Accuracy of An Inconvenient Truth

[bascule]

You still refuse to confirm what it is you feel is unevidenced. Why is this?

 

Asking for empirical evidence that "man is causing global warming" is like asking for empirical evidence that man evolved from single cell organisms. The amount of evidence required to corroborate that assertion is enormous.

 

So let me ask you this: Will you at least admit that CO₂ is a first order climate forcing?

[Dr. Dalek]

Dr. Dalek.

The article you quote need not be queried' date=' 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.

[/quote']

My point was the section in the article that called IPCC's conclusions into question.

Please read this quote from the text.

Intergovernment Panel on Climate Change (IPCC) released in 1995. . . . As Dr. John W. Zillman, one of the scientists who participated in the process noted, "[The IPCC was] meticulous in insisting that the final decision on whether to accept particular review comments should reside with chapter Lead Authors. This was at variance with the normal role of journal editorial boards and led to suggestions that some Lead Authors ignored valid critical comments or failed to adequately reflect dissenting views when revising their text."

My point wasn't to show lack of concensus but to show that bascule was perhaps, overrelient on IPCC as a source. He reflects their opinion but when I presented information that was also from IPCC ,and I felt proved my point, he dismissed it, reflecting their conclusion which seem to be tainted.

You still haven't told me what "empirical evidence" you find lacking. Do you seriously contend that we lack scientific knowledge that CO_{2[/sub'] is the primary climate forcing affecting the radiative imbalance of Earth's climate system?}

_{He wants "empirical evidence' that shows a direct one-to-one relationship between man made Greenhouse gasses and the tempeature.}

_{Natural CO2 may be rising, have any studies been done on that possibility? If so was your long praised IPCC involved?}

_{There are explanations for the increase in tempeature other than man made greenhouse gasses. Has IPCC explored them? If so how thuroughly?}

 

_{So let me ask you this: Will you at least admit that CO2[/sub'] is a first order climate forcing?}

_{It's a possibility, but I think SkepticLance's point is that it is not definite.}

_{In the past four billion years that the earth as we know it has been in existence the Earth has warmed and cooled over and over again. This happens because geological and biological activity has changed CO2 levels, and altered surface albedo, and aerosols. Solar and Cosmic activity has warmed and cooled the Earth. Violent impacts and Glacial activity have changed geological activity over and over again.}

_{There is alot that effects the climate, CO2 has been a major player befor, but it's not the only one.}

[SkepticLance]

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.

[bascule]

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' date=' 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.[/quote']

 

There are several forcings which affect the Earth's radiative imbalance:

 

 

Furthermore, changes in surface albedo affect the Earth's radiative imbalance. This can come from anthropogenic sources (i.e. pave relatively reflective sand with black asphalt). There are also feedback loops which affect surface albedo, such as a warming climate melting highly reflective sea ice, turning it into highly absorbant ocean water which further increases warming.

 

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.

 

You still haven't stated what form you would like this evidence in. Can you describe what kind of evidence would convince you that anthropogenic CO₂ is a first order climate forcing and the primary one affecting the climate system? What form would it take? Your question is so vague I simply don't know what you're asking for.

 

He wants "empirical evidence' that shows a direct one-to-one relationship between man made Greenhouse gasses and the tempeature.

 

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.

[SkepticLance]

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.

[bascule]

http://news.yahoo.com/s/ap/20060627/ap_on_sc/gore_s_science

 

WASHINGTON - The nation's top climate scientists are giving "An Inconvenient Truth,"

Al Gore's documentary on global warming, five stars for accuracy.

 

The former vice president's movie — replete with the prospect of a flooded New York City, an inundated Florida, more and nastier hurricanes, worsening droughts, retreating glaciers and disappearing ice sheets — mostly got the science right, said all 19 climate scientists who had seen the movie or read the book and answered questions from The Associated Press.

 

The AP contacted more than 100 top climate researchers by e-mail and phone for their opinion. Among those contacted were vocal skeptics of climate change theory. Most scientists had not seen the movie, which is in limited release, or read the book.

 

But those who have seen it had the same general impression: Gore conveyed the science correctly; the world is getting hotter and it is a manmade catastrophe-in-the-making caused by the burning of fossil fuels.

[bascule]

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!

 

Where's their paper? And the peer review?

[Dr. Dalek]

Where's their paper? And the peer review?

He said book not paper, furthermore your article is from the AP, hardly a peer reveiwed scientific journel.

The media, being an imperfect entitiy, is subject to reporter bias. For instance "Top" climate scientist would seem to indicate that they are the lead reasearchers, or they might be people that the reporter thought would agree with him.

If there is a list of those scientists it would be helpful. Some of the scientists are mentioned in the article, I'll see about looking them up.

I am at the Univerity of Maine right now. I'll spend some time in the library later. They have scientific papers there I'll look one up.

 

Also, I think I'll clarify things by formaly stating my position:

Global Warming, in my mind, is a natural phenominon, as is evident from Ice cores. How man kind may be effecting it is uncertain and subject to study and debate.

[SkepticLance]

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.

[SmallIsPower]

We can not afford to wait until we've proven that we're past the tipping point! This is not an abstract theory that won't mean much. The potential is devistating, therefore we must act since the danger is quite plausible.

 

No it dosn't' date=' Man made CO[sub']2[/sub] only represents about 3% of the total CO₂ released annulay the rest being natural. There is a very big and obvious hole in your facts.

 

http://www.ujae.org/globalwarming/Presentations%20on%20GW/slideshow%20january%202002.pdf

Page 16

The only 3% number I saw on that presentation was where it said 97% of greenhouse gases are H₂O, by weight. The critical question is how much each gas heats up the atmosphere. Also, of the "natural" outlay, how much remains in the atmosphere as a result of a lack of carbon sequestrestation in forests we've cut down?

 

Bascule, that chart was hopeful. Anthropmorhic warming comes to 4Watts, anthropmorhic cooling comes to 3 Watts, so we we'll only have to negate 25% of our warming effects to have them cancel out.

[Dr. Dalek]

We can not afford to wait until we've proven that we're past the tipping point![/b'] This is not an abstract theory that won't mean much. The potential is devistating, therefore we must act since the danger is quite plausible.

Here is a quote from a article found in the June issue of Nature, Volume 441, Issue no. 7095.

It is reasonable to worry about such things, but ther are three dangers attendent on focusing humanity's responce to the climate crisis* too much on tipping points. The first is the uncertainty of the science`; the second is the tendancy of such an emphasis to distort our responces; the third is the danger of fatalism.

The modles through which our understanding of the climate system are channeled into assessments of how it might behave in the future are impressive by the standards of human investigation, but crude with respect to the details of the Earth system. All sorts of phenomina, from the formaion of clouds to the respiration of soils, are hard to capture accuratly, and it is on such details that an understanding of possible tipping points depends . . . . . The concept of the tipping point is, in fact more pertinent to the climate crisis in the social sphere than in the physical world.

.

*"crisis" is what is from the text, not me

`UNCERTAINTY

So you see your urgency may not be validated.

In the text "Fatalism" is essentialy as follows:

. . . The belief that a complete solution is the only worthwhile one, as any other course may allow the climate system to tumble past the crucial threshold. This sort of all-or-nothing approach is already over-stressed in climate policy . . . . . which calls for complete avoidence of dangerous anthropogenic climate change, rather than the more reasonable and more feasible goal of minimizing and controlling it.

Hope I called attention to everything that was neccissary.

The only 3% number I saw on that presentation was where it said 97% of greenhouse gases are H_{2[/sub']O, by weight. The critical question is how much each gas heats up the atmosphere. Also, of the "natural" outlay, how much remains in the atmosphere as a result of a lack of carbon sequestrestation in forests we've cut down?}

_{Try page 15, I was counting the title page so the numbers were all one higher.}

_{Quantifying the relative 'force' of the difference influences is the trick.}

_{Yes that is the trick and we humans are not very good at it.}

[bascule]

Quantifying the relative 'force' of the difference influences is the trick.

 

What is your argument against the IPCC's methodology for doing so and the empirical data they used to justify their position?

 

They've made an argument based upon empirical data. You're committing the shifting the burden of proof fallacy by failing to undermine their argument. In fact it seems you simply pretend it doesn't exist.

[swansont]

I haven't seen the movie, and I am in no way anything like an expert on global warming or climatology. But there are some obvious logical fallacies and errors of science interpretation floating around this thread, besides the ones bascule has called out (or if he did address them, I missed it).

 

Given that the amount of CO2, produced by mankind annually is only 2% of all the CO2 (the rest being natural) produced, I would say there is an over emphasis on CO2.

Effect must reflect cause. In a graph' date=' that means that the graphed effect (temperature rise) must follow pretty much the same pattern as that of cause.

...

I never claimed the need for a one to one relationship. A sufficiently high correlation is enough.[/quote']

 

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.

 

 

I believe you are over-impressed by computer models.

...

 

In science' date=' the only evidence that is truly acceptable is Empirical. That is: real world experiments or observations. Processes of logic and computer models do not qualify.[/quote']

 

I can't begin to express how wrong this is. Empirical evidence is important, but modeling is used quite a lot, too. (seems good enough for e.g. the folks that want to build new nuclear weapons, but can't empirically test them, anyway)

[SkepticLance]

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.

[SkepticLance]

Apologies.

In my post above, I meant 1976 to 1998.

[bascule]

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.

 

So I take it you completely reject the Mann "hockey stick" reconstruction and the dozen other independent northern hemisphere reconstructions AND the instrumental record which give nearly identical results:

 

 

And you further reject the IPCC's detection and attribution studies:

 

http://www.grida.no/climate/ipcc_tar/wg1/025.htm

 

And studies of Antarctic ice core data which show a clear correlation between CO₂ concentrations and global average temperature:

 

 

So the question becomes, is there any climate science research you do accept?

[Dr. Dalek]

These statements appear to assume some linear relationship' date=' 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.[/quote']

It is also incorrect to assume that a small change in condition WILL lead to a larger effect. Climate change is uncertain!

 

I can't begin to express how wrong this is. Empirical evidence is important, but modeling is used quite a lot, too. (seems good enough for e.g. the folks that want to build new nuclear weapons, but can't empirically test them, anyway)

Reread this!

It is reasonable to worry about such things, but ther are three dangers attendent on focusing humanity's responce to the climate crisis* too much on tipping points. The first is the uncertainty of the science`; the second is the tendancy of such an emphasis to distort our responces; the third is the danger of fatalism.

The modles through which our understanding of the climate system are channeled into assessments of how it might behave in the future are impressive by the standards of human investigation, but crude with respect to the details of the Earth system. All sorts of phenomina, from the formaion of clouds to the respiration of soils, are hard to capture accuratly, and it is on such details that an understanding of possible tipping points depends . . . . . The concept of the tipping point is, in fact more pertinent to the climate crisis in the social sphere than in the physical world.

.

bascule; I'd like to point out that the current warming looks a heck of alot like previous warming cycles. Also who is to say that that CO₂ isn't natural.

[Dr. Dalek]

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' date=' 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.

[/quote']

Actualy I think bascule's comments were directed at me.

[CPL.Luke]

has anyone ever factored in dwindling oil supplies into the models for warming? I imagine that any model out there is partly based on an increased consumption of fossil fuels over the next ten to twenty years, however if the supply of said fossil fuels dwindles naturally over the next ten to twenty years and thus effects the rate at which they are consumed, then global warming may not be as severe as previously thought

 

so the question beomes "is there enough oil in the world to significantly effect the climate?"

 

I know that this isn't taking into account coal and liquid natural gas, but I have a fealing that in the US at least as the oil runs out nuclear plants will be built to replace the oil ones.

[SkepticLance]

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.

[bascule]

"I do not know. And neither does anyone else."

Sure' date=' the IPCC might be right. So might the various climate scientists who are skeptics. We do not know.[/quote']

 

Maybe the scientific concensus among biologists is wrong, and Michael Behe is right. Well, that settles it, evolution isn't scientific, and intelligent design is an equally likely explanation.

 

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.

 

Okay, another caveat: natural forcings were predominant 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.

[SkepticLance]

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]

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).

 

The graph in red is the empirical measurements you were asking for. The rest of the graphs are from model output. That graph is showing that the models agree with the empirical measurements. These are independent studies, conducted with different models, all showing similar results which, surprise surprise, agree with the empirical data. *gasp*

 

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.

 

When the models and empirical data agree, maybe the models are accurate.

 

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.

 

I have a graph which shows a direct correlation between pirates and global warming. Some guy pulled it out of his ass. The graphs I gave there are from the results of multiple, independent climate science research groups. What do they illustrate? A scientific concensus.

 

It will be interesting to see where your graph comes from.

 

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.

 

Ooh, a "number of suggested mechanisms". Well, according to the pirate theory of global warming, the creation of robot pirates which displaced human pirates is responsible. How would that theory survive climate science peer review?

 

You already agreed that increases in CO₂ throughout the 20th century come from primarily anthropogenic sources. No backpedaling. You can't turn around now and say that this isn't the case.

[SkepticLance]

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]

bascule

There is nothing new and startling about the hockey stick graph. I first saw it years ago. In spite of your comments' date=' 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.[/quote']

 

That's the urban heat island argument. You may want to read the RealClimate article on that point:

 

http://www.realclimate.org/index.php/archives/2004/12/the-surface-temperature-record-and-the-urban-heat-island/

 

Bottom line, the UHI effect is negligable.

 

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.

 

Why is that more likely?

 

Where's the study?

 

Who peer reviewed it?

 

I will repeat my point in case you miss it again. On your graph, temperature increases first, followed by carbon dioxide levels.

 

To pound the point into your head again: CO₂ isn't the only forcing affecting the climate system

 

This means that the warming is the cause, and the rise in carbon dioxide is the effect.

 

No, it doesn't. It means other forcings beyond CO₂ affect the climate system.