"excessively large" means it doesn't show the few tenths of a degree smoothed "average" temperature variations to a sufficiently scary scale?
If you would like to draw trend lines, they are down.
Now that I understand how the baselines have been derived let me respond to this.
It reinforces the argument about the pitfalls of looking for trends in data that is dominated by noise. The problem is also magnified by using too short a time frame for analysis.
Huh? It IS modelled, how do you think weather forecasts are made? The whole point of a model is to simplify a complex system. It's the accuracy of those models you are questioning.
Weather forecasting around here is really quite easy. It will be cloudy at new moon and fine at full.
says in his book "Heaven and Earth", of the 19 variables that influence climate, CO2 is the least important.
Ah, the good Dr Plimer. Remind me again how many scientists he accuses of being part of a conspiracy to foist the myth of AGW onto us for their own selfish ends. The number certainly makes the moon landing conspiracy look like a school-yard prank.
For our benefit, what are the other 18 variables on his list and what are their relevance to the present debate?
The Earth's climate is an extremely complicated beast and is affected by many, many variables in those physical and dynamic processes which impinge upon it. Be it more CO2, or less, changes in solar insolation, atm' water content etc etc etc. Just concentrating on one particular variable or process is not how you go about understanding what's happening. Whether there's more or less CO2, or water vapour or any other "greenhouse" gas in the atmosphere is immaterial. What is important is how adding or reducing the amount of those gases effects the processes which drive the changes that occur, and in what direction they occur. We all know that putting any "greenhouse" gas into the atmosphere in concentrations higher than what is statistically normal over the long term measurements, will cause some changes in the overall temperature balance of the planet. CO2 being the least effective of the gases, in comparison with others such as methane or water vapour. However, it's how the increase in CO2 not only changes the heat balance but also how it affects the capacity of those other gases to also effect the climate. Nothing is changed or effected in isolation from everything else. Change one variable and you affect all the others.
Paradoxically, an increase in the amount of CO2, over time and normal levels...given its effect on sea level, water salinity and such...could most likely produce a rapid decrease in global temperatures, and for a rather protracted period, before any overall warming occured. Witness the last Ice Age...the Northern icecaps were already undergoing melting well before any change in global atmospheric CO2 levels. The crazy thing is that when the levels of CO2 began to change rapidly, it actually helped trigger a rapid cooling and return to deep ice age conditions...the Younger Dryas. It lasted for about 1000 or so years, until the atmopshere, oceans and land came back into balance and normal interglacial conditions established themselves.
What annoys me is the vested interests on both sides of the argument. One, on the alarmist scientists and eco' lobby who are pushing the own agendas and two, the global petrochemical and energy producing corporations who have a vested interest in keeping the status quo and have many of the politicians in their pockets. Neither side is right in their assumptions and all this arguing too and fro...and the general misunderstanding of the general public w.r.t. this matter (something encouraged and promulgated by an even more ignorant media) is not helping the situation. Yes, you can't expect the public in general to have a detailed understanding of the science, or even the politics involved. But they are not being given anything better to hang their opinions and concerns upon than what's being fed to them. That's where grave mistakes can be made. We need to take a pragmatic, but measured and well informed approach to the problem. Either way, not doing anything or doing too much would be disasterous, just the same as not moving fast enough or moving too fast would be deletarious.
We know we're affecting the climate, that's a given. We've been causing large scale regional climate changes for thousands of years, and these have been in addition to those that occur naturally. What we should realise is that doing nothing will be just as bad as doing too much and putting ourselves in a position that when change does occur we can't adapt ourselves to those changes...at least in a way that doesn't impact too much on us. Change will occur, that's inevitable. It won't be easy but let's not make things more difficult than what they would otherwise be. Stop all this nonsensical arguing about who's right and who's wrong and just get on with what needs to be done.
The Earth's climate is an extremely complicated beast and is affected by many, many variables in those physical and dynamic processes which impinge upon it. Be it more CO2, or less, changes in solar insolation, atm' water content etc etc etc. Just concentrating on one particular variable or process is not how you go about understanding what's happening.
Indeed, but as far as the science is concerned no one is concentrating on one variable, and it is exactly that complexity that makes it difficult for those of us without the relevant background (including me) to argue about what is or isn't driving climate change. It's weird how people will accept all kinds of wacky ideas in astronomy but refuse to accept far better proven ideas in climatology.
Quote:
Originally Posted by renormalised
Whether there's more or less CO2, or water vapour or any other "greenhouse" gas in the atmosphere is immaterial. What is important is how adding or reducing the amount of those gases effects the processes which drive the changes that occur, and in what direction they occur. We all know that putting any "greenhouse" gas into the atmosphere in concentrations higher than what is statistically normal over the long term measurements, will cause some changes in the overall temperature balance of the planet. CO2 being the least effective of the gases, in comparison with others such as methane or water vapour. However, it's how the increase in CO2 not only changes the heat balance but also how it affects the capacity of those other gases to also effect the climate. Nothing is changed or effected in isolation from everything else. Change one variable and you affect all the others.
Absolutely, but again, as far as science is concerned no one is claiming anything is due to a single factor.
Quote:
Originally Posted by renormalised
Paradoxically, an increase in the amount of CO2, over time and normal levels...given its effect on sea level, water salinity and such...could most likely produce a rapid decrease in global temperatures, and for a rather protracted period, before any overall warming occured. Witness the last Ice Age...the Northern icecaps were already undergoing melting well before any change in global atmospheric CO2 levels. The crazy thing is that when the levels of CO2 began to change rapidly, it actually helped trigger a rapid cooling and return to deep ice age conditions...the Younger Dryas. It lasted for about 1000 or so years, until the atmopshere, oceans and land came back into balance and normal interglacial conditions established themselves.
That is a rather gross simplification. Firstly, the evidence that CO2 increased during the Younger Dryas is limited (ice core data only) and there is other data that suggests otherwise (e.g. stomatal counts). One explanation is that there was a very large decrease in CO2 at the start of the Younger Dryas followed by a slower (and more limited) rise. As far as science is concerned this is something that isn't decided. But you should bear in mind that both CO2 and temperature are higher than they have been for at least the last six ice ages. It hasn't been this hot and CO2 hasn't been this high for at least 600,000 years.
Quote:
Originally Posted by renormalised
What annoys me is the vested interests on both sides of the argument. One, on the alarmist scientists and eco' lobby who are pushing the own agendas and two, the global petrochemical and energy producing corporations who have a vested interest in keeping the status quo and have many of the politicians in their pockets. Neither side is right in their assumptions and all this arguing too and fro...and the general misunderstanding of the general public w.r.t. this matter (something encouraged and promulgated by an even more ignorant media) is not helping the situation.
I'm not sure what the vested interests of science are, unless you mean more funding? How do we know that the 'assumptions' of anyone are wrong? I'm not sure what 'assumptions' the scientists are making.
Quote:
Originally Posted by renormalised
Yes, you can't expect the public in general to have a detailed understanding of the science, or even the politics involved. But they are not being given anything better to hang their opinions and concerns upon than what's being fed to them.
The public can't conduct the science, so they can only take what is being fed to them. If you read the summary for policy makers from the IPCC Fourth Assessment, it is easily understandable by most people. But bear in mind that the IPCC represents a compromise view and is necessarily slightly out of date, so is almost certainly an UNDERESTIMATE of the real scientific understanding.
Quote:
Originally Posted by renormalised
That's where grave mistakes can be made. We need to take a pragmatic, but measured and well informed approach to the problem. Either way, not doing anything or doing too much would be disasterous, just the same as not moving fast enough or moving too fast would be deletarious.
We know we're affecting the climate, that's a given. We've been causing large scale regional climate changes for thousands of years, and these have been in addition to those that occur naturally. What we should realise is that doing nothing will be just as bad as doing too much and putting ourselves in a position that when change does occur we can't adapt ourselves to those changes...at least in a way that doesn't impact too much on us. Change will occur, that's inevitable. It won't be easy but let's not make things more difficult than what they would otherwise be. Stop all this nonsensical arguing about who's right and who's wrong and just get on with what needs to be done.
I agree, but we can only base what's being done on the science and the science indicates that we cannot do enough to undo what is done, therefore we have to decide how much climate change we are prepared to put up with which, comes down to politics. I would remind everyone that so far we are tracking the worst case scenario in both CO2 (and other greenhouse gas emissions) and global temperatures and have been ever scince the iPCC was created. So in effect to date we have done nothing and we are pretty much getting what was predicted 20 years ago.
BUGGER!!!!. You're not going to believe this!!! I was typing out a really good response in reply to you, Everard, and then trust me to hit the wrong key!!!. I lost it all
Had a good train of thought going and then threw a spanner in the works!!!.
However, one thing I will say here (that I had already written but lost) in the last 20 or so glacial/interglacial periods in the preceding 1 million or so years BP, our present interglacial was not the warmest, nor the most stable climatically. The last interglacial (125-110Ka BP) was some 6 degrees warmer and the atmospheric CO2 content was about 5-10% higher than normal. Sea levels were 6 metres higher globally than at present. One of the consequences was that most of the Sahara wasn't desert but savannah with scattered woodlands. The planet was wetter overall than now. However, along with the last interglacial and about 2 or so others, ours is one of the warmer ones.
I don't think we need to add to it!!!!.
Let's not see the CO2 level reach late Paleocene-Eocene levels...they were some 3 or so times higher than now. Global temps were 12-15 degrees warmer and there were no deserts or polar icecaps!!!. Antarctica was covered in warm temperate forests!!!.
Last edited by renormalised; 05-07-2009 at 10:26 AM.
The Earth's climate is an extremely complicated beast and is affected by many, many variables in those physical and dynamic processes which impinge upon it......
We know we're affecting the climate, that's a given. We've been causing large scale regional climate changes for thousands of years,.
Yes we have.....ever since the beginning of the late Neolithic to Bronze Age (depending on where you are...it's different for different regions on the planet) and the beginnings of widespread agriculture and deforestation, we have been effecting the climate. Much of Europe had already been deforested from it's previous biome type by about 4000BC. What you see there now, except in some parts, has been completely altered from what was there when the population was mainly hunter gatherers. And, that alteration occurred a lot earlier than most people know or realise, hence your response. The UK, for example, had been almost completely cleared of it's virgin forests by the last Bronze Age, except for some patches here and there. Along with the natural changes in climate, our own interference has contributed quite markedly to what we see now. You change the local regional microclimate, and any changes globally will impact on them rather differently than what they would normally otherwise have. And, that's precisely what we see.
BUGGER!!!!. You're not going to believe this!!! I was typing out a really good response in reply to you, Everard, and then trust me to hit the wrong key!!!. I lost it all
It's annoying when that happens. Sometimes, Firefox seems to remember and hitting the back button brings it back - but sometimes it doesn't.
Quote:
Originally Posted by renormalised
However, one thing I will say here (that I had already written but lost) in the last 20 or so glacial/interglacial periods in the preceding 1 million or so years BP, our present interglacial was not the warmest, nor the most stable climatically. The last interglacial (125-110Ka BP) was some 6 degrees warmer and the atmospheric CO2 content was about 5-10% higher than normal. Sea levels were 6 metres higher globally than at present. One of the consequences was that most of the Sahara wasn't desert but savannah with scattered woodlands. The planet was wetter overall than now. However, along with the last interglacial and about 2 or so others, ours is one of the warmer ones.
Not sure what "normal" is, but CO2 has certainly not reached the current levels for a few million years. See attached figure.jpg for CO2 over the last 600ky it doesn't get close to now. You might be right on temp (look at the delta-D on the same figure), but temp is much more an estimate than CO2 as we can't measure it directly (CO2 conc in air bubbles in ice is measured). Sea levels look pretty similar to me (see figure 2). However, certainly the further back we go the more sketchy our data is and the more error involved in it's estimates. Both figures from the Fourth Assessment Report by the way.
Quote:
Originally Posted by renormalised
I don't think we need to add to it!!!!.
Let's not see the CO2 level reach late Paleocene-Eocene levels...they were some 3 or so times higher than now. Global temps were 12-15 degrees warmer and there were no deserts or polar icecaps!!!. Antarctica was covered in warm temperate forests!!!.
Yes we have.....ever since the beginning of the late Neolithic to Bronze Age (depending on where you are...it's different for different regions on the planet) and the beginnings of widespread agriculture and deforestation, we have been effecting the climate. Much of Europe had already been deforested from it's previous biome type by about 4000BC. What you see there now, except in some parts, has been completely altered from what was there when the population was mainly hunter gatherers. And, that alteration occurred a lot earlier than most people know or realise, hence your response. The UK, for example, had been almost completely cleared of it's virgin forests by the last Bronze Age, except for some patches here and there. Along with the natural changes in climate, our own interference has contributed quite markedly to what we see now. You change the local regional microclimate, and any changes globally will impact on them rather differently than what they would normally otherwise have. And, that's precisely what we see.
Indeed, I was brought up by the Pennines in England and for a long time it was thought that the peat bogs were the climax vegetation there, until peat mining got to a big scale and they found that underneath the peat were preserved tree stumps where you could still see the marks from the bronze age axes....
Normal is around 250-275 ppm CO2. It was around 300ppm during the last interglacial. The sea level was higher than now. Apart from the usual academic sources, I'm not more than half a mile away from the old, last interglacial beach ridge and foreshore here at home. Most of it has been built over and you can't see it but there are spots where the topography and the soil type betrays it's presence. Not only that, but I've cored through it before and gotten sea shells
You can age climate change researchers by the atmospheric CO2 when they started. So for me when I was at university CO2 was about 365ppm, when I started in research about 370 or so, and now it's more like 380. Some of the older guys started off when it was only 340odd. I see it as a bit like tree rings!
For me it is more appropriate to quote the change in the 13C/12C ratio of atmospheric CO2 since I started working in stable isotopes. The ratio has decreased by 0.24 permil (parts per thousand) in that time. The reason the atmosphere is becoming isotopically lighter is that fossil fuel has a much lower 13C content than CO2 from natural sources - principally the ocean.
For me it is more appropriate to quote the change in the 13C/12C ratio of atmospheric CO2 since I started working in stable isotopes. The ratio has decreased by 0.24 permil (parts per thousand) in that time. The reason the atmosphere is becoming isotopically lighter is that fossil fuel has a much lower 13C content than CO2 from natural sources - principally the ocean.
Out of interest, what is the typical delta-C of fossil fuels? Rubisco fractionates by about -28 per mil, is that pretty much what you see? Or is it shifted significantly from that? We can use the fractionation in plants to estimate the long-term stomatal condutance (well the Ci/Ca ratio anyway), it would be fascinating if you could do that on geological timescales!
Out of interest, what is the typical delta-C of fossil fuels? Rubisco fractionates by about -28 per mil, is that pretty much what you see? Or is it shifted significantly from that? We can use the fractionation in plants to estimate the long-term stomatal condutance (well the Ci/Ca ratio anyway), it would be fascinating if you could do that on geological timescales!
Unfortunately, you're not going to be able to do that, because of the way organic matter gets preserved in the fossil record. You may not even see any stomata on leaves at all, unless the preservation medium is extremely fine grained and the process of fossilisation rather benign. Your best bet is low temp/pressure burial in very fine grain siltstone. Even then, you're going to get C ratios that are out of whack due to low temp metasomatic effects. You may not have any carbon left at all, having been completely replaced by silicates and oxides in the fossilisation process.
The only way you could get the right sort of preservation conditions under normal circumstances would be to have some freak occurrence within a coal bed perfectly preserving the leaves etc. Though, the older the coal, the less chance you'd have of seeing those conditions occur. I do know of some cases where leaves have been so perfectly preserved in coal beds that you could see stomata and even chloroplasts in the leaves (they were still green leaves), but only in coal beds of very recent origin. None of your normal Permo-Carboniferous coal beds have that kind of preservation, as far as I can remember.
not on this planet 
