Freethought & Rationalism Archive

nermal · 04-17-2003, 09:13 PM

The kitten ain't runnin, he's just too busy right now to check the sources listed in depth. He has a full time job, a kid, and is wrapping up a math degree.
He'll get to things as he can.

Ed

nermal · 04-18-2003, 04:27 AM

Had a chance to browse the articles. The Greenland ice sheet is thinning. Noted. If the trend continues, it will affect sea levels. Understood.
Now demonstrate two things:
1. sea levels have been measured as rising. That is the subject we were discussing as of the posting of these articles, I believe.
2. The cause is anthropogenic. That is the subject by which I insinuated myself into this thread. Recall, I have stated from the outset that the climate is dynamic. I also asserted that there is no physical evidence that people are changing the global climate. I will concede local affects ie. heat island effects.

You might look at John Daly's site. Heck, go see him. He's just down the street, as I'm sure you know. Maybe he's not a nice guy?
He has monitoring station data from all over Greenland charted from the early part of this century to 1999. It's kind of surprising just how "great" the warming trend is in Greenland. Maybe the other explanation for the ice thinning offered by the sources (lubrication) makes some sense.

As for the Arctic Ice thinning, the author of ps418's article emphatically stated that there was thinning, and not relocation. Given the sketchiness of the measurements, such an unequivocal statement arrouses suspicion. Look here:
acsys.npolar.no/news/2001/No1_p2.htm

It must also be pointed out that major recessions of the arctic ice sheet has ocurred before, as noted by ships logs from the 1700's.

Just for giggles, you might also look here:
http://news.bbc.co.uk/1/hi/in_depth/...ge/1026375.stm

Ed

ps418 · 04-18-2003, 05:50 AM

Quote:

Originally posted by nermal
As for the Arctic Ice thinning, the author of ps418's article emphatically stated that there was thinning, and not relocation. Given the sketchiness of the measurements, such an unequivocal statement arrouses suspicion. Look here:
acsys.npolar.no/news/2001/No1_p2.htm

Ed

The Rignot and Thomas paper I cited was published in 2002, whereas nearly all of the papers cited at the above link are based on data published before 2000. The past few years have seen more rapid changes than that seen in the past few decades. Whether this is due to anthropogenic warming, natural variability, or some combination of both, is much harder to say.

Quote:

It must also be pointed out that major recessions of the arctic ice sheet has ocurred before, as noted by ships logs from the 1700's.

Ships logs from the 1700s could give no more than a tiny glimpse of what is happening in Antarctica as a whole. But, yes it is correct that the Antarctic ice volume has fluctuated greatly in the past, particularly between glacial and interglacial periods, but also probably during the Holocene (e.g. Pudsey and Evans, 2001).

Patrick

Pudsey, Carol J., Evans, Jeffrey. 2001: First survey of Antarctic sub�ice shelf sediments reveals mid-Holocene ice shelf retreat. Geology: Vol. 29, No. 9, pp. 787�790.

SULPHUR · 04-18-2003, 07:38 AM

Climate,2002. Easy to get access to. And contains latest data.Or are you scared to look.

nermal · 04-18-2003, 03:01 PM

I'm too skeered. My eyes are shut tight.
Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there......

Ok I'll look.

Ed

Jesse · 07-13-2003, 02:58 PM

As a follow-up to the article in the initial post of this thread, another group of leading climate scientists has reviewed the evidence and concluded that the claim that the middle ages were warmer than today is unfounded:

http://www.eurekalert.org/pub_releas...-lcs070703.php

Quote:

WASHINGTON - A group of leading climate scientists has reaffirmed the "robust consensus view" emerging from the peer reviewed literature that the warmth experienced on at least a hemispheric scale in the late 20th century was an anomaly in the previous millennium and that human activity likely played an important role in causing it. In so doing, they refuted recent claims that the warmth of recent decades was not unprecedented in the context of the past thousand years.

...

The Eos article is a response to two recent and nearly identical papers by Drs. Willie Soon and Sallie Baliunas of the Harvard-Smithsonian Center for Astrophysics, published in Climate Research and Energy & Environment (the latter paper with additional co-authors). These authors challenge the generally accepted view that natural factors cannot fully explain recent warming and must have been supplemented by significant human activity, and their papers have received attention in the media and in the U.S. Senate. Requests from reporters to top scientists in the field, seeking comment on the Soon and Baliunas position, lead to memoranda that were later expanded into the current Eos article, which was itself peer reviewed.

Paleoclimatologists (scientists who study ancient climates) generally rely on instrumental data for the past 150 years and "proxy" indicators, such as tree rings, ice cores, corals, and lake sediments to reconstruct the climate of earlier times. Most of the available data pertain to the northern hemisphere and show, according to the authors, that the warmth of the northern hemisphere over the past few decades is likely unprecedented in the last 1,000 years and quite possibly in the preceding 1,000 years as well.

Climate model simulations cannot explain the anomalous late 20th century warmth without taking into account the contributions of human activities, the authors say. They make three major points regarding Soon and Baliunas's recent assertions challenging these findings.

First, in using proxy records to draw inferences about past climate, it is essential to assess their actual sensitivity to temperature variability. In particular, the authors say, Soon and Baliunas misuse proxy data reflective of changes in moisture or drought, rather than temperature, in their analysis.

Second, it is essential to distinguish between regional temperature anomalies and hemispheric mean temperature, which must represent an average of estimates over a sufficiently large number of distinct regions. For example, Mann and his co- authors say, the concepts of a "Little Ice Age" and "Medieval Warm Period" arose from the Eurocentric origins of historic climatology. The specific periods of coldness and warmth differed from region to region and as compared with data for the northern hemisphere as a whole.

Third, according to Mann and his colleagues, it is essential to define carefully the modern base period with which past climate is to be compared and to identify and quantify uncertainties. For example, they say, the most recent report of the Intergovernmental Panel on Climate Change (IPCC) carefully compares data for recent decades with reconstructions of past temperatures, taking into account the uncertainties in those reconstructions. IPCC concluded that late 20th century warmth in the northern hemisphere likely exceeded that of any time in the past millennium. The method used by Soon and Baliunas, they say, considers mean conditions for the entire 20th century as the base period and determines past temperatures from proxy evidence not capable of resolving trends on a decadal basis. It is therefore, they say, of limited value in determining whether recent warming in anomalous in a long term and large scale context.

ps418 · 07-14-2003, 05:55 AM

The library I use has a subscription to EOS, so I'll be interested to see both of the articles, claiming that natural processes can/cannot explain 20th century climate change.

Quote:

Second, it is essential to distinguish between regional temperature anomalies and hemispheric mean temperature, which must represent an average of estimates over a sufficiently large number of distinct regions. For example, Mann and his co- authors say, the concepts of a "Little Ice Age" and "Medieval Warm Period" arose from the Eurocentric origins of historic climatology. The specific periods of coldness and warmth differed from region to region and as compared with data for the northern hemisphere as a whole.

I'll have to read the article, since it is possible that new evidence has emerged, but it is not correct that the MWP was restricted to Europe, as the statement above suggests. Tree-ring analyses from 14 seperate sites distributed across the northern hemisphere suggested that the MWP was hemisphere-wide and similar to the 20th century trend (Esper et al, 2002). However, in the commentary on Esper et al by Mann and Hughes, they point out that Esper et al only used the modern data up to 1980, and that the last two decades add to the warming and show that the late 20th century is anamolous.

Esper et al, 2002. Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability. Science 295, Number 5563, Issue of 22 Mar 2002, pp. 2250-2253.

Patrick

nogods4me · 07-14-2003, 06:43 AM

Here you can find the UN's IPCC reports on global climate changes. More info than you can shake a fundie at. Much is in PDF format so it can be printed out and perused at your leisure. Summaries, charts, recommendations, etc, etc, etc.

04-18-2003, 07:38 AM	#54
SULPHUR Senior Member Join Date: Nov 2002 Location: hobart,tasmania Posts: 551	NCDC Climate,2002. Easy to get access to. And contains latest data.Or are you scared to look.

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04-17-2003, 09:13 PM	#51
nermal Veteran Member Join Date: Mar 2003 Location: Colorado Posts: 1,969	The kitten ain't runnin, he's just too busy right now to check the sources listed in depth. He has a full time job, a kid, and is wrapping up a math degree. He'll get to things as he can. Ed

04-18-2003, 04:27 AM	#52
nermal Veteran Member Join Date: Mar 2003 Location: Colorado Posts: 1,969	Had a chance to browse the articles. The Greenland ice sheet is thinning. Noted. If the trend continues, it will affect sea levels. Understood. Now demonstrate two things: 1. sea levels have been measured as rising. That is the subject we were discussing as of the posting of these articles, I believe. 2. The cause is anthropogenic. That is the subject by which I insinuated myself into this thread. Recall, I have stated from the outset that the climate is dynamic. I also asserted that there is no physical evidence that people are changing the global climate. I will concede local affects ie. heat island effects. You might look at John Daly's site. Heck, go see him. He's just down the street, as I'm sure you know. Maybe he's not a nice guy? He has monitoring station data from all over Greenland charted from the early part of this century to 1999. It's kind of surprising just how "great" the warming trend is in Greenland. Maybe the other explanation for the ice thinning offered by the sources (lubrication) makes some sense. As for the Arctic Ice thinning, the author of ps418's article emphatically stated that there was thinning, and not relocation. Given the sketchiness of the measurements, such an unequivocal statement arrouses suspicion. Look here: acsys.npolar.no/news/2001/No1_p2.htm It must also be pointed out that major recessions of the arctic ice sheet has ocurred before, as noted by ships logs from the 1700's. Just for giggles, you might also look here: http://news.bbc.co.uk/1/hi/in_depth/...ge/1026375.stm Ed

04-18-2003, 03:01 PM	#55
nermal Veteran Member Join Date: Mar 2003 Location: Colorado Posts: 1,969	I'm too skeered. My eyes are shut tight. Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there.Don't be there...... Ok I'll look. Ed

07-14-2003, 06:43 AM	#58
nogods4me Contributor Join Date: Jun 2001 Location: Baltimore, MD USA Posts: 17,432	Here you can find the UN's IPCC reports on global climate changes. More info than you can shake a fundie at. Much is in PDF format so it can be printed out and perused at your leisure. Summaries, charts, recommendations, etc, etc, etc.

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