4 ms·

Could you repost it here? Reddit is behind a firewall where I am.

andyjohnson0 12y ago
Reddit post, reposted here without comment or endorsement: ---- [–]horvybaby 1515 points 11 hours ago*x3 Okay, so let's get a few things correct: because perhaps Nature is behind a paywall for some people. Rahmstorf et. al. show a decrease in THC/MOC variability for the period 1970-1990, which we have then partially recovered from. The title of the Nature article is inflammatory, but the Washington Post article is significantly more so. We do not know nearly enough about THC variability to make millenial scale arguments. We only recently actually made a measurement system that can calculate the overturning (the RAPID array). Rahmstorf and others had some issues with THC shutdown in the 90's when previous studies, which at one point suggested a shutdown in THC or meridional overturning, turned out to be incorrect because of an aliasing from a sampling error: they just happened to be measuring at points in the seasonal cycle that were spaced in such a way so as to show a decrease when there was none. This led to our modern understanding of inter-annual variability in the THC, so it all worked out well. The nature paper takes pains to note that the RAPID array is just 11 years old and so we can't say anything from the results. But this proxy data must be referenced to something, and the only reasonable measurement apparatus to use is RAPID. It isn't. Using proxy data to infer something about the overturning, while reasonable, doesn't give great coherence towards present understanding of complicated, long-timescale events like the heating of the deep ocean. Furthermore, even at theirs strongest the conclusions absolutely do not support the WaPo headline. This is the sort of things that makes climate scientists like myself furious. The results end up overhyped, overblown, and for soundbites like press releases and Nature papers. This just misinforms people. Unless I hear from RAPID that the MOC/THC is reducing, I'm not trusting the authors. Just because climate change is a hot-button issue, and we want ways to convince people about its impacts, doesn't mean MOC/THC shutoffs can be pulled out of nowhere. edit: Just want to mention: this doesn't say anything about the method of analysis. The method seems to be well done and scientific and careful, given the data at hand. The issue is rather the paper title and subsequent inflation in popular media, which is silly.
- Gravityloss 12y ago
  Would you perhaps say that one could only say something about thermohaline circulation trends 20 years from now, when there's 30 years of data? Until that, what should our policy be based on?
  - andyjohnson0 12y ago
    I have no idea! I was simply re-posting the Reddit comment referenced by @dm3 and requested by @Patient0. In case its not abundantly clear from the first line: the Reddit comment was not written by me.
deleted 12y ago
[deleted]

Reddit post, reposted here without comment or endorsement: ---- [–]horvybaby 1515 points 11 hours ago*x3 Okay, so let's get a few things correct: because perhaps Nature is behind a paywall for some people. Rahmstorf et. al. show a decrease in THC/MOC variability for the period 1970-1990, which we have then partially recovered from. The title of the Nature article is inflammatory, but the Washington Post article is significantly more so. We do not know nearly enough about THC variability to make millenial scale arguments. We only recently actually made a measurement system that can calculate the overturning (the RAPID array). Rahmstorf and others had some issues with THC shutdown in the 90's when previous studies, which at one point suggested a shutdown in THC or meridional overturning, turned out to be incorrect because of an aliasing from a sampling error: they just happened to be measuring at points in the seasonal cycle that were spaced in such a way so as to show a decrease when there was none. This led to our modern understanding of inter-annual variability in the THC, so it all worked out well. The nature paper takes pains to note that the RAPID array is just 11 years old and so we can't say anything from the results. But this proxy data must be referenced to something, and the only reasonable measurement apparatus to use is RAPID. It isn't. Using proxy data to infer something about the overturning, while reasonable, doesn't give great coherence towards present understanding of complicated, long-timescale events like the heating of the deep ocean. Furthermore, even at theirs strongest the conclusions absolutely do not support the WaPo headline. This is the sort of things that makes climate scientists like myself furious. The results end up overhyped, overblown, and for soundbites like press releases and Nature papers. This just misinforms people. Unless I hear from RAPID that the MOC/THC is reducing, I'm not trusting the authors. Just because climate change is a hot-button issue, and we want ways to convince people about its impacts, doesn't mean MOC/THC shutoffs can be pulled out of nowhere. edit: Just want to mention: this doesn't say anything about the method of analysis. The method seems to be well done and scientific and careful, given the data at hand. The issue is rather the paper title and subsequent inflation in popular media, which is silly.

Gravityloss 12y ago
Would you perhaps say that one could only say something about thermohaline circulation trends 20 years from now, when there's 30 years of data? Until that, what should our policy be based on?
- andyjohnson0 12y ago
  I have no idea! I was simply re-posting the Reddit comment referenced by @dm3 and requested by @Patient0. In case its not abundantly clear from the first line: the Reddit comment was not written by me.

deleted 12y ago

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