Und wenn man weiter zurückblickt...

verfasst von fridolin, 01.12.2005, 12:58

-->..., nämlich auf geologische Zeiträume, sieht es so aus:

[img][/img]

In a new paper in Nature (v.411, p.287, 17 May 2001), Gregory Retallack compared leafstomata of Ginko
trees with similar stomata from fossil remains of related ginko trees as far back as 300 million years.
From this, he was able to reconstruct the history of atmospheric carbon dioxide as shown left. Today's
CO2 level (370 ppmv) is added (horizontal red line), and it is readily apparent that CO2 in the distant
past reached between 2,000 and 3,000 ppmv, or to 10 times the pre-industrial level of 280 ppmv. And
we are paranoid about a mere doubling to 560 ppmv in the next 150 years. If anything, our present
level of CO2 is very low by geological standards (perhaps even dangerously low during recent
glaciations).

The above graph compares CO2 (solid blue line, with standard deviations shown in shaded blue) with
a low resolution temperature chart covering the same period. The author concludes in his abstract -
"These results support the role of water vapour, methane, and CO2 in greenhouse climate warming
over the past 300 Myr." These are carefully crafted words, given the editorial policy toward global
warming of the journal he was publishing in. CO2 was mentioned only as a third factor, the primary
role being attributed to water vapour, a very safe and correct choice to preserve the integrity of his
findings.

But what else do we find in the above chart? The resolution of the CO2 chart is coarse, ± 6 million
years, but even with that caveat, it is clear that as with many other palaeo-climate studies comparing
CO2 with temperature, this study shows the same tendency for temperature changes to lead CO2
changes. This is apparent as a `right shift' in the CO2 chart when compared with the temperature chart
above it. This means that the CO2 changes were caused by the temperature changes, not the other
way around.

It is also apparent that the Earth cruised through periods of very low CO2 (such as today) and periods
when CO2 was up to ten times greater, with no ill effects to the climate. Indeed, the Earth was more
biologically productive during the high CO2 regimes (it needed to be to support all those hungry
dinosaurs).This provides us with the confidence that higher levels of CO2 (but still low by geological
standards) will have no ill effects on the Earth's climate, but make the Earth much more productive
biologically. The greening of the Earth is the only significant consequence of rising CO2.

Hinweis zum Lesen: http://www.schulphysik.de/klima/alvens/klima.html

Thread gesperrt

 

gesamter Thread:

• OT: Umwelt-Schäden durch Antennen-Strahlungen (Smog) - Emerald, 30.11.2005, 22:01
  • Antennen-Strahlung und Golfstrom?? - fridolin, 30.11.2005, 22:26
    • Re: Antennen-Strahlung und Golfstrom?? - Emerald, 30.11.2005, 22:32
      • Vorsicht mit Kyoto-Protokoll - Ecki1, 30.11.2005, 22:51
        • Re: Vorsicht mit Kyoto-Protokoll - crosswind, 01.12.2005, 00:39
          • Und ich dachte, es könne nur einen geben ;-))) (o.Text) - Ecki1, 01.12.2005, 16:01
        • Re: Vorsicht mit Kyoto-Protokoll - CRASH_GURU, 01.12.2005, 09:06
          • CO2 und Methan während der letzten 650 000 Jahre. - Georges, 01.12.2005, 12:25
            • Re: CO2 und Methan während der letzten 650 000 Jahre. - CRASH_GURU, 01.12.2005, 12:50
            • Und wenn man weiter zurückblickt... - fridolin, 01.12.2005, 12:58
          • Re: Vorsicht mit Kyoto-Protokoll - T. Mai, 01.12.2005, 13:53
            • Re: Vorsicht mit Kyoto-Protokoll - CRASH_GURU, 01.12.2005, 14:45
      • Re: Antennen-Strahlung und Golfstrom?? - Dieter, 01.12.2005, 09:11
    • Emerald, lies mal hier... - pecunia, 01.12.2005, 09:38