Convince me that anthropogenic golobal warming is a load of horsehooey.

[Skald_the_Rhymer]

I’m going to be something of a dick and NOT begin this thread by stating a position one way or the other, partly because my degree is in a whole 'nother discipline and partly because I am opening this thread so as to divert debate from the poll in this one.

[DSeid]

You really can’t just read one of the kajillion past threads on this?

[Skald_the_Rhymer]

@DSeid

You really can’t just read one of the kajillion past threads on this?

I just started a poll in IMHO-- you know, the FORUM for POLLS-- that is aimed specifically at persons who are convinced of AGW. I opened this thread so that anyone convinced that AGW is a load of horsehooey and wishing to argue same would have a place to do so, so that the other thread might remain on-topic. I stated that in the OP, which you appear not to have read for reasons opaque to me.

[Quartz]

I suggest you search for threads with intention and jshore. I am thoroughly unconvinced by current AGW theories. Equally, I’m not convinced they’re wrong either. For me, it boils down to two things:

1 - Correlation is not causation. Sure there appears to be a significant correlation, but there are other correlations too. Plus the Earth may be in a warming phase anyway following the Little Ice Age.

2 - The use of models. Good data mangled by garbage software becomes garbage.

[WarmNPrickly]

Do any models not predict a direct correlation between global temperature and atmospheric carbon dioxide concentration? If there are, what is the rational?

[Chronos]

2 - The use of models. Good data mangled by garbage software becomes garbage.

As opposed to using unicorn manes and leprechaun gold? The only way we can ever make any sense of any data whatsoever is through use of models. Why do I believe that the Sun will rise tomorrow? Because the models consistent with past behavior of the Sun predict that it will.

[brazil84]

@Skald_the_Rhymer

I’m going to be something of a dick and NOT begin this thread by stating a position one way or the other, partly because my degree is in a whole 'nother discipline and partly because I am opening this thread so as to divert debate from the poll in this one.

I laid out my argument here.

[WarmNPrickly]

@WarmNPrickly

Do any models not predict a direct correlation between global temperature and atmospheric carbon dioxide concentration? If there are, what is the rational?

I should really have an editor to post. The second question should read: "If there are (models that do not correlate global temperature with atmospheric carbon dioxide), what is the rational (behind not correlating the two)?

I know it it makes little difference in interperetation, but it was bugging me.

[brazil84]

@Chronos

As opposed to using unicorn manes and leprechaun gold? The only way we can ever make any sense of any data whatsoever is through use of models. Why do I believe that the Sun will rise tomorrow? Because the models consistent with past behavior of the Sun predict that it will.

According to legend, the ancient Greeks believed the same thing, i.e. that the sun would rise because it was consistent with their model. However, their model was that Apollo got in a chariot every morning and rode across the sky.

Their are two morals to this story:

(1) The best tool for making predictions is an actual track record.

(2) For any set of observations, there are numerous possible models which can explain them. The fact that a particular model is consistent with history does not, standing alone, validate the model. (There is one exception to this principle which does not apply here.)

So, strictly speaking, the objection to the hypothesis commonly referred to as “AGW” (which I refer to as “CAGW”), is not that it relies on models. The problem is that it relies on models which have not been tested and validated.

[GIGObuster]

@Quartz

I suggest you search for threads with intention and jshore. I am thoroughly unconvinced by current AGW theories. Equally, I’m not convinced they’re wrong either. For me, it boils down to two things:

1 - Correlation is not causation. Sure there appears to be a significant correlation, but there are other correlations too. Plus the Earth may be in a warming phase anyway following the Little Ice Age.

I’m still waiting for evidence that scientists just ignored that “correlation is not causation” point, I have to conclude that their the points is to just repeat that with no evidence to support it.

9 ways we know humans caused climate change

MYTH: Global warming is just part of a natural cycle. The Arctic has warmed up in the past.

FACT: The global warming we are experiencing is not natural. People are causing it.

People are causing global warming by burning fossil fuels (like oil, coal and natural gas) and cutting down forests. Scientists have shown that these activities are pumping far more CO2 into the atmosphere than was ever released in hundreds of thousands of years. This buildup of CO2 is the biggest cause of global warming. Since 1895, scientists have known that CO2 and other greenhouse gases trap heat and warm the earth. As the warming has intensified over the past three decades, scientific scrutiny has increased along with it. Scientists have considered and ruled out other, natural explanations such as sunlight, volcanic eruptions and cosmic rays. (IPCC 2001)

Though natural amounts of CO2 have varied from 180 to 300 parts per million (ppm), today’s CO2 levels are around 380 ppm. That’s 25% more than the highest natural levels over the past 650,000 years. Increased CO2 levels have contributed to periods of higher average temperatures throughout that long record. (Boden, Carbon Dioxide Information Analysis Center)

As for previous Arctic warming, it is true that there were stretches of warm periods over the Arctic earlier in the 20th century. The limited records available for that time period indicate that the warmth did not affect as many areas or persist from year to year as much as the current warmth. But that episode, however warm it was, is not relevant to the issue at hand. Why? For one, a brief regional trend does not discount a longer global phenomenon.

We know that the planet has been warming over the past several decades and Arctic ice has been melting persistently. And unlike the earlier periods of Arctic warmth, there is no expectation that the current upward trend in Arctic temperatures will reverse; the rising concentrations of greenhouse gases will prevent that from happening.

2 - The use of models. Good data mangled by garbage software becomes garbage.

How reliable are climate models?

There are two major questions in climate modelling - can they accurately reproduce the past and can they successfully predict the future?
Reproducing the past

A way to test the accuracy of models is through hindcasting - see whether they successfully predict what has been observed over the past century. Here is the IPCC model of surface temperature from the 1800’s - both with and without anthropogenic forcings.

The key point is that all the models fail to predict recent warming without taking rising CO2 levels into account. Noone has created a general circulation model that can explain climate’s behaviour over the past century without CO2 warming.

Another way to look at it is multiple studies (both using models and independently) calculate a climate sensitivity of around 3°C (Hegerl 2006, Annan 2006, Tung 2007). In other words, global temperatures would warm 3°C if CO2 was doubled. To deny anthopogenic warming, you need to not only explain what’s causing global warming but also explain why increasing CO2 isn’t causing the expected and observed warming.

Climate projection is a difficult and ever refining art. There’s the problem that future behaviour of the sun is very difficult to predict. Similarly, short term perturbations like El Nino or volcanic eruptions are difficult to model. Nevertheless, climate scientists have a handle on the major drivers of climate. Way back in 1988, James Hansen projected future temperature trends (Hansen 1988). Those initial projections show remarkable agreement with observation right to present day (Hansen 2006). Hansen even speculated on a volcanic eruption in 1995 but missed the date by a few years (we’ll cut him some slack there).

Hansen’s Scenario B (described as the most likely option and in hindsight, the one that most closely matched the level of CO2 emissions) shows close correlation with observed temperatures. In fact, Hansen overestimated future CO2 levels by 5 to 10% so if his model was given the correct forcing levels, the match would be even closer. There are deviations from year to year but this is to be expected. The chaotic nature of weather will add noise to the signal but the overall trend is predictable. More on predicting the future…
Other results successfully predicted and reconstructed by models

* Cooling of the stratosphere
* Warming of the lower, mid, and upper troposphere
* Warming of ocean surface waters (Cane 1997)
* Trends in ocean heat content (Hansen 2005)
* An energy imbalance between incoming sunlight and outgoing infrared radiation (Hansen 2005)
* Amplification of warming trends in the Arctic region (NASA observations)

[beowulff]

What I really don’t get is this:

Humans have been dumping GigaTons of CO2 into the air each year for decades. For all those people who think that humans couldn’t possibly affect the Earth, well, what effect do they think that this has, and if the answer is “none”, why so?

That’s all. It’s a simple question.

[GIGObuster]

@brazil84

So, strictly speaking, the objection to the hypothesis commonly referred to as “AGW” (which I refer to as “CAGW”), is not that it relies on models. The problem is that it relies on models which have not been tested and validated.

Of course that is not true, as scientists from other nations validate the results of the latest models. The thing is that deniers of AGW always want all to ignore that models from other countries (like the Met office in England and universities in Japan) get virtually the same results.

[WarmNPrickly]

@brazil84

According to legend, the ancient Greeks believed the same thing, i.e. that the sun would rise because it was consistent with their model. However, their model was that Apollo got in a chariot every morning and rode across the sky. …

Since there was never any reason to believe that Apollo had anything to do with the sun rising it is really irrelevant. On the other hand, it is scientifically indisputable that the earth is a radiating body and that carbon dioxide is an infrared absorber. Any models that do not include this into the global temperature need a rational unless they are deliberately avoiding the subject. The details of how much radiation the CO2 absorbs may be disputable, but whether or not CO2 absorbs radiation is not.

[Skald_the_Rhymer]

@brazil84

I laid out my argument here.

Glancing at your link, I notice that, in your rules for debate, all the comments on said rules are from you. That seems…odd.

[GIGObuster]

@Skald_the_Rhymer

Glancing at your link, I notice that, in your rules for debate, all the comments on said rules are from you. That seems…odd.

Of course not, his post is his cite, so only he can comment on them.

[Skald_the_Rhymer]

@GIGObuster

Of course not, his post is his cite, so only he can comment on them.

I don’t mean to attack brazil84; I just saw it and was perplexed.

[DanBlather]

@WarmNPrickly

Since there was never any reason to believe that Apollo had anything to do with the sun rising it is really irrelevant. On the other hand, it is scientifically indisputable that the earth is a radiating body and that carbon dioxide is an infrared absorber. Any models that do not include this into the global temperature need a rational unless they are deliberately avoiding the subject. The details of how much radiation the CO2 absorbs may be disputable, but whether or not CO2 absorbs radiation is not.

Rationale.

[brazil84]

@WarmNPrickly

Since there was never any reason to believe that Apollo had anything to do with the sun rising it is really irrelevant.

It’s relevant to the claim that we can trust a model simply because it matches history. Clearly we cannot.

On the other hand, it is scientifically indisputable that the earth is a radiating body and that carbon dioxide is an infrared absorber. Any models that do not include this into the global temperature need a rational unless they are deliberately avoiding the subject. The details of how much radiation the CO2 absorbs may be disputable, but whether or not CO2 absorbs radiation is not.

So what? The dirty little secret of the warmist position is that the entire theory rests on water vapor feedback. The only evidence (such as it is) for water vapor feedback comes from models.

[brazil84]

@Skald_the_Rhymer

Glancing at your link, I notice that, in your rules for debate, all the comments on said rules are from you. That seems…odd.

Let’s assume for the sake of argument that it’s odd. It doesn’t change the case I laid out against CAGW, which starts in post 2.0 and goes through 7.0

[GIGObuster]

@brazil84

It’s relevant to the claim that we can trust a model simply because it matches history. Clearly we cannot.

So what? The dirty little secret of the warmist position is that the entire theory rests on water vapor feedback. The only evidence (such as it is) for water vapor feedback comes from models.

Secret? Surely you jest.

Water Vapor Feedback Loop Will Cause Accelerated Global Warming, Professor Warns

Andrew Dessler, a professor in the Department of Atmospheric Sciences who specializes in research on climate, says that warming due to increases in greenhouse gases will lead to higher humidity in the atmosphere. And because water vapor itself is a greenhouse gas, this will cause additional warming. This process is known as water vapor feedback and is responsible for a significant portion of the warming predicted to occur over the next century.

“It’s a vicious cycle – warmer temperatures mean higher humidity, which in turn leads to even more warming,” Dessler explains.

The perspective by Dessler and co-author Steven Sherwood of the Climate Change Research Centre at the University of New South Wales is published in the journal Science. In the article, they review and summarize the peer-reviewed evidence in support of a strong water vapor feedback and conclude that the evidence supporting it is overwhelming.

“For years, there was a debate over this mechanism, with some even questioning if the water vapor feedback existed at all. But recent work on this feedback has moved its existence and strength beyond argument,” Dessler adds.

Predictions of significant global warming over the next 100 years by climate models require a strong water vapor feedback. Recent estimates suggest the earth will warm from 2 to 4 degrees Celsius (4 to 8 degrees Fahrenheit) over the next century – a scenario that could have devastating long-term consequences.

“Everything shows that the climate models are probably getting the water vapor feedback right, which means that unless we reduce emissions, it is going to get much, much warmer on our planet by the end of the century,” he adds.

That last bold part shows that indeed the scientists here did not base their conclusions in models, but the evidence.