Eric, I assume you don't want to do the work, or you don't want to allocate time doing so. So I'll close this out.

First, I want to be clear about the context for my challenging that slide you pointed me to located at https://climate.nasa.gov/evidence -- I am not challenging whether climate change is real or not, and I'm not challenging whether humans are or aren't the cause of it.

I am challenging the specific evidence you point to, and not blindly accepting a graph without questioning what data it is based on and how that data was analyzed. The problem with providing a slide like that to people as evidence is that it fits what they already believe, and so no one questions the source that generated these results. Slapping an atmospheric CO2 value in ppm onto a graph taken from a study that measures CO2 values in ppmv from ice cores isn’t science.

The slide you point to on that page shows a graph from the study mentioned in the graph’s caption, and purports to show historical atmospheric CO2 over the past 800,000 years, to measurements of the actual CO2 taken from actual current atmosphere. I have read and annotated the study, and I’ll accept that data as accurate for now and won’t challenge what is in that study.

However:

1. The graph you point to is not the graph that the referenced study supplied -- it is that graph with a portion added on the end that did not come from the study. It looks like someone took the graph from the study, and tacked on the ‘1950 on’ CO2 levels measured from the actual atmosphere (which are from the NOAA Mauna Loa measurements).

2. The “1950s on” label is inaccurate. The study states that accurate measurements of atmospheric CO2 did not begin until 1958. It’s minor, but it’s important to be accurate here.

3. How do we know that the CO2 in an ice core can be directly compared to a measurement taken of actual, live atmosphere? How do we know there isn’t some process whereby the CO2 in an ice core shows up as lower than an actual atmospheric measurement? That may be in the end notes of the study, but I’m not going to do the work to dig through that now. It’s something that needs to be validated, if it hasn’t already, before being accepted as fact.

4. The study says that CO2 levels and arctic temps are strongly coupled (correlated). Correlation isn’t causation. Correlation is correlation. We see that two things are correlated, and our brain immediately sees a causal connection. STOP DOING THAT. Cholesterol is correlated with coronary heart disease, but it is not a cause of CHD.

5. Despite the study stating that CO2 levels and arctic temps are strongly coupled (correlated), it also states that there were significant deviations between Temperature and CO2 levels multiple times over that period, meaning that there were multiple times where the CO2 levels were not correlated with arctic temperatures. Clearly then, CO2 levels are not always in line with what you would expect temps to be if CO2 were driving the temps higher -- what mechanism is causing temps to be what they were despite CO2 levels suggesting the temps should be different? Maybe CO2 levels were higher, but the temps stayed lower, meaning that more CO2 was released from some other mechanism -- or maybe something else prevented temps from going higher despite increases in CO2.

6. Let’s assume that there is a strong correlation in the evidence of the study’s data that actually points to there being a true cause and effect result between CO2 levels and temperature levels. You still have to prove what is causing what, not just that one causes the other. You have to show whether temperature rise is the result of increased CO2 in the atmosphere, OR increased CO2 in the atmosphere is the result of increasing temperatures. Even if CO2 increases show up prior to temperature rises, it still doesn’t mean CO2 is causing the temperature rises. CO2 could be a leading indicator of future temperature increases, not a cause of them, meaning that whatever mechanisms are increasing the temperature, they are first triggering increases in CO2 in the atmosphere. That could mean that both CO2 levels and temperature rises are both caused by a something else.

7. By far the biggest error I find in the slide you pointed to: They used different unit measurements!!! The ice cores measure CO2 in ppmv, the NOAA atmospheric measure of CO2 is in ppm. They are not the same! It is quite possible that if you could convert the ppm of the NOAA data into ppmv units, it might fit right in to the study’s graph! I haven’t proven anything, I’m saying it’s now an open question, that the slide you pointed me to is a result of someone tacking together two separate graphs of data that is measured in two different units. You cannot compare them directly. See here:

http://www.differencebetween.net/language/difference-between...

I wouldn’t be surprised if you can convert the 400 ppm CO2 value into ppmv and that it comes out to around the 280 ppmv CO2. Try these calculators:

https://www.lenntech.com/calculators/ppm/converter-parts-per...

http://www.aresok.org/npg/nioshdbs/calc.htm

That could make the NOAA data comparable to the units of the study’s data, and plot that and it might fit the study graph perfectly, and not the slide you showed me. Even if it doesn’t, it’s not proof of the opposite. The CO2 in the ice cores is in water; the CO2 in the NOAA measurements is in gaseous form. That alone might account for the difference, but still, I question whether CO2 measurements in water can be compared to CO2 measurements in air without some conversions and adjustments for units, or other factors.

So I’ve poked holes in that graph you provided as evidence. It isn’t proof that climate change isn’t happening, and it isn’t proof that humans are not to blame -- it is simply showing that the evidence in that graph you provided has serious problems, and should not be used as ‘evidence’ until those problems are resolved. But it will be passed around and people will believe it is evidence and not question it, because they've already decided what the truth is and aren't interested in challenging evidence that fits their already selected belief.

I highly recommend watching Michael Crichton’s talk:

https://www.youtube.com/watch?v=JIAQJVlg54E

Over and out.