<h2>There are a few ways</h2>

<p>Basically the best way is to see how many experts in the field are convinced, as great as it would be to assess the evidence individually, one person can't be an expert in everything and unless you and your audience are a climate scientists most papers are going to be beyond a lay assessment. So the best thing you can do for the lay public is look to the experts, people who have spent decades researching the subject and have the best ability to assess the data, and see what their assessment is. </p>

<p>NASA has a <a href="https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-change/" rel="nofollow noreferrer">wonderful site</a> dedicated to collecting assessments. They fall into three rough categories. </p>

<p><strong>Meta analysis</strong></p>

<p>A meta <a href="https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024" rel="nofollow noreferrer">analysis</a> of published works shows the number of scientific papers rejecting anthropomorphic climate change is vanishingly small (0.7%) and shrinking. those uncertain was even smaller (0.3%)</p>

<p><strong>Professional survey</strong></p>

<p>the same <a href="https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024" rel="nofollow noreferrer">analysis</a> also surveyed 29,000 published climatologists and showed a 97% support for anthropomorphic climate change and the rest being largely no-position. this is even skewed by expertise, when accounting for the number of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901439/" rel="nofollow noreferrer">published</a> papers (a rough way of measuring expertise) it shows even stronger support among more published authors with most of the opposition being from authors that only publish a small number of papers. </p>

<p><strong>Public statements by relevant scientific societies.</strong> </p>

<p>The <a href="https://www.ametsoc.org/index.cfm/ams/about-ams/ams-statements/archive-statements-of-the-ams/climate-change1/" rel="nofollow noreferrer">American Meteorological Society</a> and <a href="https://www.geosociety.org/gsa/positions/position10.aspx" rel="nofollow noreferrer">Geological Society of America</a> as well <a href="https://climate.nasa.gov/scientific-consensus/" rel="nofollow noreferrer">as many others</a> have made public statements in favor of anthropomorphic climate change. And of course you have the <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_summary-for-policymakers.pdf" rel="nofollow noreferrer">statements</a> by the Intergovernmental Panel on Climate Change.</p>

CC BY-SA 4.0
2019-10-29T05:10:35.580Z
That is very good. 
I am trying to find a very effective way to convince the key group targeted by disinformation specialists: evangelical Christians to understand the elements of correct scientific inference so that I can help disconnect them from short-circuiting to conspiracy theories. The end goal is to convert all skeptics to the truth.
polcott
CC BY-SA 4.0
2019-10-29T09:38:50.877Z
+1 Nice summary.  I think your 29000 scientists link should point to Cook et al (2013) rather than Anderegg et al (2010) though, no?
Deditos
CC BY-SA 4.0
2019-10-29T11:07:18.317Z
@Deditos good catch got them flipped.
John
CC BY-SA 4.0
2019-10-29T22:03:37.453Z
A key point in attribution is that the isotopic nature of the CO2 in the atmosphere has changed. Analysis of pre-industrial air samples when CO2 was 280 parts per million vs. modern air samples when the CO2 is 415ppm find that the increase is due to the introduction of very ancient carbon into the air -- by human burning of fossil fuels, that is. A review of research in the field will show you that every plausible alternative to the impact of CO2 on global heat retention has been examined over the last few decades. Ask why critics don't agree with each other on "what's really going on?"
jeffronicus
CC BY-SA 4.0
2019-10-29T22:23:03.387Z
@jeffronicus short answer to your question, experts don't disagree, only lay people do. Which I blame or modern media and political practices. Truth and accuracy take a distant back seat to power and money agenda. Although these are not new the power they wield thanks to technology is.
John
CC BY-SA 4.0
2019-10-31T04:27:55.147Z
@polcott Climate scientist and "perhaps the best communicator on climate change" [Katharine Hayhoe](https://en.wikipedia.org/wiki/Katharine_Hayhoe) is an evangelical Christian.
Keith McClary
CC BY-SA 4.0
2019-10-31T04:45:34.110Z
@KeithMcClary We need her and people like John Cook join together in a larger coalition that wars against counterfactual disinformation. I requested to connect with John Cook today on linked in. He is one of the greatest hero's fighting against this disinformation with his skepticalscience.com and this paper: https://www.climatechangecommunication.org/wp-content/uploads/2019/10/America_Misled.pdf.
polcott
CC BY-SA 4.0
2019-10-29T02:49:23.760Z
2019-10-30T10:38:14.277Z
2019-10-30T10:38:14.277Z
John
<p>No, it is not possible to establish a human cause with the degree of certainty you are asking for. There have been similar episodes in the distant past when either there were no humans at all, or the total emissions of all the worlds cooking fires were comparable with the emissions of one solitary and unremarkable volcano  If global heating with humans as the sole cause were as certain as the existence of gravity, there would be no controversy or debate about it.</p>

<p>What can be established with certainty is that since the industrial revolution got well under way there has been a fairly substantial ppm rise in atmospheric CO2, and this has coincided with a small but measurable rise in global temperature. Whether this is entirely coincidence or whether it is cause and effect is hotly debated, and there is not unanimous agreement even among professional meteorologists and climatologists. There was already some global warming (called an interglacial) long before the industrial revolution added some extra CO2 to the atmosphere, but most scientists think this additional CO2 has accelerated global warming.</p>

<p>There are natural mechanisms which extract CO2 from the atmosphere, and these natural mechanisms are very slightly more effective when CO2 content increases. However, if the increase is too rapid it can be more than these natural mechanisms can deal with. Climate change is a natural phenomenon which has been under way for the past 4.5 billion years and is likely to continue for as long as the world exists.</p>

CC BY-SA 4.0
2019-11-01T12:23:07.793Z
Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/100580/discussion-on-answer-by-michael-walsby-how-can-we-accurately-quantify-the-degree).
gerrit
CC BY-SA 4.0
2019-10-25T22:19:42.467Z
2019-10-25T22:52:19.820Z
2019-10-25T22:52:19.820Z
Michael Walsby
<p>How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?</p>

<p>It seem virtually certain that the huge 100 ppm spike in <span class="math-container">$\small\mathsf{CO_2}$</span> since 1950 can only be caused by humans. Can we be as sure that this huge spike in <span class="math-container">$\small\mathsf{CO_2}$</span> caused the 1 <span class="math-container">$\small\mathsf{^o}$</span>C increase in global temperatures as we are that tobacco causes cancer? </p>

<p>Do validated alternative explanations exist?</p>

<h1>What kinds of objective measures are typically used to determine the specific degree of scientific certainty?</h1>

<p><a href="https://i.sstatic.net/A0eOU.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/A0eOU.png" alt="enter image description here"></a></p>

<p><a href="https://i.sstatic.net/wei6D.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/wei6D.png" alt="enter image description here"></a></p>

<p><strong>There is a trend showing an increasing slope in the following graph data</strong><br>
1910 to 1960---0.41---50 years / 0.41 = <strong>122 years per degree</strong><br>
1960 to 2018---1.03---58 years / 0.87 =  <strong>67 years per degree</strong><br></p>

<p><a href="https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt" rel="nofollow noreferrer">https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt</a></p>

<p><a href="https://i.sstatic.net/sXH4u.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/sXH4u.png" alt="enter image description here"></a></p>

<h1>I am trying to point out exactly how implausible global heating NOT CAUSED BY BY HUMANS really is to skeptical minds that are not very good with science.</h1>

CC BY-SA 4.0
2019-10-26T05:25:36.257Z
@FuzzySquid So the spike in the data would indicate that the CO2 increase is caused by humans?
polcott
CC BY-SA 4.0
2019-10-26T17:21:41.407Z
"Do validated alternative explanations exist?" The only one I am aware of involves fitting the temperature curve with a sum of periodic cycles.
Keith McClary
CC BY-SA 4.0
2019-10-26T17:25:28.243Z
@KeithMcClary Hasn't that one been discounted as counter-cyclic? Because we are in the cooling portion of the Milankovitch Cycles and we are instead experiencing heating, then the Milankovitch Cycles can not explain the heating. https://skepticalscience.com/global-warming-natural-cycle.htm
polcott
CC BY-SA 4.0
2019-10-26T18:13:05.563Z
I was referring to explanations like [this](https://www.researchgate.net/publication/284205134_The_Approaching_New_Grand_Solar_Minimum_and_Little_Ice_Age_Climate_Conditions): (continued)
Keith McClary
CC BY-SA 4.0
2019-10-26T18:13:27.387Z
"The Earth experienced speeding-up periods at grand solar minima and slowing-down periods at grand solar maxima. This controls the main ocean surface circulation. In the North Atlantic this is seen in the beat and directional shifts of the Gulf Stream as illustrated in Figure 1. It is also recorded in the rises and falls in sea level in the Indian Ocean (Figure 2 of [29]). The link between solar variability and terrestri-al responses must go via the interaction of the Solar Wind with the Earth’s magnetosphere"
Keith McClary
CC BY-SA 4.0
2019-10-26T18:44:33.860Z
@KeithMcClary It looks like the effect is pretty minimal: https://skepticalscience.com/print.php?r=448
polcott
CC BY-SA 4.0
2019-10-27T02:40:26.997Z
@FuzzySquid I just always want to make 100% sure of these things, thanks.
polcott
CC BY-SA 4.0
2019-10-28T19:04:15.450Z
Wikipedia  has [Attribution of recent climate change](https://en.wikipedia.org/wiki/Attribution_of_recent_climate_change) with a section on Non-consensus views.
Keith McClary
CC BY-SA 4.0
2019-11-20T16:06:50.587Z
@BarryCarter  "it doesn't matter if it's anthropogenic or not." If it is not anthropogenic then there is nothing we can do. If it is anthropogenic then we must cut GHG emissions ASAP.
polcott
CC BY-SA 4.0
2019-11-20T16:10:39.020Z
@FuzzySquid As far as effective communication you are correct. Ultimately it does not matter how clear the graph is what matters is the climate sensitivity causative relationship between increases in CO2 and increases in global temps. Most idiot deniers simply write this off by calling CO2 plant food.
polcott
CC BY-SA 4.0
2019-11-20T19:20:10.793Z
@BarryCarter I can't imagine any other causes of global heating that humans can have any impact on besides AGH, cutting GHG emissions.
polcott
CC BY-SA 4.0
2019-11-20T19:51:55.027Z
@BarryCarter If the cause is that the Earth orbit has changed (we would already know this) there is basically no chance at all that we could fix this in time. If the cause is that the Sun does not have enough Sun spots, probably the same answer. I am not aware of any other causes.
polcott
<climate-change>
How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?
polcott
# How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?

(Asked by: username_0 on 2019-10-25)

How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?

It seem virtually certain that the huge 100 ppm spike in $\small\mathsf{CO\_2}$ since 1950 can only be caused by humans. Can we be as sure that this huge spike in $\small\mathsf{CO\_2}$ caused the 1 $\small\mathsf{^o}$C increase in global temperatures as we are that tobacco causes cancer?

Do validated alternative explanations exist?

# What kinds of objective measures are typically used to determine the specific degree of scientific certainty?

[![enter image description here](https://i.sstatic.net/A0eOU.png)](https://i.sstatic.net/A0eOU.png)

[![enter image description here](https://i.sstatic.net/wei6D.png)](https://i.sstatic.net/wei6D.png)

**There is a trend showing an increasing slope in the following graph data**  
1910 to 1960---0.41---50 years / 0.41 = **122 years per degree**  
1960 to 2018---1.03---58 years / 0.87 = **67 years per degree**

<https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt>

[![enter image description here](https://i.sstatic.net/sXH4u.png)](https://i.sstatic.net/sXH4u.png)

# I am trying to point out exactly how implausible global heating NOT CAUSED BY BY HUMANS really is to skeptical minds that are not very good with science.

**Tags:** climate-change

> **Comments:**
> **username_0**: @FuzzySquid So the spike in the data would indicate that the CO2 increase is caused by humans?  
> **username_1**: "Do validated alternative explanations exist?" The only one I am aware of involves fitting the temperature curve with a sum of periodic cycles.  
> **username_0**: @username_1 Hasn't that one been discounted as counter-cyclic? Because we are in the cooling portion of the Milankovitch Cycles and we are instead experiencing heating, then the Milankovitch Cycles can not explain the heating. https://skepticalscience.com/global-warming-natural-cycle.htm  
> **username_1**: I was referring to explanations like [this](https://www.researchgate.net/publication/284205134_The_Approaching_New_Grand_Solar_Minimum_and_Little_Ice_Age_Climate_Conditions): (continued)  
> **username_1**: "The Earth experienced speeding-up periods at grand solar minima and slowing-down periods at grand solar maxima. This controls the main ocean surface circulation. In the North Atlantic this is seen in the beat and directional shifts of the Gulf Stream as illustrated in Figure 1. It is also recorded in the rises and falls in sea level in the Indian Ocean (Figure 2 of [29]). The link between solar variability and terrestri-al responses must go via the interaction of the Solar Wind with the Earth’s magnetosphere"  
> **username_0**: @username_1 It looks like the effect is pretty minimal: https://skepticalscience.com/print.php?r=448  
> **username_0**: @FuzzySquid I just always want to make 100% sure of these things, thanks.  
> **username_1**: Wikipedia  has [Attribution of recent climate change](https://en.wikipedia.org/wiki/Attribution_of_recent_climate_change) with a section on Non-consensus views.  
> **username_0**: @BarryCarter  "it doesn't matter if it's anthropogenic or not." If it is not anthropogenic then there is nothing we can do. If it is anthropogenic then we must cut GHG emissions ASAP.  
> **username_0**: @FuzzySquid As far as effective communication you are correct. Ultimately it does not matter how clear the graph is what matters is the climate sensitivity causative relationship between increases in CO2 and increases in global temps. Most idiot deniers simply write this off by calling CO2 plant food.  
> **username_0**: @BarryCarter I can't imagine any other causes of global heating that humans can have any impact on besides AGH, cutting GHG emissions.  
> **username_0**: @BarryCarter If the cause is that the Earth orbit has changed (we would already know this) there is basically no chance at all that we could fix this in time. If the cause is that the Sun does not have enough Sun spots, probably the same answer. I am not aware of any other causes.  

---

## 2 answers

### Answer by username_2 on 2019-10-29. Score: 3

## There are a few ways

Basically the best way is to see how many experts in the field are convinced, as great as it would be to assess the evidence individually, one person can't be an expert in everything and unless you and your audience are a climate scientists most papers are going to be beyond a lay assessment. So the best thing you can do for the lay public is look to the experts, people who have spent decades researching the subject and have the best ability to assess the data, and see what their assessment is.

NASA has a [wonderful site](https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-change/) dedicated to collecting assessments. They fall into three rough categories.

**Meta analysis**

A meta [analysis](https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024) of published works shows the number of scientific papers rejecting anthropomorphic climate change is vanishingly small (0.7%) and shrinking. those uncertain was even smaller (0.3%)

**Professional survey**

the same [analysis](https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024) also surveyed 29,000 published climatologists and showed a 97% support for anthropomorphic climate change and the rest being largely no-position. this is even skewed by expertise, when accounting for the number of [published](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901439/) papers (a rough way of measuring expertise) it shows even stronger support among more published authors with most of the opposition being from authors that only publish a small number of papers.

**Public statements by relevant scientific societies.**

The [American Meteorological Society](https://www.ametsoc.org/index.cfm/ams/about-ams/ams-statements/archive-statements-of-the-ams/climate-change1/) and [Geological Society of America](https://www.geosociety.org/gsa/positions/position10.aspx) as well [as many others](https://climate.nasa.gov/scientific-consensus/) have made public statements in favor of anthropomorphic climate change. And of course you have the [statements](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_summary-for-policymakers.pdf) by the Intergovernmental Panel on Climate Change.

> **Comments:**
> **username_0**: That is very good.  I am trying to find a very effective way to convince the key group targeted by disinformation specialists: evangelical Christians to understand the elements of correct scientific inference so that I can help disconnect them from short-circuiting to conspiracy theories. The end goal is to convert all skeptics to the truth.  
> **username_3**: +1 Nice summary.  I think your 29000 scientists link should point to Cook et al (2013) rather than Anderegg et al (2010) though, no?  
> **username_2**: @username_3 good catch got them flipped.  
> **username_4**: A key point in attribution is that the isotopic nature of the CO2 in the atmosphere has changed. Analysis of pre-industrial air samples when CO2 was 280 parts per million vs. modern air samples when the CO2 is 415ppm find that the increase is due to the introduction of very ancient carbon into the air -- by human burning of fossil fuels, that is. A review of research in the field will show you that every plausible alternative to the impact of CO2 on global heat retention has been examined over the last few decades. Ask why critics don't agree with each other on "what's really going on?"  
> **username_2**: @username_4 short answer to your question, experts don't disagree, only lay people do. Which I blame or modern media and political practices. Truth and accuracy take a distant back seat to power and money agenda. Although these are not new the power they wield thanks to technology is.  
> **username_1**: @username_0 Climate scientist and "perhaps the best communicator on climate change" [Katharine Hayhoe](https://en.wikipedia.org/wiki/Katharine_Hayhoe) is an evangelical Christian.  
> **username_0**: @username_1 We need her and people like username_2 Cook join together in a larger coalition that wars against counterfactual disinformation. I requested to connect with username_2 Cook today on linked in. He is one of the greatest hero's fighting against this disinformation with his skepticalscience.com and this paper: https://www.climatechangecommunication.org/wp-content/uploads/2019/10/America_Misled.pdf.  

---

### Answer by username_5 on 2019-10-25. Score: -8

No, it is not possible to establish a human cause with the degree of certainty you are asking for. There have been similar episodes in the distant past when either there were no humans at all, or the total emissions of all the worlds cooking fires were comparable with the emissions of one solitary and unremarkable volcano If global heating with humans as the sole cause were as certain as the existence of gravity, there would be no controversy or debate about it.

What can be established with certainty is that since the industrial revolution got well under way there has been a fairly substantial ppm rise in atmospheric CO2, and this has coincided with a small but measurable rise in global temperature. Whether this is entirely coincidence or whether it is cause and effect is hotly debated, and there is not unanimous agreement even among professional meteorologists and climatologists. There was already some global warming (called an interglacial) long before the industrial revolution added some extra CO2 to the atmosphere, but most scientists think this additional CO2 has accelerated global warming.

There are natural mechanisms which extract CO2 from the atmosphere, and these natural mechanisms are very slightly more effective when CO2 content increases. However, if the increase is too rapid it can be more than these natural mechanisms can deal with. Climate change is a natural phenomenon which has been under way for the past 4.5 billion years and is likely to continue for as long as the world exists.

> **Comments:**
> **username_6**: Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/100580/discussion-on-answer-by-username_5-username_5-how-can-we-accurately-quantify-the-degree).  

---

