Comments on: Gotland by Esper

By: Paul Penrose

Paul Penrose — Tue, 13 Sep 2005 23:15:06 +0000

Max,
The problem seems to be that the researchers are offended that anybody would even question their methods or data. We should just trust them – they are the experts after all, and incapable of making mistakes, let alone fabricating data.

By: Steve McIntyre

Steve McIntyre — Tue, 13 Sep 2005 14:23:49 +0000

Re #13: Max, you understand wrong. In climate science, you don’t have to archive data and results. There is a great deal of data that is archived, but it is patchy and compliance in the major multiproxy studies is abysmal. The authors have genrally refused to provide the data upon specific request as well.

As to your neatly expressed query about “patched together well-wishing”, that summarizes my entire line of questioning.

By: TCO

TCO — Tue, 13 Sep 2005 14:13:05 +0000

In the physical sciences, data is often not archived. That’s why Wilson urges actually PUBLISHING data. It becomes part of the record that way and allows people to see if previous work was flawed and even to correct after the fact to still get some value out of flawed work. Of course, this becomes a logistical issue. With modern computers and such, however, we may be moving more towards a world of data being “published”. Of SI-like journals even. It is an interesting issue…

By: Max

Max — Tue, 13 Sep 2005 14:05:10 +0000

I have got a question. You are speaking of archiving, as if it were something totally unheard of in climate science. You have to archive all your data and results, to make a reasonable study and to show evidence for your findings.
If you don’t do it, how would other scientists know that it was rightfully done in a scientific way, or just patched together well-wishing.

Or did I understand something wrong?

By: Steve McIntyre

Steve McIntyre — Mon, 12 Sep 2005 18:04:17 +0000

Paul, the moden trees tend to be sampled with a minimum of 5 cm trunk at 1 m height. These tend to be either younger fast growing trees or older slow growing trees. So if you look at the “grass plot” for Polar Urals, you’ll see that there are no trees with cumulative ring width

By: Paul Gosling

Paul Gosling — Mon, 12 Sep 2005 15:01:43 +0000

Steve

A question and a point.

1) Why are modern trees older? I seem to remember a post on this but cannot find it.

2) I doubt that the effect you are referring to is a germination effect. Woodland floors tend to have a much less variable temperature than above the canopy and germination is pretty robust. It is the first few years after germination (in trees) which are the most precarious. Young trees are more vulnerable to frost damage and to browsing by large herbivores. If conditions are unfavourable they will be in this vulnerable stage longer. There may be an issue with seed availability. If the adult trees are stressed they will probably not be producing much seed.

By: Paul Gosling

Paul Gosling — Mon, 12 Sep 2005 14:55:51 +0000

Steve

Couple of questions.

1) Why are modern trees older? I seem to remember a post on this but cannot find it.

By: TCO

TCO — Mon, 12 Sep 2005 13:56:56 +0000

Dave, you’re a shmarty…first beer is on me.

I agree with Paul about the 1900s, looking like something is different.

By: Steve McIntyre

Steve McIntyre — Mon, 12 Sep 2005 13:49:23 +0000

Paul, the modern trees are much older than the average sample throughout the history – so there is a fundamental non-homogeneity in nearly EVERY tree ring chronology – called by Melvin “modern sample bias”. Most species have narower ring widths as they get older. So the dendro guys adjust for aging. Then, all of a sudden, the 20th century instead of having narrow ring widths, ends up showing “unprecedented” warmth. Age adjustment becomes an important issues.

There are a lot of effects going on. One that interests me (and this is a deleted preamble to another post where the preamble was inapplicable): germination seems to require even warmer temperatures than staying alive. So if you have changing climate in a temperature-stressed site, the germination will be more heavily biased to warm periods. Thus, on average, as trees get older, they will be experiencing a colder climate. Thus, some portion of the age-adjustment curve will be a result of biased getting colder: presumably the slope of the actual age-adjustment curve would not be as steep as the estimate resulting from biased germination.

By: Dave Eaton

Dave Eaton — Mon, 12 Sep 2005 13:36:18 +0000

Fascinating stuff. I need to see what archiving requirements there are in physical science journals I’m familiar with. Our data tended to come from samples, which we would provide, even to people we didn’t like much, and the data not subject to too much manipulation. I just assumed these were the rules, but it might be the folkways of the scientific area I worked in when my stuff could still appear in the open literature.

TCO- not to pry, but when I see TCO, I read ‘transparent conducting oxide’. Is this the origin of the initials? Again, feel free to ignore this inquiry- I do, however, respect your commentary here, and I just gather from the way you say things that our backgrounds might be somewhat parallel.