Global warming discussion III

[DC]

This is better. At least you are directly quoting and asking questions.

Natural variability is the correct null assumption when analysing climate change, until it is shown to be not natural variability. I can't speak for Koonin as I am not him, but this is an entirely reasonable position to adopt.

Of course the complex dynamics in climate mean there are many spurious and nonsense correlations which are often mistaken for causality, and we already have a plethora of papers claiming to explain the pause. For those of us experienced in complex dynamics (and I'm sure Koonin has such experience as a computational physicist), such an outcome is not a surprise; I would call it self-delusion, or drinking one's own bathwater. Again, I can't speak for Koonin.

natural variability cannot explain the observed global warming in the late 20th century. that is why experts concluded that the cause is not natural variability, but Human Activity. what do you even mean with natural variability? we are talking about forcings on the climate system, not internal natural variability.


btw, when the IPCC ARs are too complicated and long for you, try this, shorter and less complicated.

https://royalsociety.org/~/media/Ro...nce-causes/climate-change-evidence-causes.pdf

 

[CoolSceptic]

LOL, really? that is how you go about that? this btw, is not a conclusion that changed since AR4, i guess you did not read either of them?

I have read parts of AR4 and AR5, but not all. I'm well aware of the IPCC authors rather dubious non-quantitative claims about amount of human influence. As you can imagine, as a scientist such qualitative claims do not impress me much.

yes the IPCC AR's are a bit complicated and it needs a bit more than a word search try reading it one day.
http://www.realclimate.org/images/ipcc_rad_forc_ar5.jpg

Leaving a huge document to read with a claim which you incorrectly word is massively unhelpful (although from your posts it is entirely possible obfuscation is your goal). I can do the same thing if you want; leave you with hundreds of pages of reference material and just say "that proves you wrong". As you can imagine, such a discussion along the way you present it would not make any useful progress any time soon.

btw: i already pointed out one of the claism in the article that lacks evidence. He seems to be saying that Nature counteracted AGW. speaking of "vague terms"

Natural variability is not a vague term (unless you think weather, or year-to-year changes, which is a part of natural variability, doesn't exist). It is a correct and reasonable null hypothesis in the context of climate change.

 

[CoolSceptic]

natural variability cannot explain the observed global warming in the late 20th century.

Evidence for this please. And not just a link to an IPCC non-quantitative assessment.

Many papers question whether or not we can rule out natural variability, through natural dynamics, and come to the conclusion that no, we can't. AR5 even tacitly acknowledges this (AR4 doesn't). Example paper below.

https://water.usgs.gov/osw/pubs/Naturally_Trendy-Cohn-Lins_GRL_2005.pdf

 

[DC]

I have read parts of AR4 and AR5, but not all. I'm well aware of the IPCC authors rather dubious non-quantitative claims about amount of human influence. As you can imagine, as a scientist such qualitative claims do not impress me much.


Leaving a huge document to read with a claim which you incorrectly word is massively unhelpful (although from your posts it is entirely possible obfuscation is your goal). I can do the same thing if you want; leave you with hundreds of pages of reference material and just say "that proves you wrong". As you can imagine, such a discussion along the way you present it would not make any useful progress any time soon.


Natural variability is not a vague term (unless you think weather, or year-to-year changes, which is a part of natural variability, doesn't exist). It is a correct and reasonable null hypothesis in the context of climate change.

LOL actually, proponents and the IPCC are the only ones i have ever seen providing quantifications of the climate forcings.
deniers are mostly like, well it warmed in the past without humans, or CO2 is plantfood, it's the sun.... etc etc. never anything quantified.

and my previous link to the IPCC AR5 figure with the climate forcings and the link to the AR5, shows your claim to be wrong. they did make quantified claims.

and how exactly is natural variability a climate forcing? explain in detail how exactly do you think did it rise the global average temperature in the late 20th century?

 

[DC]

Evidence for this please. And not just a link to an IPCC non-quantitative assessment.

Many papers question whether or not we can rule out natural variability, through natural dynamics, and come to the conclusion that no, we can't. AR5 even tacitly acknowledges this (AR4 doesn't). Example paper below.

https://water.usgs.gov/osw/pubs/Naturally_Trendy-Cohn-Lins_GRL_2005.pdf

LOL speaking about non quantitative assessments.......

the paper does not quantivy any possible natural influence, it jsut says, based on what we know, it might well be that nature is the main cause.....
that is it. wow.

do you have anything quantified? you know, in the manner the IPCC ARs do. quantification of the climate forcings.

 

[CoolSceptic]

LOL actually, proponents and the IPCC are the only ones i have ever seen providing quantifications of the climate forcings.
deniers are mostly like, well it warmed in the past without humans, or CO2 is plantfood, it's the sun.... etc etc. never anything quantified.

and my previous link to the IPCC AR5 figure with the climate forcings and the link to the AR5, shows your claim to be wrong. they did make quantified claims.

and how exactly is natural variability a climate forcing? explain in detail how exactly do you think did it rise the global average temperature in the late 20th century?

Wow so many misconceptions about climate.

I did not claim natural variability was a "climate forcing", however it should be trivially obvious to anyone that changes in weather patterns (e.g. water vapour content, cloud cover) can have a very large impact on surface temperatures and radiative imbalance.

As for quantifying it, I've already given you a paper. The IPCC makes no attempt to account for the impact of the issues raised in that paper.

 

[DC]

The models predict that the lower atmosphere in the tropics will absorb much of the heat of the warming atmosphere. But that "hot spot" has not been confidently observed, casting doubt on our understanding of the crucial feedback of water vapor on temperature.

the WSJ seems to dig up the old "tropical hot spot" nonsense again.



atleast the deniers are big in recycling, even the old myths.

 

[CoolSceptic]

LOL speaking about non quantitative assessments.......

the paper does not quantivy any possible natural influence, it jsut says, based on what we know, it might well be that nature is the main cause.....
that is it. wow.

do you have anything quantified? you know, in the manner the IPCC ARs do. quantification of the climate forcings.

Natural variability is stochastic, not deterministic, and so is inappropriate to apply the concept of "climate forcing", which is a strictly deterministic concept.

The paper I linked quantifies in the sense of stochastics, and provides a range of probabilities for different assumptions about persistence. These are clear quantifications - unfortunately you have to understand a little about stochastics to understand them. I can show you the paper, but I can't make you understand the numbers inside it.

 

[CoolSceptic]

LOL speaking about non quantitative assessments.......

the paper does not quantivy any possible natural influence, it jsut says, based on what we know, it might well be that nature is the main cause.....
that is it. wow.

do you have anything quantified? you know, in the manner the IPCC ARs do. quantification of the climate forcings.

It's funny how you lot complain about how we must have peer reviewed papers showing the points being made, then when we do actually produce peer reviewed papers you dismiss them while simultaneously displaying staggering levels of ignorance as to the actual content of the papers.

Still, sauce for the goose and all.

 

[DC]

Wow so many misconceptions about climate.

I did not claim natural variability was a "climate forcing", however it should be trivially obvious to anyone that changes in weather patterns (e.g. water vapour content, cloud cover) can have a very large impact on surface temperatures and radiative imbalance.

As for quantifying it, I've already given you a paper. The IPCC makes no attempt to account for the impact of the issues raised in that paper.

no quantivication in the paper....

But could this warming be
due to natural dynamics? Given what we know about the
complexity, long-term persistence, and non-linearity of the
climate system, it seems the answer might be yes. Finally,
that reported trends are real yet insignificant indicates a
worrisome possibility: natural climatic excursions may be
much larger than we imagine. So large, perhaps, that they
render insignificant the changes, human-induced or other-
wise, observed during the past century.

and has he researched more on this? did he come up with a quantitative assesment?

 

[Reality Check]

I don't answer dishonest people, or read their responses.

Apparently anyone who asks you to back up your assertions with evidence is "dishonest", r-j !
It is not dishonest to ask simple questions that you should already know the answers to such as:

1. r-j (8 September 2014): Please cite the source you used to check the temperature records of from 1930 to about 1950 (1930's and 1940's) for the weather station mentioned in the [URL="http://www.realclimate.org/index.php/archives/2014/03/new-daily-temperature-dataset-from-berkeley/"]RealClimate article.[/URL]
2. r-j (19 September 2014): Please cite your source for these specific temperatures which you state are from the University station.
3. r-j (19 September 2014): Please cite your source that shows that the University station is the rooftop one that was moved to O'Hare.
4. r-j (19 September 2014): Please cite the source for your "NCDC NH land winter trend" image.
5. r-j (19 September 2014): Please justify what seems to be an arbitrary selection of 1995 as the starting date of the trend line when there is pre-1995 data in the graph.

 

[CoolSceptic]

no quantivication in the paper....

Huh, that's odd, this table seems to have numbers in it:

White noise Tb,{0,0,0} 0.0045 1.8e-27
MA(1) Tb,{0,0,q} 0.0046 1.9e-21
AR(1) Tb,{f,0,0} 0.0047 5.2e-11
LTP Tb,{0,d,0} 0.0050 4.8e-3
LTP Tb,{0,d,0} A 0.0050 9.4e-3
ARMA(1,1) Tb,{f,0,q} 0.0053 1.7e-4
LTP + MA(1) Tb,{0,d,q} 0.0045 7.2e-2
LTP + AR(1) Tb,{f,d,0} 0.0045 7.1e-2

How about that, there IS quantification in the paper.

and has he researched more on this? did he come up with a quantitative assesment?

Yes, there is a quantitative assessment in the paper. The fact you do not understand there is a quantitative assessment in the paper does not change this fact.

 

[Reality Check]

If you make a claim, you need to provide evidence.

r-j: Where is the evidence such as sources for your claims that has been lacking since 8 Septembers 2014?

 

[DC]

Huh, that's odd, this table seems to have numbers in it:

How about that, there IS quantification in the paper.




Yes, there is a quantitative assessment in the paper. The fact you do not understand there is a quantitative assessment in the paper does not change this fact.

oh my bad, didn't know those numbers show how much the influence of nature is and how much the influence of human activity, so how much % is do to human activity according to those numbers?
how do those trend significance tests show the amount of human influence on global warming?

 

[CoolSceptic]

oh my bad, didn't know those numbers show how much the influence of nature is and how much the influence of human activity, so how much % is do to human activity according to those numbers?
how do those trend significance tests show the amount of human influence on global warming?

Wow you really don't understand how stochastic models work, do you?

Do I really have to explain what a p-value is and what it means? There are plenty of websites that explain it.

I hope this helps:
http://en.wikipedia.org/wiki/P-value

A failure to reject the null means there is no point in assuming ANY of the change is not associated with the null. To do otherwise is pure pseudoscience.

 

[DC]

Wow you really don't understand how stochastic models work, do you?

Do I really have to explain what a p-value is and what it means? There are plenty of websites that explain it.

I hope this helps:
http://en.wikipedia.org/wiki/P-value

A failure to reject the null means there is no point in assuming ANY of the change is not associated with the null. To do otherwise is pure pseudoscience.

so the MIT, Yale, Oxford, MPI, ETHZ, NASA, ESA, JAXA are all misstaken because we used the wrong trend significance tests?

and all this just because Cohn failed to convince his collegues in his field of expertise?

 

[Reality Check]

Thank you r-j, that is a convincing argument that winters have become colder.

Actually, ideogram, that does not look like r-j's original assertion - just what looks moving of the goalposts to "parts of the NH" from the boreal winter trend. Boreal is mid to high latitudes.

IThis mythical claim was made in order to avoid answering the questions that came up when I first made the points about the boreal winter trend.

This is why macdoc cited Has the Northern Hemisphere been warming or cooling during the boreal winter of the last few decades? and quoted the boreal parts.

r-j cited Arctic warming, increasing snow cover and widespread boreal winter cooling Cohen et al (2012)
(my emphasis added)

The most up to date consensus from global climate models predicts warming in the Northern Hemisphere (NH) high latitudes to middle latitudes during boreal winter. However, recent trends in observed NH winter surface temperatures diverge from these projections. For the last two decades, large-scale cooling trends have existed instead across large stretches of eastern North America and northern Eurasia. We argue that this unforeseen trend is probably not due to internal variability alone. Instead, evidence suggests that summer and autumn warming trends are concurrent with increases in high-latitude moisture and an increase in Eurasian snow cover, which dynamically induces large-scale wintertime cooling. Understanding this counterintuitive response to radiative warming of the climate system has the potential for improving climate predictions at seasonal and longer timescales.

Predictions from models: warming during boreal winter.
Results in the paper:

While the hemispheric winter trend is neutral, specific regions have experienced negative temperature trends. As shown in figure 1(c), spatially, the strongest winter cooling trends are observed over the eastern United States, southern Canada and much of northern Eurasia.

 

[greybeard]

It's funny how you lot complain about how we must have peer reviewed papers showing the points being made, then when we do actually produce peer reviewed papers you dismiss them while simultaneously displaying staggering levels of ignorance as to the actual content of the papers.

Still, sauce for the goose and all.

This paper was discussed at real climate nine years ago where they explain why the paper does not contradict the majority scientific view that the warming we are seeing is due to greenhouse gas emissions.

In summary, statistics is a powerful tool, but blind statistics is likely to lead one astray. Statistics does not usually incorporate physically-based information, but derives an answer from a set of given assumptions and mathematical logic. It is important to combine physics with statistics in order to obtain true answers. And, to re-iterate on the issues I began with: It’s natural for molecules under Brownian motion to go on a hike through their random walks (this is known as diffusion), however, it’s quite a different matter if such behaviour was found for the global planetary temperature, as this would have profound physical implications. The nature is not trendy in our case, by the way – because of the laws of physics.

- See more at: http://www.realclimate.org/index.php/archives/2005/12/naturally-trendy/#sthash.Qe0mbmEF.dpuf

 

[CoolSceptic]

so the MIT, Yale, Oxford, MPI, ETHZ, NASA, ESA, JAXA are all misstaken because we used the wrong trend significance tests?

Depends on what their null hypothesis is and what they are testing for.

If we are testing that there is warming of unknown origin (e.g. using the sampling and sensing errors to form the null), I would expect a positive result.

If someone is explicitly testing for natural variability, that is another matter, and they need a correct model for natural variability in the statistical test. That's the point the papre makes.

and all this just because Cohn failed to convince his collegues in his field of expertise?

Who says Cohn failed to convince his colleagues? His paper passed peer review and was published.

If the paper contains an error, please point it out to me.

 

[DC]

Depends on what their null hypothesis is and what they are testing for.

If we are testing that there is warming of unknown origin (e.g. using the sampling and sensing errors to form the null), I would expect a positive result.

If someone is explicitly testing for natural variability, that is another matter, and they need a correct model for natural variability in the statistical test. That's the point the papre makes.


Who says Cohn failed to convince his colleagues? His paper passed peer review and was published.

If the paper contains an error, please point it out to me.

we know for a fact that most of the warming we observed in the late 20th century was caused by the enhanced greenhosue effect, and we know for a fact that human activity is the main cause of the enhanced greenhosue effect.

we measured it, AGW is an observed fact. and the paper does not refute that conclusion at all.

who says Cohn failed to convince his colleagues? His colleagues. the overwhelming majority of them agrees that AGW is real, happening now and is a problem.