Global Warming

General physics and astronomy discussions not directly related to Celestia
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BobHegwood
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Global Warming

Post #1by BobHegwood » 14.09.2009, 20:44

Just had an interesting visit to a blog located HERE.

Was quite surprised to read that global warming has been somewhat countered by a slow-down in the
activity of the Sun since 2002.

Anyone else heard this before? Any other discussion of the Sun's apparent slow-down?

Just curious...
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asteroid
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Re: Global Warming

Post #2by asteroid » 14.09.2009, 20:58

I tend to side with Michael Crichton on this one. GW is more myth/religion than science in the first place.

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Re: Global Warming

Post #3by selden » 14.09.2009, 21:32

There is not doubt that average global temperature has risen in recent decades:
both the Arctic and Antarctic ice caps have shrunk dramatically and so have the Greenland glaciers and mountain glaciers around the world.

How much of that is due to human influences is not clear.
Selden

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Re: Global Warming

Post #4by BobHegwood » 15.09.2009, 11:24

Thanks asteroid, Selden, but I was really curious to learn that the Sun's "activity"
has decreased? I was peripherally aware of such things, but was also somewhat
interested to note that this effect could possibly have some long-term (to me)
effect on our little planet. 7 years is long-term to me. :wink:

At any rate, was just interested to see if anyone knows more about this
cycling of the Sun. More information?

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Re: Global Warming

Post #5by selden » 15.09.2009, 12:56

The amount of heating of the Earth which is a result of variations of solar luminosity seems to be a combination of several cycles with various multi-year periods. The Wikipedia article has several references.
http://en.wikipedia.org/wiki/Solar_vari ... irradiance

Among other things, the current minimum in the 11 year sunspot cycle is deeper and longer than usual. i.e. the number of sunspots is unusually low, although longer minima have been recorded. That might result in lower temperatures. See http://en.wikipedia.org/wiki/Maunder_Minimum
Selden

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Re: Global Warming

Post #6by Reiko » 15.09.2009, 13:13

It seems the globe goes through cycles of warming and cooling. In the past there was no ice caps and ours are melting today. Is this because of us or the sun? I really don't know but I find it interesting.

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Re: Global Warming

Post #7by BobHegwood » 15.09.2009, 15:29

selden wrote:The amount of heating of the Earth which is a result of variations of solar luminosity seems to be a combination of several cycles with various multi-year periods. The Wikipedia article has several references.
http://en.wikipedia.org/wiki/Solar_vari ... irradiance

Among other things, the current minimum in the 11 year sunspot cycle is deeper and longer than usual. i.e. the number of sunspots is unusually low, although longer minima have been recorded. That might result in lower temperatures. See http://en.wikipedia.org/wiki/Maunder_Minimum

Many thanks, Selden...

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Re: Global Warming

Post #8by ajtribick » 15.09.2009, 22:24

asteroid wrote:I tend to side with Michael Crichton on this one. GW is more myth/religion than science in the first place.
Because obviously a medical doctor/bad-technothriller writer would know more about this issue than climate scientists. :-P

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Re: Global Warming

Post #9by asteroid » 16.09.2009, 20:00

ajtribick wrote:
asteroid wrote:I tend to side with Michael Crichton on this one. GW is more myth/religion than science in the first place.
Because obviously a medical doctor/bad-technothriller writer would know more about this issue than climate scientists. :-P
http://www.sitewave.net/news/s49p628.htm
http://www.globalwarminghysteria.com/te ... l-warming/
(Not the dozen or so links to other sites on the right)
Just sayin ;)

FYI, While I do believe the GW 'scare' is a myth, I hope my posts are not being read as "in your face" or 'slams' against any member here.

Sorry Bob if I took your thread in an unwanted direction.

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Re: Global Warming

Post #10by ajtribick » 16.09.2009, 20:08

The point is that Michael Crichton is absolutely the wrong person to reference in relation to these issues. Most of his "science" is a load of rubbish... witness the appalling treatment of chaos theory in the Jurassic Park novels.

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Re: Global Warming

Post #11by t00fri » 16.09.2009, 20:25

ajtribick wrote:The point is that Michael Crichton is absolutely the wrong person to reference in relation to these issues. Most of his "science" is a load of rubbish... witness the appalling treatment of chaos theory in the Jurassic Park novels.

I am definitely at your side ;-)

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Re: Global Warming

Post #12by Fenerit » 16.09.2009, 21:43

asteroid wrote:I tend to side with Michael Crichton on this one. GW is more myth/religion than science in the first place.

In the myth men talks about God(s), in the religion God(s) reveal the truth to men; therefore global warming is God(s). The most reasonable answer is that global warming isn't myth/religion.
Never at rest.
Massimo

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Re: Global Warming

Post #13by BobHegwood » 17.09.2009, 00:50

asteroid wrote:FYI, While I do believe the GW 'scare' is a myth, I hope my posts are not being read as "in your face" or 'slams' against any member here.

Sorry Bob if I took your thread in an unwanted direction.

No problem here my friend, but you will certainly encounter some form of hostility here if
you believe that Michael Crichton is truly a scientist... :wink:

He is just popularizing shock theories in order to make a buck or two.
The good Doctor Schrempp has more doctorates than you can shake a stick at, so you might do
well to listen to the gentleman some time.

If you are truly interested in the scientific approach, you can find more at the
Celestial Matters web site.

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Re: Global Warming

Post #14by JamesC » 19.09.2009, 10:51

BobHedgewood:

This is not news - it's perfectly understood that within the warming trend, there is variation.
It's being talked about as if it was a hot topic because of comments on the subject by Latif of Kiel Uni. at the world climate conference.

There have been many others: For example, the biggest is the cooling in the 40ies. See for example
http://www.newscientist.com/article/dn11639-climate-myths-the-cooling-after-1940-shows-cosub2sub-does-not-cause-warming.html

About the warming, the observations are:
- Long term trend is warming and coincides with human emissions
- Natural variability (sun especially, earth orbit also) on the other hand does not coincide with this observed warming trend
- Natural variabilities do, obviously, affect the effects of warming: Both amplifying, and, at present, mitigating. There are short-term phases on an underlying long term trend.

On the last point, the paper from Kiel by Latif seems to predict a lull of 10 to 20 years - a large error bar.
He also states that this is temporary, and the the underlying warming is still continuing.

The magnitude of the underlying warming is uncertain - see large error bars in IPCC summary papers - but the lower numbers with 95% confidence are still enough to cause significant sea level rise, changes in human health, and more violent weather events.
What is less sure is what effects any action taken can have on this: Is there much point ?
But what is sure is that if no action is taken, the consequences will be more severe.

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Re: Global Warming

Post #15by BobHegwood » 19.09.2009, 12:53

JamesC wrote:BobHedgewood:

First of all, as my named is plainly spelled, it is Hegwood not Hegdewood.
If you miss details like this, it makes me wonder if perhaps you miss other details. :wink:

JamesC wrote:This is not news - it's perfectly understood that within the warming trend, there is variation.
It's being talked about as if it was a hot topic because of comments on the subject by Latif of Kiel Uni. at the world climate conference.

There have been many others: For example, the biggest is the cooling in the 40ies. See for example
http://www.newscientist.com/article/dn11639-climate-myths-the-cooling-after-1940-shows-cosub2sub-does-not-cause-warming.html

About the warming, the observations are:
- Long term trend is warming and coincides with human emissions
- Natural variability (sun especially, earth orbit also) on the other hand does not coincide with this observed warming trend
- Natural variabilities do, obviously, affect the effects of warming: Both amplifying, and, at present, mitigating. There are short-term phases on an underlying long term trend.

On the last point, the paper from Kiel by Latif seems to predict a lull of 10 to 20 years - a large error bar.
He also states that this is temporary, and the the underlying warming is still continuing.

The magnitude of the underlying warming is uncertain - see large error bars in IPCC summary papers - but the lower numbers with 95% confidence are still enough to cause significant sea level rise, changes in human health, and more violent weather events.
What is less sure is what effects any action taken can have on this: Is there much point ?
But what is sure is that if no action is taken, the consequences will be more severe.

Please be aware that I do understand all of this now, but I was completely unaware of such variabilities in the past.
My fault, and I apologize. Thanks very much for the lucid explanation of these variabilities though. It is appreciated.

Again, many thanks, Brain-Dead
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Re: Global Warming

Post #16by Fenerit » 19.09.2009, 23:20

Global warming it's a quantity (number and measure) and meanwhile its number is unclear, it's measure is only the temperature (K). The temperature is a scalar quantity and how in a room with a fire inside the thermometre change it's number whether insert in the fire or put at room's corner, this happen also in the world. A measure taken above a factory town will be much more high than one taken at pole. But whether also the poles raise their values... This is the problem (horrendous declaration, I apologize). :blue:
Never at rest.
Massimo


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