6 ms·

Anyone searching for outright fraud in in these emails is going to be disappointed. The problem is not fraud, but rather scientists who believe that they are co

by thras 17y ago

Anyone searching for outright fraud in in these emails is going to be disappointed. The problem is not fraud, but rather scientists who believe that they are correct, and that their job is now not science but public relations. That said, finding this was a big deal: http://camirror.wordpress.com/2009/11/26/new-the-deleted-data/ http://camirror.wordpress.com/2009/11/26/new-the-deleted-dat...

spoondan 17y ago
The only thing that's a "big deal" about that is the laziness and mendacity of its author. The data he found was published in 1998 and 2000, a fact he mentions without irony while arguing that the data was "hidden". The linked article also claims that the NOAA "deleted" the post-1960 data from a data set (briffa2001jgr3.txt) put together for an article that doesn't use these data. In other words, what really happened, is that Briffa and his collaborators created a data set only containing the data they used, and this derived data set was archived by NOAA. That's hardly nefarious or even the least bit worrisome. Now to the heart of the issue: Why was the post-1960 not used after 1998/2000? Why do all of the e-mails talk about "hiding the decline" and the code talk about stopping in 1960 to "avoid the decline"? The answer, it turns out, is right in the very Briffa 1998 paper your link mentions (but fails to cite). It's title is Reduced sensitivity of recent tree growth to temperature at high northern latitudes and it's about how temperatures reconstructed using Briffa's MXD (maximum latewood density) data diverge from actual temperature readings after 1960. The implication of the word "reconstructed" is very important to understand: Briffa's MXD data don't show an actual decline in temperature. They show a decline in a particular measurement of tree-ring density that had, until 1960, been a good indicator of actual temperature. All that's going on here is that data that is known to be inaccurate is not being used. It's no big deal.
- thras 17y ago
  No, you are misinformed. Further, your tone is unhelpful. This was the first time that the data was available. As McIntyre points out in the top of his post, the decline was discussed in the 1998 and 2001 Briffa papers. Of course, scientists could not actually evaluate this because the data was not released. But that's not the issue. The issue is, as McIntyre also points out, that the IPCC 2001 graph (and later graphs) simply truncated the climate reconstruction data in 1960 and pasted the (more accurate) direct temperature station measurement data onto the graph after 1960. While this was done it plain sight, it's still lousy scientific practice. Why? After all, shouldn't more accurate data be used? The problem is that comparison of temperature reconstructions with direct measurement tells you a lot about the accuracy of your reconstruction. In this case it tells you a lot about the inaccuracy of the reconstruction and the sorts of signals that are missed. I'm sorry, the paleoclimate reconstructions available in the literature are not convincing. They often use dodgy statistical techniques, mixing data gathering steps with data correlation steps to increase apparent agreement with the instrument record. There have been huge problems with releasing data and there are often bizarre choices made in proxy record selection. Without good paleoclimate reconstructions, it's hard to know how far outside (or inside) the historical standard deviation for temperature we are. I happen to think it's an important question to have answered. A trillion dollar question.
  - smcq 17y ago
    You seem completely confused by the scientific method. They do not have an obligation to release all data, but rather to release the method by which data can be acquired. They released data for the paper actually published to justify their statistical analysis. Any data that you receive from another scientist with the intention of reproducing their experiment is fundamentally tainted and violates the scientific method. Please don't argue against straw men, it's annoying.
    - yummyfajitas 17y ago
      It's you who is confused. Scientists are normally obligated to release all data. It's the standard in most other fields (e.g., biology, econometrics). Running the same data analysis on existing data doesn't count as reproducing the experiment. Running a different analysis on the same data is, however, doing new science. In contrast, failing to release the data does count as "violating the scientific method".
      - smcq 17y ago
        No. You are wrong.
- motters 17y ago
  How do we know that post 1960 tree ring data is bad, and needs to be adjusted, yet pre 1960 data is good? What happened to tree growth after 1960?
  - thras 17y ago
    It's even better if you read the Briffa letter to Nature that he cited: http://www.nature.com/nature/journal/v391/n6668/abs/391678a0.html http://www.nature.com/nature/journal/v391/n6668/abs/391678a0... Something completely unknown is making tree rings too small after 1960. And if you correlate your tree ring data to post-1960 temperatures it makes historical temperature look way too high. Bizarro-Briffa sent a similar letter to Bizarro-Nature warning of an unknown divergence problem and saying not to correlate tree rings to pre-1960 temperatures because it makes historical temperature look way too low.
    - spoondan 17y ago
      I don't know what you're trying to argue. Tree rings underestimate current, not historical, temperatures. This means that, yes, if you calibrate to current temperature, the past will look comparatively hotter. This is a causal relationship.
      - waterlesscloud 17y ago
        At what other periods to tree rings not correctly correlate to temperature? How do we know the last 50 years is the only time this has happened? Since we do not know why the temperature has not correctly correlated over the last 50s years, we can't really know when else that has been the case, can we? So why do we rely on tree rings for any period? They are proven to be unreliable over a signifcant period, and we don't know if or how often that's also true of the past.
        spoondan 17y ago
        You can cross-check historical reconstructions to assess their accuracy for given periods. I don't know how often this has been done and if other significant, unexplained, and unaccounted for divergences have been found. I haven't heard of any, but I'm not an expert. For complete answers to your questions, I'm afraid you may have to review the literature.
- defen 17y ago
  Isn't it possible that thermometers got better after 1960, especially when measuring temperatures at "high northern latitudes"? This seems more likely than assuming that trees somehow got worse at measuring temperatures.
  - spoondan 17y ago
    Not really. If the issue was thermometers getting more accurate, other proxy methods would show a similar divergence. Trees are complex organisms whose growth relies on many factors in a complicated relationship. Just as a simple example, if you have a long, hot drought, do you expect tree growth to be more affected by the temperature or the lack of moisture? The scientists must control for these kinds of factors to isolate the temperature signal. But when you're dealing with the interactions of complex systems, new factors can emerge and the methods need to change to keep up.

by thras 17y ago

spoondan 17y ago

The only thing that's a "big deal" about that is the laziness and mendacity of its author. The data he found was published in 1998 and 2000, a fact he mentions without irony while arguing that the data was "hidden". The linked article also claims that the NOAA "deleted" the post-1960 data from a data set (briffa2001jgr3.txt) put together for an article that doesn't use these data. In other words, what really happened, is that Briffa and his collaborators created a data set only containing the data they used, and this derived data set was archived by NOAA. That's hardly nefarious or even the least bit worrisome. Now to the heart of the issue: Why was the post-1960 not used after 1998/2000? Why do all of the e-mails talk about "hiding the decline" and the code talk about stopping in 1960 to "avoid the decline"? The answer, it turns out, is right in the very Briffa 1998 paper your link mentions (but fails to cite). It's title is Reduced sensitivity of recent tree growth to temperature at high northern latitudes and it's about how temperatures reconstructed using Briffa's MXD (maximum latewood density) data diverge from actual temperature readings after 1960. The implication of the word "reconstructed" is very important to understand: Briffa's MXD data don't show an actual decline in temperature. They show a decline in a particular measurement of tree-ring density that had, until 1960, been a good indicator of actual temperature. All that's going on here is that data that is known to be inaccurate is not being used. It's no big deal.

thras 17y ago
No, you are misinformed. Further, your tone is unhelpful. This was the first time that the data was available. As McIntyre points out in the top of his post, the decline was discussed in the 1998 and 2001 Briffa papers. Of course, scientists could not actually evaluate this because the data was not released. But that's not the issue. The issue is, as McIntyre also points out, that the IPCC 2001 graph (and later graphs) simply truncated the climate reconstruction data in 1960 and pasted the (more accurate) direct temperature station measurement data onto the graph after 1960. While this was done it plain sight, it's still lousy scientific practice. Why? After all, shouldn't more accurate data be used? The problem is that comparison of temperature reconstructions with direct measurement tells you a lot about the accuracy of your reconstruction. In this case it tells you a lot about the inaccuracy of the reconstruction and the sorts of signals that are missed. I'm sorry, the paleoclimate reconstructions available in the literature are not convincing. They often use dodgy statistical techniques, mixing data gathering steps with data correlation steps to increase apparent agreement with the instrument record. There have been huge problems with releasing data and there are often bizarre choices made in proxy record selection. Without good paleoclimate reconstructions, it's hard to know how far outside (or inside) the historical standard deviation for temperature we are. I happen to think it's an important question to have answered. A trillion dollar question.
- smcq 17y ago
  You seem completely confused by the scientific method. They do not have an obligation to release all data, but rather to release the method by which data can be acquired. They released data for the paper actually published to justify their statistical analysis. Any data that you receive from another scientist with the intention of reproducing their experiment is fundamentally tainted and violates the scientific method. Please don't argue against straw men, it's annoying.
  - yummyfajitas 17y ago
    It's you who is confused. Scientists are normally obligated to release all data. It's the standard in most other fields (e.g., biology, econometrics). Running the same data analysis on existing data doesn't count as reproducing the experiment. Running a different analysis on the same data is, however, doing new science. In contrast, failing to release the data does count as "violating the scientific method".
    - smcq 17y ago
      No. You are wrong.
motters 17y ago
How do we know that post 1960 tree ring data is bad, and needs to be adjusted, yet pre 1960 data is good? What happened to tree growth after 1960?
- thras 17y ago
  It's even better if you read the Briffa letter to Nature that he cited: http://www.nature.com/nature/journal/v391/n6668/abs/391678a0.html http://www.nature.com/nature/journal/v391/n6668/abs/391678a0... Something completely unknown is making tree rings too small after 1960. And if you correlate your tree ring data to post-1960 temperatures it makes historical temperature look way too high. Bizarro-Briffa sent a similar letter to Bizarro-Nature warning of an unknown divergence problem and saying not to correlate tree rings to pre-1960 temperatures because it makes historical temperature look way too low.
  - spoondan 17y ago
    I don't know what you're trying to argue. Tree rings underestimate current, not historical, temperatures. This means that, yes, if you calibrate to current temperature, the past will look comparatively hotter. This is a causal relationship.
    - waterlesscloud 17y ago
      At what other periods to tree rings not correctly correlate to temperature? How do we know the last 50 years is the only time this has happened? Since we do not know why the temperature has not correctly correlated over the last 50s years, we can't really know when else that has been the case, can we? So why do we rely on tree rings for any period? They are proven to be unreliable over a signifcant period, and we don't know if or how often that's also true of the past.
      - spoondan 17y ago
        You can cross-check historical reconstructions to assess their accuracy for given periods. I don't know how often this has been done and if other significant, unexplained, and unaccounted for divergences have been found. I haven't heard of any, but I'm not an expert. For complete answers to your questions, I'm afraid you may have to review the literature.
defen 17y ago
Isn't it possible that thermometers got better after 1960, especially when measuring temperatures at "high northern latitudes"? This seems more likely than assuming that trees somehow got worse at measuring temperatures.
- spoondan 17y ago
  Not really. If the issue was thermometers getting more accurate, other proxy methods would show a similar divergence. Trees are complex organisms whose growth relies on many factors in a complicated relationship. Just as a simple example, if you have a long, hot drought, do you expect tree growth to be more affected by the temperature or the lack of moisture? The scientists must control for these kinds of factors to isolate the temperature signal. But when you're dealing with the interactions of complex systems, new factors can emerge and the methods need to change to keep up.