Is the Hansen “controversy” as complex as some make it out to be?
Question by Jose Bosingwa: Is the Hansen “controversy” as complex as some make it out to be?
In his 1988 testimony to Congress, Dr. Hansen laid out three potential global warming predictions. He did not say “here’s a range.” Each prediction correlated to three distinct scenarios concerning CO2 and other factors – with the primary driver assumed to be CO2.
The three Scenarios are plotted here in black – actual CO2 is plotted in red – - as you can see, CO2 concentration has tracked Scenario A quite closely. Because Scenarios A and B do not diverge this early, one could argue that we have also tracked Scenario B – except that, as will be seen in the below attached graph, the difference between CO2 levels Scenarios A and B, while small, were assumed to have a significant effect on temperature.
http://www.climateaudit.org/wp-content/uploads/2008/01/cfc_ha45.gif
Here are all three Scenarios plotted against actual temperatures – BOTH surface and land-ocean (shown plotted in light gray and dark gray):
http://bp2.blogger.com/_X93w7bCMCS8/SJBFVxWNckI/AAAAAAAAAFQ/0cuoQzPB_N0/s1600-h/hansen20.jpg
As you can see there is no confusion as to temperature data set – both are shown, and both track below Scenario C, which assumed a leveling off of CO2 and which represented the lowest-CO2-Scenario.
Both also track WELL below Scenarios A and B.
Is it difficult to comprehend that under any measure, the 1988 predictions significantly overstated the actual, modest, warming that occurred subsequent to 1988?
Dana, nobody’s comparing anything to the temperature of your butt.
Both sets of temperature measurements are plotted alongside all three predictions and they’re both BELOW all three predictions.
And CO2 has tracked the scenario that correlates to the highest level of predicted warming.
And Dana please – Scenario C clearly shows CO2 leveling off – - that obviously hasn’t happened, otherwise we would have nothing to debate.
Best answer:
Answer by Dana1981, Master of Science
I don’t think it’s complicated at all, as long as you compare apples to apples. But if you compare Hansen’s surface air temperature predictions to the temperature of my butt, you’re going to overcomplicate things and get the wrong answer. That’s what the blogs you link are doing.
In your “blogger.com” link, the black line (“GISS Surf”) is the GISS land-ocean data.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
This is colder than the surface air, because it includes satellite data of ocean temperatures.
The gray line (“RSS Sat”) is satellite data collected by Remote Sensing Systems.
http://www.ssmi.com/msu/msu_data_description.html#figures
I don’t know a lot about how they collect their data, but I presume it’s going to have similar results to the GISS method of collecting ocean temperature data with satellites. Again, it’s lower than surface air temperatures.
This is why you can’t rely on random blogs to do accurate scientific analysis. But, deniers cherrypick the sources which tell them what they want to hear, regardless of their quality and accuracy. This is why you’re PFs.
And for the record, your climateaudit link is incorrect about CO2 concentrations. Just because it’s in a nice little graph doesn’t make it right. Even Roger Pielke admits CO2 has followed Scenario C most closely.
http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/000838scenarios_scenarios.html
If you look at Hansen’s orginal paper and the subsequent data, you can calculate it for yourself and see it’s nowhere near Scenario A. But again, you believe what you want to believe.
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