5 ms·

Central England temperature dataset: 0.26°C increase per century since 1659

28 points by dublinclontarf 17y ago

dublinclontarf 17y ago
The link that the article is refering to: http://www.c3headlines.com/2010/01/cet-temperatures.html http://www.c3headlines.com/2010/01/cet-temperatures.html
- ZeroGravitas 17y ago
  The 30 year rises listed in that article, differ markedly from the other blog by Lubos Motl, which he links to in support. http://motls.blogspot.com/2010/01/warming-trends-in-england-from-1659.html http://motls.blogspot.com/2010/01/warming-trends-in-england-... What am I missing? Can I also take this opportunity to point out the very dodgy choice of scales on his first graph. The temperature data is limited to 1/7th of the height of the graph, while the C02 changes are stretched to full height. Graph here: http://c3headlines.typepad.com/.a/6a010536b58035970c0120a7c87805970b-pi http://c3headlines.typepad.com/.a/6a010536b58035970c0120a7c8... The obvious impact of this is to downplay any shift in temperature in response to changes in CO2 levels and any deviations from the linear trend line.
jgrahamc 17y ago
Just go get HadCET yourself and do some analysis: http://hadobs.metoffice.com/hadcet/ http://hadobs.metoffice.com/hadcet/ I wouldn't listen to the rantings of The Daily Telegraph, and specifically not this commentator: http://blogs.telegraph.co.uk/news/author/jamesdelingpole/ http://blogs.telegraph.co.uk/news/author/jamesdelingpole/ OK. Downvote me then, but if you read the original blog post he's talking about (http://motls.blogspot.com/2010/01/warming-trends-in-england-from-1659.html http://motls.blogspot.com/2010/01/warming-trends-in-england-...) and you look at the '30 year bands' he's chosen they are cherry picked. And he's saying 'Look here in 1661 or whatever it warmed faster than it's warming now'. Seeing fast warming in central English in the past doesn't disprove man-made global warming now. If you dig into his Mathematica code and take a look at it you'll see a plot he's made (which he doesn't blog about) that looks just like the global warming trend plots everyone is putting out. See: http://imgur.com/K8Pcn.png http://imgur.com/K8Pcn.png Wonder why that doesn't get a mention?
- dublinclontarf 17y ago
  Simply because you don't like him or the paper doesn't make them wrong. And could you get a mirror for that post on blogspot for me, I live in China and can't access it, cheers.
  - jgrahamc 17y ago
    Simply because you don't like him or the paper doesn't make them wrong. Agreed. But the underlying analysis for his article isn't a paper, it's a random blog posting. The guys at the Met Office publish the actual data set and they have put out papers based on them which are linked from their web site. The HadCET dataset is referenced constantly in their other work.
    - deleted 17y ago
      [deleted]
      - jgrahamc 17y ago
        Nope. I'll point to HadCET all I want since that's the actual dataset that this newspaper article is talking about. OK?
- gaius 17y ago
  The 30-year thing is significant; the AGW advocates quote trends since 1979 usually, which is significant as during the 1970s scientists were most worried about global cooling and pointed out a cooling trend since the 1950s. The side with the least-arbitrary data set wins the credibility debate; "since records began" is a good one.
  - spamizbad 17y ago
    Scientists were not most worried about global cooling in the 1970s. What you had were scientists who published papers positing the idea, and then having their work scooped-up, dumbed-down, by journalists and crammed into into middle-brow publications like Time and Newsweek. That's not a scientific consensus: That's the press stirring the pot.
yungchin 17y ago
Just remember: you only measure what you measure. This data suggests that Central England temperatures have only been slowly rising. It doesn't say anything about average world temperatures. (The Gulf Stream might be one of the reasons North-West Europe is a relative stable point.) I'd be interested to see similar plots from the Arctic.
Tichy 17y ago
If you hand pick your data set, you can probably show anything you want. I remember reading about the stock market, that if you just shift the starting and end points of "measurements" (for example about your fund's value), you could always claim an x% increase over the last y years. So this here is an interesting data point - but it really is just that. I wouldn't be surprised if there were places on earth where temperatures have been falling steadily, or have been rising or falling by extreme amounts.
- paulodeon 17y ago
  I think the point is that this is simply the best dataset out there, it hasn't been cherry-picked. The only problem with this article is that there is no mention of how the gulfstream could have had a stabilising effect. The 30 year periods aren't cherry-picked either, they are picked because they were the ones with the greatest increase in temperature.
  - fnargle 17y ago
    "The 30 year periods aren't cherry-picked either, they are picked because they were the ones with the greatest increase in temperature." Lol. If that's not it, would you mind explaining to me exactly what you think cherry-picking is?
  - Tichy 17y ago
    It seems to be one data set from one location. How can this be "the best data set" out there? I don't think looking at one location is sufficient at all.
    - Retric 17y ago
      If you are going to measure a dataset by its completeness and its length you are going to find it's the best based on that scale. However, if you want to define some other scale which cares less about those factors and more about geographic coverage feel free, but don't try to mix there definition with yours because your "best" will be less compleat or cover a shorter period. PS: If you feel some other dataset would be a better proxy feel free to argue the point on its own merits. But be careful when you start to redefine the terms someone else is using, it has little to do with their argument and is not useful.
ZeroGravitas 17y ago
The linked blog lists the top ten tri-decades, ordered by temp rise. Here they are in chronological order: 1687 - 1716, 4.333 °C/century 1688 - 1717, 4.7 °C/century 1689 - 1718, 4.446 °C/century 1690 - 1719, 4.754 °C/century 1691 - 1720, 5.039 °C/century 1692 - 1721, 4.642 °C/century 1694 - 1723, 4.524 °C/century 1977 - 2006, 4.95 °C/century 1978 - 2007, 5.038 °C/century 1979 - 2008, 4.705 °C/century Can you see a pattern there? So the first 7 are consecutive apart from skipping one year/tri-decade (1693-1722) and the most recent three are 3 out of the last 4 years. And indeed the 2nd, 3rd and 5th highest rise. And yet the point he chooses to highlight directly after this list, is that the most recent tri-decade (1980-2009) isn't in the (totally arbitrary cut off point) top ten at all. It is however the 13th biggest rise. In other words 4 of the last 4 tri-decades are in the top 13 and at least 7 of the remaining 9 all are from consecutive periods starting 1687-1694. Does this really show what he's suggesting it does? I'm not seeing anything particularly useful drawn out by his analysis apart from records from around the turn of the 17th century show a large drop followed by a large rise then another massive, but short lived drop.
- deleted 17y ago
  [deleted]
benl 17y ago
There's a lot of back-and-forth in this thread about whether this disproves AGW or not. Before people get too invested in these arguments, it might make sense to step back for a second or two and ask yourself the question: "What is the null hypothesis?" As far as my understanding goes, in order to be doing good science, the null hypothesis must be that there is no phenomenon to explain. So the qustion we should be asking is: "is this evidence consistent with, or does it refute, the null hypothesis?" As far as I can tell, this evidence is consistent with the null hypothesis. While that is interesting, it's not super-important, so we should all save our passion and debating time for evidence that potentially refutes the null hypothesis. That kind of evidence is much more important to find and pore over... * [edit] fixed a few typos

The link that the article is refering to: http://www.c3headlines.com/2010/01/cet-temperatures.html http://www.c3headlines.com/2010/01/cet-temperatures.html

ZeroGravitas 17y ago
The 30 year rises listed in that article, differ markedly from the other blog by Lubos Motl, which he links to in support. http://motls.blogspot.com/2010/01/warming-trends-in-england-from-1659.html http://motls.blogspot.com/2010/01/warming-trends-in-england-... What am I missing? Can I also take this opportunity to point out the very dodgy choice of scales on his first graph. The temperature data is limited to 1/7th of the height of the graph, while the C02 changes are stretched to full height. Graph here: http://c3headlines.typepad.com/.a/6a010536b58035970c0120a7c87805970b-pi http://c3headlines.typepad.com/.a/6a010536b58035970c0120a7c8... The obvious impact of this is to downplay any shift in temperature in response to changes in CO2 levels and any deviations from the linear trend line.

jgrahamc 17y ago

Just go get HadCET yourself and do some analysis: http://hadobs.metoffice.com/hadcet/ http://hadobs.metoffice.com/hadcet/ I wouldn't listen to the rantings of The Daily Telegraph, and specifically not this commentator: http://blogs.telegraph.co.uk/news/author/jamesdelingpole/ http://blogs.telegraph.co.uk/news/author/jamesdelingpole/ OK. Downvote me then, but if you read the original blog post he's talking about (http://motls.blogspot.com/2010/01/warming-trends-in-england-from-1659.html http://motls.blogspot.com/2010/01/warming-trends-in-england-...) and you look at the '30 year bands' he's chosen they are cherry picked. And he's saying 'Look here in 1661 or whatever it warmed faster than it's warming now'. Seeing fast warming in central English in the past doesn't disprove man-made global warming now. If you dig into his Mathematica code and take a look at it you'll see a plot he's made (which he doesn't blog about) that looks just like the global warming trend plots everyone is putting out. See: http://imgur.com/K8Pcn.png http://imgur.com/K8Pcn.png Wonder why that doesn't get a mention?

dublinclontarf 17y ago
Simply because you don't like him or the paper doesn't make them wrong. And could you get a mirror for that post on blogspot for me, I live in China and can't access it, cheers.
- jgrahamc 17y ago
  Simply because you don't like him or the paper doesn't make them wrong. Agreed. But the underlying analysis for his article isn't a paper, it's a random blog posting. The guys at the Met Office publish the actual data set and they have put out papers based on them which are linked from their web site. The HadCET dataset is referenced constantly in their other work.
  - deleted 17y ago
    [deleted]
    - jgrahamc 17y ago
      Nope. I'll point to HadCET all I want since that's the actual dataset that this newspaper article is talking about. OK?
gaius 17y ago
The 30-year thing is significant; the AGW advocates quote trends since 1979 usually, which is significant as during the 1970s scientists were most worried about global cooling and pointed out a cooling trend since the 1950s. The side with the least-arbitrary data set wins the credibility debate; "since records began" is a good one.
- spamizbad 17y ago
  Scientists were not most worried about global cooling in the 1970s. What you had were scientists who published papers positing the idea, and then having their work scooped-up, dumbed-down, by journalists and crammed into into middle-brow publications like Time and Newsweek. That's not a scientific consensus: That's the press stirring the pot.

yungchin 17y ago

Just remember: you only measure what you measure. This data suggests that Central England temperatures have only been slowly rising. It doesn't say anything about average world temperatures. (The Gulf Stream might be one of the reasons North-West Europe is a relative stable point.) I'd be interested to see similar plots from the Arctic.

Tichy 17y ago

If you hand pick your data set, you can probably show anything you want. I remember reading about the stock market, that if you just shift the starting and end points of "measurements" (for example about your fund's value), you could always claim an x% increase over the last y years. So this here is an interesting data point - but it really is just that. I wouldn't be surprised if there were places on earth where temperatures have been falling steadily, or have been rising or falling by extreme amounts.

paulodeon 17y ago
I think the point is that this is simply the best dataset out there, it hasn't been cherry-picked. The only problem with this article is that there is no mention of how the gulfstream could have had a stabilising effect. The 30 year periods aren't cherry-picked either, they are picked because they were the ones with the greatest increase in temperature.
- fnargle 17y ago
  "The 30 year periods aren't cherry-picked either, they are picked because they were the ones with the greatest increase in temperature." Lol. If that's not it, would you mind explaining to me exactly what you think cherry-picking is?
- Tichy 17y ago
  It seems to be one data set from one location. How can this be "the best data set" out there? I don't think looking at one location is sufficient at all.
  - Retric 17y ago
    If you are going to measure a dataset by its completeness and its length you are going to find it's the best based on that scale. However, if you want to define some other scale which cares less about those factors and more about geographic coverage feel free, but don't try to mix there definition with yours because your "best" will be less compleat or cover a shorter period. PS: If you feel some other dataset would be a better proxy feel free to argue the point on its own merits. But be careful when you start to redefine the terms someone else is using, it has little to do with their argument and is not useful.

ZeroGravitas 17y ago

The linked blog lists the top ten tri-decades, ordered by temp rise. Here they are in chronological order: 1687 - 1716, 4.333 °C/century 1688 - 1717, 4.7 °C/century 1689 - 1718, 4.446 °C/century 1690 - 1719, 4.754 °C/century 1691 - 1720, 5.039 °C/century 1692 - 1721, 4.642 °C/century 1694 - 1723, 4.524 °C/century 1977 - 2006, 4.95 °C/century 1978 - 2007, 5.038 °C/century 1979 - 2008, 4.705 °C/century Can you see a pattern there? So the first 7 are consecutive apart from skipping one year/tri-decade (1693-1722) and the most recent three are 3 out of the last 4 years. And indeed the 2nd, 3rd and 5th highest rise. And yet the point he chooses to highlight directly after this list, is that the most recent tri-decade (1980-2009) isn't in the (totally arbitrary cut off point) top ten at all. It is however the 13th biggest rise. In other words 4 of the last 4 tri-decades are in the top 13 and at least 7 of the remaining 9 all are from consecutive periods starting 1687-1694. Does this really show what he's suggesting it does? I'm not seeing anything particularly useful drawn out by his analysis apart from records from around the turn of the 17th century show a large drop followed by a large rise then another massive, but short lived drop.

deleted 17y ago
[deleted]

benl 17y ago

There's a lot of back-and-forth in this thread about whether this disproves AGW or not. Before people get too invested in these arguments, it might make sense to step back for a second or two and ask yourself the question: "What is the null hypothesis?" As far as my understanding goes, in order to be doing good science, the null hypothesis must be that there is no phenomenon to explain. So the qustion we should be asking is: "is this evidence consistent with, or does it refute, the null hypothesis?" As far as I can tell, this evidence is consistent with the null hypothesis. While that is interesting, it's not super-important, so we should all save our passion and debating time for evidence that potentially refutes the null hypothesis. That kind of evidence is much more important to find and pore over... * [edit] fixed a few typos