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| Titel |
Granger causality from changes in level of atmospheric CO2 to global surface temperature and the El Niño–Southern Oscillation, and a candidate mechanism in global photosynthesis |
| VerfasserIn |
L. M. W. Leggett, D. A. Ball |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-21), S.11571-11592 |
| Datensatznummer |
250120106
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| Publikation (Nr.) |
 copernicus.org/acp-15-11571-2015.pdf |
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| Zusammenfassung |
A significant difference, now of some 16 years' duration, has been shown to
exist between the observed global surface temperature trend and that expected
from the majority of climate simulations. For its own sake, and to enable
better climate prediction for policy use, the reasons behind this mismatch
need to be better understood. While an increasing number of possible causes
have been proposed, the candidate causes have not yet converged.
With this background, this paper reinvestigates the relationship between
change in the level of CO2 and two of the major climate variables,
atmospheric temperature and the El Niño–Southern Oscillation (ENSO).
Using time-series analysis in the form of dynamic regression modelling with
autocorrelation correction, it is shown that first-difference CO2 leads
temperature and that there is a highly statistically significant correlation
between first-difference CO2 and temperature. Further, a correlation is
found for second-difference CO2 with the Southern Oscillation Index, the
atmospheric-pressure component of ENSO. This paper also shows that both these
correlations display Granger causality.
It is shown that the first-difference CO2 and temperature model shows no
trend mismatch in recent years.
These results may contribute to the prediction of future trends for global
temperature and ENSO.
Interannual variability in the growth rate of atmospheric CO2 is
standardly attributed to variability in the carbon sink capacity of the
terrestrial biosphere. The terrestrial biosphere carbon sink is created by
the difference between photosynthesis and respiration (net primary
productivity): a major way of measuring global terrestrial photosynthesis is
by means of satellite measurements of vegetation reflectance, such as the
Normalized Difference Vegetation Index (NDVI). In a preliminary analysis,
this study finds a close correlation between an increasing NDVI and the
increasing climate model/temperature mismatch (as quantified by the
difference between the trend in the level of CO2 and the trend in
temperature). |
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