SYNERGISM OF TERRESTRIAL CARBON CYCLE FEEDBACKS IN SIMULATIONS OF FUTURE CLIMATE CHANGE
Description: This paper examines two key feedbacks that
operate between the terrestrial carbon cycle, atmospheric carbon dioxide (CO2)
and climate: the positive carbon cycle-climate feedback and the negative CO2
fertilization feedback. Both feedbacks
affect strongly the growth rate of future atmospheric CO2, and
interact in such a way that the effect of one is notably modified in the
absence of the other.
Author's Names: H.D. Matthews
Filesize: 76.93 Kb
Added on: 16-Sep-2005 Downloads: 20
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POTENTIAL VARIATIONS IN THE O-17 TO O-18 RELATION OF WATER AND ICE SAMPLES
Description: It is generally assumed
that the variations of O-17 and O18 contents of water samples are closely
related. In literature there are different relations described, for instance
the Craig relation that assumes O-17 to vary half compared to O-18. O-17 of
water can be determined from the measured ...
Author's Names: M. C. Leuenberger
Filesize: 53.59 Kb
Added on: 01-Aug-2005 Downloads: 19
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ON THE SENSITIVITY OF OCEAN BIOGEOCHEMISTRY AND AIR-SEA CO2 FLUX TO CLIMATE DRIVEN VARIATIONS ...
Description:
A
coupled Biogeochemistry-Ecosystem-Circulation (BEC)
ocean model is used to examine the sensitivity of ocean biogeochemical cycling
and air-sea CO2 exchange to variations in mineral dust deposition
from the atmosphere. Mineral dust
deposition estimates from four different climate regimes are used to force the
ocean model. Our estimated climate-induced
changes in dust deposition to the oceans significantly modify phytoplankton
community composition, and global-scale rates of nitrogen fixation, export
production, and air-sea CO2 flux. Dust driven variations in air-sea CO2
exchange exceeding 1 PgC/yr are of similar magnitude to present net oceanic
anthropogenic uptake. Dust deposition
directly modifies rates of export production and CO2 flux over large
regions where iron is the primary growth-limiting nutrient. Dust deposition also indirectly influences
these rates by modifying the rates of nitrogen fixation in the tropics and
subtropics where nitrogen is the primary limiting nutrient. Initially the direct pathway dominates the
ocean biogeochemical response to dust variations, but over multi-decadal
timescales the indirect response may be equally important. Our predicted decrease in mineral dust
deposition over the next century would significantly slow oceanic uptake of CO2
and act as a positive feedback mechanism for the ongoing global warming.
Author's Names: J. K. Moore, S. C. Doney, K. Lindsay, and N. Mahowald
Filesize: 22.54 Kb
Added on: 02-Aug-2005 Downloads: 18
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