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| Titel |
Constrained projections of high northern latitudinal photosynthesis increase by satellite observations of vegetation greenness |
| VerfasserIn |
Alexander J. Winkler, Ranga Myneni, Victor Brovkin |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250150633
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| Publikation (Nr.) |
 EGU/EGU2017-15114.pdf |
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| Zusammenfassung |
| Satellite observations of the last three decades provide strong evidence that the Earth is
greening. Especially in northern high latitudes, a substantial increase of the leaf area index
(LAI), an indicator of greening, is observed. For these regions, it is assumed that plant growth
benefits from higher temperature (radiative effect) and rising atmospheric CO2 concentration
(CO2 fertilization effect). This greening trend, in terms of increasing LAI, is also simulated
by various global ecosystem models. We also found a persistent greening trend analyzing
historical simulations of Earth system models (ESM) participating in Phase 5 of the Coupled
Model Intercomparison Project (CMIP5). However, a wide spread in magnitude of an
associated increase of terrestrial gross primary production (GPP) among the ESMs is found,
and thus contributes to pronounced uncertainties in projections of future climate
change.
Here we demonstrate that the tight correlation between enhanced GPP of high northern
latitudinal ecosystems and their LAI sensitivity to both key environmental factors,
temperature and CO2 concentration, opens up the possibility of an Emergent Constraint on
plant photosynthesis. Combining this almost linear relationship across the ensemble of
CMIP5 models with the LAI trends in the long-term satellite records, we are able
to constrain projections of vegetation growth increase for respective ecosystems. |
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