4 ms·

They don't have the data to model it the way they predict the course of hurricanes. Models are just models, they're only as good as their design and the data t

They don't have the data to model it the way they predict the course of hurricanes. Models are just models, they're only as good as their design and the data they are fed. We have solid temperature data for only a few hundred years, if that. That's a lot of time to try to model something with so many variables. Both sides have been found to be tweaking the models and input data to tune the output to their agenda, and nearly every time I see it presented, it's "average global temperature rise of x over the last y years has contributed to z inches of sea level rise. We must reduce CO2 because climate change" Average global temperatures have gone up, and down, and up, and down many many times, even before we were even here. If the science were more solid, there wouldn't be so much controversy over it. For every model presentation you can find that predicts it, I can find one that doesn't. Is CO2 a greenhouse gas? Yes. Can it trap heat? Yes. Does that conclude that the extra CO2 we are generating is the cause of global temperature rise? Not by a long shot. Does it warrant further investigation? Absolutely. The consequences of being wrong are far to great to ignore.

throwaway5752 10y ago
Sorry if I wasn't clear, I was saying that since they are real scientists, they are not abject idiots and running a linear regression on atmospheric CO2 vs mean global surface temperature. I can't tell you what to think or what models to select, but the rapid and sustained increase in temperatures over the past 30 years would suggest something is up, so I would at least focus on models that would have retroactively explained that rise.
- graycat 10y ago
  As in the US National Academy of Sciences report in http://www.nap.edu/catalog/11676.html http://www.nap.edu/catalog/11676.html (1) the temperature in 2006, and, thus, also now, is essentially the same as in the year 1000 and (2) there was a rapid rise in temperature from year 900 to year 1000. But for the temperature increase from year 900 to year 1000, the usual arguments about CO2 from human activity do not apply. Apparently CO2, from humans or anything else, had nothing to do with it. So, the current temperature and the rise of the past 100 years also happened between year 900 and year 1000. Can't blame humans for the rise from 900 to 1000. And, since the rise of the past 100 years is much like 900 to 1000, it doesn't have to look like "something is up" now, especially not human activity.
  - throwaway5752 10y ago
    You are referring the the midieval warm period? i do not have access to the PDF. Can you share the citation for 2006 vs MWP peak being the same? I would like to square it with the various source data represented in https://commons.wikimedia.org/wiki/File:2000_Year_Temperature_Comparison.png https://commons.wikimedia.org/wiki/File:2000_Year_Temperatur...
    - graycat 10y ago
      I downloaded the PDF from that URL years ago, for free, no membeships, etc. Their main graph is on their page 2 of the PDF. By eyeball, their graph looks a lot like the graph in the Wikipedia page you gave. I was unsure just when the Medieval Warm Period was, but the Wiki graph seems to say it was near year 1000. My eyeball reading of the graph in the PDF says that the temperature in year 1000 is essentially the same as in year 2006 when the PDF was published, and the increase from year 900 to year 1000 was much like the increase from 1906 to 2006. I may be off by some 0.1 C or some such, but there are several curves so that about get to take your pick. Bottom line: Year 1000 wasn't a disaster and wasn't caused by humans releasing CO2, so I'm not much worried about now and not convinced that the current temperature or recent increases were caused by CO2. E.g., was the Little Ice Age caused by less CO2? I doubt it!
      - throwaway5752 10y ago
        We will have to agree to disagree on the chart. For better or worse, the 2016 global land+ocean anomaly is on track to be double 2006 (1.2 C vs 0.6 C), or .06 C past the cutoff of the y-axis and well above the reconstructed MWP peak. "E.g., was the Little Ice Age caused by less CO2? I doubt it!" Who knows? Based on what I could find from ice core studies it appears atmospheric CO2 was 5-10% lower from 1600-1800. I don't anyone making a causative claim.
        graycat 10y ago
        You may be reading the graphs more carefully than I am. For anomalies since 2006, I am skeptical because it looks to me like the current administration has NASA, NOAA, EPA, or whatever cooking the books. From you is the first I've heard that CO2 levels decreased during the Little Ice Age (LIA). Makes some sense -- it was darned cold then which means less biological activity. But there is a cute point: During the LIA, no doubt a lot of people were burning everything they could find to stay warm and, thus, emitting more CO2. Still, CO2 concentrations went down. Gee! The biggie point about the LIA is the Maunder Minimum: That is during the LIA, the sun had nearly no sun spots. Then that agrees with the model in the YouTube video with the URL I gave that claims that the cause of climate change is changes in the rates of sun spots. Just why sun spots could change climate (not really that the sun might be hotter) is explained in the video. The model in that video is not really predictive if can't predict sun spots. At times in the past could do that since there was a definite cycle to sun spots, and the period was right at 11 years. Then, if from such a cycle can predict sun spots, then can use that model to predict climate. To me now, a question is, what the heck are the sources of the rise in CO2 concentrations of the past, say, 100 years? While I'm not convinced that the CO2 levels now are affecting the climate, I'd still like to know where the CO2 is coming from. So, there is a big system with some parts emitting CO2 sources, and others taking it in, sinks. One source is volcanoes, and maybe over half of those are in the ocean. Supposedly another source is sea water: So the warming, from wherever, is slowly heating the ocean, and warmer water absorbs less CO2. So, maybe left over from the LIA, the oceans have a lot of CO2 and as the climate warms from whatever causes are releasing that CO2. The estimates I've seen for the amount of CO2 from human activities has too much variation to take seriously. Then the estimates of CO2 from other sources also has huge variation. Ah, back to work.

throwaway5752 10y ago

Sorry if I wasn't clear, I was saying that since they are real scientists, they are not abject idiots and running a linear regression on atmospheric CO2 vs mean global surface temperature. I can't tell you what to think or what models to select, but the rapid and sustained increase in temperatures over the past 30 years would suggest something is up, so I would at least focus on models that would have retroactively explained that rise.

graycat 10y ago
As in the US National Academy of Sciences report in http://www.nap.edu/catalog/11676.html http://www.nap.edu/catalog/11676.html (1) the temperature in 2006, and, thus, also now, is essentially the same as in the year 1000 and (2) there was a rapid rise in temperature from year 900 to year 1000. But for the temperature increase from year 900 to year 1000, the usual arguments about CO2 from human activity do not apply. Apparently CO2, from humans or anything else, had nothing to do with it. So, the current temperature and the rise of the past 100 years also happened between year 900 and year 1000. Can't blame humans for the rise from 900 to 1000. And, since the rise of the past 100 years is much like 900 to 1000, it doesn't have to look like "something is up" now, especially not human activity.
- throwaway5752 10y ago
  You are referring the the midieval warm period? i do not have access to the PDF. Can you share the citation for 2006 vs MWP peak being the same? I would like to square it with the various source data represented in https://commons.wikimedia.org/wiki/File:2000_Year_Temperature_Comparison.png https://commons.wikimedia.org/wiki/File:2000_Year_Temperatur...
  - graycat 10y ago
    I downloaded the PDF from that URL years ago, for free, no membeships, etc. Their main graph is on their page 2 of the PDF. By eyeball, their graph looks a lot like the graph in the Wikipedia page you gave. I was unsure just when the Medieval Warm Period was, but the Wiki graph seems to say it was near year 1000. My eyeball reading of the graph in the PDF says that the temperature in year 1000 is essentially the same as in year 2006 when the PDF was published, and the increase from year 900 to year 1000 was much like the increase from 1906 to 2006. I may be off by some 0.1 C or some such, but there are several curves so that about get to take your pick. Bottom line: Year 1000 wasn't a disaster and wasn't caused by humans releasing CO2, so I'm not much worried about now and not convinced that the current temperature or recent increases were caused by CO2. E.g., was the Little Ice Age caused by less CO2? I doubt it!
    - throwaway5752 10y ago
      We will have to agree to disagree on the chart. For better or worse, the 2016 global land+ocean anomaly is on track to be double 2006 (1.2 C vs 0.6 C), or .06 C past the cutoff of the y-axis and well above the reconstructed MWP peak. "E.g., was the Little Ice Age caused by less CO2? I doubt it!" Who knows? Based on what I could find from ice core studies it appears atmospheric CO2 was 5-10% lower from 1600-1800. I don't anyone making a causative claim.
      - graycat 10y ago
        You may be reading the graphs more carefully than I am. For anomalies since 2006, I am skeptical because it looks to me like the current administration has NASA, NOAA, EPA, or whatever cooking the books. From you is the first I've heard that CO2 levels decreased during the Little Ice Age (LIA). Makes some sense -- it was darned cold then which means less biological activity. But there is a cute point: During the LIA, no doubt a lot of people were burning everything they could find to stay warm and, thus, emitting more CO2. Still, CO2 concentrations went down. Gee! The biggie point about the LIA is the Maunder Minimum: That is during the LIA, the sun had nearly no sun spots. Then that agrees with the model in the YouTube video with the URL I gave that claims that the cause of climate change is changes in the rates of sun spots. Just why sun spots could change climate (not really that the sun might be hotter) is explained in the video. The model in that video is not really predictive if can't predict sun spots. At times in the past could do that since there was a definite cycle to sun spots, and the period was right at 11 years. Then, if from such a cycle can predict sun spots, then can use that model to predict climate. To me now, a question is, what the heck are the sources of the rise in CO2 concentrations of the past, say, 100 years? While I'm not convinced that the CO2 levels now are affecting the climate, I'd still like to know where the CO2 is coming from. So, there is a big system with some parts emitting CO2 sources, and others taking it in, sinks. One source is volcanoes, and maybe over half of those are in the ocean. Supposedly another source is sea water: So the warming, from wherever, is slowly heating the ocean, and warmer water absorbs less CO2. So, maybe left over from the LIA, the oceans have a lot of CO2 and as the climate warms from whatever causes are releasing that CO2. The estimates I've seen for the amount of CO2 from human activities has too much variation to take seriously. Then the estimates of CO2 from other sources also has huge variation. Ah, back to work.