SkepticLance

Swansont. We all know there is no such thing as conclusive proof, and we are not asking for it. What we need is convincing evidence. That evidence, by the most basic standards of good science, must be empirical. That is, from experiments and observations in the real world. What is NOT empirical evidence is processes of logic, calculations, and models. Sadly, that appears to be the main evidence supplied. Empirical evidence is rare. If the 'hockey stick' graph could be shown, beyond any reasonable doubt, to be correct, that would be sufficient evidence for me. However, it was derived from improper scientific technique (a change in measurement technique mid-study) and does not agree with at least two other sets of real data I have seen.

bascule said. Yes, there is... please review the NRC report and the IPCC report I linked earlier in the thread bascule, I am sorry. But neither graph you posted represents conclusive evidence. The graph on thermal forcings is the result of various calculations, and those are based on a series of assumptions that may, or may not be correct. The graph on temperature versus carbon dioxide levels over the past 500,000 years implies that warming comes first and that this warming causes carbon dioxide rise, not the reverse. I am not saying that this is true for the last 100 years. However, you need to be careful of the evidence you present.

bascule. I said that the urban heat argument may or may not be correct. Whichever really does not matter. The point is that Mann used an improper technique to get his results, and others have achieved different results using a more scientifically sound approach. I am reluctant to reveal the dendrochronology study here since I am still in my debate with herpguy and want to use it there. One source of error in all these arguments is data selection (I am just as guilty as you). We tend to use data that supports our viewpoint. Temperature increase over the 20th Century has been measured in many different ways and many different sets of results have been obtained. By selecting the set we prefer, we skew the argument. We should all be aware that there are many different possible graphs of temperature rise. Another data set is the study of 169 glaciers with average shrinkage measured showing a nearly linear melting from 1810 to 2000. The world is warming up, and the hockey stick shows a drastic spike to tie in with greenhouse gas theories. However, some of the other sets of data do not show this at all, including glacier meltings. bascule, as I have always said, you may be right. However, you may be quite wrong. The doubts and uncertainties in this whole issue are too great. bascule, you have gone quite funny in your response to my comments on your temperature/carbon dioxide graph over the past 500,000 years. Your original point was that this showed carbon dioxide driving temperature. I have shown that the reverse applies. You now appear to be arguing something else entirely. Do you now agree that your graph does not prove your original point?

bascule There is nothing new and startling about the hockey stick graph. I first saw it years ago. In spite of your comments, it still reflects lousy science. You cannot change measurement method mid study and claim the difference in results is caused by anything other than the change in measurement. The normal skeptics explanation (which may or may not be correct) is that thermometer measurements are averaged from mostly city and airport measurements. Since both are growing in area and density, and the micro-climate effect of that growth is increased temperature, then the results are exaggerated. I have the results of a study by dendrochronologists (which also may or may not be a good model) which shows continuing global warming 19th and 20th Century, but without the spike. It actually looks to be a much more likely result, since it is a steadier continuation of existing trends, rather than a startlingly different 'jerk' upwards. Your snide comments about pirates and global warming should be ignored as lousy science also. You seem to have missed my point about the temperature vs carbon dioxide graph you posted. Nor am I changing my tune on the cause of 20th Century greenhouse gas emissions. Your graph covers half a million years, not the 20th Century. I will repeat my point in case you miss it again. On your graph, temperature increases first, followed by carbon dioxide levels. This means that the warming is the cause, and the rise in carbon dioxide is the effect. That is the pattern over 500,000 years, according to your own graph. This does not affect the special case of the 20th Century.

bascule said : Okay, another caveat: natural forcings were perdominant in the period of time between the "Little Ice Age" and 1940. In particular, we saw a period of decreased volcanic activity which brought about a decrease in reflective sulfate aerosols in the atmosphere, altering Earth's albedo and causing increased warming. Furthermore, we saw an overall increase in solar luminosity during this time. These forcings are not applicable past 1940 . You are probably not far wrong in that caveat. I would point out, though, that greenhouse gas increases were exponential from about 1910. Also, after 1940 we need to think about sunspots. They reached a peak (higher than any time for 8000 years) in the 1990's. There is quite a lot of evidence to suggest that this can be called a 'natural forcing'.

bascule. I accept fact. I query interpretations. Take another look at your hockey stick graph. The massive spike at the end 'coincides' with the change in method of measuring temperature. This is shown by the fact that it is a new line in a different colour (red). It is definitely unscientific to change your method of measuring something and then draw conclusions from the fact that measurements using that different method are different to measurements from the old method. I have an alternate graph which uses the same method of measuring temperature throughout. Surprise, surprise! There is no dramatic spike. I plan to use this graph in my debate with herpguy. As far as the ice core record is concerned, of course there is correlation between carbon dioxide and temperature. The key question is : which is cause, and which is effect? Cause ALWAYS precedes effect. This is clear cut in your graph. Temperature increase precedes carbon dioxide increase. Take a look. This strongly suggests that temperature increase is what causes carbon dioxide increase, not the other way round. There are a number of suggested mechanisms for this.

Apologies. In my post above, I meant 1976 to 1998.

bascule. Your comments about me failing to undermine the IPCC arguments miss the whole point of everything I am saying. I have always said : "I do not know. And neither does anyone else." Sure, the IPCC might be right. So might the various climate scientists who are skeptics. We do not know. I am not interested in undermining anyone's arguments. If they present convincing empirical evidence to support their statements, I will believe them. If they do not, and they have not as yet, then I will keep pointing out the doubt and uncertainty. swansont said : These statements appear to assume some linear relationship, even though it has been recognized elsewhere that the behavior of the climate is very nonlinear and complicated. It is incorrect to assume that a small change in conditions can't lead to a large effect. If global warming is caused, predominantly, by anthropogenic greenhouse gases, then the increase in greenhouse gases will precede increase in temperature, and the two patterns will be similar. They do not have to be identical, but similar. Your argument does not obviate this basic rule. And for the 20th Century at least, with the minimal exception of the 1996 to 1998 period (22 years out of 100) this rule is not met. Your comment about nuclear weapons is not relevent. Computer models were not used in the design of nuclear weapons until they had been proved to work, empirically. In other words, the modellers used their computer programs to simulate known weapons designs, and found they could achieve the results that were seen in the real world. This has not yet happened with global warming computer models. As witness the simple fact that no computer model has yet accurately modelled the pattern of the last 100 or 200 years.

My own view is slightly different to Dr. Dalek. While I admit I do not know the true situation (nor do I think anyone else does either), I suspect that global warming is a combination of natural factors, which began about 1750, and continue to the present day, and human activity. Anthropogenic greenhouse gases clearly could not have been a factor before about 1910. However, since then, they have doubtless had an effect. Quantifying the relative 'force' of the difference influences is the trick.

bascule. Your comments on forcings actually reinforce what I said. ie. that global warming is multi-factorial. The graph you present I have seen before, and it pre-dates the conference of 2003 in which it was pointed out that current computer models do not take into account changes in cloud formation. A factor that is more potent than carbon dioxide of methane. What kind of empirical evidence would I accept? By definition, it refers to experiments or observations of the real world, as opposed to models, calculations or process of logic. To meet the requirement, it must be experiment or observation that indicates a strong likelihood that anthropogenic greenhouse gas increase is the primary driver of global warming. For example : had the increase in greenhouse gases been reflected by temperature increase in a way that meets the laws of cause and effect, then that would have met the criteria. Two vital laws are : 1. Cause must ALWAYS preceed effect. 2. Effect must reflect cause. In a graph, that means that the graphed effect (temperature rise) must follow pretty much the same pattern as that of cause. Sadly for your case, the 20th century warming does not obey these laws in relation to greenhouse gas increase. There are two main periods of significant warming. First is 1910 to 1940. This was NOT preceeded by an equivalently great increase in greenhouse gases. Second is 1976 to 1998. This short period met the criteria. However ... In 1940 to 1976, there was a period of cooling, which was preceeded by significant increase in greenhouse gases. The reverse of the cause / effect rule. You said : There isn't a direct one-to-one relationship between greenhouse gasses and mean surface temperature, because greenhouse gasses aren't the only forcing affecting the climate system. For example, in the early 20th century there were no governmental controls on sulfate emissions, and the effect of sulfate aerosols (which cause acid rain) caused a cooling effect (see the "reflective aerosols" section of the chart I linked above). Once environmental regulations were in place to limit emissions of sulfates, we began to see the global average surface temeprature rise again. You both have a rather sophomoric view of the climate system. I suggest you both educate yourselves better on the issues before attempting to debate them. Apart from the unnecessary insult in the last paragraph, my coments are : I never claimed the need for a one to one relationship. A sufficiently high correlation is enough. The sulfate emission argument is refuted by climate scientists Michaels and Balling in their book : 'The Satanic Gases.' but the argument is long winded and I do not want to repeat it here. I would get extreme writers cramp! We may have reduced sulfate aerosols in the West, but China is taking up the slack very effectively.

CharonY said : In general I'd say that ecological damage is probably given as a more or less sudden disruption of the given state of a system, resulting in an ecosystem that is distinctly different from the starting point Thank you for this. An honest attempt at a good definition. Only criticism I have of this definition is that it encompasses a lot of what seems to be necessary natural changes. For example : the land slides I first mentioned, that provide an essential habitat for some species that would otherwise go extinct. Any comments?

herpguy. Forgive me if I don't understand what you are getting at. My point is that, in ecology, nothing is destroyed (except when extinction occurs). The balance of nature is never destroyed. Ecological change (or damage) simply results in a new balance point. Food webs are not 'collapsed' or destroyed - simply morphed into a new food web. It is tough to try to define 'damage'. I was hoping someone would have a better idea than I have been able to come up with. So far, if species extinction does not occur, the idea of ecological damage appears to be intuitive, rather than scientific. This is not a good situation.

herpguy. Thank you for your efforts. However, I am not sure of the depth of your understanding of ecology. (No offense intended). Ecological change is pretty much ubiquitous. However, such change, even when driven by the worst excesses of human effort does not destroy a food web. Merely changes it. We may get a lake that is pure and pristine, and so damage it that it is overwhelmed by bacteria - both photosynthetic (cyanobacteria) and anaerobic (which cause the nasty smells from bogs). However, a food web is still present and active. In fact, the purest lakes often have the lowest biomass and biological productivity. By contaminating them with nutrients we may make the lake far more biologically productive, but still call the result undesirable. This is why I have a problem with definition. If something cannot be clearly defined, its value as a scientific measure is debatable. Yet ecological or environmental damage is very important. it needs clear definition.

herpguy. Ecological 'balances' are changing all the time. Sometimes the change is natural and sometimes man-made. I am aware of several forest plants that specialise in colonising bare land after a land-slide. A land-slide seems to be a clear case of ecological damage, since it wipes out a section of forest. Yet without them, these specialised plants would go extinct. I am looking for an idea of ecological damage that goes beyond simply 'any ecological change'. Another example is the Australian bell frog. This species is highly endangered due to a fungus disease. Just before the Sydney 2000 Olympic games, some developers were checking sites for building sports facilities. They found a polluted pond that looked as though it would be a good site. However, an environmental study of the site showed that the pond had the largest population in Australia of the endangered frog. Apparently the chemicals in the polluted pond killed the fungus. The only clear cut example of ecological damage I can think of is extinction. I suspect that a lot of other damages are more aesthetic than real. However, there are some we would all agree on. Polluting the air over a city is damage. Acid rain is damage. Yet how can we define ecological damage in such a way as to make the meaning clear?

For all you medieval weapons fantasists, I recommend reading the thriller "High Citadel" by Desmond Bagley. The situation : our heroes are trapped up an alpine road. Below them is a bridge crossing a canyon, that has been toppled. Across the ravine is a bunch of terrorists who are determined to build a bridge and come at them and kill them. Terrorists have all the usual modern weapons. Luckily for our heroes, their number includes a professor who knows medieval weapons, and an engineer who can build them. Let battle commence.

What I am hoping for is some decent definition from someone. I am not sure that a phrase such as 'reduction in species diversity and richness' quite covers it? Let me give another example . I spent most of my adult life in Auckland. This used to have (100 years ago) a harbour with lots of clear water, and pristine reefs covered with seaweeds and reef dwelling fish etc. Due to development (deforestation and removal of ground soil by bulldozers etc) a lot of soil has washed into the sea, and sediment now covers those reefs, while the water has become very silty. Logically, this is a case of ecological damage. Yet a biologist friend of mine assures me that the explosion in sediment dwelling life-forms, and especially nematode worms, means the total number of species has probably increased. From an intuitive viewpoint, the Auckland harbour has suffered ecological damage. Yet, how do we define this damage?

An example of ecological damage appeared in the 17 June 2006 New Scientist. Page 43. Chongming is the world's largest alluvial island, formed by sediment at the mouth of the Yangtse River. Due to deforestation further up the river, lots more sediment has been washed down to this site, and the island has doubled in size since 1950. While this is not a clear cut case of ecological damage, the implication in the article was that it is a bad thing. I started wondering about the reverse. Imagine that the river was dredged to improve access for shipping, and the subsequent higher water flows caused the island to shrink. That would definitely be seen as ecological damage. It seems to me that the idea of such damage is imprecisely defined. Perhaps someone could pass on his / her definition of ecological damage?

bascule asked if I accepted whether carbon dioxide increase is a first order cause of global warming. I am not quite sure what he means by first order. If he means important, then yes. If he means greater than other causes, then I have to put it into the 'we don't know' category. I am personally aware of three causes of global warming. There may be others I am unaware of. Carbon dioxide and other greenhouse gases Sunspots Solar output increase. The latter is a small influence, but must be significant, since Mars is also undergoing global warming, as evidenced by telescopic observations of ice cap retreat. I can, if you wish, show data that gives a clear correlation between sunspot activity and global temperature over the past 500 years. I do not claim it is the number 1 influence. But it is almost certainly a powerful influence. The current episode of global warming began around the year 1750. It increased after the year 1810. Glacier retreat since 1810 has been very consistent, and shows no sign of an increase in retreat speed since 1910, when greenhouse gases started to increase in a non-trivial way. This is clear cut empirical evidence that greenhouse gases are NOT the main influence. bascule, you claim that human released greenhouse gases are the number 1 influence. I do not believe I am out of line in asking for empirical evidence to support this assertion. Anything less is unscientific.

This is not exactly a rare situation. At least 85% of all sexually active people, male and female, get the virus before marriage.

It is a moot point as to whether the effects you are talking about actually matter in any current practical sense. The effect is enormously tiny, if that makes sense. Of course, if you actually travelled a few hundred light years to another star, the error would add up. However, I cannot see myself undergoing such a journey in the near future...

bascule. I hope we have not got to the stage of insulting each other. I did not say you were ignorant or stupid - merely lacking the data to answer my query. I am not to be compared to creationists. They have no scientific backing. I can, however, name a number of climatologists who espouse the view I also hold. My quibble with the position held by yourself is just that we have not been presented with the proper scientific data to support it. If I am wrong, then show me, by presenting me with the proper scientific evidence, realising that deduction, and computer modelling is not, by itself, enough.

Dr. Dalek. The article you quote need not be queried, as to source or any other point. It says that there is no consensus on global warming. If we take my own skepticism as the point on which consensus is lacking, then your article is absolutely correct. There is, of course, consensus on points of fact, such as that the world is warming and that carbon dioxide is increasing. It is when we go from fact into deduction, that consensus disappears. I don't think anyone will dispute this point. I have come to the conclusion that bascule has not, in fact, any empirical evidence to support his assertions, except such data as supports the points we all agree on anyway. Studies of glaciers shrinking, which is supposed to be one of the most sensitive measures of global warming, shows no difference in warming rate on average over 200 years. Yet warming caused by human activities is supposed to have begun about 1910. I am still searching for any convincing empirical evidence to show that human activity has somehow, suddenly, become the big influence. Ditto for evidence that it is going to drive the world into disaster. I think we had better give up on bascule. He has not got the data required.

bascule said : but you're infuriating bascule. As I have said before, the main cause of argument is misunderstanding. You are attacking points I have never made. For the record, I accept the following : 1. The world is warming. 2. Greenhouse gases are increasing, and the increase is due to human effort. 3. Greenhouse gases increase the insulating effects of the atmosphere. 4. Ergo, human activities probably cause at least some of the global warming. bascule, please don't argue these points with me. I have already conceded them. What I am asking for is the next required step, and definitely required by good science. What is the empirical evidence that human activities are the dominant cause of global warming? Please don't quote me another document that is full of generalities. I want something specific. I have already seen examples of what I am asking for, albeit very weak evidence, so I know it exists. So far, the empirical evidence I have seen is too weak to do more than confirm point 4 above. You claim to be an expert of global warming. You should then be able, at least, to find the empirical evidence I already knows exists. Yet you evade the question. Why?

bascule said : Here's the IPCC report: http://www.grida.no/climate/ipcc_tar/ Please read "The Scientific Basis". It extensively documents the empirical evidence you claim doesn't exist. bascule, I have seen this before, and been through it before. Like your graph of armospheric forcings, it is NOT empirical evidence. It is a mix of basic theory, and the results of calculations. Empirical evidence is NOT seen in general writings like this. It is best seen in peer reviewed articles showing the clear cut results of specific experiments and observations. That is what I am after. Not a hotch potch mixture like the IPCC writings.

bascule. Quite often in arguments like this one, it turns out that misinterpretation is the cause of the disagreement. I think others are saying that non-anthropogenic sources create most greenhouse gases. Correct. I think you are saying that anthropogenic sources create most of the recent INCREASE in greenhouse gases. Also correct.