Humans are responsible for most of the recent global warming

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:

Which part of "I do not deny that the climate is changing" is so hard to understand. Not only in this thread, but in other threads - dating back to July last year. The only part of the Global Warming that I dispute (or rather, question) is the extent of the role human activity plays in climate change.

I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.


At least two papers illustrate the scientific consensus discuss in point 1:

"Quantifying the consensus on anthropogenic global warming in the scientific literature"
iopscience.iop.org/1748-9326/8/2/024024/article

"We examined a large sample of the scientific literature on global CC, published over a 21 year period, in order to determine the level of scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)

[...]

Explicit endorsements were divided into non-quantified (e.g., humans are contributing to global warming without quantifying the contribution) and quantified (e.g., humans are contributing more than 50% of global warming, consistent with the 2007 IPCC statement that most of the global warming since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations).

[...]

Among abstracts that expressed a position on AGW, 97.1% endorsed the scientific consensus. Among scientists who expressed a position on AGW in their abstract, 98.4% endorsed the consensus."

"Expert credibility in climate change"
pnas.org/content/107/27/12107.full

"Here, we use an extensive dataset of 1,372 climate researchers and their publication and citation data to show that (i) , and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.

[...]

We compiled a database of 1,372 climate researchers and classified each researcher into two categories: convinced by the evidence (CE) for anthropogenic climate change (ACC) or unconvinced by the evidence (UE) for ACC. We defined CE researchers as those who signed statements broadly agreeing with or directly endorsing (3)."

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Here are some useful illustrations that support 2, by showing how recent global warming is best accounted for using anthropogenic factors:

http://www.bloomberg.com/graphics/20...ing-the-world/

http://ossfoundation.us/projects/env...n-caused/image

I'm starting with these sources, since they are relatively straightforward, so one does not a background in science in order to understand these sources. However, these sources aren't really enough for me, especially the first source since it's published in the press. It's better to get scientific information from peer-reviewed scientific papers, as opposed to the press. So I'll present some of scientific evidence from scientific papers, in a subsequent post.

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Here's an overview of some of the scientific evidence in support of 2:

http://www.skepticalscience.com/print.php?n=1213

"All of these studies, using a wide range of independent methods, provide multiple lines of evidence that humans are the dominant cause of global warming over the past century, and especially over the past 50 to 65 years (Figure 1)."

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

The following paper identifies atmospheric factors that provide evidence of recent anthropogenic global warming, as opposed to warming due to non-anthropogenic factor (such as solar activity or volcanic activity):

"Identifying human influences on atmospheric temperature"
pnas.org/content/110/1/26.full

"We used a multimodel archive to obtain fingerprints of atmospheric temperature change. These fingerprints are estimates of the climate responses to external forcing by the combined effects of anthropogenic factors, volcanoes, and solar irradiance. The primary components of external forcing over the past century are human-caused increases in well-mixed greenhouse gases, depletion of stratospheric ozone, and changes in atmospheric burdens of various aerosol particles (20, 57). Our fingerprints, therefore, mainly reflect human influences on climate (7, 19, 29).

[...]

Our fingerprint results are interpretable in terms of basic physical mechanisms. The global-scale lower stratospheric cooling is primarily a direct radiative response to human-caused depletion of stratospheric ozone (29, 39, 58). Tropospheric warming is mainly driven by human-caused increases in well-mixed greenhouse gases (16, 29). The multidecadal cooling of the stratosphere and warming of the troposphere, which is evident in all satellite datasets and simulations of forced climate change examined here, cannot be explained by solar or volcanic forcing, or by any known mode of internal variability (3, 11).

Our ability to identify an externally forced fingerprint in satellite estimates of atmospheric temperature change is robust to current uncertainties in both models and observations, and to choices made in the application of our fingerprint method (SI Appendix). However, important questions still remain. Although we found a match between modeled and observed geographical patterns of temperature change, there are still noticeable differences in the size of these changes. On average, the CMIP-5 models underestimate the observed cooling of the lower stratosphere and overestimate the warming of the troposphere."

And the following paper shows that natural variability does not adequately explain recent global warming. Instead, recent global warming is largely accounted for due to anthropogenic CO2 [the paper also discusses other issues, such as how a recent slowdown in global warming is simply statistical variation due to sampling a small sample size, as opposed to some revelation showing that there is no AGW]:

"Return periods of global climate fluctuations and the pause"
onlinelibrary.wiley.com/doi/10.1002/2014GL060478/pdf

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[Jichard]

[url]http://ossfoundation.us/projects/environment/global-warming/myths/global-warming-is-only-part-human-caused/image

This graph is originally from:

Combinations of Natural and Anthropogenic Forcings in Twentieth-Century Climate
cawcr.gov.au/staff/jma/meehl_additivity.pdf

For further discussion, see:

http://ossfoundation.us/projects/environment/global-warming/human-caused

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

More evidence on 2:

""
fws.gov/southwest/es/documents/R2ES/LitCited/LPC_2012/Huber_and_Knutti_2012.pdf
especially

"A probabilistic quantification of the anthropogenic component of twentieth century global warming"
nldr.library.ucar.edu/repository/assets/osgc/OSGC-000-000-015-460.pdf

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Some further evidence for 2 (at this point, it's hard to see how any sensible, informed person could deny claim X):

https://www.ipcc.ch/pdf/assessment-r..._FINAL_SPM.pdf
especially Figure SPM.3 on page 6


"Attribution of observed historical near-surface temperature variations to anthropogenic and natural causes using CMIP5 simulations"
onlinelibrary.wiley.com/doi/10.1002/jgrd.50239/pdf

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

More evidence on 2:

"Evidence for external forcing on 20th-century climate from combined ocean-atmosphere warming patterns"
www1.ethz.ch/iac/people/knuttir/papers/sedlacek12grl.pdf

"Another argument for a strong anthropogenic influence on climate, independent of patterns, comes from understanding the basic physical principles of the greenhouse effect, from estimates of the response of temperature to greenhouse gases based on various lines of evidence [Knutti and Hegerl, 2008], and knowledge about changes in radiative forcing and the global energy balance over the instrumental period [Huber and Knutti, 2011]. Here we argue that these arguments can be complemented by looking model simulated patterns of change without necessarily invoking a complex fingerprint method. In particular, we argue that the combined evidence of warming in the atmosphere and ocean, and the horizontal and vertical structure of the ocean warming is consistent with a dominant external and rather smoothly increasing forcing, and inconsistent with internal variability alone. Simple physical arguments can explain the differences between unforced and forced variability. Because the arguments can be made based on normalized patterns rather than magnitudes of change, a potential underestimation of multi-decadal variability in climate models [Gleckler et al., 2012] is unlikely to question the results presented here. The magnitude of change further increases the confidence for dominant external cause."

And an overview of some of the methods for determining that claim X is true:

"Patterns of change: whose fingerprint is seen in global warming?"
storage.bodekerscientific.com/Hegerl2011.pdf

[tabibito]

Here are some useful illustrations that support 2, by showing how recent global warming is best accounted for using anthropogenic factors:
[INDENT]http://www.bloomberg.com/graphics/20...ing-the-world/

That explanation "alone" is enough to tip the balance to the predominantly-caused-by-man argument (most logically and highly probable). If computer modelling proves to be an efficient predictor (taking into account variables introduced by the unpredictable) I'll take the case as proven beyond reasonable doubt.

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Further scientific evidence in support of 2:

"Causes of the Global Warming Observed since the 19th Century"
http://file.scirp.org/Html/24283.html


"Improved constraints on 21st-century warming derived using 160 years of temperature observations"
http://onlinelibrary.wiley.com/doi/1...1GL050226/full

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

A recent paper in support of 1:

""
http://pubs.acs.org/doi/pdf/10.1021/es501998e

An objection to said paper:

""
http://pubs.acs.org/doi/pdf/10.1021/es504574v

The objection fails, largely due to the supplemental information provided in the first paper listed above.

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Some more evidence that most of the recent warming in support of 2:

"A fractal climate response function can simulate global average temperature trends of the modern era and the past millennium"
https://www.rug.nl/research/portal/f...ynvHateren.pdf

[Jichard]

Humans are responsible for most of the recent global warming; that is: most of the late-20th century and 21st century global warming has been anthropogenic.

Calling the above statement "X".

I want to address X since some people may doubt or deny X. For instance:


I will address X in at least two ways:

1. Show the scientific consensus in favor of X
2. Discuss some of the scientific evidence that supports the scientific consensus in favor of X

This first post will go over 1. A subsequent post will go over 2.

Some older papers in support of 2:

""
http://www.nature.com/nature/journal...f/399569a0.pdf


"Causes of Climate Change Over the Past 1000 Years"
http://www.whoi.edu/science/GG/paleo...pdf/crow00.pdf


"Detecting Climate Signals in the Surface Temperature Record"
http://www.met.tamu.edu/class/atmo63...6Stevens98.pdf

The following older paper places the anthropogenice forcing around 50%, though said paper is focusing on warming from 1976 to 1990, and thus working with much less warming and a much smaller data-set. More recent studies with larger data-sets and more warming, attribute the warming predominantly to anthropogenic sources

"Causes of global temperature changes during the 19th and 20th centuries"
http://climate.engin.umich.edu/figur...uses_of_dT.pdf

Figure 1 and Figure 3 especially

"The warming observed during 1976-1990 (Fig. 3D) is about equally due to anthropogenic radiative forcing and the residual factor, with volcanoes contributing a cooling, and the sun at most a small warming (2140)."

[Adrift]

Who are you talking to?

[Jichard]

Who are you talking to?

I'm posting evidence that supports the claim mentioned in the OP. tabibito found the evidence helpful. If you don't have anything of relevance to say on the evidence, then that's fine; that would just be a repeat of previous conversations I've had with you. You can now go back to (as usual), talking about me to other people, as opposed to addressing the content of my posts.

[Adrift]

I'm posting evidence that supports the claim mentioned in the OP. tabibito found the evidence helpful. If you don't have anything of relevance to say on the evidence, then that's fine; that would just be a repeat of previous conversations I've had with you. You can now go back to (as usual), talking about me to other people, as opposed to addressing the content of my posts.

So, basically you're just using this thread as a blog, is that right? I mean, outside of this back and forth I don't really see any discussion here, and this is a discussion forum.

[Jichard]

So, basically you're just using this thread as a blog, is that right? I mean, outside of this back and forth I don't really see any discussion here, and this is a discussion forum.

No, that isn't actually what I said. The discussion was between tabibito and I, regarding the evidence that humans have caused most of the global warming. The discussion occurred on this thread, and a number of other threads. For example:

By "proven", I mean with the "beyond reasonable doubt" - which is to say, to the point where entertaining doubt would be unreasonable. And I note, you managed to do that on your latest thread - at least* insofar as human activity being the predominant cause, beyond the combined sum of all other causes, is concerned.

at least* My convincability level seems to be a little higher than what most people consider reasonable. Particularly when a pro~ or anti~ group leaves off debate and starts screaming "heretic" at anyone who questions their decrees.

From June to August last year on TWeb my stated attitude was that anthropogenic forcing was real, but trivial. Global warming had been demonstrated as a fact, but I didn't consider that a compelling case had been made for human activity as the most significant cause, much less the sole cause. Geographic record shows that warmer climate has been recorded twice (at least) in the past 3 000 years.
During that time, the whole "hiatus" nonsense blew up. "Ice caps expanding" proves Global Warming is a myth rubbish. Sea levels were still rising at the nice steady pace that they had been for the past 200 years (or then abouts). .... information then to hand wasn't quite accurate - it seems that the pace of sea level increase has in fact increased.

My response: I don't buy it.
Someone else queries - Don't buy what?

someone else comments about the "hiatus" in warming

By February/March this year I had come to the conclusion that human activity is a significant factor in forcing. Information provided during the past few days shows that to be the case - more than 50% wasn't expected, but neither was it any real surprise.

So this evidence I've presented has persuaded you?

It has been most useful - My thanks to you and to Jichard for your assistance.

So I use this thread to provide further evidence for tabibito to look at and discuss.

Again, I don't expect you to know this, since all you really do is text-snipe, as opposed to saying of relevance to the topic of the thread or following along with the topic. But just because you're not involved in the discussion, doesn't mean no one is. Don't worry; your lack of input is not missed. The whole world does not revolve around you, and just because I'm not in discussion with you, doesn't mean I'm not in discussion with someone else.

[klaus54]

...And dogs apparently.