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That was a terrible use of graphs. The biggest error in this presentation is that author-chose a scale to ensure that the carbon scale was amplified just right
by cjensen 10y ago
That was a terrible use of graphs.
The biggest error in this presentation is that author-chose a scale to ensure that the carbon scale was amplified just right to appear to be the same as the temperature scale. In all other cases, he chose small amplifications so that the other factors would appear to be unchanged.
The second error in this presentation is that the graphs plainly show that aerosols do have a negative correlation with temperature.
The third error is that correlation is not causation. Lack of correlation can prove non-causation, which is what the author was mostly going for. So this is a minor point.
- nom 10y agoNo it wasn't. All values share the same Y axis and are calculated by simulating climate models. As I understand it, the graphs show how temperature would have evolved if there was only one of the influencing factors present. They also tell you right in the the graph title that some aerosols have the adverse effect and can cool the atmosphere.
- cjensen 10y agoOkay, I am wrong about the Y-Scale between graphs. Nevertheless the author did make the incomparable y-scales between temperature and causes intentionally similar.
- 37 10y agoWhat even is the scale for these comparisons? I don't know how one can measure orbital changes, land use, or solar or volcanic activity in degrees Fahrenheit.
- scatters 10y agoThe graph shows predicted global temperature from climate models, with 90% confidence intervals, varying only that factor and keeping other factors unchanged. So the scale is exactly the same unit - Kelvin.
- 37 10y agoThank you for explaining this. I should also admit that, at first I didn't notice the "Methodology" notes at the bottom.
- aaronharnly 10y ago1. As nom points out, the Methodology section just below the graphs states clearly "The colored temperature lines are the modeled estimates that each climate factor contributes to the overall temperature." So the black line and the various lines of the hypothesized contributing factors are on the same scale. 2. Yes, the graph shows the increase in aerosols having a cooling effect over time. The text states, "Some pollutants cool the atmosphere, like sulfate aerosols from coal-burning. These aerosols offset some of the warming. (Unfortunately, they also cause acid rain.)" Perhaps you thought the graph was a graph of aerosol levels, rather than a graph of modeled impact of aerosols on temperature? 3. WRT "Correlation is not causation": this phrase is quite abused. As you note, non-correlation can be evidence of non-causation, and correlation can be indicative of causation. Since we have straightforward causal theories for the relationship between atmospheric CO2 and increased temperature, and experimental evidence, and historical evidence, its a rather silly point to dispute in this simple representation of various factors that get offered as alternatives to atmospheric greenhouse gasses.