Here's my take on it Cloud man. It's proven that CO2 is a "greenhouse" gas. What is not proven is that feedback effects such as clouds will magically cancel out the greenhouse gas.

If you are an atmospheric science with a PhD, I suggest you check-out the co2science.org project that seeks to prove the existence of the medieval warming period. Basically they list a paper, and then write their own summary of it.

I haven't spent long checking it but the first paper I checked reviewed ice cores from six glaciers, but co2science ignored the 5 that showed no MWP and that matched the hockey stick, and included the one that showed that "some times it was a bit warmer then than it is now". I then checked a paper on the MWP in New Zealand as shown by tree rings. The details of the paper showed that there were only two warming periods of about 50 years in the 350 year MWP period, and that New Zealand was actually the coldest it has been for 1200 years during 991-1050 when the Vikings were colonizing Greenland.

So in short, I haven't reviewed all of their evidence, but the evidence I did review from co2science.org leads me to believe that the climate change deniers are seeking to distort it. Feel free to review it yourself.

Mond,

You post data from the Met Office yet fail to state which dataset it is and what it refers to.

I'm not quite sure what you're doing there but to compare months you'd need to average months over at least a 5 year window to remove year to year weather and expose any longer term significance.

Actually you'd expect enhanced global warming to impact more on winter and night temperatures since it traps outgoing longwave.

Finally are you comparing year to year? i.e. 1920 to 1970, 1930 to 1980 etc? Because this is of no use. That's the sort of trick used in the discredited "reducing trend since 1998" argument. Start and end dates have a severe impact on conclusions when looking at spot figures.


Hello Robbie Writer,

What's even worse about the quote from qube is that qube seems to be unaware that the increase in atmospheric CO2 is defintely due to human activity. And it's the increase that counts, not proportions of CO2, i.e. CO2 causes the same greenhouse effect regardless of whether it's emitted from fossil fuels, bacterial activity, or smoking cigs.


Periurban,
It was after the 50s that CO2 emissions took off, and modelling studies show that the post 1970's warming of 0.6degC is due to CO2. Satellites show that since 1976 the sun has not increased it's energy output and neutron counts have no trend since 1950 (so cosmic ray flux and implied cloud changes are not a factor).

It's not an accident that we know the recent warming is due to CO2, it's good evidence.


Cloud Man,
There are some 6 paleo climate studies that show the recent warming to be unusual. However in any case regardless of paleo studies the recent evidence shows clear reason to attribute the current warming to CO2 forcing.


Cloud research and parametisation is cutting edge now. It is being pursued with vigour.

As we know that Cosmic Ray flux does not exhibit a trend since the 50s, we know that any trends seen in cloud data cannot be due to that.

So how do we know that any trend is not epiphenominal of enhanced global warming? Anyway the models are able to attribute the recent trend in warming to CO2.

CobblyWorlds has done a nice job on this forum of throwing out web pages trying to convince you that global warming is linked to CO2 and therefore man made. Instead of wasting days going back a forth on who is paid by big oil, or if CO2 came before temp, or if the sun is causing the change why don’t we just look at how much of the “global warming” effect comes from humans. The answer is about .28%. CobblyWorlds gave an example earlier that a bottle filled with CO2 would heat faster than a bottle filled with air. A more honest comparison would have been a bottle filled with air versus a bottle filled with air + .28% more CO2. In this example the temperature difference would have been so minute I doubt it even could be measured. CO2 may cause temperature increases, but it is so infinitesimally small that we shouldn’t even consider trashing the world’s economy and dooming the third world with big cuts in C02. There are new amazing technologies in development that will eventually end our dependence on fossil fuels, but a crappy economy will dampen that development and force us to use more fossil fuels.

http://www.geocraft.com/WVFossils/greenhouse_data.html
http://www.junkscience.com/Greenhouse/

Sorry, I meant to link to it http://www.metoffice.gov.uk/climate/uk/seriesstatistics/ewtemp.txt

I admit that I used mainly decade time points, except 2000-2005 were I included all years. I will try again using 1980-2005. I also am interested in whether this may be true for global changes. Obviously if the warming is in the summer only, then if you include both north and southern hemispheres together you will lose that fact (summer is opposite, so over all all months will have an increase in temp obscuring the fact that the winter months dont) and so it is important to look at them inderpendently.

quote:

Originally posted by fifelee:
why don’t we just look at how much of the “global warming” effect comes from humans. The answer is about .28%. CobblyWorlds gave an example earlier that a bottle filled with CO2 would heat faster than a bottle filled with air. A more honest comparison would have been a bottle filled with air versus a bottle filled with air + .28% more CO2.

This is the difference between politics and science. Science takes a theory and scrutinises it examining as many details about it until it can be disproven or it becaomes fact. Politics takes a theory and scrutinises it until facts appear that support the theory disregarding those that do not - hence man-made global warming.

You are quite right these man-made global warming supporters cannot eliminate thse most fundamental arguments as to how such an insignificant amount of CO2 can contribute to such a high degree of warming - and that when we give them the benefit of accepting that CO2 causes (rather than a result of) global warming.

Thanks Mond,

I've played around with the England and wales Areal series before.

There's various global datasets here:
http://www.cru.uea.ac.uk/cru/data/temperature/#datdow

But when it says you need to refer to the supporting science you really do need to.

Better still leave it to scientists who's published work is checked by other scientists under peer review.

For example how do you know that changes in the Eng/Wales Areal series aren't due to changes in prevailing wind direction pressure track etc?

quote:

Originally posted by APL:
You are quite right these man-made global warming supporters cannot eliminate thse most fundamental arguments as to how such an insignificant amount of CO2 can contribute to such a high degree of warming - and that when we give them the benefit of accepting that CO2 causes (rather than a result of) global warming.

You need to up your game APL.

It is already posted around here that we know ALL of the increase in CO2 is definitely due to humans.


How can we know that such an insignificant amount of CO2 can cause global warming?

Physics of course.

It's not controversial that it causes warming, and the evidence is converging on 3degC for about 560ppmCO2.

I’m not convinced one way or the other but I’m thinking it is not man.
There are so many variables as with the climate models. I know from my school days that there is good science and bad science. I once conducted an experiment and managed to get two opposite results from the same data. Looking at the posts on here a lot of people from both sides of the argument have fallen into the bad science trap by only extracting what they want to hear.
Remember the Global Warming policies from various governments is having an effect on the money in your pocket never mind the third world development.
You are allowed to take the "it is not man" view and you won’t have the men in black knocking at your door.............or will you?

Finally I’m not saying we should not look after our planet but lets do it for the right reasons.

quote:

You are quite right these man-made global warming supporters cannot eliminate thse most fundamental arguments as to how such an insignificant amount of CO2 can contribute to such a high degree of warming - and that when we give them the benefit of accepting that CO2 causes (rather than a result of) global warming.

Another thing the programme didn't say is that it is completely undisputed, even by the scientists on last night's programme, that CO2 is a greenhouse gas without which the earth would freeze (even though it only accounts for some .03 percent of the atmosphere).

All the discussion is about what degree the changes in CO2 change the strength of the greenhouse effect, and to what degree other changes enhance or reduce the effect.

It is clear to me that they neglected to report this undisputed fact because it provides an opportunity to the less-informed viewer to doubt their polemic.

quote:

Originally posted by CobblyWorlds:
It is already posted around here that we know ALL of the increase in CO2 is definitely due to humans.

How can we know that such an insignificant amount of CO2 can cause global warming?

Physics of course.

It's not controversial that it causes warming, and the evidence is converging on 3degC for about 560ppmCO2.

Come on CobblyWorld. You know damn well that CO2 levels have been much higher than they are now and much lower with marginal temp swings. Plus CO2 is a very minor greenhouse gas. You don't give mother much credit. Minor changes in a minor gas will not cause drastic temp changes.
http://www.junkscience.com/Greenhouse/
http://www.oism.org/pproject/s33p37.htm

It seems to me that the idea of anthropogenic global warming has been quite scuppered by this porgram. It seems that yet again we have been misled by various groups using this theory to support their own political agenda.

A number of arguments have been put forward in order to try and obfuscate the ideas presented in the program, such as the fact that a bottle full of CO2 will warm faster in sunlight than a bottle with just air in it, and that the increase in CO2 concentrations is pureley from fossil sources. Both these things are true, but the nub of the argument is not wether CO2 has increased or where it came from, but whether or not that increase is the main cause of global warming.

In the case of a bottle full of CO2, the key word is full. The concentration of CO2 in that bottle is much higher than in the atmosphere. The same thing that warms beer as warms the gas in the bottle, clearly the sun. Also those who partake in the products of the brewers art will note that a warm beer is invairably a flat beer.

As to whether the additional CO2 is from fossil sources, ie coal, oil, and gas, another source of the the same C12 isotope is of course vulcanism. It would seem to me obvious that carbon which has been mulling around in the earths crust for many hundred thousands of years would contain comapartively small amounts of C14. Also please note here that vulcanism does not just mean huge eruptions, but includes all geological emissions.

What I would like to see is the real evidence, presented dispassionately by researchers who I can trust are not influenced by politics. Unfortunately this does not seem to be possible.

The accusations of political influence thruough funding are quite convincing. I remember when I was a student the faculty in which I studied semmed to change it's name each term. The reason for this was I was told was in order to improve the chances of obtaining funding, and followed whatever political notion which happend to be currently in fashion.

Also it seems that we have a topic here that both sides of the political divide have at times found usful to promote. Mr's Thatcher seems to have used it in support of mine closures, and the political left use it now as a general critique of the capitalist system, and America in particular. Also it is now a useful tool for those who would prefer to avoid competition from industrial expansion in the third world.

So it would appear that this particular issue is one which can be used to justify just about any political stance. That's a dangerous tool in the hands of politicians.

While I acknowledge that human activity may well contribute to global warming, I remain to be convinced that it is the prime cause.

However, it seems to me that the issue has become so obfuscated by political bandwaggoning that as with many issues, we won't know for sure until after the event.

Even if it is true that our activities are the cause I don't believe it will be possible to do very much about it. The greater part of the worlds population want to use the cheapest source of power available to them to improve their own lives, and they are not going to listen very carefully to the bleatings of wealthy nations about the dire consequences. To them the downside of global warming is insignificant when compared to their ordinary everyday lives.

Because of these reasons, the question of whether or not we are the cause of global warming, and whether or not we can control it is a pureley academic one. If in theory we can control it, in practice we won't. In fact in practice we can't. Not at least quickly enough with a clear concience.

The fact is it is probably too late whatever the cause, and the question is rather one of what the changes are likely to be and what we need to do about living with them.

That is not to say that we should not consider 'green' issues carefully. There are more noxious substances then CO2 that come out of the tailpipes of our cars, and from power-station smoke stacks, and there are definite gains to be made from using energy more efficiantly. An let us not forget that oil is a limited rescource which is in danger of running out. Neither is it a recycling issue, there are big problems concerned with the sheer bulk of waste, much of which can be re-used. (I'm one of those people who can't walk past a skip without looking for anything which caan be salvaged. It truly is amazing what some people throw away. I also like to be warm, but like most I hate large heating bills.) Don't forget re-cycling is not a new thing, the rag-and-bone man was still a common sight as recently as thirty years ago, and I can remember collecting bottles, an putting out old newspapers every Wednesday for 'the salvage'.

So carry on re-cycling and insulating your homes. Big 'Chelsea tractors' are expensive, (the real reason people buy them, some people just love to show off!) smelly, dirty, wasteful, take up far too much parking space, and relatively unsafe, which are good enough reasons to dislike them for their own sake. Please feel free to insulate your homes, and install solar heating, other means of reducing your energy bills.

Energy will become more expensive in the future. In the UK we no longer have enough natural gas for our own needs, and we threw away our coal reserves just so that one political party could feel secure in office. (Beware politicans with visions. If you or I have visions we would be bundled off to see a doctor.) Other countries will run out of cheap oil and gas a lot sooner than I suspect we are perpared for.

Global warming is a separate issue.

Did any of guys actuall watch the program?

The program very convincingly showed that historical CO2 levels LAGGED BEHIND temperatures by about 800 years. Surely this proves beyond reasonable doubt that CO2 levels do not cause temperature rises - if anything it is the other way around.

Andy.

quote:

Originally posted by fifelee:

quote:

Originally posted by CobblyWorlds:
It is already posted around here that we know ALL of the increase in CO2 is definitely due to humans.

How can we know that such an insignificant amount of CO2 can cause global warming?

Physics of course.

It's not controversial that it causes warming, and the evidence is converging on 3degC for about 560ppmCO2.

Come on CobblyWorld. You know damn well that CO2 levels have been much higher than they are now and much lower with marginal temp swings. Plus CO2 is a very minor greenhouse gas. You don't give mother much credit. Minor changes in a minor gas will not cause drastic temp changes.
http://www.junkscience.com/Greenhouse/
http://www.oism.org/pproject/s33p37.htm

Go learn the physics, as I have done.

Argument by incredulity is a basic logical falacy.


Cobblyworlds (an ex-sceptic), signing out for now.

Steve_M

I did not say that clouds would act to offset the effect of increased CO2 concentration. Cosmic rays are not the only source of CCN for clouds and we know that the albedo and abundance of clouds depends on the CCN spectrum. It is entirely possible that we have by deforestation, change of land use, etc, modified the CCN and that this could be a significant contributor to warming. By promoting a "its CO2, case closed" attitude we risk the very real danger that we will fail to look for other, perhaps more important contributory factors.

As for the level of cloud physics research, the UK has a very aged C130 that may eventually get replaced by the BAE146 based ARA as and when they can overcome the numerous bugs. Not the level of activity one would expect if the politicians were really convinced by the need.

Indeed, it is true that there could be other reasons etc.

While I agree that it is best to leave it to peer review etc, I have seen many papers on other subjects which really makes you wonder how it ever got through.

Having put it together over the 25 years, I see a pretty convincing increasing trend for all months except Dec and maybe jun. The only problem I still have is the variation is so large, it is almost imposible to say with any certainty that the increase is a true increase. Of course if you only take anual temps, you will potenitally obsure the monthly variation meaning it is not a fair test.

Using a correlation test (does increase in time cause an increase in temperature), I found that while the anual trend to increase over time was significant, only the months of April, May and June were themseleves significant. When removed, the anual trend was still significant, but was less so than when those months were included. So those three months appear to be the main driving force using a better method than before, but combination of all the other months is still enough suggesting that the positive trend there is true, just not as marked. The anual trend only becomes non-significant once the only months left are Oct, Nov and Dec.

quote:

As to whether the additional CO2 is from fossil sources, ie coal, oil, and gas, another source of the the same C12 isotope is of course vulcanism. It would seem to me obvious that carbon which has been mulling around in the earths crust for many hundred thousands of years would contain comapartively small amounts of C14. Also please note here that vulcanism does not just mean huge eruptions, but includes all geological emissions.

That seems reasonable, but is wrong for 3 reasons:
1. The amount of CO2 released by volcanoes is small compared with humans, and the rate of production by vulcanism hasn't changed in the last few hundred years. It is the change CO2 levels and the change in the isotope ratios that identifies the rise in fossil fuel CO2.
2. When humans burn CO2 it combines with atmospheric oxygen. CO2 out of volcanoes is ancient. The isotope signature of atmospheric oxygen is also different from "fossil" oxygen, so the combination points to fossil fuel-sourced CO2.
3. If you study the amount of coal, oil and gas burnt in the last 200 years it matches well with the amount of additional CO2. I actually did a rough calculation of this myself a couple of weeks ago using data from oil and coal usage statistics websites, and worked out enough oil and coal had been burnt to add 115ppm CO2 to the atmosphere (there were a few approximations, I didn't include gas, and I know that some of the extra additional CO2 is absorbed by the ocean).

quote:

Originally posted by CobblyWorlds:
Go learn the physics, as I have done.
Argument by incredulity is a basic logical falacy.
Cobblyworlds (an ex-sceptic), signing out for now.

The fact is man has caused .28% of the global warming effect mother nature (what you call physics) controls the rest. Saying CO2 was higher and lower in the past isn't "augument by incredulity" it is fact.

The existence of a time lag only shows that in those past instances CO2 was not the first driver of the climate change. It may still have contributed to a positive feedback loop, increasing what might otherwise have been less severe warming.

The "common sense" comments about CO2 only being a tiny part of the atmosphere have no place in sensible discussion. The fact that we are dealing with small percentages is irrelevant- it makes about as much sense as saying a tiny little bit of cyanide dust couldn't possibly hurt someone.

Besides which, the projected increases of a few degrees are not large when you consider the whole energy balance of the Earth or the variations in geological time. Most people are not saying that CO2 or humans can drastically "control" the climate, just that we can slightly adjust the balance.

quote:

Originally posted by BrianBlessed:
The "common sense" comments about CO2 only being a tiny part of the atmosphere have no place in sensible discussion. The fact that we are dealing with small percentages is irrelevant- it makes about as much sense as saying a tiny little bit of cyanide dust couldn't possibly hurt someone.

I didn't argue CO2 was only a tiny part of the atmosphere and therefore no effect. I said humans only cause a tiny percent of the greenhouse gases. So when greenhouse gases warm or cool, humans can only be blamed for a tiny percent. To use your argument. Yes a tiny amoutn of cyanide can hurt someone, but 99.72% of the cyanide is natural. Humans only casue .28%.

quote:

I did not say that clouds would act to offset the effect of increased CO2 concentration. Cosmic rays are not the only source of CCN for clouds and we know that the albedo and abundance of clouds depends on the CCN spectrum. It is entirely possible that we have by deforestation, change of land use, etc, modified the CCN and that this could be a significant contributor to warming. By promoting a "its CO2, case closed" attitude we risk the very real danger that we will fail to look for other, perhaps more important contributory factors.

Sorry, I did not mean to put words into your mouth, I did say it was my take on it.

Yes there are big uncertainties, particularly on the detailed effect of aerosols, so in the science world it is by no means "case closed", particularly with the current generation of more and more detailed chemistry and dust models.

But CO2 does have physically well known properties that would, in the absence of all other effects, induce global warming, and ditto for CH4, ozone, blackening of ice from soot etc. Equally there are known sources of cooling. So while more research on the interactions of all of these is desirable, a sensible policy decision in the light of the very good available evidence is to consider CO2 reduction strategies.

Yes to more cloud research too!

Accoring to the Wiki enry on the greehouse effect CO2 conributes about 9% to the total global warming effect, when all othe gases are taken into account. On the face of it, it would appear that 1/3 of that ie, 3% is due to human activity.

Also we are led to beleive that the average global temperature without greenouse gases would be about -18 centigrade and the current global average is about 5 centigrade. The difference is 23 degrees, three percent of which is 0.69 degrees.

Ok, a very naive calculation, and Wikipedia may not be the most relaible source, and I have no idea of exactly how the percentages given were arrived at, but the numbers look right to me!

It does not change my view though that it is very unlikely that we could do anything about it. It's too late for one thing, the carbon that's already there will be there for many hundreds of years if we accept current theory.

And a greater proportion of the worlds population are likely to suffer if we impose carbon restrictions upon them.

But that does not mean that we should not clean up our own back yard.