The National Forum   Donate   Your Account   On Line Opinion   Forum   Blogs   Polling   About   
The Forum - On Line Opinion's article discussion area



Syndicate
RSS/XML


RSS 2.0

Main Articles General

Sign In      Register

The Forum > Article Comments > The atmosphere at 4-degrees above the present > Comments

The atmosphere at 4-degrees above the present : Comments

By Andrew Glikson, published 4/5/2010

A lesson from the recent geological record and a blueprint for CO2 draw-down.

  1. Pages:
  2. 1
  3. 2
  4. 3
  5. 4
  6. Page 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10
  12. All
I've tried to stay away from this argument but I have to bite. Qanda (I assume you are the Q&A of old) why is 15 years -> climate trend uncertain but 30 years -> climate trend certain? I am aware that the classical period for averaging these variables is 30 years, as defined by the World Meteorological Organization, that such time periods are called climate normals, and they are generally used as reference values for comparative purposes. As this is an arbitrary figure then how about 60 years -> climate trend certain. This could take into account longer term natural climate variability such as the Pacific Decadal Oscillation (among others) and would surely give you and other scientists a better idea of the natural varibility in GAMSAT temperatures, making any anthropogenic influence likely to be easier to determine.

Regarding this point I would suggest not only is the 30-year average the barest minimum time frame in which to compare changes in climatic averages but the current international standard also partially coincides with the measurable warming that occurred within the last three decades of the 20th century. In addition, the shortness of this time frame excludes previous warming periods, such as those experienced in the 1920–40s – as well as previous cooling periods – thus casting doubt on the current international standard time frame as a long-term measure of climate in my mind.

I am also amused by the notion that 30 years is required for a certain climate trend (though I do not necessarily agree with it) but that barely 30 years of satellite Arctic sea ice records is more than sufficient for many scientists and advocates (not necessarily you though) to proclaim we can expect Arctic sea ice to disappear, as some have postulated, in the near and not too distant future. Who sets these time periods and with what justification?
Posted by Raredog, Thursday, 6 May 2010 2:18:11 PM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
This might seem a little confusing to you Raredog, but the data itself actually dictates what time frame is needed to gain a measure of statistical significance. When trends are strong and noise(variability) low, then far less data points are needed to gain statistical significance threshold (or confidence if you like). Phil Jones has said that the trend is for warming over the last 15 years, but the statistical significance isn't quite there, "but only just" under the statistical significance threshold of 95%. If one goes out to 30 years, the trend is clear and the significance no problem at all. Since Jones said that the trend was very close to the significance level, then if the data was taken out to 16, 17 or 18 years, then the significance would likely pass the 95% threshold, but that wasn't the question asked of him.

Phil Jones didn't say what you think he did spindoc, get over it.
Posted by Bugsy, Thursday, 6 May 2010 8:33:00 PM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
The author's warmist assertions are typical of those of members of the AGW Fearmongers Club.
Given that the warmists, after more than 20 years of intense searching (particularly by the IPCC), have failed to prove that global warming is man-caused, it is now time for them to shut up. It is not generally known that the 2007 IPCC Report cited over 18,000 references, but that not one contained proof that CO2 emissions are the driver of climate change. Despite continually increasing CO2 emissions, the IPCC has been unable to explain the global cooling trend from 1940 to 1975, and why there has been no statistically significant global warming for the last 15 years -- the latter is acknowledged even by Phil Jones, the scientist at the centre of the Climategate scandal.
The ongoing regurgitation of assertive blurb by warmists has led to dysfunctional behaviour . Gullible politicians have been misled into proposing emission reduction policies that have no effect on climate, but damage economies and living standards. The renewable energy legislation severely curtails investment in efficient low-cost coal-derived power generation, and instead encourages investment in high-cost unreliable wind turbine and solar energy, that are twice and ten-times more expensive respectively.
If the Rudd Government is serious about eliminating unnecessary expenditure, it should stop forking out $90 million a year to keep more than 400 public servants employed within the federal Climate Change Department. It also should stop funding warmist socalled research in Government authorities and the universities.
Posted by Raycom, Thursday, 6 May 2010 11:32:23 PM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
Bugsy, << Phil Jones didn't say what you think he did spindoc, get over it.>>

Really? Perhaps you could post the transcript of the UK Parliamentary Hearing, then we can disscuss what Phil Jones actually "said". That way we don't need to discuss what "I think he said".

Over to you.
Posted by spindoc, Friday, 7 May 2010 10:22:17 AM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
One and the same Raredog.

While the PDO is termed an oscillation, there is no evidence to show that it is “periodic”. Many people also assume the Southern Oscillation Index is also “periodic”. These people don’t understand the concept of periodicity and that the time scales assigned to the PDO is a “characteristic” time scale – they are not periods. For example, the PDO time scale includes 50 to 90 year and 10 to 30 year scales, as you have alluded to.

Yes, the PDO (and ENSO) does impact our major ocean and the enveloping continents, however, the cause of the PDO is still unresolved. Predicting the PDO is still very uncertain because of the limited time we have been making direct observations, although they go back to the early 1900’s. In other words, we really don’t know if the PDO is a long term pattern of variation or just another unexplained unknown. It certainly is not “periodic” (by definition) so any predictions based on it are meaningless.

Therefore, what you suggest is not very practical, sorry. To make strategic policy decisions in the next few years but that we should have to wait another 100 years (by inplication) just to see if an unknown unknown validates anything at all towards making those important decisions, is just plain silly, imho.

Raredog, we already know a helavulot, but as comments above typically demonstrate, joe and jill ‘six-packs’ don’t have a clue about ‘climate science’. It is obvious that people are running scared, helped by ideologues pushing their own “she’ll be right’ agenda. It is not all doom and gloom as the ‘alarmists’ AND the ‘deny-n-delay’ brigade would have us believe. However, it would certainly make things better if we could all live in a more environmentally and ecologically sustainable way - that is definitely not happening.

Why? I have no idea.
Posted by qanda, Friday, 7 May 2010 11:04:59 AM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
Raycom, still waiting for your reply. See the post below yours:

http://forum.onlineopinion.com.au/thread.asp?article=10243#168034
Posted by qanda, Friday, 7 May 2010 11:23:24 AM
Find out more about this user Recommend this comment for deletion Return to top of page Return to Forum Main Page Copy comment URL to clipboard
  1. Pages:
  2. 1
  3. 2
  4. 3
  5. 4
  6. Page 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10
  12. All

About Us :: Search :: Discuss :: Feedback :: Legals :: Privacy