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Most of the CO2 emissions are natural, but they aren't the main concern. In the Northern hemisphere growing season, atmospheric CO2 declines sharply. In the f

by elihu 7y ago

Most of the CO2 emissions are natural, but they aren't the main concern. In the Northern hemisphere growing season, atmospheric CO2 declines sharply. In the fall and winter, the leaves fall off of trees and decompose, and that CO2 goes right back into the atmosphere. We don't worry about that CO2 because it's part of a natural cycle that absorbs and emits roughly equal amounts of carbon dioxide. If you look at an atmospheric CO2 plot over time, you'll notice that it's a sawtooth, for the reasons I just described. However, this sawtooth has an upward slant. That's the part we're worried about, and that's the part that humans are responsible for. We're pulling carbon out of the ground and burning it, and there isn't any natural process to cancel that out on the scale of what we're doing. So far, atmospheric CO2 has gone from about 280 parts per million before the industrial revolution to about 420 or so now. That's a pretty big change, and it's happening faster than ecosystems can adapt to it. It is also having an increasing impact on human life. Here's something to put the current rate of change into historical context: https://xkcd.com/1732/ https://xkcd.com/1732/

chrisco255 7y ago
I love xkcd but it's not a very good source for scientific argument. It's a pop science cartoon. The cartoon isn't accurate and misses a lot of major temperature swings. See this chart on second page "Long Term Trends in Climate Variability of Caucasus Region 1Bakhram S. Nurtaev, 2Lali Nurtaev" http://openjournals.gela.org.ge/index.php/GGS/article/viewFile/1886/pdf http://openjournals.gela.org.ge/index.php/GGS/article/viewFi...
- eesmith 7y ago
  How neat to have a reference to the Journal of the Georgian Geophysical Society. I so rarely get to see Georgian script, like in the subsequent paper by ბ. ნურტაევი and ლ. ნურტაევი (last page on the document). What makes it odd, however, is that the chart you mentioned is an uncited reprint of a chart made by noted global warming denialist David Archibald. See https://wattsupwiththat.com/2011/02/12/david-archibald-on-climate-and-energy-security/ https://wattsupwiththat.com/2011/02/12/david-archibald-on-cl... . You'll note that this paper by Nurtaev and Nurtaev uses a low quality image paste, so almost certainly did not generate it themselves. Also odd is the source citations, from Dansgaard (1969) and Schönwiese (1995). You'll note that those are 1) not stated in the references, and 2) they are very old, at 50 and nearly 25 years, respectively. Compare that to the citations in the xkcd comic, which are to 2012 and 2013. This is important because we've improved our understanding of the temperature records. The xkcd comic notes "Medieval warm period in Europe and some northern regions (too regional to affect the global average much)" and Wikipedia's entry for the Medieval Warm Period comments "Other regions were colder, such as the tropical Pacific. Averaged global mean temperatures have been calculated to be similar to early-mid 20th century warming" While the chart in Nurtaev and Nurtaev says there is a distinct global warming during that period. How odd that they use information which is so out of date. How odd that the paper promotes a solar model which has long been demonstrated to be wrong - and mostly only lives among the fringe group of global warming denialists. How odd that you decided to post a link to this paper, instead of the source material, and argued that it was more accurate when it appears to be less. Could you describe how you came across this paper, and what about it lead you to conclude it was a more accurate source of information?
  - chrisco255 7y ago
    Are you suggesting that studies or papers which have been published more recently are automatically more correct? I think that's an incredulous statement and suggests a recency bias in your line of thinking. Dansgaard was the guy who discovered that isotopes in ice cores could be used to measure past climates. In particular, when we are discussing climatic events from 300, 1000, and many millennia ago, these events have ice core records that have not changed. And unless you have evidence of Dansgaard's faulty measurements of said isotopes, you've got to accept this as scientific fact: The climate has warmed as much as 8 degrees Celsius in less than 40 years in the prehistoric past. See Dansgaard–Oeschger event: https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event See "Ice-core evidence of abrupt climate changes" (2000) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC34297/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC34297/
    - eesmith 7y ago
      I would like you to answer my questions concerning "how you came across this paper, and what about it lead you to conclude it was a more accurate source of information". You haven't done that. Obviously I am not suggesting what you think I did, as I've already answered your question by saying "we've improved our understanding of the temperature records" since 25 and 50 years ago, respectively. I don't think you are denying that fact, just like I don't think you are suggesting that that older sources of information are automatically more correct than more recent ones. I'm asking why you believe the publication you pointed to is more accurate than the xkcd comic. What's the point of bringing up the Dansgaard–Oeschger events? The most recent D-O event was about 11,500 years ago, while the chart in Nurtaev and Nurtaev only goes back to 11,000 years ago. Plus, if you believe the smoothing in Nurtaev and Nurtaev is valid then you must surely believe the smoothing in the xkcd comic is valid. If you don't like the smoothing in the xkcd comic, the relevant source - cited as Marcott et al. (2013) - is "A Reconstruction of Regional and Global Temperature for the Past 11,300 Years", in Science, available from http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_Global%20Temperature%20Reconstructed.pdf http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_G... . You'll note it cites Oeschger, and describes the 73 globally distributed records used, and several different methods used to estimate the global temperature anomaly, along with associated errors. How did Nurtaev and Nurtaev come up with their graph, that being a paper which you suggest is a good source for scientific argument? Which temperature records were used? How was the curve fitting done? What are the estimated errors? Quite clearly at least one of them is wrong as Nurtaev and Nurtaev give a 0.5C global temperature rise above baseline during the "Medieval warm period", while Marcott et al. show it at about baseline, with a 0.5C temperature rise being above the uncertainty band. How did you decide that the Marcott et al. paper (and hence xkcd) is less likely to be correct than Nurtaev and Nurtaev?

by elihu 7y ago

chrisco255 7y ago

I love xkcd but it's not a very good source for scientific argument. It's a pop science cartoon. The cartoon isn't accurate and misses a lot of major temperature swings. See this chart on second page "Long Term Trends in Climate Variability of Caucasus Region 1Bakhram S. Nurtaev, 2Lali Nurtaev" http://openjournals.gela.org.ge/index.php/GGS/article/viewFile/1886/pdf http://openjournals.gela.org.ge/index.php/GGS/article/viewFi...

eesmith 7y ago
How neat to have a reference to the Journal of the Georgian Geophysical Society. I so rarely get to see Georgian script, like in the subsequent paper by ბ. ნურტაევი and ლ. ნურტაევი (last page on the document). What makes it odd, however, is that the chart you mentioned is an uncited reprint of a chart made by noted global warming denialist David Archibald. See https://wattsupwiththat.com/2011/02/12/david-archibald-on-climate-and-energy-security/ https://wattsupwiththat.com/2011/02/12/david-archibald-on-cl... . You'll note that this paper by Nurtaev and Nurtaev uses a low quality image paste, so almost certainly did not generate it themselves. Also odd is the source citations, from Dansgaard (1969) and Schönwiese (1995). You'll note that those are 1) not stated in the references, and 2) they are very old, at 50 and nearly 25 years, respectively. Compare that to the citations in the xkcd comic, which are to 2012 and 2013. This is important because we've improved our understanding of the temperature records. The xkcd comic notes "Medieval warm period in Europe and some northern regions (too regional to affect the global average much)" and Wikipedia's entry for the Medieval Warm Period comments "Other regions were colder, such as the tropical Pacific. Averaged global mean temperatures have been calculated to be similar to early-mid 20th century warming" While the chart in Nurtaev and Nurtaev says there is a distinct global warming during that period. How odd that they use information which is so out of date. How odd that the paper promotes a solar model which has long been demonstrated to be wrong - and mostly only lives among the fringe group of global warming denialists. How odd that you decided to post a link to this paper, instead of the source material, and argued that it was more accurate when it appears to be less. Could you describe how you came across this paper, and what about it lead you to conclude it was a more accurate source of information?
- chrisco255 7y ago
  Are you suggesting that studies or papers which have been published more recently are automatically more correct? I think that's an incredulous statement and suggests a recency bias in your line of thinking. Dansgaard was the guy who discovered that isotopes in ice cores could be used to measure past climates. In particular, when we are discussing climatic events from 300, 1000, and many millennia ago, these events have ice core records that have not changed. And unless you have evidence of Dansgaard's faulty measurements of said isotopes, you've got to accept this as scientific fact: The climate has warmed as much as 8 degrees Celsius in less than 40 years in the prehistoric past. See Dansgaard–Oeschger event: https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event https://en.wikipedia.org/wiki/Dansgaard–Oeschger_event See "Ice-core evidence of abrupt climate changes" (2000) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC34297/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC34297/
  - eesmith 7y ago
    I would like you to answer my questions concerning "how you came across this paper, and what about it lead you to conclude it was a more accurate source of information". You haven't done that. Obviously I am not suggesting what you think I did, as I've already answered your question by saying "we've improved our understanding of the temperature records" since 25 and 50 years ago, respectively. I don't think you are denying that fact, just like I don't think you are suggesting that that older sources of information are automatically more correct than more recent ones. I'm asking why you believe the publication you pointed to is more accurate than the xkcd comic. What's the point of bringing up the Dansgaard–Oeschger events? The most recent D-O event was about 11,500 years ago, while the chart in Nurtaev and Nurtaev only goes back to 11,000 years ago. Plus, if you believe the smoothing in Nurtaev and Nurtaev is valid then you must surely believe the smoothing in the xkcd comic is valid. If you don't like the smoothing in the xkcd comic, the relevant source - cited as Marcott et al. (2013) - is "A Reconstruction of Regional and Global Temperature for the Past 11,300 Years", in Science, available from http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_Global%20Temperature%20Reconstructed.pdf http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_G... . You'll note it cites Oeschger, and describes the 73 globally distributed records used, and several different methods used to estimate the global temperature anomaly, along with associated errors. How did Nurtaev and Nurtaev come up with their graph, that being a paper which you suggest is a good source for scientific argument? Which temperature records were used? How was the curve fitting done? What are the estimated errors? Quite clearly at least one of them is wrong as Nurtaev and Nurtaev give a 0.5C global temperature rise above baseline during the "Medieval warm period", while Marcott et al. show it at about baseline, with a 0.5C temperature rise being above the uncertainty band. How did you decide that the Marcott et al. paper (and hence xkcd) is less likely to be correct than Nurtaev and Nurtaev?