Image talk:Co2-temperature-plot.svg

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[edit] Cut discussion

I don't think its appropriate for a figure caption to have a lot of (contentious) science discussion on it. So I cut it all out. This should be discussion on the page that references this figure instead. Whatever the lag/leads are, they can't be properly seen on a figure of this scale anyway William M. Connolley 09:29, 9 November 2006 (UTC)

I disagree with this action. I propose the cut is reverted. Leland McInnes, it is your picture so you should retain ultimate editorial control. Chris Line, 9 November 2006
Please sign your messages (with ~~~~; better still, get an account). LM doesn't retain control, of course. Looking at what links here the answer seems to be nothing. Which is a bit odd... I thought it was used. But if its not linked, this entire discussion is pointless, as no-one will see it (another reason to have it in the article instead) William M. Connolley 10:29, 9 November 2006 (UTC)
You can link to the page by clicking on the image at the 'Global Warming' page. The editing of this page is restricted and the discussion could not be written in the main article. Although some of it may be more appropriate there as you suggest. Chris Line, 9 November 2006
OK, it *is* linked from the GW page, but doesn't show up in what-links-here. Odd. William M. Connolley 11:26, 9 November 2006 (UTC)
Can we at least agree that the temperature signal leads the CO2 signal? You can see this, particularly in the Vostok data. You can also check it statistically by computing the cross-covariance of the two signals using the original data. Chris Line, 9 November 2006
We could, but then the question would be, why are you so keen on that particular factoid? I ask because this is a common skeptic argument in the GW wars. As a fact, its semi-OK (though there are complexities: T is from the ice, and CO2 from the bubbles, and getting these onto the sam age scale is non-trivial). But the implication that people like to leave dangling from it (CO2 doesn't affect T; its the other way round) is wrong. I still think the text better belongs on an article page, but which? William M. Connolley 11:26, 9 November 2006 (UTC)
The text might belong on the article page where the picture appears. Or it could be retained in its original location. Chris Line
I am keen because the matter is very important to us all and our planet. We should be able to discuss the facts and their implications. Chris Line, 9 November 2006
If this forms an argument for those who are skeptics of global warming then it is important that a counter-argument is available. We should be able to justify our views. Chris Line, 9 November 2006
Revert the changes? Add to the discussion if you would like and explain as you have in your comment? Chris Line, 9 November 2006
I don't think many people are watching this image page, unlike say the GW page where people *are* watching. So if you want a decent discussion, don't have it in this dark corner. As for the science, try: http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/ William M. Connolley 11:55, 9 November 2006 (UTC)
I will take a look and consider your suggestion. Although, it is late getting late here so I best get some rest soon and say goodnight. (Chrisnumbers2000 11:59, 9 November 2006 (UTC))
It is a good article. Cheers. (Chrisnumbers2000 12:11, 9 November 2006 (UTC))
WMC, if temperature & CO2 are operating on a mutual positive-feedback loop (i.e., warming causes CO2 release, which causes more warming, which releases more CO2 and so on) as your link claims, shouldn't the earth have undergone a runaway greenhouse effect a long time ago? Your source doesn't seem to mention anything about what brings the temperature back down. If you've got info on the subject, I'd like to see it. 130.36.62.140 20:07, 9 November 2006 (UTC)

Some of the feedbacks are limited (vegetation related, say). However, I believe that where exactly the glacial-interglacial CO2 comes from isn't really known William M. Connolley 21:40, 9 November 2006 (UTC)

I like the improvement. The progression of the time axis from left to right appears more standard and facilitates a standard interpretation. (Chrisnumbers2000 13:20, 20 January 2007 (UTC))

In the 250+ years we have been burning coal and gas, only the last ~100 have been on a massive scale and it is difficult to asses the effects if any we may have had. Not to mention, C02 is not necessarily the primary greenhouse gas as others are many times as potent, take methane and certain bromides. While the temperatures have obviously been slightly increasing since the industrial age heated up, feedback effects on this planet tend to be negative, up to a point, as in biological systems. On a planetary scale a positive feedback loop means fluctuating temperatures, not just nice steady warming. The main concern is the health of the ocean life which allows us to live. (2/3 of oxygen anyone?) —Preceding unsigned comment added by 75.165.105.221 (talk) 03:59, 7 May 2008 (UTC)

[edit] Basic question

Just curious, why use delta-deuterium instead of delta-18O, and what implications (if any) does this have for the interpretation? I'm not a paleo guy, so this could be a dumb question... Raymond Arritt 18:22, 9 November 2006 (UTC)

I was simply working with available data. The Antarctic cores seem to have gone with delta-deuterium, while Greenland cores went with delta-18O. My (admittedly limited) understanding is ultimately it makes little difference, and it is consistency (within each core sample) that counts, so it's probably just one of those historical accidents as to which was initially measured. Leland McInnes 20:29, 9 November 2006 (UTC)

[edit] No temperature scale on y axis

There is, as far as I can see..., no temperature scale on the y axis. (Also, the reversed time axis may be confusing).Narssarssuaq 00:23, 28 November 2006 (UTC)

It was confusing. I've noted that the scale is deuterium, a temperature proxy William M. Connolley 09:40, 28 November 2006 (UTC)


Not only that, the current C02 level is prominently shown, but the current duterium level is omitted.

The implication of the graph is that the C02 level and duterium level are connected. Then to show the current C02 level, the intention is to say, look, given the connection, we are well outside the historical record, so it must mean that temperatures are much higher.

However, not showing current levels has probably been done because even though the current C02 levels are high, the deuterium levels aren't.

Nick

[edit] Present C02 level arrow

What the hell? The present C02 level varries enormously depending on who you talk to. What bothers me is that the graph is cited, but it doesn't say where this "present C02 level" information comes from. Don't remove the arrow, but PLEASE get some kind of citation for it. --24.239.174.223 16:17, 7 January 2007 (UTC)

Don't understand "various enormously", since it doesn't. See Greenhouse_gas. Current value is about 383 ppmv, with regular seasonal variation of about 8 [1] William M. Connolley 17:25, 7 January 2007 (UTC)
The "varies enormously" was me misreading some stuff. My bad. Still, a citation would make it look better if nothing else.
--24.239.174.223 22:11, 13 January 2007 (UTC)

[edit] Global dimming question

I have seen a documentary on global dimming that suggested that evaporation follows humidity, wind, and sunlight more than temperature. I think that the conclusion that the deuterium is an indicator of just temperature needs to be checked. I see it as fallacious. Large scale erruptions, forest fires, desertification will change all this. Besides the argument about the local sources of the evaporated water changing holds water. They follow wind currents not temperature. Finally what about CO2 diffusion in ice? 67.72.98.108 01:48, 8 June 2007 (UTC)

The use of deuterium as a T proxy is well established, as are various errors/problems/complications (take your pick). But you'll need to read up on that science if you want to criticise it - your opinion from a TV prog isn't good enough William M. Connolley 09:06, 8 June 2007 (UTC)