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:
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:
Here are some useful illustrations that support 2, by showing how recent global warming is best accounted for using anthropogenic factors:
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.
Here's an overview of some of the scientific evidence in support of 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):
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]:
Calling the above statement "X".
I want to address X since some people may doubt or deny X. For instance:
Originally posted by tabibito
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- Show the scientific consensus in favor of X
- 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
"Expert credibility in climate change"
pnas.org/content/107/27/12107.full
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."
[...]
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)."
[...]
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)."
Originally posted by Jichard
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http://www.bloomberg.com/graphics/20...ing-the-world/
http://ossfoundation.us/projects/env...n-caused/image
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.
Originally posted by Jichard
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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)."
"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)."
Originally posted by Jichard
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"Identifying human influences on atmospheric temperature"
pnas.org/content/110/1/26.full
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."
[...]
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
onlinelibrary.wiley.com/doi/10.1002/2014GL060478/pdf
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