taxes). They just don't recommend that you ONLY do that: you should also spend some effort on technology R&D as well as adaptation to climate changes you don't mitigate. Indeed, they find that R&D gets you a lot of short term gains, tax-induced mitigation gets you the most long-term gain, and adaptation helps cushion the blow.
Well, that's the same as what the IPCC recommends, a mixture of mitigation, adaptation, and technology improvements. Maybe the IPCC recommends a different quantitative mix, but it's not accurate to claim that Lomborg or anyone else has shown that carbon taxes or other economic instruments are unnecessary or improper solutions. I think the CC find that you should have a carbon tax maybe 30% lower than what mainstream economists like Nordhaus recommend.
In addition, Lomborg and the CC have been rightly criticized for taking more benign or just middle-of-the-road estimates with no uncertainty. It's long been known that the real need for strong mitigation is driven by the lower probability but high impact possibilities. (See, e.g., Weitzman's "dismal theorem" arguments about the "heavy tail" for a worst case scenario.) When you fix a central estimate and ignore the probability that the true outcome could be either higher or lower, you systematically lowball the amount of mitigation you need to insure against the more severe outcomes. (They tend to dominate the decision analysis since, even if a worse outcome is no more probable than a better outcome, the worse outcome gets more weight because the damages increase nonlinearly.) I don't know if Lomborg has ever acknowledged this, but the CC explicitly mentions it, and says that the possibility of large climate sensitivities can drastically change their cost-benefit analysis. Other economists have taken this uncertainty into account, and generally find even stronger justification for economic manipulation of CO2 emissions. That's the kind of analysis that the IPCC uses in their policy review. In general free market enthusiasts should be supportive of either price or quantity policy instruments to correct any distortion in the market, such as that due to negative externalities like CO2, whether it's by Pigovian tax or emissions trading or whatever.
If the best experts agree that it might work, it's worth testing on a small scale and see what happens in terms of cloud reflectivity and any adverse effects. It could probably even be tested to some extent without building a single ship.
Unfortunately, it's probably hard to test this on a small scale. Other kinds of geoengineering can be, like stratospheric aerosol injection: that experiment has already been done, by volcanoes. But it's really hard to attribute cloud behavior to specific causes, which is why cloud physics is the largest uncertainty in climate prediction. You have to collect a lot of statistics in order to be able to disentangle all the causal factors, which means you probably have to do it on a large scale, and for some time, before you can tell what effect it's having. The natural variability of cloud cover is already large, and with that low signal-to-noise ratio, it takes a while to see if there's been any real change at all, let alone one whose cause you can isolate and attribute to your intervention.
Those are some nice cognitive filters you've constructed for yourself. Any scientific paper cited by the IPCC (regardless of whether it was written by anybody in the IPCC)? Simply ignorable! Arbitrarily large amounts of evidence dismissible in one fell swoop! Ah, to be so unencumbered by knowledge and facts.
Generally, economists find that the best policy is a mix of CO2 emissions abatement coupled with adaptation to whatever climate change remains. It's not cheaper to just adapt without reducing the warming at all, but if you can adapt it means that you can live with more warming than otherwise.
And yet, despite the much higher levels of carbon dioxide than we have now, life flourished.
This kind of misses the point. Much of the planet were lush tropical jungles in the Cretaceous, but that doesn't necessarily mean that we want to return to a Cretaceous climate. Especially when we haven't seen that kind of climate for tens of millions of years. How well are existing species going to do if we return to it in the span of a century or two?
And it's not true that plants are automatically going to do wildly better, anyway. Direct-manipulation FACE-type experiments show C4 plants don't see much benefit from CO2 fertilization, and even the C3 plants don't get as big a boost as you might think. More importantly, CO2 is often not the rate-limiting factor. Pumping it up doesn't help if the plant really needs more water, or nitrogen; similarly, CO2 doesn't help if it's near the upper end of its temperature envelope. CO2 fertilization does help in general, but it's not really going to turn the planet into a new Eden with superabundant crops.
Using plants as a means of carbon sequestration isn't the simple silver bullet solution you seem to think, either. You would have to turn a truly huge amount of the urbanized land surface back into vegetation to get any sequestration, and then you have to store it all somewhere. No, you aren't going to be able to turn more than a small fraction of it into buildings and furniture, and that's just counting trees. People have looked into reforestation as a means of carbon sequestration before. It just doesn't help enough, at the rate we're emitting. It's probably worth doing, in the right places (too far north and you actually make global warming worse, as dark trees replace sunlight-reflecting snow), but it's not going to by itself reduce CO2 to pre-industrial levels any time soon, or even come close.
The Romans and early Middle Age citizens experienced global warming & they did not die.
How do you know? Maybe it was peachy for England but the poor sods in Ethiopia got heatstroke and drought. Or maybe not. We don't really have good records of the mortality impacts at the time.
Note also that the warming expected over the last century is larger and more rapid than anything the Romans or Middle Age citizens experienced.
In fact, they grew grapes as far north as Scotland, so it was actually beneficial.
... to Scottish grape farmers, maybe. (Note also that we are already at those levels of warmth today, the question is what happens when we go even farther beyond that.)
It's true that some people will benefit from global warming, particularly in cold regions. Others will be harmed, particularly in hot regions. A climate which changes too quickly tends to be bad for everybody, as it takes time to adapt to new climates (especially if you've got political borders and can't just move whichever climate dependent industries are no longer supported in your region.)
And by the way, anticipating your probable weaselly response based on your past behavior in these threads: I don't accept "go do a Google search and come back later" as an argumment. No, if you're making bold claims, I want to see you put together a substantive critique of the science with specific citations into the peer reviewed climate literature, not vague "hunt through a million blog links for unspecified references and I'm sure you'll find something supporting my claims". (And no, I also don't count "peer review sucks so I'm going to rely on uninformed web sites instead": you made a claim about what the scientific community thinks, not what skeptical web site authors think.)
I posted a whole bunch of links here in the last big discussion of global warming on/. You can go find them if you want, it should not be difficult.
I found this post of yours, which does not actually contain links to any scientific papers disputing CO2 as a major cause of global warming. Perhaps you were referring to some other post of yours?
The post I did find follows the usual scattershot creationist strategy: quote-mine an arbitrarily large number of supposed "refutations" out of Google, and when your opponent doesn't want to spend the next two months refuting them all, declare victory.
How about picking one or two of the best scientific arguments which you think make the case that CO2 is not the main contributor to the recent warming, and defending those scientifically with references to the scientific literature? (Note the word "science" here.)
I did see some posts of yours with the usual wrong claims about tropospheric warming, solar influence on climate, etc. But no links to any actual scientific publications.
The NEWS might still be claiming that CO2 is the most likely culprit, but scientists -- even the majority of scientists -- are not.
That's manifestly false. I read the main journals weekly/monthly (Science/Nature/Nature Geosci., GRL, JGR, J. Climate, Climate Dynamics etc.) and by vast majority the papers which discuss global warming either implicitly or explicitly attribute it to CO2. Disagree? Go look at the latest issues of each of those journals, and count how many articles attribute it mostly to something other than CO2. Seriously. Go look.
Sheesh, even the UN's IPCC committee has retracted their former stance on CO2!
If by "their former stance" you mean their attribution of most of the 20th century warming to CO2 and other greenhouse gases, and their projections of several degrees of warming by 2100 due to continued GHG emissions, that's a flat lie.
In my attempt to turn up your links, I did come across a previous claim of yours that the UN "retracted their famous, hysterical report about greenhouse warming" and that "The UN has subsequently issued another report, in which they state (I am paraphrasing) that we are not seeing greenhouse warming today, and may not for many years." This is, as I said, a bald faced lie. The IPCC never retracted their Fourth Assessment Report in which they attributed global warming to CO2, and they never issued a report claiming that we are not seeing greenhouse warming today. If you want to continue making this claim, please post a link to this supposed "new report".
Gee, no bias there. Just because they went into the study looking for a particular result, their impartiality should not be called into question.
The IPCC doesn't conduct studies or research. It summarizes the existing body of research: it conducts literature reviews. If you think the report's summary of model hindcast and projection skill is at odds with anything published in the climate literature, feel free to cite the papers documenting this discrepancy.
And once again, "they went into the study looking for a particular result" is an example of an unsupported assertion, not a criticism. A very handy one for you: no matter what the state of knowledge, simply accuse somebody of bias and ignore arbitrarily large amounts of evidence. Pretty much the creationist denial strategy.
Never mind the fact that you obviously didn't read this:
Who said I didn't read it? I saw it when it first came out. What's your point?
because it doesn't fit with your political worldview.
You have no idea what my political worldview is, but go ahead and ignorantly blunder on like you have in the rest of the thread.
The snobby, elitist remark you made was that someone should "go back and read the decades of research" which you of course have done to be "allowed" to criticize the use of ice cores
Once again, you are sadly confused. Pointing out that you have to actually know something about a subject in order to criticize it is not snobby or elitist, it's a basic epistemological truth. You have no basis for criticizing the use of ice cores when you know nothing about them, the circumstances under which can be used, how they're calibrated, how temperatures are derived, what the uncertainties are, and what methods are used to control for errors.
You are certainly "allowed" to criticize the use of the ice cores. But as a corollary, you're also allowed to be exposed as an ignorant fool when you make such criticisms in the absence of any scientific argument. Indeed, nothing you've written even rises to the level of a criticism, it's just a naked assertion. If you'd like to start over and try again with an actual scientific argument, feel free.
My ark comment was obviously aimed at the doomsday scenario crowd, which by your Karl Rove comment, you are part of.
Your logical skills are as poor as your knowledge of climate science.
But, of course, you have done this research with regards to radioactive isotopes and snow compaction in the Antarctic.
In fact, I have. I'm a scientist and although paleoclimate is not my field, I have been studying some of the paleoclimate proxy literature for a couple years, particularly the calibration and use of oxygen isotope proxies in ice cores. If you would care to read some of this literature, you would learn what the main sources of error are and how big they are, instead of waving your hands and making unsupported assertions about them. The references cited in the cryosphere chapter of the latest IPCC report is one place you can start.
I think this about your seventh post here that has been entirely free of any scientific content, despite your claims to be "criticizing the science". Curious.
When you do, you will have already failed, since the data provided is not enough to make an accurate projection. This has been proven again and again as projections and simulations falter and fail
Have you, um, ever looked at any of those model projections and the observational data? (Silly question, given your behavior in this thread.) You could start with Rahmstorf et al. (2007) in Science, or chapter 10 of the IPCC WG1 report. The observations remain fully consistent with the models.
(As was pointed out by someone above, who I am too lazy to quote).
Great! Previously you were too lazy to read any science. Now you're too lazy to even quote somebody on Slashdot. Quite an improvement.
Of course, you may say that you only want me to prove my point using references [...] There's only one problem with that, which is that I am not required to prove the negative.
Nice attempt at burden-of-proof shifting in lieu of actually having to know something. Sadly, you are required to support your claims, and if you claim that "it has been proven again and again" that models are crap, you need to cite evidence.
Awesome, so given the past performance of the London Stock Exchange, you could predict it's future performance?
The unpredictability of the stock market doesn't somehow imply that nothing in science can be predicted.
Even assuming that the data you have is perfect, it doesn't mean the result of a simulation is going to be perfect.
Nobody claimed that proxy measurements are perfect. Hell, thermometers aren't perfect. And what simulation?
In the case of your proxy data for global(???) temperature...is it at all possible that other factors affect the growth rate of coral?
Of course it is. That's why they went out and measured coral growth under a bunch of different conditions to quantify how much such factors may contribute.
Or that maybe just maybe fluctuations in the rate of deposition of sediment may have a looser correlation with temperature fluctuations than you think??
Sediment deposition rates are not temperature proxies. (Or at least, I've never heard of anyone using them that way.) If anything, they're used for dating, not temperature. And usually not for that, unless you can count explicit layers; typically, dating of sediments is done by isotopic analysis of their contents.
but I would have thought that just collating more and more "probably correct" data points doesn't necessarily make them more accurate,
It will reduce the random error and leave any systematic error unchanged, so it will make them more accurate but only up to a point. To reduce the systematic error you have to come up with better calibration methods, or compare to independent sources.
especially when you're plugging them into a simulation...
Proxy data is rarely derived by simulation; it usually comes from just fitting a statistical regression. Something like the second figure here. There is some scatter in the data, and therefore uncertainty, but it's not totally unpredictable either.
No, it's "learn something about what the hell you're talking about or shut up". But hey, go ahead and try to politicize it. When you don't know any science, that's all you've got.
Its a fallacy simply because everytime scientists try to model starting from any other point the models do not show the same thing.
What is the factual basis for this claim?
The LIA was about 300-400 years ago. There are models which have been forced starting 1000-2000 years ago, and models which have been forced starting 100 years ago. They all predict pretty much the same thing. You can look, e.g., in the IPCC report comparing chapters 6 and 8 for the long-term vs. shorter term models. The IPCC models in chapter 8 were all started at the same time (by agreement), but you can find plenty of examples in the literature of models being started later, when the authors were only looking at the 20th century and didn't want to run them all the way back from the LIA.
As for Ice core readings, this science is in its infancy and although we are making headway into this crucial temperature reading method, its still a long way off from showing how much human influence is effecting climate.
Really? Upon what science is that conclusion based? It seems that no matter what we know or learn, there's always "just enough uncertainty" to avoid concluding that we have anything to do with it.
I do think its a conspiracy by the worlds climate scientists. They get more money and more grants if they show the sky is falling,
This has got to be the worst argument against global warming I've ever heard.
First off, it's basically insane to believe that any group of tens of thousands of people has literally gotten together in a back room and agreed to only publish certain results. And I don't see you alleging scientific conspiracies against any other branch of science. Why isn't everybody lying to get grant money?
Moreover, the incentive structure in science is not to keep your head down and agree with the heard. The fastest way to fame and fortune in science is by overturning established theories, not adding yet another scrap of evidence to support them.
Take climate sensitivity to CO2. Estimates of its magnitude have been unable to rule out high sensitivities. Doing so is one of the holy grails of climate science, and believe me, there is a whole industry of scientists trying to eliminate this "high tail". And no, they're not skeptics, these are people whose work is highlighted by the IPCC.
so go figure, what do they do? They don't report findings that contradict themselves, just report what does.
You've never actually read a scientific journal, have you? They argue with and refute each other all the time.
That is, the easiest explanation is money in this case
Conspiracy theories are never the easiest explanation, they're almost always the most bizarre and contrived explanation, constructed for no reason other than to avoid uncomfortable facts. Whenever someone has to resort to invoking conspiracy theories to defend their point, they've basically lost.
Intelligent discussion is not allowed!
Intelligent discussion is allowed, but for some reason you'd rather talk about conspiracy theories and make unsupported claims about the science.
So the thermometer is less accurate than the ice core and coral growth?
I said no such thing. I explicitly said the opposite, in response to the last time you made that absurd implication. You may recall that you choice to make sarcastic comments about arks instead of paying attention to the science being discussed. Thus you produce embarrassingly stupid responses like the above. It's increasingly clear that you are not, in fact, interested in the science.
Allow me to repeat the point, since it seems to have whizzed past you twice. All measurement devices have uncertainty; none of them are exact. Some of them have errors larger than others; indirect methods are always less accurate than direct methods. However, that doesn't make them useless. They are useful when calibrated, when many measurements are combined to make a more accurate average, and when the changes being measured are larger than the error bars on the measurement.
Hmm... I might get a snobby, elitist reply
What, do you work for Karl Rove or something? Argue on the wrong side of the scientific evidence, lose, but "win" by labelling your opponent "snobby and elitist". Presumably one should then prefer ignorance and sarcasm?
It's not "snobby and elitist" to inform someone that if they want to spout off about science, they ought to try reading something about it first.
Nothing gives you "exact" temperatures, not even a thermometer. If you have a lot of observations then you can average them to improve your overall accuracy over any individual measurement, by the central limit theorem. The same is true is you have a lot of different proxies. Of course you have to be careful to account for potential correlation between the data. There is several decades worth of literature on this subject, you should spend some time reading about what can and can't be done before blatantly asserting random "facts" about the method's accuracy.
Maybe you should spend less time being sarcastic and more time reading about science.
Measuring ice core Oxygen isotope proxies is so effective, soon we will be using it to monitor daily temperatures.
If you want to wait a century for the firn to compact, and want to know the temperature at some undisturbed location that gets regular snowfall like central Greenland or Antarctica (the two places where this method works), you could do so. It's not as accurate as a modern digital thermometer, so there's no point in using it to replace thermometers even if you could, but it's more than accurate to measure things like the glacial-interglacial cycle.
I'm sure you came to your conclusions reading literature written by someone who has spent a lot of time trying to measure temperature by looking at ice cores.
Yes, which is what you want to read if you're interested in how well the method works. Or you could, you know, make sarcastic comments instead.
Tell me, how do you measure an "ice core" from this year.
You don't measure an ice core from this year. That's why ice cores are used for paleoclimate.
Please be specific as to the steps involved, and how you blindly test this hypothesis
You don't "blindly test" the hypothesis. It is based on the observed correlation between temperature and isotopic ratios. If you want to do cross validation, leave some of the temperature/isotope measurements out of the regression and see how well the regression line predicts the withheld data. It is actually surprisingly linear.
If you're looking at oxygen fractionated in biological organisms like benthic foraminifera, there are extra factors you have to control for, like the species and where it lives in the water column.
How does anyone know what else might have affected the growth rate of coral at the time?
For one, they look at corals of the same species from around the world which grow in regions of different temperature, salinity, etc., and see how those factors are affect the coral's growth.
The other poster has a more complete answer to the broader question.
but you can't tell someone what the temperatures were without a measurement of said temperatures with an accurate temperature measurement device
That's manifestly false. Oxygen isotope proxies in ice cores are one of the prime examples of good paleothermometers, when they can be used; they depend on the rate at which heavier isotopes are transported in warmer or colder air, which is just physics. You don't need to worry about biological fractionation and such. Other proxies do good or fair jobs, depending on the type and the circumstances. Ocean proxies often do better than land proxies, since conditions are more stable. Almost all proxies are better at measuring temperature changes than absolute temperatures, though.
We have no reasonably accurate measurement of temperature before the existence of reasonably accurate measurement devices.
I'm sure you came to that conclusion from a thorough reading and analysis of the paleoproxy climate literature.
Slashdot Mirror
It's probably rated troll because it's intentionally misleading. (Ok, I'll give you the benefit of the doubt: maybe it's just ignorantly misleading.) Or more likely, because of uninformed snide comments about "being had".
Human emissions are small compared to natural sources, but that misses the point. The point is that normally natural sinks are in close balance with natural sources, so the net flux is near zero and the net CO2 concentration is near constant. (This changes during large climate shifts like the ice age cycle.) When humans add emissions, it unbalances the system, so that the sources are slightly greater than the sinks. Over time, CO2 accumulates. Analogy: if every year natural sources put 100 units of CO2 into the air and natural sinks take 100 units out, you get no net accumulation or decrease. If in addition human sources put 1 unit in every year, then you get 101 units into the air and 100 out, so 1 extra unit stays in the air. There is a net accumulation over time.
Over the last 150 years (coinciding with the Industrial Revolution), CO2 levels have increased 35% despite being nearly constant (to within a few percent) for 10,000 years. Almost all of that excess CO2 is due to humans. This has been demonstrated by about a half dozen independent and mutually consistent lines of evidence, including records of fossil fuel extraction and use, the C13 isotopic signature of fossil fuels, the C14 signature, the corresponding O2 decrease, ecosystem flux measurements, ocean flux measurements, and ocean dissolved carbon penetration patterns. It's one of the most strongly confirmed lines of evidence in the whole debate.
If you insist on being a climate skeptic, you need to catch up with the skeptical dialogue. They don't still argue about whether the CO2 is due to humans, or whether there's warming. Or even so much whether there is warming due to humans; that's no longer a very tenable position. Mostly the argument is about how strong the climate feedbacks are, i.e. whether we're going to get weak CO2 warming that will eventually be dominated by other natural factors, or strong CO2 warming.
The point is that we should focus on reducing CO2 emissions now, because relying on geoengineering has very high costs of failure down the road if it doesn't work or we fail to maintain it for a very long time. To use the medical analogy, an ounce of prevention is worth a pound of cure. The time to use geoengineering is later, if really bad things loom near that we weren't able to prevent. Ideally, we wouldn't have to resort to geoengineering at all, because it's a risky intervention. But we should have it ready as a backup.
Exactly right. You're committed to maintaining and replacing this huge geoengineering infrastructure for as long as the excess CO2 is in the atmosphere, which could be hundreds or thousands of years.
Worst case scenario: these ships are actively harmful, so we shut them off, the water vapor precipitates in a week or so, and we've wasted the budget equivalent of 12 days in Iraq.
Depends on how quickly we learn they're harmful. If it's quickly, no problem. If we only learn that after a hundred years, then we turn them off and boom, the water precipitates out and all of a sudden we get all the global warming that those ships were suppressing. That's a VERY much worse case.
This is well known regarding the total greenhouse effect, but the relevant issue is that CO2 is responsible for most of the increase in the baseline greenhouse effect since pre-industrial times. That is, you get tens of degrees of natural warming that's already been there from water vapor and other greenhouse gases, and then our excess CO2 comes along and adds another degree on top of that (and a few more in coming centuries, if we keep emitting it).
I forgot to mention that one of the CC perspective papers does make a larger point about uncertainty, and unsurprisingly advocates a stronger role for economically induced mitigation policies. The other perspective paper argues that such mitigation will be too expensive unless accompanied by serious R&D into alternative energy — a fair point, but one which is not inconsistent with other conclusions such as the IPCC WG3 report. I don't think anybody believes that mitigation is going to work without more technology R&D, or that mitigation will eliminate the need for adaptation. Note that the perspective papers also agree that policy instruments like carbon taxes are an important component of the portfolio of solutions.
If you read the challenge paper from Lomborg's Copenhagen Consensus (CC), you will find that they conclude the optimal mitigation policy includes cutting CO2 emissions by economic force (e.g., taxes). They just don't recommend that you ONLY do that: you should also spend some effort on technology R&D as well as adaptation to climate changes you don't mitigate. Indeed, they find that R&D gets you a lot of short term gains, tax-induced mitigation gets you the most long-term gain, and adaptation helps cushion the blow.
Well, that's the same as what the IPCC recommends, a mixture of mitigation, adaptation, and technology improvements. Maybe the IPCC recommends a different quantitative mix, but it's not accurate to claim that Lomborg or anyone else has shown that carbon taxes or other economic instruments are unnecessary or improper solutions. I think the CC find that you should have a carbon tax maybe 30% lower than what mainstream economists like Nordhaus recommend.
In addition, Lomborg and the CC have been rightly criticized for taking more benign or just middle-of-the-road estimates with no uncertainty. It's long been known that the real need for strong mitigation is driven by the lower probability but high impact possibilities. (See, e.g., Weitzman's "dismal theorem" arguments about the "heavy tail" for a worst case scenario.) When you fix a central estimate and ignore the probability that the true outcome could be either higher or lower, you systematically lowball the amount of mitigation you need to insure against the more severe outcomes. (They tend to dominate the decision analysis since, even if a worse outcome is no more probable than a better outcome, the worse outcome gets more weight because the damages increase nonlinearly.) I don't know if Lomborg has ever acknowledged this, but the CC explicitly mentions it, and says that the possibility of large climate sensitivities can drastically change their cost-benefit analysis. Other economists have taken this uncertainty into account, and generally find even stronger justification for economic manipulation of CO2 emissions. That's the kind of analysis that the IPCC uses in their policy review. In general free market enthusiasts should be supportive of either price or quantity policy instruments to correct any distortion in the market, such as that due to negative externalities like CO2, whether it's by Pigovian tax or emissions trading or whatever.
If the best experts agree that it might work, it's worth testing on a small scale and see what happens in terms of cloud reflectivity and any adverse effects. It could probably even be tested to some extent without building a single ship.
Unfortunately, it's probably hard to test this on a small scale. Other kinds of geoengineering can be, like stratospheric aerosol injection: that experiment has already been done, by volcanoes. But it's really hard to attribute cloud behavior to specific causes, which is why cloud physics is the largest uncertainty in climate prediction. You have to collect a lot of statistics in order to be able to disentangle all the causal factors, which means you probably have to do it on a large scale, and for some time, before you can tell what effect it's having. The natural variability of cloud cover is already large, and with that low signal-to-noise ratio, it takes a while to see if there's been any real change at all, let alone one whose cause you can isolate and attribute to your intervention.
Those are some nice cognitive filters you've constructed for yourself. Any scientific paper cited by the IPCC (regardless of whether it was written by anybody in the IPCC)? Simply ignorable! Arbitrarily large amounts of evidence dismissible in one fell swoop! Ah, to be so unencumbered by knowledge and facts.
Would it be cheaper to just mitigate the change?
Generally, economists find that the best policy is a mix of CO2 emissions abatement coupled with adaptation to whatever climate change remains. It's not cheaper to just adapt without reducing the warming at all, but if you can adapt it means that you can live with more warming than otherwise.
And yet, despite the much higher levels of carbon dioxide than we have now, life flourished.
This kind of misses the point. Much of the planet were lush tropical jungles in the Cretaceous, but that doesn't necessarily mean that we want to return to a Cretaceous climate. Especially when we haven't seen that kind of climate for tens of millions of years. How well are existing species going to do if we return to it in the span of a century or two?
And it's not true that plants are automatically going to do wildly better, anyway. Direct-manipulation FACE-type experiments show C4 plants don't see much benefit from CO2 fertilization, and even the C3 plants don't get as big a boost as you might think. More importantly, CO2 is often not the rate-limiting factor. Pumping it up doesn't help if the plant really needs more water, or nitrogen; similarly, CO2 doesn't help if it's near the upper end of its temperature envelope. CO2 fertilization does help in general, but it's not really going to turn the planet into a new Eden with superabundant crops.
Using plants as a means of carbon sequestration isn't the simple silver bullet solution you seem to think, either. You would have to turn a truly huge amount of the urbanized land surface back into vegetation to get any sequestration, and then you have to store it all somewhere. No, you aren't going to be able to turn more than a small fraction of it into buildings and furniture, and that's just counting trees. People have looked into reforestation as a means of carbon sequestration before. It just doesn't help enough, at the rate we're emitting. It's probably worth doing, in the right places (too far north and you actually make global warming worse, as dark trees replace sunlight-reflecting snow), but it's not going to by itself reduce CO2 to pre-industrial levels any time soon, or even come close.
The Romans and early Middle Age citizens experienced global warming & they did not die.
How do you know? Maybe it was peachy for England but the poor sods in Ethiopia got heatstroke and drought. Or maybe not. We don't really have good records of the mortality impacts at the time.
Note also that the warming expected over the last century is larger and more rapid than anything the Romans or Middle Age citizens experienced.
In fact, they grew grapes as far north as Scotland, so it was actually beneficial.
... to Scottish grape farmers, maybe. (Note also that we are already at those levels of warmth today, the question is what happens when we go even farther beyond that.)
It's true that some people will benefit from global warming, particularly in cold regions. Others will be harmed, particularly in hot regions. A climate which changes too quickly tends to be bad for everybody, as it takes time to adapt to new climates (especially if you've got political borders and can't just move whichever climate dependent industries are no longer supported in your region.)
And by the way, anticipating your probable weaselly response based on your past behavior in these threads: I don't accept "go do a Google search and come back later" as an argumment. No, if you're making bold claims, I want to see you put together a substantive critique of the science with specific citations into the peer reviewed climate literature, not vague "hunt through a million blog links for unspecified references and I'm sure you'll find something supporting my claims". (And no, I also don't count "peer review sucks so I'm going to rely on uninformed web sites instead": you made a claim about what the scientific community thinks, not what skeptical web site authors think.)
I posted a whole bunch of links here in the last big discussion of global warming on /. You can go find them if you want, it should not be difficult.
I found this post of yours, which does not actually contain links to any scientific papers disputing CO2 as a major cause of global warming. Perhaps you were referring to some other post of yours?
The post I did find follows the usual scattershot creationist strategy: quote-mine an arbitrarily large number of supposed "refutations" out of Google, and when your opponent doesn't want to spend the next two months refuting them all, declare victory.
How about picking one or two of the best scientific arguments which you think make the case that CO2 is not the main contributor to the recent warming, and defending those scientifically with references to the scientific literature? (Note the word "science" here.)
I did see some posts of yours with the usual wrong claims about tropospheric warming, solar influence on climate, etc. But no links to any actual scientific publications.
The NEWS might still be claiming that CO2 is the most likely culprit, but scientists -- even the majority of scientists -- are not.
That's manifestly false. I read the main journals weekly/monthly (Science/Nature/Nature Geosci., GRL, JGR, J. Climate, Climate Dynamics etc.) and by vast majority the papers which discuss global warming either implicitly or explicitly attribute it to CO2. Disagree? Go look at the latest issues of each of those journals, and count how many articles attribute it mostly to something other than CO2. Seriously. Go look.
Sheesh, even the UN's IPCC committee has retracted their former stance on CO2!
If by "their former stance" you mean their attribution of most of the 20th century warming to CO2 and other greenhouse gases, and their projections of several degrees of warming by 2100 due to continued GHG emissions, that's a flat lie.
In my attempt to turn up your links, I did come across a previous claim of yours that the UN "retracted their famous, hysterical report about greenhouse warming" and that "The UN has subsequently issued another report, in which they state (I am paraphrasing) that we are not seeing greenhouse warming today, and may not for many years." This is, as I said, a bald faced lie. The IPCC never retracted their Fourth Assessment Report in which they attributed global warming to CO2, and they never issued a report claiming that we are not seeing greenhouse warming today. If you want to continue making this claim, please post a link to this supposed "new report".
Gee, no bias there. Just because they went into the study looking for a particular result, their impartiality should not be called into question.
The IPCC doesn't conduct studies or research. It summarizes the existing body of research: it conducts literature reviews. If you think the report's summary of model hindcast and projection skill is at odds with anything published in the climate literature, feel free to cite the papers documenting this discrepancy.
And once again, "they went into the study looking for a particular result" is an example of an unsupported assertion, not a criticism. A very handy one for you: no matter what the state of knowledge, simply accuse somebody of bias and ignore arbitrarily large amounts of evidence. Pretty much the creationist denial strategy.
Never mind the fact that you obviously didn't read this:
Who said I didn't read it? I saw it when it first came out. What's your point?
because it doesn't fit with your political worldview.
You have no idea what my political worldview is, but go ahead and ignorantly blunder on like you have in the rest of the thread.
The snobby, elitist remark you made was that someone should "go back and read the decades of research" which you of course have done to be "allowed" to criticize the use of ice cores
Once again, you are sadly confused. Pointing out that you have to actually know something about a subject in order to criticize it is not snobby or elitist, it's a basic epistemological truth. You have no basis for criticizing the use of ice cores when you know nothing about them, the circumstances under which can be used, how they're calibrated, how temperatures are derived, what the uncertainties are, and what methods are used to control for errors.
You are certainly "allowed" to criticize the use of the ice cores. But as a corollary, you're also allowed to be exposed as an ignorant fool when you make such criticisms in the absence of any scientific argument. Indeed, nothing you've written even rises to the level of a criticism, it's just a naked assertion. If you'd like to start over and try again with an actual scientific argument, feel free.
My ark comment was obviously aimed at the doomsday scenario crowd, which by your Karl Rove comment, you are part of.
Your logical skills are as poor as your knowledge of climate science.
But, of course, you have done this research with regards to radioactive isotopes and snow compaction in the Antarctic.
In fact, I have. I'm a scientist and although paleoclimate is not my field, I have been studying some of the paleoclimate proxy literature for a couple years, particularly the calibration and use of oxygen isotope proxies in ice cores. If you would care to read some of this literature, you would learn what the main sources of error are and how big they are, instead of waving your hands and making unsupported assertions about them. The references cited in the cryosphere chapter of the latest IPCC report is one place you can start.
I think this about your seventh post here that has been entirely free of any scientific content, despite your claims to be "criticizing the science". Curious.
When you do, you will have already failed, since the data provided is not enough to make an accurate projection. This has been proven again and again as projections and simulations falter and fail
Have you, um, ever looked at any of those model projections and the observational data? (Silly question, given your behavior in this thread.) You could start with Rahmstorf et al. (2007) in Science, or chapter 10 of the IPCC WG1 report. The observations remain fully consistent with the models.
(As was pointed out by someone above, who I am too lazy to quote).
Great! Previously you were too lazy to read any science. Now you're too lazy to even quote somebody on Slashdot. Quite an improvement.
Of course, you may say that you only want me to prove my point using references [...] There's only one problem with that, which is that I am not required to prove the negative.
Nice attempt at burden-of-proof shifting in lieu of actually having to know something. Sadly, you are required to support your claims, and if you claim that "it has been proven again and again" that models are crap, you need to cite evidence.
Awesome, so given the past performance of the London Stock Exchange, you could predict it's future performance?
The unpredictability of the stock market doesn't somehow imply that nothing in science can be predicted.
Even assuming that the data you have is perfect, it doesn't mean the result of a simulation is going to be perfect.
Nobody claimed that proxy measurements are perfect. Hell, thermometers aren't perfect. And what simulation?
In the case of your proxy data for global(???) temperature...is it at all possible that other factors affect the growth rate of coral?
Of course it is. That's why they went out and measured coral growth under a bunch of different conditions to quantify how much such factors may contribute.
Or that maybe just maybe fluctuations in the rate of deposition of sediment may have a looser correlation with temperature fluctuations than you think??
Sediment deposition rates are not temperature proxies. (Or at least, I've never heard of anyone using them that way.) If anything, they're used for dating, not temperature. And usually not for that, unless you can count explicit layers; typically, dating of sediments is done by isotopic analysis of their contents.
but I would have thought that just collating more and more "probably correct" data points doesn't necessarily make them more accurate,
It will reduce the random error and leave any systematic error unchanged, so it will make them more accurate but only up to a point. To reduce the systematic error you have to come up with better calibration methods, or compare to independent sources.
especially when you're plugging them into a simulation...
Proxy data is rarely derived by simulation; it usually comes from just fitting a statistical regression. Something like the second figure here. There is some scatter in the data, and therefore uncertainty, but it's not totally unpredictable either.
No, it's "learn something about what the hell you're talking about or shut up". But hey, go ahead and try to politicize it. When you don't know any science, that's all you've got.
Its a fallacy simply because everytime scientists try to model starting from any other point the models do not show the same thing.
What is the factual basis for this claim?
The LIA was about 300-400 years ago. There are models which have been forced starting 1000-2000 years ago, and models which have been forced starting 100 years ago. They all predict pretty much the same thing. You can look, e.g., in the IPCC report comparing chapters 6 and 8 for the long-term vs. shorter term models. The IPCC models in chapter 8 were all started at the same time (by agreement), but you can find plenty of examples in the literature of models being started later, when the authors were only looking at the 20th century and didn't want to run them all the way back from the LIA.
As for Ice core readings, this science is in its infancy and although we are making headway into this crucial temperature reading method, its still a long way off from showing how much human influence is effecting climate.
Really? Upon what science is that conclusion based? It seems that no matter what we know or learn, there's always "just enough uncertainty" to avoid concluding that we have anything to do with it.
I do think its a conspiracy by the worlds climate scientists. They get more money and more grants if they show the sky is falling,
This has got to be the worst argument against global warming I've ever heard.
First off, it's basically insane to believe that any group of tens of thousands of people has literally gotten together in a back room and agreed to only publish certain results. And I don't see you alleging scientific conspiracies against any other branch of science. Why isn't everybody lying to get grant money?
Moreover, the incentive structure in science is not to keep your head down and agree with the heard. The fastest way to fame and fortune in science is by overturning established theories, not adding yet another scrap of evidence to support them.
Take climate sensitivity to CO2. Estimates of its magnitude have been unable to rule out high sensitivities. Doing so is one of the holy grails of climate science, and believe me, there is a whole industry of scientists trying to eliminate this "high tail". And no, they're not skeptics, these are people whose work is highlighted by the IPCC.
so go figure, what do they do? They don't report findings that contradict themselves, just report what does.
You've never actually read a scientific journal, have you? They argue with and refute each other all the time.
That is, the easiest explanation is money in this case
Conspiracy theories are never the easiest explanation, they're almost always the most bizarre and contrived explanation, constructed for no reason other than to avoid uncomfortable facts. Whenever someone has to resort to invoking conspiracy theories to defend their point, they've basically lost.
Intelligent discussion is not allowed!
Intelligent discussion is allowed, but for some reason you'd rather talk about conspiracy theories and make unsupported claims about the science.
So the thermometer is less accurate than the ice core and coral growth?
I said no such thing. I explicitly said the opposite, in response to the last time you made that absurd implication. You may recall that you choice to make sarcastic comments about arks instead of paying attention to the science being discussed. Thus you produce embarrassingly stupid responses like the above. It's increasingly clear that you are not, in fact, interested in the science.
Allow me to repeat the point, since it seems to have whizzed past you twice. All measurement devices have uncertainty; none of them are exact. Some of them have errors larger than others; indirect methods are always less accurate than direct methods. However, that doesn't make them useless. They are useful when calibrated, when many measurements are combined to make a more accurate average, and when the changes being measured are larger than the error bars on the measurement.
Hmm... I might get a snobby, elitist reply
What, do you work for Karl Rove or something? Argue on the wrong side of the scientific evidence, lose, but "win" by labelling your opponent "snobby and elitist". Presumably one should then prefer ignorance and sarcasm?
It's not "snobby and elitist" to inform someone that if they want to spout off about science, they ought to try reading something about it first.
An entirely content-free post. Your contribution to this thread is not improving.
Nothing gives you "exact" temperatures, not even a thermometer. If you have a lot of observations then you can average them to improve your overall accuracy over any individual measurement, by the central limit theorem. The same is true is you have a lot of different proxies. Of course you have to be careful to account for potential correlation between the data. There is several decades worth of literature on this subject, you should spend some time reading about what can and can't be done before blatantly asserting random "facts" about the method's accuracy.
Maybe you should spend less time being sarcastic and more time reading about science.
Measuring ice core Oxygen isotope proxies is so effective, soon we will be using it to monitor daily temperatures.
If you want to wait a century for the firn to compact, and want to know the temperature at some undisturbed location that gets regular snowfall like central Greenland or Antarctica (the two places where this method works), you could do so. It's not as accurate as a modern digital thermometer, so there's no point in using it to replace thermometers even if you could, but it's more than accurate to measure things like the glacial-interglacial cycle.
I'm sure you came to your conclusions reading literature written by someone who has spent a lot of time trying to measure temperature by looking at ice cores.
Yes, which is what you want to read if you're interested in how well the method works. Or you could, you know, make sarcastic comments instead.
Tell me, how do you measure an "ice core" from this year.
You don't measure an ice core from this year. That's why ice cores are used for paleoclimate.
Please be specific as to the steps involved, and how you blindly test this hypothesis
You don't "blindly test" the hypothesis. It is based on the observed correlation between temperature and isotopic ratios. If you want to do cross validation, leave some of the temperature/isotope measurements out of the regression and see how well the regression line predicts the withheld data. It is actually surprisingly linear.
If you're looking at oxygen fractionated in biological organisms like benthic foraminifera, there are extra factors you have to control for, like the species and where it lives in the water column.
How does anyone know what else might have affected the growth rate of coral at the time?
For one, they look at corals of the same species from around the world which grow in regions of different temperature, salinity, etc., and see how those factors are affect the coral's growth.
The other poster has a more complete answer to the broader question.
but you can't tell someone what the temperatures were without a measurement of said temperatures with an accurate temperature measurement device
That's manifestly false. Oxygen isotope proxies in ice cores are one of the prime examples of good paleothermometers, when they can be used; they depend on the rate at which heavier isotopes are transported in warmer or colder air, which is just physics. You don't need to worry about biological fractionation and such. Other proxies do good or fair jobs, depending on the type and the circumstances. Ocean proxies often do better than land proxies, since conditions are more stable. Almost all proxies are better at measuring temperature changes than absolute temperatures, though.
We have no reasonably accurate measurement of temperature before the existence of reasonably accurate measurement devices.
I'm sure you came to that conclusion from a thorough reading and analysis of the paleoproxy climate literature.