Safe Speed Forums

Temperature data is measured with the TIROS-N satellites. Not sure how many there are but they have went through quite a few.



http://www.met.fsu.edu/explores/Guide/Tirosn_Html/tirosn.html

There is also the NOAA satellites

http://www.met.fsu.edu/explores/Guide/Tirosn_Html/noaa7.html


The suraface record referred to is measure with traditional land based weather stations. There are many issues with these including

* They're land based so cover only a minority of the Earths surface
* They tend to be in built up areas so are open to urban heat island effects
* A lot are in third world areas with poor records and poor maintenace of records and procedures


I manged to find this on data upto 1998. (My emphasis)



Source: http://www.sepp.org/reality/NASA98temp.html

I find that the worst kind of tailgaters are 4x4 drivers. I think that the main reason that some drivers tailgate is because they're late for their parents' wedding. It's not easy, but I just try to ignore their behaviour. The thing to do is control your own vehicle. Tailgaters do try to push you into exceeding the speed limit, but if you get caught speeding and tell the magistrate that a tailgater was responsible, it won't help at all.

As I said earlier, I've not heard that the end of the world is on the cards. Journos and politicians have come out with some corkers from time to time, but that's another matter. Ever see the one that said global warming costs each American $160 per ton of emitted carbon? So, let's see, £160 x 280 million yanks x 5 billion tons of carbon equals $224,000,000,000,000,000,000. As GDP of the US is in the $7 trillion area that means the global warming costs are more than 20 million times the size of the American economy. Which proves nothing except that journos won't let silly things like facts get in the way of good headlines.

But the weight of evidence does not back the end of the world hypothesis. Proponents of anthropogenic global warming theory (let's call it AGW okay?) have made various claims, predictions, projections and "storylines", and the end of the world ain't among them. It would have been page 1 double bold above the fold headlines. The physical evidence is actually appearing increasingly weak to many. Personally, what really pisses me off is that there are immediate and unarguable environmental problems that are virtually ignored as AGW gets all the media attention. Habitat destruction is a good example. No one can argue that it isn't occuring as you can catch a plane and go count the tree stumps (or walk round the freshly drained swamp, or whatever). It's going on all the time, but the media make fairly little mention of it. No emoticon is available to express what I think of that. Anyway, going back to Kerry. As I said before, the Kyoto Protocol will not be ratified by Congress, so from that perspective it's pretty irrelevant if he wins or not.

ROTFLMAO - even you're calling 'em scameras now. Anyhow, I was thinking that their attempt to bring more stability in the middle east has gone a bit Pete Tong and made it less stable, which will surely have had a negative effect on oil prices. Maybe I've got that wrong, I did fail economics A level . Point taken about 20:20 hindsight though, and after all, we've elected the eejit twice now. I wasn't sorry to see the back of Major, and even my True Blue Tory dad believes that Maggie went a bit nuts after about 8 or 9 years. But this one seemed to lose the plot after about a fortnight!

President Gas has stolen some of my thunder here. Yes, the MSU record and tropospheric measurements was what I was referring to. The interesting thing about taking the temperature of the lower troposphere (ie up to about 8km up IIRC) is that this part of the atmosphere is warmed by the surface below it (or so I understand). This means that if the surface temperature goes up, so will that of the troposphere, and ditto if it goes down. The reverse also holds - that fi the temperature in the troposphere is rising that means the temperature on the surface is also rising. When the MSU measurements began the two records were initially in agreement, but rapidly began to diverge. The gap has got larger ever since, bar a recent very small revision of the satellite record.

Now, although this has only been around since 1978 it has shown increasing divergence from the surface record. The satellite record is further backed up by measurements from radiosonde balloons. It is also interesting to note that there are a large number of surface stations that show little or no warming, many of which are reliably maintained and are in rural areas to avoid Urban Heat Island effects. I've been looking through my bookmarks for you, basingwerk, and http://www.greeningearthsociety.org/Articles/2000/surface1.htm is probably a good place to start. It discusses the surface record, the satellites, the radiosonde balloons and the various reasons why the surface record differs from the other two. I must admit that there's a specific reason for me giving you that link. It was one of the things that changed my mind about global warming.

You might also be interested in sea levels - http://www.greeningearthsociety.org/Articles/2000/sea.htm, http://www.john-daly.com/deadisle/index.htm and http://www.john-daly.com/deadisle/part2.htm (all by the same author - home page http://www.john-daly.com though he has recently died and the site isn't maintained as well as in the past). I'd also recommend looking at http://www.co2science.org which has links to many scientific papers that cast doubt on AGW, usually within their own articles. One that you might be interested in is http://www.co2science.org/subject/a/summaries/antarcticaiceshv.htm covering Antarctic ice shelves. http://www.countryguardian.net/ has some good info about the problems with windfarms, though driven by NIMBYism to some extent.

And in other circles some considerable doubt exists about these theories. I've not read up on this much yet, but even I know that the conveyor moves from year to year. How do we know the measurements are always taken in the right place?

You mention "the current period of stability". This is a misconception. There has never been any period of stability in the climate. Again, we might percieve stability in our lifetimes, and even over short term historical records. But once you start looking at periods of 1000 years plus it is apparent that stability has simply never existed. Again, the question is, if global temperature has always been going up and down like a honeymooner's duvet, why should we think that there is anything special about what's happening now? We know that our contribution to atmosheric carbon is pitifully small compared to that of nature, and indeed that natural variability is greater than mankinds efforts. So, if nature can in one year dump in an extra 5 or 6 gigatons of carbon without any adverse effects, why is the 5 or 6 gigatons we produce so damaging? How does the climate tell the difference between 5 gigatons of naturally produced carbon and 5 gigatons of carbon produced by man?

Nope. The warming began long ago, at the end of the Little Ice Age. Although AGW supporters would prefer it if the Little Ice Age, and for that matter the Medieval Warm Period and the Roman Warm Period, only happened in Northern Europe there is plenty of evidence, both historical and geological, that these were global events. The LIA was pre-industrial of course, and was almost certainly due to changes in the sun. In the past we know that global temperature closely tracks solar activity. In roman times we had warming and an active sun, which was followed by inactivity and cooling, followed by the Medieval Warm period during which the sun was again quite active, followed by reduced activity and more cooling, after which we had the Maunder Minimum and the LIA. The current increase in CO2 levels could be what we should expect as a result of the post LIA warming. Of course, mankind has put a certain amount of CO2 into the atmosphere, which migt explain why the increase has occured in only 3 centuries or so this time, rather than five or more. Temperature wise, between the end of the LAI and now we could simply have been returning to normal, but we're now told that the sun is more active now than it has been for some time, possibly a couple of thousand years. Perhaps we are not merely in the late stages of recovering from the LIA but are also returning to the solar and clmate conditions of Roman times. Pass the otter's noses when you've finished with them. .

Hmmm, coral bleaching. Not too hot on this, must read more. I assume bleaching from pollutants has been ruled out? Again, like habitat destruction I feel the tendency in some parts of the world to dump any old unwanted shit into the nearest body of water is largely overlooked due to the hype about warming.

Moving on, you mention erosion of island communities. I'm very glad you used the term erosion, as erosion is clearly not due to warming. Erosion is another one of those processes that has been going on for billions of years, and will continue long after the human race is gone. It is simply not relevant. What about seal level rise? Well, see links above, but also consider that if you were on the Titanic, the sea may have appeared to rise for you personally, but what actually happened is that you sank. This is also happening in many parts of the world. Some places are simply subsiding and will gruadually slip beneath the waves anyway. The island of Tuvalu is one, and was one of the most vocal about rising sea levels until it was found that basically, they ain't rising as fast as the island is sinking.

Another known effect I've heard about is called Post Glacial Rebound. Basically, during the last ice age the earth's crust was being kind of squashed in higher and lower latitudes by the mass of the ice sheets sitting on it. Sea levels were, of course, much lower in the ice free temperate latitudes than they are today, on top of which the crust was bowing outwards in these ice free areas in responce to the compresion in the areas under the ice sheets. Basically, it's like compressing a tennis ball at opposite points. There is some compression where you apply pressure and some expansion in the areas furthest from the compression. Now, when you take the compression away the ball returns to it's normal shape. In the same way, the earth's crust has been gradually rising in places that had previously been compressed by the ice, and sinking in other areas that had expanded outwards during the ice age. And in coastal areas, that means "sinking" might well be the operative word. However, since the cause for this is thousands of years in the past, absolutely nothing we do about emissions will make the slightest difference. Again, we have to remember that the planet is much bigger and older than us, and it is only our arrogance that deludes us into thinking we can control these processes.

One swallow does not make a summer, and one, or even a few, hot summers do not make global warming. These are meteorological events, not climate events. Nobody suggests that a few bad winters are evidence of global cooling, and yet while we have had heatwaves other parts of the world have suffered unseasonably cold weather. El Ninos and La Ninas are climate events, albeit short term ones. A high pressure induced heatwave over Northern Eurpoe is not. Personal experience is also extremely deceptive. David Suzuki once mentioned how the winters in his hometown had got warmer over the years, but unfortunately the local weather station showed the opposite. There is a link about that on the late John Daly's website.

Now, about the oil and other fossil fuels. Yes, it is finite, and yes there will eventually be a need for long term alternatives. That is unarguable, and I'd be a lot happier if some more research was being done into other energy sources. However, as you point out, past estimates have proved to be miles out and it might not be so urgent. I can't find the story right now, but I read recently that the current worst case was about 40 years left, and the best case was a couple of hundred (I think) as oil shale beaches are a potential source. That doesn't mean I'm all for going aftter every last drop. Ole Dubya is keen on drilling in the ANWR, and having been to Alaska and been totally blown away by the beauty of the place (photographers paradise, mate, can't wait to go back with about a hundred weight of Velvia ), I have to say I hope like hell it doesn't happen. Even if that's only good for power rather than transport, I suspect we'll still be burning something for a long while yet, even if it's bio-diesel or alcohol fuels. Still, like you I'd be happier if there was an alternative to burning fossil fuels, just because the world will be a nicer place to live in. Not, however, because I think we'll all fry if we don't.

As I said before, the more I read the weaker all that evidence seems to become. What I found compelling a few years ago looks extremely shaky now. The surface record and GCMs were utterly convincing to me once, but I have come to realize that this is enitirely due to selective reporting on the part of the media. Far from being settled, the debate is still ongoing and more doubters and sceptics seem to be pointing out the gaping holes in the theory. The reactions of some of the AGW supporters have been rather extreme too. Lots of name calling and so on. Well, basingwerk, you're an educated man. Do ad hominem attacks in any way validate one's pet theory? Or invalidate contrary evidence brought up by one's opponents? Errrrrrrr, nope! In fact, do AGW sceptics even need to prove their own case? Isn't it accepted scientific practice that disproving a theory is sufficient? The principle of falsification I think, isn't it?

As for testing the data... to a large extent the data does not yet exist to be tested. How can you test a prediction, er I mean projection, er I mean storyline (see progressive changes in terminology in the IPCC reports) about temperatures in 2100 without waiting 95 years? Well, you can input past data and see if the GCMs can predict today's climate... oh bugger. Tried that and they got it wrong! See what I mean about looking shaky? Can we test AGW any other way? Well, if right the first warming effects should be in the polar regions and should already be well underway. Double bugger! Antarctica is cooling over 98% of it's area and accumulating ice rather than losing it, in fact the whole southern hemisphere has cooled slightly overall, and the northern hemishpere has only warmed by a slightly larger amount, but not as much at the pole as it should have. Okay greenhouse gang, we have limited options here... deny the evidence, attack the opponents who've come up with the evidence, attempt to find holes in the evidence, ignore the evidence, or simply say that despite the evidence we should take action just in case. Er, wouldn't it be more, you know, scientific, to admit that you've got it wrong and either discard or refine the theory to take the new evidence into account. Call me Mr Cynical, but I suspect that bad politics rather than good science prevents this.

Now, about "events that have come together in recent times". Again, the majority are not actually climate events. Flooding is a media favourite, but it's often down to construction in areas that historically have been subject to flooding. This is like living in an earthquake zone and acting all surprised when your house falls over along with the rest of the town. Storms and tornados? Well, again, we have far more people about than ever before (as you said yourself), and with better recording and reporting too. Inevitably pepole have settled in areas that have always been prone to certain weather events, areas that in the past simply had no-one living there to observe them. Do we suppose that tornados did not exist in Kansas before anyone lived there? Of course not. Going back briefly to the glaciers. As I said before, if it is correct that glaciers normally go through a long period of slow retreat followed by a short period of rapid advance, then we should expect that at any particular time the majority of glaciers we look at should be retreating. This is precisely what we see. Further, that implies that in pre-industrial times a majority of glaciers would also have been retreating during warming phases simlair to the one we are currently in. Again, the question must be asked, what's so special about now?

A reasonable sentiment, but one that must be grounded in fact rather than faith. If the satellite record showed the same warming as the surface record I would be saying something similar. As it is, AGW is largely based on the surface record and the GCMs, and there are serious doubts as to the accuracy of both. The Precautionary Principle, as this approach has been called, would be fine except for two things. First, it would be damn sight cheaper to simply adapt to warming rather than these King Canute efforts at halting or reversing it. Many believe that if we only have a major recession as a result, we'd have got off bloody lightly. Secondly, and to me far worse, we are ignoring real problems which can be solved in order to concentrate on a potential problem that we might be able to affect a bit. And calling it a potential problem is being generous considering all the evidence that suggests that the warming is neither man made nor as severe as we are led to believe.

And some believe that between conventinoal back up power and construction wind farms are responsible for more CO2 than they save over their lifetimes. I suspect this won't be proved one way or the other until they've been around a while longer though.

But... but... but... that means satellites, and launching the bloody things is extremely unsound, environmentally speaking. Rocket exhaust, ba-a-a-a-ad! Trees, g-o-o-o-o-d!!! You can't have your cake and eat it, mate. I won't go into the othe reasons why I'm anti this scheme. You already know, and this post is already too long, so just take it as read, eh? Oh yeah, and what's this about "if it works, it's obsolete"? What happened to "if it ain't broke, don't fix it"? I mentioned elsewhere about looking at new ways of doing things. The big question is always, is it really better or is it just new? The pros and cons go beyond road safety.

One last thing. In a feeble attempt to look like I've kept to topic, aren't tailgaters total tossers?

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If this was true, there would be a lot of weddings going on. In the last year for which I have statistics (2000), there were 126,000 re-marriages in the UK. If I make a generous assumption of 6 children from previous marriages for each re-marriages, that means a total of 126,000*6 ~ 750K possible "children late for their parents' wedding". If I then divide that by the proprotion of such children lilely to possess a 4x4 (say 4 in1), that comes to around 200,000. On an average journey to the church of say, 20 miles, it seems likely that the maximum number of different drivers they could possibly tailgate is around 10, making a total of 2 million tailgating offences.

On the other had, there are 20 million drivers in the country, and most are tailgated at least twice per week, giving a total of 2,000,000,000, or 2 billion offecnes. So children late for thier parents wedding account for only around 0.1 % of all cases. What could be the reason for the others? Perhaps they are "normal" drivers going too fast and breaking the speed limit?



That would be because you are responsible for setting your own speed. My advice is never break the speed limit, especially when you have a tailgater behind you - it would only make them think they are getting thier way. In any case, if a tailgater smashes into your back, its better to be going more slowly.

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You see, basingberk (I concede you're not a troll so my alternative conclusion applies), that's your problem. You spout forth with brain disengaged.

It is self-evident, if a tailgater is going to "smash into your back", that it will be better (for you and him) if you are moving rather than stationary and moving faster rather than slower (excluding, of course, other external factors). If you were moving fast enough (in a forwards direction), the tailgater would never catch you at all!

and the proof...

crashes depend on "delta v" for severity.

if a 60mph tailgater hits a stationary car delta v=60
if a 60mph tailgater hits a 30mph car delta v=30
if a 60mph tailgater hits a 50mph car delta v=10
if a 60mph tailgater hits a 60mph car delta v=0 (ie no crash can happen)

and if you factor in the debunked 4th power rule then going at 50 is safer that going at 30 by a whopping 81 times. Who says slower speeds are always better?

Simon

Is it one of your nice days, or one of your nasty days?



I reckon a tailgater is someone who is driving for a period close to your tailgate, and this implies the tailgater is equal in speed, otherwise he wouldn't be tailgating. If he has to do this, I'd rather it be at 20 mph, than 80 mph, because if I had to stop or turn, he'd have more reaction time.

Its the 'equal in speed' requirement for tailgating that is fouling things up for you. Simon, who talks about delta-v, hasn't reckoned on that, and if he tried to, his equations would break. My advice is to sharpen your pencils.

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Let's call it a "baiting basingberk" day (I like a little alliteration).

Yeah, that proves it alright! Please continue by telling me how a tailgater can tailgate a stationary car; that's some trick, Si!

BW

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'Tailgating' cannot be defined by distance alone - it is a function of speed and time.



The impact speed (delta 'v') is what's important - not the previous free travelling speed.

If your implied argument is "it's better to drive slower rather than faster because any tailgater who hits you will cause less damage", the argument (as is so often the case with "speed camera" and "speed kills" proponents) is shallow and specious - as Paul would say, it assumes accidents/collisions are rooted in physics, not psychology.

For myself, I am more uneasy about a 30mph tailgater, at a 0.5s separation (22'), than a 60mph tailgater at a separation distance of 44', for several reasons:

1. the sense of physical intimidation by a 'tailgating' vehicle (0.5s time separation) is much greater at 30mph (22') than 60mph (44');

2. if I am travelling at only 30mph, the implied hazard density is much greater and the risk that I may have to take evasive action/brake unexpectedly is also much greater;

3. a high(er) speed tailgater is more likely to be simply driving aggressively so, if I want to get rid of him, I can easily facilitate an overtake; or, if I do have to brake suddenly, there's still a fair chance he is focussed sufficiently on the driving task to avoid collision. On the other hand, lower speed tailgaters are more likely to be the ones in 'autopilot' mode, which is far more dangerous.

my pencils are fine, it's your head that needs sharpening. these 'equal in speed' tailgaters will never hit you, unless you slow down! if you emergency stop from 80 (illegal but maybe safe) to 0 and the other car, that was tailgating you at 80's reaction is late and it goes into the back of you at 60 then you would get a delta-v of 60, and it was a tailgater!

how can "impact speed 1-impact speed 2" break at high speeds? I did say that when the difference in speed is 0 the cars won't collide. (btw for the uninformed, ie Basingberk, delta is greek for "D" and is used to show differences)

Also driving slower (especially slower than the limit) frustrates the tailgater more, meaning that you are more likely to have a crash, regardless of speed.

Seeing that both cars take roughly the same time and distance to brake to a standstill when the pedal is pushed, it's thinking time that is the biggest problem. a tailgater at 90km/h might be 37.5 feet away (0.5 second gap), yet at 4 kph it's less than 2 foot away for the same time gap. which if you break is more likely to hit you? both of them perhaps? (ignoring 4kph gap isn't enough to see brake lights and other stuff). tailgaters are a function of time, hence "the two second rule", and not "the 88 foot rule" (which is 2 seconds at 30mph).

Just follow Paul's advice of trying to facilitate an overtake and not trying to piss the guy off, and everything will be a lot better for you Basingberk.

Simon

On my recent 600+mile road trip on Friday and saturday I conducted an experiment on tailgating. I normally don't spare the horses shall we say on motorways. So as there was time to kill the miles were put on at a more leisurly pace. Sure I held people up for a few moments, but all you have to do is keep your eyes on your mirrors and let people past. I have nothing to gain by holding people up so why do it?

I saw plenty of middle lane hogging, but as I was in lane 1 I just cruised by without changing lanes.

I drove through 15 counties and saw exactly no patrol cars. I did see a road tax camera van. Good idea I thought, until I drove past it and saw nobody pulling up untaxed vehicles. No point sending demands through the post, they will ignore them. They should have their vehicles taken off them at the side of the road and make 'em walk home.

basingwerk mate - Not surprised you get tailgated if you are driving at 20mph unnecessarily. Driving too slowly deliberately is another form of road rage - and two wrongs do not make a right.

You need to use your rear view mirror more! If there is chance that chap at speed limit will catch you up - then you need to move your speed closer to the limit to keep the distance between you and bloke behind. If you do not want to do this and remain at very slow speed (and you would fail your L-test for "not making progress and causing annoyance to other road users") then you need to create the space to let the other driver pass you.

There - sorted!

Yes, we can agree on that - the damage done is most related to delta-v.



That's true. I too am more uneasy about a 30mph tailgater, at a 0.5s separation (22'), than a 60mph tailgater at a separation distance of 44'.

It's also true to say that I am more uneasy about a 60mph tailgater at a separation distance of 0.5s separation (22') than a 30mph tailgater, at 0.5s separation (22').

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Yes, but in this hypothetical situation, I was in the 20mph limit zone



No way, MadDoc. When I get tailgated when driving near the absolute top limit, there is no way I'll just speed up. I don't want the tailgater to get away with it, and I certainly don't want to get a ticket myself, and last, if he's going to climb in through my back window, I'd rather there be low potential delta-v when it happens.




That's right - slow down for tailgaters, although I have been told off about this by SafeSpeed, because it tests their stress limits. Perhaps just ignore them is the best policy - it depends on the weather - litterally, because tailgating is much worse in the rain.

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I reckon we should go like California and have no lane prioritisation - it cuts down on tailgaters, speeders, agreesive testosterone driven drivers and inapprorprate lane changers. Mind you, for some reason, nobody agrees with me here!



I hope that the yellow RF boxes that are supposed to be in the pipleline will announce to the world when a car is untaxed, allowing such drivers to be picked off by rocker propelled grenade, sorry I meant to say by traffic cops with auto-disable technology.

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That sounds right.



Yes, and if you emergency stop from 20 to 0 and the other car, that was tailgating you at 20's reaction is late and it goes into the back of you at 20 then you would get a delta-v of 20, and it was a tailgater, and its a lot less delta-v, and that's my point in a nutshell. But I thought you were with Observer, arguing against me! Thanks, though, for chipping in on my side.



I bear what you say in mind. Thanks for thinking of my welfare, Simon.

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That’s not fair - let me know your mailing address and I'll send round the heavies, sorry, I meant to say, I'll send you some of the work I did on geostationary satellite manoeuvre planning and emergency collision avoidance strategies, repositioning and colocation techniques, which contain some delta-v related calculations, and might show that it is you who is the uninformed one!

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0.5s separation at 60mph is 44' not 22' (that's 0.25s separation which I'd agree is much worse than 22' at 30mph).

Ahh! Your head is in the clouds!

Perhaps that's why you didn't notice that when a 20mph vehicle strikes another at 0mph (of similar mass) the crash delta V approximates to 10mph, not 20mph, because the resultant speeds are both 10mph.

Something worrying about tailgating is that if there's zero separation between the vehicles you can't get any delta V at all. I honestly haven't really got my head around all the safety implications, but clearly under certain circumstances driving extremely close to another vehicle might cause a collision, but also we must expect that collision to be very light. This observation frightens me. On the one hand I believe tailgating to be dangerous, but on the other I can't really identify how tailgating might typically be expected to increase impact energies. Rather the opposite.

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