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| MINERAL CARBON DIOXIDE SEQUESTRATION: STILL A VIABLE OPTION Description:
This
paper provides background and summarizes evidence supporting the possibility of
developing a low-cost mineral carbon dioxide sequestration technology.
Filesize: 19.09 Kb Added on: 01-Aug-2005 Downloads: 295 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
LONG-TERM CONSEQUENCES OF CONTINUED CARBON DIOXIDE EMISSION TO THE ATMOSPHERE Description: Continued emissions of carbon dioxide to the
atmosphere will affect climate and ocean chemistry. These consequences can be
anticipated by consideration of basic physical principles, past climates, and
calculations. Emission of 5,000 PgC (= amount of carbon in conventional fossil-fuel
resources) over a few centuries could produce radiative forcing of climate of
about 10 W m-2 which could be expected to produce global mean
warming of ~4 to 12 °C. Warming in this
range would have large biological and human consequences. It could threaten the
ice sheets and lead to a long-term sea-level rise of 70 m. Ocean pH could decrease by 0.7 units, making
the oceans more corrosive to carbonate minerals than they have been for many
millions of years. From the perspective of geology and biological evolution,
these changes would occur rapidly, overwhelming most natural processes that
would buffer CO2 changes occurring
over longer time intervals, and thus may produce changes at a rate and of a
magnitude that exceed the adaptive capacity of at least some biological
systems. To find comparable events in Earth history, we need to look back tens
of millions of years to rare catastrophic events. Filesize: 21.50 Kb Added on: 27-Jul-2005 Downloads: 275 Home Page | Comment on Proceeding | Details | Comments (1) Category: Opening Talks
IMPACT OF CLIMATE-CARBON CYCLE FEEDBACKS ON EMISSIONS SCENARIOS TO ACHIEVE STABILISATION Description: At present, approximately half of anthropogenic CO2
emissions are absorbed by the land and oceans [Jones and Cox, 2005], but climate changes may act to reduce this
uptake, leading to higher CO2 levels for a given emission scenario [Cox et al., 2000, Friedlingstein et al., 2005, in prep.]. Less attention has been
paid to the potential impact of carbon cycle feedbacks on the emissions
reductions required to achieve stabilisation (the so called “permissible
emissions”), although this is arguably more pertinent to the issue of avoiding
dangerous climate change in the context of the United Nations Framework
Convention on Climate change. Filesize: 103.88 Kb Added on: 29-Jul-2005 Downloads: 211 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
GREENHOUSE GAS CO2, CH4 AND CLIMATE EVOLUTION SINCE 650KYRS DEDUCED FROM ANTARCTIC ICE CORES Description: Ice cores are unique archives of past climatic and atmospheric
conditions through the isotopic composition of the ice and the analysis of the
air bubbles trapped. In 1999 Petit et al published the reconstruction of the
Antarctic climate and atmospheric composition over the last 420 000 years from
the Vostok ice core. This record covered the last four glacial inter glacial
cycles back to the end of the marine interstadial 11 (MIS 11). It has revealed
the close relationship between the atmospheric part of the carbon cycle and the
climate. With CO2 concentration oscillating between 180 and 280 ppmv
during the last 4 climatic cycles. In
a similar way the methane concentration followed closely
temperature on glacial interglacial time scales, with millennial-scale
structures during glacial times which appear out of phased with Antarctic
temperature but, at least for the last glaciation, in phase with the Greenland rapid climatic oscillations, as revealed by the
GISP and GRIP ice cores. Filesize: 15.87 Kb Added on: 27-Jul-2005 Downloads: 200 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
SUBSTRATE INDUCED GROWTH RESPONSE OF SOIL AND RHIZOSPHERE MICROBIAL COMMUNITIES UNDER ELEVATED CO2 Description: The
maximal specific growth rate of microorganisms from rhizospheres of Populus deltoides grown under normal CO2 concentration
in the atmosphere (400 ppm) was lower compared to the assessments made for
plots under elevated CO2 (800 and 1200 ppm). A similar conclusion
was made for microbial communities from soil under winter wheat and sugar beets
grown under 370 and 550 ppm CO2 in the atmosphere. Three to four
years fumigation of field plots with elevated CO2 has been shown to
result in the formation of rhizosphere microbial communities characterized by
faster specific growth rates as compared to microbial community under control
plants. Filesize: 147.23 Kb Added on: 26-Jul-2005 Downloads: 196 Home Page | Comment on Proceeding | Details Category: Abstracts/Impacts of High CO2 on Land and Ocean Ecosystems
FREQUENT MEASUREMENTS OF ATMOSPHERIC CO2 AND OTHER TRACE SPECIES USING COMMERCIAL AIRLINES Description:
A
new research project has started in 2003 to develop Continuous CO2
Measurement Equipment (CME) and
Automatic Air Sampling Equipment (ASE)
for commercial airlines. CMEs are planning to be installed on five aircrafts
and fly to South East Asia, East Asia, Europe, North America, Pacific and Australia.
Routine air sampling by ASE will
be done twice a month between Japan
and Australia.
After issuing the certification, first observation flight by Boeing 747-400
will be conducted in October, 2005. Preliminary observation by small research
aircraft indicates that CME
produces reasonable results.
Filesize: 77.95 Kb Added on: 01-Aug-2005 Downloads: 194 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
DECADAL CHANGES IN OCEAN CARBON UPTAKE Description:
There
is growing evidence that the rate of anthropogenic CO2 uptake in the
ocean is changing over time. Several programs are poised to assess current and
future ocean CO2 uptake rates, but there are issues with how to
extrapolate these measurements to decadal-scale changes over entire ocean
basins. One possibility is to exploit the growing network of ARGO floats that
are collecting profiles throughout the global oceans. We explore the viability
of this approach and make recommendations for how the ARGO network might be
made more useful for biogeochemical applications.
Filesize: 25.55 Kb Added on: 04-Aug-2005 Downloads: 193 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
NEW COUPLED CLIMATE-CARBON SIMULATIONS WITH THE IPSL MODEL: FROM VALIDATION WITH ATMOSPHERIC ... Description: We have developed a
Climate-Carbon coupled model based on the IPSL OAGCM and on two biogeochemical
models, ORCHIDEE for the continent and PISCES for the ocean, to investigate the
coupling between climate change and the global carbon cycle. We have performed
four climate-carbon simulations over the 1860-2100 period in which atmospheric
CO2 is interactively calculated. They are :
§
A control coupled
simulation with no anthropogenic emissions.
§
A coupled
simulation with anthropogenic emissions.
§
A coupled
simulation with anthropogenic emissions including non-CO2 greenhouse
and sulfate aerosols.
§
An uncoupled
carbon simulation with the same anthropogenic emissions as second simulation
but for which atmospheric CO2 change has no impact on climate.
Compared to the first IPSL
Climate-Carbon coupled model [Dufresne,
et al., 2002], the simple carbon models have been replaced by IPSL advanced
ocean and land biogeochemical models, respectively PISCES and ORCHIDEE. CO2
is transported in the atmosphere and compared with observations. Comparison
with satellite data is also done. We then analyze the coupled and uncoupled
simulations, highlight the importance of the climate change both on the oceanic
and biosphere sink and estimate the climate-carbon feedback. The results are
also compared to the outputs of other models participating in the C4MIP
inter-comparison project. Finally, off-line simulations are carried out to
perform sensitivity tests (fire, dynamics of land and ocean ecosystems, soil
respiration) in order to identify the key processes which govern the simulated
response. Filesize: 35.21 Kb Added on: 27-Jul-2005 Downloads: 183 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
EUROPEAN-WIDE REDUCTION IN PRIMARY PRODUCTIVITY CAUSED BY THE HEAT AND DROUGHT IN 2003 Description:
Future climate warming is expected to enhance plant
growth in temperate ecosystems and to increase carbon sequestration. But
although severe regional heatwaves may become more frequent in a changing
climate, and their impact on terrestrial carbon cycling is unclear. Europe experienced a particularly extreme climate anomaly
during 2003, with July temperatures up to 6°C above long-term means, and annual
precipitation deficits up to 300 mmy-1, that is 50% below the
average. We used the 2003 heatwave as a ‘laboratory assistant’ to estimate the
impact on terrestrial carbon cycling.
Filesize: 23.98 Kb Added on: 28-Jul-2005 Downloads: 180 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
ROLE OF AGRICULTURAL MANAGEMENT IN MITIGATING GREENHOUSE EMISSIONS Description: Analyses of
Northern Hemisphere carbon fluxes indicate that a number of ecosystem processes
jointly contribute to source and sink exchanges of CO2 which affect
the net carbon sequestered from the atmosphere. These processes (e.g., CO2,
N2O, CH4, and H2O dynamics) exhibit high
variability in time and space with the largest variability corresponding to
human land management events. Therefore, the spatial and temporal incorporation
of land management information is needed to properly represent net carbon and
other GHG fluxes. Filesize: 34.12 Kb Added on: 03-Aug-2005 Downloads: 175 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
HAZARDS OF TEMPERATURE ON FOOD AVAILABILITY IN CHANGING ENVIRONMENTS Description: Global
temperatures are predicted to increase from rising
levels of atmospheric carbon dioxide (CO2) and other greenhouse
gases. We conducted experiments in sunlit, controlled-environment chambers and
temperature-gradient greenhouses to determine effects of elevated temperature
and doubled CO2 concentration on pollination and yield of rice,
soybean, dry bean, peanut, and grain sorghum. Photosynthesis and vegetative
growth were more tolerant of increasing temperatures than reproductive
processes. Rice seed yields were optimum at 25°C mean daily temperature and
decreased with increasing temperature (typically about 10% decline for each 1°C
rise in temperature). Grain sorghum yield response to temperature was similar to
rice, but dry bean was more sensitive, and soybean and peanut were more
tolerant. Pollen viability followed a temperature response similar to seed
yield. Comparisons of 43 rice cultivars in temperature-gradient greenhouses
showed genetic variation in percent seed-set in response to a 4.5°C increase
above ambient temperatures in Florida.
Thus, there appears to be a range of adaptation of seed crops to temperature.
Elevated CO2 did not prevent high temperature decline in yield; in
dry bean it made pollination more sensitive to high temperature. In summary, global
warming will be a greater threat to crop seed yields than to photosynthesis and
vegetative growth. However, crop genetic improvements might ameliorate part,
but not all, of the high temperature hazards for seed yields and global food
security.
Filesize: 28.20 Kb Added on: 25-Jul-2005 Downloads: 174 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
PERSISTENCE OF NITROGEN LIMITATION OVER TERRESTRIAL CARBON UPTAKE Description: Because
vegetation growth in the Northern Hemisphere is typically nitrogen-limited,
increased nitrogen deposition could have attenuating effect on rising
atmospheric CO2 by stimulating the accumulation of biomass. Given
the high carbon to nitrogen ratios and long lifetimes of carbon in wood, a most
significant effect of nitrogen fertilization is expected in forests. Forest
inventories indicate that the carbon content of northern forests have increased
concurrently with increased nitrogen deposition since the 1950s [Spiecker et al.,
1996]. In addition, variations in atmospheric CO2 indicate a
globally significant carbon sink in northern mid-latitude forest regions [Schimel et al.,
2001]. It is unclear however, whether elevated nitrogen deposition or other
factors are the primary cause of carbon sequestration in northern forests. We
argue that the elevated nitrogen deposition is unlikely to enhance vegetation
carbon sink significantly because of its differentiating effect on the carbon
sequestration capacity of uneven aged forests and climatic limitations on
carbon sequestration in the Northern Hemisphere. We estimate the potential of
forests with lifted nitrogen limitation to decelerate CO2
concentrations rise in the atmosphere and therefore to mitigate climate
warming. We also outline areas of the Northern Hemisphere which are most
sensitive to increased nitrogen deposition. Filesize: 135.93 Kb Added on: 28-Jul-2005 Downloads: 173 Home Page | Comment on Proceeding | Details | Comments (1) Category: Abstracts/Carbon Cycle Response to Environmental Change
TOP-DOWN REGIONAL CO2 FLUXES FOR NORTH AMERICA ESTIMATED FROM NOAA-CMDL CO2 OBSERVATIONS Description:
We present an analysis of terrestrial net CO2 fluxes from North America for the period 2000-2004. These fluxes
consist of hourly maps at ~70km×100km resolution that are consistent with
observed atmospheric CO2 mixing ratios, as well as with varying
climatic conditions across different ecosystems as observed from space. The
flux maps are created in a newly developed ensemble data assimilation system
that consists of the atmospheric Transport Model v5 (TM5), the Vegetation
Photosynthesis Respiration Model (VPRM), and an efficient Bayesian
least-squares algorithm to optimize the fluxes from different biomes in VPRM
against CO2 mixing ratios from the NOAA-CMDL
observing network. The stochastic nature of the ensemble data assimilation
system allows us to consistently include uncertainty on net CO2 fluxes from the neighboring oceans and more distant continents
in the flux estimates for North America.
Filesize: 364.14 Kb Added on: 03-Aug-2005 Downloads: 168 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
A DECREASING TREND IN NORTHERN HEMISPHERE CARBON UPTAKE SINCE 1992 Description: Increases in the north-south gradient of
atmospheric CO2
at Northern Hemisphere measurement sites of the NOAA/CMDL Global Air Sampling
Network reveal a shrinking carbon sink.
14 of 16 low altitude sites show differences with South Pole increasing
at a faster rate than can be explained by fossil fuel emissions, resulting in
an average north-south difference at remote marine sites nearly 1 ppm larger in
2003 than in 1992. Regardless of whether
this trend will persist, it shows that large changes in the carbon cycle can
occur rapidly and is a strong indication of the tenuous nature of terrestrial
carbon sinks.
Filesize: 89.53 Kb Added on: 02-Aug-2005 Downloads: 166 Home Page | Comment on Proceeding | Details | Comments (2) Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
ESTIMATION OF ATMOSPHERIC CO2 FROM AIRS INFRARED SATELLITE RADIANCES IN THE ECMWF DATA ASSIMILATION Description:
Atmospheric
CO2 concentrations have been obtained from the Atmospheric Infrared
Sounder (AIRS) radiance data within the European Centre for Medium-Range
Weather Forecasts (ECMWF) data assimilation system. In a first explorative
configuration, a subset of channels from the AIRS instrument has been
assimilated providing estimates of tropospheric column-averaged CO2
mixing ratios representative of a layer between the tropopause and about 700
hPa at observation locations only. Results show considerable geographical and
temporal variability with values ranging between 370 and 382 ppmv. The 5-day
mean estimated random error is about 1%, which is confirmed by comparisons with
flask observations on board flights of Japanese airliners in the west-Pacific
region. This study demonstrates the feasibility of global CO2
estimation using high spectral resolution infrared satellite data in a
numerical weather prediction data assimilation system. Currently, the system is
being improved to treat CO2 as a full three-dimensional atmospheric
variable included in the forecast model. This allows more flexibility in the
constraints on the CO2 estimation as well as the possibility of
assimilating other data sources (e.g., near-infrared satellite data and
flasks). The CO2 fields provided by the data assimilation system
have great potential to assist the surface flask network in constraining
current top-down carbon flux estimates.
Filesize: 217.21 Kb Added on: 28-Jul-2005 Downloads: 164 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
A 50 YEAR RECORD OF THE EVOLUTION OF THE MERIDIONAL GRADIENT IN ATMOSPHERIC CO2 AND ITS ... Description:
Measurements of atmospheric CO2 began in
1957-1958 at a wide range of locations, including at fixed stations, on ice
floes, on oceanic expeditions, and on aircraft flights, with logistical and
financial support provided by the International Geophysical Year (IGY) program.
Although the measurement effort was reduced in scope immediately following the
IGY, today, measurements are made at more than 100 locations. Over this same time interval, emissions of CO2
from fossil fuel combustion increased from 2.3 thousand million metric tons per
year (GtC/yr) in 1958 to 7.1 GtC/yr in 2003 [Marland et
al., 2005, and personal communication]. More than 90% of this CO2 was
released into the northern hemisphere where it lingered before mixing fully
world-wide. The atmospheric CO2
concentration, in response, rose faster in the northern hemisphere than in the
southern, the interhemispheric difference increasing from near zero during the
IGY to about 3 parts per million (ppm) in 2003. For all northern hemisphere
stations where our program has measured CO2, the gradient changes
relative to the South Pole are generally proportional to the rate of fossil
fuel CO2 emissions, disregarding seasonal and short term interannual
variability in the CO2 data.
Here, we use this fact to diagnose how the carbon cycle has evolved over
the past half century.
Filesize: 40.33 Kb Added on: 01-Aug-2005 Downloads: 164 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
PROPOSING A MECHANISTIC UNDERSTANDING OF ATMOSPHERIC CO2 DURING THE LATE PLEISTOCENE... Description: Paleo-climate records in ice cores revealed high
variability in temperature, atmospheric dust content and carbon dioxide. The
longest CO2 record from the Antarctic ice core of the Vostok station
went back in time as far as about 410 kyr BP showing a switch of glacials and
interglacials in all those parameters approximately every 100 kyr during the
last four glacial cycles with CO2 varying between 180-300 ppmv [Petit et al., 1999]. New measurements of dust and the
isotopic temperature proxy deuterium of the EPICA Dome C (EDC) ice core covered
the last 740 kyr, however, revealed glacial cycles of reduced temperature
amplitude [EPICA community members, 2004]. These
new archives offer the possibility to propose atmospheric CO2 for
the pre-Vostok time span as called for in the EPICA challenge [Wolff et al., 2004]. Here, we contribute to this challenge
using a box model of the isotopic carbon cycle [Köhler et
al., 2005] based on process understanding previously derived for
Termination I. Our results show that major features of the Vostok period are
reproduced while prior to Vostok our model predicts significantly smaller
amplitudes in CO2 variations. Filesize: 48.63 Kb Added on: 01-Aug-2005 Downloads: 164 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
THE POTENTIAL OF UPPER OCEAN ALKALINITY CONTROLS FOR ATMOSPHERIC CARBON DIOXIDE CHANGES Description:
Extreme
global model scenarios of complete preservation and degradation of biogenic
particulate CaCO3 (calcium carbonate) in open ocean waters which are
supersaturated with respect to CaCO3 were carried out. According to
these experiments, the theoretical potential of upper ocean alkalinity controls
for changing the atmospheric pCO2 (CO2 partial pressure)
amounts to several hundred μatm on time scales of several 104 years.
Up to a timescale of 103 years, however, the respective influence is
minor as compared to an expected anthropogenic increase of the atmospheric pCO2
in the order of 500-1000
μatm.
Filesize: 80.15 Kb Added on: 29-Jul-2005 Downloads: 162 Home Page | Comment on Proceeding | Details Category: Abstracts/Impacts of High CO2 on Land and Ocean Ecosystems
INTERANNUAL VARIABILITY IN TERRESTRIAL CARBON EXCHANGE USING AN ECOSYSTEM FIRE MODEL Description: We have incorporated a
semi-mechanistic fire model into the SEVER Dynamic Global Vegetation Model (DGVM).
The model produces estimates of net primary productivity (NPP), heterotrophic
respiration (HR) and fire carbon emission (FE) for the globe. This model was
run for the period 1957-2002 with the NCEP climate reanalysis data as an input.
Results were compared with the ATSR area burnt maps and a Time Dependent
Inverse (TDI) model fluxes of CO2. We find that on interannual time
scales NPP variability explains major part of flux variability simulated by the
TDI model, followed by the HR and FE contributions. Filesize: 64.05 Kb Added on: 08-Aug-2005 Downloads: 162 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
THE CHANGING CARBON CYCLE Description: The carbon cycle has undergone
changes from 1998-2003 as a result of extensive droughts. The CO2 seasonal amplitude at MLO
halted its increase, and the CO2 growth rate accelerated as a result
of a slowing down of the North American carbon sink. In a series of coupled carbon-climate model
experiments, we show a greater probability of drier soils in the 21st
century, especially in the tropics and in mid-latitude summers as
temperature-driven evapotranspiration exceed precipitation, and a positive
feedback between the carbon cycle and climate. This positive feedback reduces
the land and ocean’s capacity to store fossil fuel CO2 and
accelerates the warming. A fossil fuel emission accelerating rapidly as the
sink capacities decrease leads to further increases in the airborne fraction of
fossil fuel CO2.
Filesize: 58.93 Kb Added on: 28-Jul-2005 Downloads: 160 Home Page | Comment on Proceeding | Details | Comments (1) Category: Abstracts/Carbon Cycle Response to Environmental Change
WHAT ARE THE MOST IMPORTANT FACTORS FOR CLIMATE CARBON CYCLE COUPLING Description: Data
from long-term measurements of carbon balance in boreal, mid-latitude and
tropical ecosystems are used to assess the mechanisms that drive changes in
ecosystem carbon balance in response to a changing climate. We find that most
model parameterizations overestimate the temperature sensitivity of ecosystem
respiration and underestimate the role of soil water balance in controlling
respiration and flammability. We conclude that model assessments of
climate—carbon feedbacks must carefully simulate regional precipitation,
evaporation, evapotranspiration, and water balance, including factors leading
to fires (e.g. sources of ignition), in addition to assessing changes in
temperature. Covariances among these drivers of ecosystem respiration and
vegetation change may be critically important for these simulations. Filesize: 686.66 Kb Added on: 09-Aug-2005 Downloads: 159 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
NITROGEN REGULATION OF CARBON SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS IN RESPONSE TO RISING ... Description:
A highly controversial issue in global change
research is the regulation of terrestrial carbon (C) sequestration by soil
nitrogen (N) availability. The Third Assessment IPCC Report predicts rising atmospheric CO2
alone could stimulate terrestrial carbon (C) sequestration by 350 – 980 Pg (=1015
g) C in the 21st Century. Sequestering 350 – 980 Gt C in terrestrial
ecosystems requires 7.7 – 37.5 Pg (N) based on a stoichiochemical relationship
that approximately 0.005 g N is required for 1 g C stored in long-lived plant
biomass (i.e., wood) and 0.067 g N for 1 g C sequestered in soil organic matter
(SOM). Thus, to realistically predict
future C sequestration in terrestrial ecosystems, we have to understand how
closely C and N processes are coupled in response to rising Ca.
Filesize: 24.39 Kb Added on: 01-Aug-2005 Downloads: 158 Home Page | Comment on Proceeding | Details Category: Abstracts/Impacts of High CO2 on Land and Ocean Ecosystems
EFFECTS OF VERTICAL DIC DISTRIBUTION ON STORAGE EFFICIENCY OF DIRECT INJECTION OF CO2 INTO THE OCEAN Description:
We estimated the effects of initial
vertical distribution of dissolved inorganic carbon (DIC) on storage efficiency
of direct injection of CO2 into the ocean. Our simulations shown
that the storage efficiencies could be reduced up to 10% if a relative large
droplet (30 mm in diameter) was injected at depth of 1500m. The storage
efficiency of CO2 ocean sequestration is strongly related with not
only injection depth but also the initial CO2 droplet diameter. With
a given injection rate, the larger droplets injected will produce a dilute DIC
plume and thus improve the acute biological impacts but a smaller storage
effective due to droplet ascending.
Filesize: 204.22 Kb Added on: 28-Jul-2005 Downloads: 156 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
THE AMAZON AND THE MODERN CARBON CYCLE Description:
Is
the massive Amazon forest a CO2 sink, a source or is it in
equilibrium?
There
is a large uncertainty in carbon fluxes estimates for the tropics as a whole
and in particular for the Amazon region in South America,
bringing the attention to the lack of information to call the region a carbon
source or sink. The production of scientific consistent and long term data
series for the region is a process that has to advance step by step.
Filesize: 35.51 Kb Added on: 03-Aug-2005 Downloads: 156 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
THE AGE OF CARBON RESPIRED FROM TERRESTRIAL ECOSYSTEMS Description: Carbon
enters ecosystems through a single process, photosynthesis, and nearly all is
returned to the atmosphere through respiration, some 50-80% of which occurs
below-ground. Soil (belowground) respiration integrates CO2 derived
from C that has resided in the ecosystem for periods of differing duration,
ranging from relatively recent photosynthetic products that fuel root
metabolism, to CO2 derived from decomposition of plant and soil
organic matter that may be decades to centuries old. A comparison of the radiocarbon content of CO2
respired by roots, microbes, and soils with the record of radiocarbon in
atmospheric CO2 allows direct estimation of the mean age of C being
respired [Trumbore 2000; Wang et al. 2000, Cisneros Dozal et al. 2005; Borken
et al. 2005].
Filesize: 21.45 Kb Added on: 08-Aug-2005 Downloads: 156 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
AN EMPIRICAL ESTIMATE OF THE SOUTHERN OCEAN AIR-SEA CO2 FLUX Description:
A discrepancy exists between current estimates of the
Southern Ocean air-sea flux of CO2.
The most recent estimate using a combination of direct and
climatologically-derived pCO2 measurements [Takahashi et al.,
2002] (herein referred to as T02) suggests a
Southern Ocean CO2 sink that is nearly two times greater that that
suggested from general circulation models, atmospheric inverse models [Gurney et al.,
2002] and oceanic inverse models [Gloor et al.,
2003]. Here we employ an independent method
to estimate the Southern ocean air-sea flux of CO2. Our method exploits all available surface
measurements for Dissolved Inorganic Carbon (DIC) and total alkalinity (ALK) from 1986 to 1996. We show that surface
age-normalized DIC can be predicted to within ~8mmol/kg and ~10mmol/kg for ALK
using standard hydrographic properties, independent of season. The predictive equations are used in
conjunction with World Ocean Atlas (2001) climatologies to estimate an annual
cycle of DIC and ALK, while the
pCO2 distribution is calculated using standard carbonate
chemistry. For consistency we use the
same gas transfer relationship and wind product from Takahashi et
al, [2002] however, we include the effects of sea-ice. We estimate a
Southern Ocean CO2 sink (>40°S) of -0.19±0.26 Pg C for 1995. Our estimates are
smaller than those estimated by Takahashi et al,
[2002], but consistent with atmospheric / oceanic inverse methods, general
circulation models and provides further evidence that the Southern Ocean CO2
sink in relation to its oceanic surface area, is moderate on a global scale.
Filesize: 119.45 Kb Added on: 02-Aug-2005 Downloads: 155 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
A DIRECT CARBON BUDGETING APPROACH TO STUDY CO2 SOURCES AND SINKS Description:
For the purpose of
exploiting upcoming measurements of atmospheric CO2 vertical
profiles by aircrafts and continuous CO2 data recorded along tall
towers as part of the North American Carbon Plan (NACP), a direct carbon
budgeting approach is being developed.
Filesize: 70.64 Kb Added on: 28-Jul-2005 Downloads: 154 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
SIGNALS OF PHOTOSYNTHESIS AND RESPIRATION AT BOREAL FORESTS IN RESPONSE TO ENVIRONMENT ... Description: The isotopic composition of the ecosystem respiration (d13CER) and the isotopic
discrimination of the ecosystem (DEco) were retrieved from intensive campaigns (1998 to 2000) and
from weekly diurnal sampling (2003) at a boreal forest site (Fraserdale, Canada,
49°53'N, 81°34'W). The results show that
d13CER was less sensitive to
temperature (T) variation compared with DEco, suggesting that the photosynthesis CO2 flux
was likely more sensitive to temperature than the ecosystem respiration CO2
flux during the same period of time at the study site. Filesize: 87.89 Kb Added on: 29-Jul-2005 Downloads: 150 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
THE UNDERPINNINGS OF LAND-USE HISTORY: THREE CENTURIES OF GLOBAL GRIDDED LAND-USE ... Description: To accurately assess the
impacts of human land-use on the Earth System, information is needed on the
current and historical patterns of land-use activities. Previous global
studies have focused on developing reconstructions of the spatial patterns of
agriculture. Here, we provide the first global gridded estimates of the
underlying land conversions (land-use transitions), wood harvesting, and
resulting secondary lands annually, for the period 1700-2000. For input, we
used two existing datasets of global gridded land-use history—HYDE [Klein Goldewijk 2001] and SAGE [Ramankutty & Foley 1999], a new
reconstruction of national wood harvest that we spatially disaggregated to a
global gridded product, and model estimates of the spatial distribution of
plant carbon density and its recovery. Since these do not fully constrain the
problem, we added assumptions related to four additional factors: the residence
time of agricultural land, the inclusiveness of wood harvest statistics, the
priority for land conversion and logging (e.g. primary- or secondary-land), and
the spatial pattern of wood harvest within countries. In order to estimate
uncertainty and characterize model sensitivity, a set of 216 alternative reconstructions
was derived using different assumptions. We estimate that the accumulated
global wood harvest 1700-2000 was approximately 112 Pg C including slash. Filesize: 17.49 Kb Added on: 29-Jul-2005 Downloads: 149 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
SIMULATING THE GLOBAL BOMB RADIOCARBON CYCLE: CLOSING THE BUDGET Description:
We estimated the production of bomb radiocarbon using available
information on atmospheric nuclear bomb tests, the simple (radio-)carbon cycle
model GRACE (Global RadioCarbon Exploration Model) and atmospheric observations
as constraints. Subsequent forward simulations of the bomb radiocarbon
inventory in the different carbon reservoirs turned out to be in very good
agreement with recent observation-based estimates, therewith for the very first
time allowing to close the global bomb radiocarbon budget. Besides confirming
original stratospheric bomb 14C data published in the reports of the
Health and Safety Laboratories [Telegadas,
1971, and references therein], our results confirm recent observation-based
ocean bomb radiocarbon inventory estimates for the time of GEOSECS (1970s) and
WOCE (1990s) from Peacock [2004] and Key et al. [2004], but refute the GEOSECS ocean inventory
estimates from Broecker et al. [1985, 1995].
Filesize: 67.02 Kb Added on: 03-Aug-2005 Downloads: 147 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
APPARENT TRENDS IN PHOTOSYNTHETIC CAPACITY OF MONSOON ASIA FROM 1982 TO 2002 Description: The
rapid economic growth of Monsoon Asia raises concerns about the future of
carbon stored in the terrestrial ecosystems of the region, especially in connection
with climate change [Tian et al.,
2003; Canadell et al., 2002; Oikawa and Ito, 2001; Esser, 1995]. The regional carbon budget
for 1980s suggests that Monsoon Asia as a whole acted as source [Tian et al., 2003], although some parts of
the region acted as sink. Here we provide some evidence from satellite data
that photosynthetic capacity of the region changed in the manner that suggests
similar conclusion. Comparing the period 1982-1992 and the period 1992-2002, we
found that the photosynthetic capacity of the territory generally decreased in
the forest zone and increased in the non-forest zone of the region. Filesize: 712.44 Kb Added on: 29-Jul-2005 Downloads: 146 Home Page | Comment on Proceeding | Details Category: Speaker Presentations
ESTIMATING LANDSCAPE-LEVEL CARBON FLUXES FROM TOWER CO2 MIXING RATIO DATA Description:
Variations
of the CO2 mixing ratio in the atmosphere near the surface result
from several processes, including photosynthesis and respiration of the
underlying ecosystems, vertical mixing near the surface and in the planetary
boundary layer (PBL), and entrainment of air above the PBL. We developed a
novel approach for isolating ecosystem metabolism signals at the landscape
scale (102-104 km2) in an hourly CO2
record using a vertical diffusion scheme coupled with an ecosystem model.
Filesize: 33.38 Kb Added on: 28-Jul-2005 Downloads: 145 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
IN AND OUT OF AFRICA: ESTIMATING THE CARBON EXCHANGE OF A CONTINENT Description: Understanding
the diverse elements of the global carbon cycle has been the focus of much
recent research [Prentice et al.
2001, Schimel et al. 2001, Gurney et al. 2002, House et al. 2003]; research that is vital to our understanding of
the missing sink, future atmospheric carbon dioxide concentrations, and future
climate [Fan et al. 1998, Houghton et al.
1998]. Much research has concentrated on carbon dynamics of the large ocean
basins [Lee et al. 1998, Le Quéré et al. 2003] and terrestrial
exchange in North America and Eurasia [Pacala et al. 2000, Schimel et al. 2000]. Despite representing 20% of the global land
mass, Africa has thus far been largely
neglected in these studies. We will examine current understanding of carbon
stocks and fluxes within Africa and discuss
how uncertainty in global carbon dynamics arises in part from uncertainty in
the African components. We outline areas where new measurements and research in
Africa can contribute to understanding at both
continental and global scales. Filesize: 50.76 Kb Added on: 29-Jul-2005 Downloads: 145 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
NEW VIEWS OF THE OCEANIC CARBON CYCLE FROM AUTONOMOUS EXPLORERS Description: A new paradigm for ocean carbon observations is
emerging with the rapid advances in autonomous measurements of carbon systems
with the success of robotic ocean profiling Carbon Explorers, autonomous
sensors for particulate organic and inorganic carbon (POC and PIC), and new instruments which will measure
year-long high frequency records of POC and PIC
sedimentation in the very observation-poor but biologically-active upper
kilometers of the ocean. The new observing capability described here is
critical for improved prediction of the substantial biotic carbon flows in the
ocean. There are excellent prospects for an enhanced ocean carbon observing
system fully capable of autonomous real time monitoring, measurement, and
verification of ocean carbon sequestration.
Filesize: 400.83 Kb Added on: 26-Jul-2005 Downloads: 144 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
THE EXPRESSION OF BIOSPHERE RESPONSE TO LIGHT LEVEL CHANGES ON 18O OF ATMOSPHERIC CO2 Description: Observations
suggest the global reflectivity of Earth changed during recent decades. Although there is some ambiguity surrounding
these findings, it is clear that, should there be changes in clouds or
scattering aerosols, a change in the total solar radiation received at the
surface and the fraction of diffuse light could result. Intriguingly, the d18O of CO2
time series measured at Mauna Loa shows variability
during the 1990s that does not match secular trends in CO2
concentration or d13C. While a decrease in total solar radiation
alone would reduce biospheric productivity, an increase in diffuse light can
increase productivity, as has been argued for the period following the eruption
of Pinatubo. Moreover, since the changes in radiation affect the surface latent
energy exchange, the isotopic composition of terrestrial water with which CO2
interacts (specifically leaf and soil water) will be modified and can thus
drive a change in isotopic fluxes. Filesize: 227.29 Kb Added on: 27-Jul-2005 Downloads: 144 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
LONG-TERM OBSERVATION OF CO2 CONCENTRATION AND ITS ISOTOPE RATIO OVER THE WESTERN PACIFIC Description: Air was collected systematically
from 1995 to 2005 over the Pacific from 30S to 55N in latitude by
ships-of-opportunity to monitor global trend of CO2 concentration
and its variation in the atmosphere. The
monitoring results showed that three El Niño events during 10 years mostly
affected regional and temporal variation of CO2 growth rate and its
budget. Variation of carbon isotope ratio showed that the CO2 flux
from terrestrial biosphere seemed to rapidly increase at that time, correlated
with global temperature anomaly. Oxygen isotope ratio had increasing trend in
this period, similar to the variation of temperature. Atmospheric 14CO2
variation also seemed to be influenced by El Niño event.
Filesize: 64.26 Kb Added on: 02-Aug-2005 Downloads: 144 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
UNRAVELING THE DECLINE IN HIGH-LATITUDE SURFACE OCEAN CARBONATE Description: For perhaps 25 million years, surface waters throughout the ocean have
remained saturated with respect to calcium carbonate (CaCO3). Yet increasing atmospheric CO2
reduces ocean pH and carbonate ion concentration [CO32-] and thus the level of saturation. Despite this acidification, it has been
estimated that all surface waters will remain saturated for centuries. However,
marine calcifiers are still expected to suffer reductions in the rate at which
they form their exoskeletons out of CaCO3. Here we show with ocean
data and models that the anthropogenic acidification will actually cause some
surface waters to become undersaturated within decades, thus exacerbating the
problem for marine calcifiers [Orr et al.,
2005]. For instance, by 2050 when atmospheric CO2 reaches 550 ppmv
under the IS92a business-as-usual scenario, Southern Ocean surface waters begin
to become undersaturated with respect to aragonite, a metastable form of CaCO3.
By 2100 as atmospheric CO2 reaches 788 ppmv under the same scenario,
undersaturation extends throughout the entire Southern Ocean (all ocean south
of 60°S) and into the surbarctic Pacific.
Filesize: 92.06 Kb Added on: 03-Aug-2005 Downloads: 142 Home Page | Comment on Proceeding | Details Category: Abstracts/Impacts of High CO2 on Land and Ocean Ecosystems
CO2 UPTAKE OF THE BIOSPHERE: FEEDBACKS BETWEEN THE CARBON CYCLE AND CLIMATE CHANGE USING A ... Description:
Different CO2 stabilization scenarios and CO2
emission scenarios have been carried out with an earth system model to
investigate feedbacks between future climate change and carbon cycle. The model
predicts a sensitivity of 1.6±0.1 K for an increase of 280 ppm in atmospheric
CO2 concentration. The decrease of the thermohaline circulation is
predominantly controlled by an enhanced atmospheric moisture transport to high
latitudes by global warming. Overall, the simulated effect of atmospheric CO2
concentration on climate change reduces the total carbon uptake of the ocean
and the land is reduced by 24-29%.
Filesize: 84.81 Kb Added on: 09-Aug-2005 Downloads: 139 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
VARIABILITY OF OCEAN CO2 PARTIAL PRESSURE AND AIR-SEA CO2 FLUXES IN THE SUBANTARCTIC ZONE ... Description: Seven CARIOCA lagrangian buoys drifted in the Subantarctic Zone, SAZ, of
the Indian and Pacific Ocean between 2001 and
2005. Measurements indicate that pCO2 in sea water is undersaturated
with respect to the atmospheric value and consequently the subantartic zone of
the Southern Ocean acts as a sink for atmospheric CO2 during all
seasons. Large observed pCO2 variability is associated with mixing
close to the subantarctic front, with biological activity and local warming.
These variabilities are higher than the seasonal cycle in the studied areas. Filesize: 92.01 Kb Added on: 27-Jul-2005 Downloads: 136 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
EVALUATION OF CO AND SF6 AS QUANTITATIVE TRACERS FOR FOSSIL FUEL CO2: THE MODELLERS VIEW Description: Simulations
with a regional transport model are evaluated in order to determine to which
extend the indirect fossil fuel combustion tracer CO or the purely
anthropogenic tracer SF6 can be used to retrieve the contribution of
fossil fuel emissions in the atmospheric CO2 signal. Filesize: 85.14 Kb Added on: 29-Jul-2005 Downloads: 136 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
METRICS TO ASSESS THE MITIGATION OF GLOBAL WARMING BY CARBON CAPTURE AND STORAGE Description:
Different metrics to assess
mitigation of global warming by carbon capture and storage are discussed. The
climatic impact of capturing 30% of the anthropogenic carbon emission and its
storage in the ocean or in a geological reservoir are evaluated for different
stabilization scenarios using a reduced-form carbon cycle-climate model. The
accumulated Global Warming Avoided (GWA) remains, after a ramp-up during the
first ~50 years, in the range of 15 to 30% over the next millennium for deep
ocean injection and for geological storage with annual leakage rates of up to
about 0.001. For longer time scales, the GWA may approach zero or become negative
for storage in a reservoir with even small leakage rates, accounting for the CO2
associated with the energy penalty for carbon capture. For an annual leakage
rate of 0.01, surface air temperature becomes higher than in the absence of
storage after three centuries only.
Filesize: 113.31 Kb Added on: 29-Jul-2005 Downloads: 134 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
STABILIZING ATMOSPHERIC CO2 CONCENTRATIONS: CAN GEOLOGIC STORAGE HELP? Description:
One option for reducing emissions of CO2 to the
atmosphere as a result of combustion of fossil fuels is to capture CO2
and inject it into porous subsurface geologic formations. High pressure CO2 has been used
for the last three decades as an agent for enhanced oil recovery, and hence
considerable experience in the technical issues associated with predicting the
movement of CO2 in the subsurface has been accumulated. Significant additional quantities of CO2
could be stored in depleted oil and gas reservoirs if CO2 were
available at low cost. These formations
are appealing as storage sites because the subsurface is known to have a trap
and seal that contains the buoyant oil or gas.
Filesize: 15.24 Kb Added on: 03-Aug-2005 Downloads: 133 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
RADIATIVE FORCING FROM A BOREAL FOREST FIRE Description: We report measurements of energy and carbon fluxes
from a boreal forest fire chronosequence. Taking into account greenhouse gas
emissions and post-fire changes in the surface radiation budget, a boreal forest
fire in interior Alaska
caused the climate to cool. This result suggests that management of forests in
northern countries to preserve carbon sinks may have the opposite effect on
climate as that intended.
Filesize: 31.78 Kb Added on: 03-Aug-2005 Downloads: 132 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
ATMOSPHERIC CO2, CARBON ISOTOPES, THE SUN AND CLIMATE CHANGE OVER THE LAST MILLENNIUM Description: The records of atmospheric CO2 and of NH surface temperature
covering the past millennium hold information on the strength of the
sensitivity of the global carbon cycle to climate changes. This sensitivity is
defined as the change in atmospheric CO2 in response to a given
change in NH temperature in units of ppm K-1. The magnitude of the
sensitivity is estimated for modest (< 1 K) temperature variations from
simulations with the Bern Carbon Cycle Climate model driven with solar and
volcanic forcing over the last millennium and from simulations with the range
of C4MIP models over the industrial periods. The model results are broadly
compatible with the data-deduced range.
Filesize: 25.84 Kb Added on: 29-Jul-2005 Downloads: 130 Home Page | Comment on Proceeding | Details Category: Abstracts/Carbon Cycle Response to Environmental Change
INFORMATION NEEDS FOR ADAPTIVE MANAGEMENT OF THE CARBON CYCLE: FROM REGIONAL CARBON BUDGETS TO A HO Description:
During
the past two centuries, human activities have undertaken a vast earth system
modification of the carbon (C) cycle. Early during this period, humans have
converted native vegetation to croplands. Such land use changes have mobilized
massive amounts of C. During the past century, increased use of fossil energy
sources, primarily coal and oil, have resulted in the rapid expansion of
industry and technology throughout the world.
The resulting impact has been to greatly increase the atmospheric
concentration of C dioxide (CO2) to where in 2004 it is estimated to
375ppm, nearly 100 pm greater than the pre-industrial levels. Fossil fuel
emissions and land use change have moved the global C cycle out of balance.
Filesize: 200.08 Kb Added on: 05-Aug-2005 Downloads: 130 Home Page | Comment on Proceeding | Details Category: Abstracts/Managing the Carbon Cycle
IMPORTANCE OF RECENT SHIFTS IN SOIL THERMAL DYNAMICS ON GROWING SEASON LENGTH, PRODUCTIVITY, ... Description: In
terrestrial high-latitude regions, observations indicate recent changes in snow
cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal
shifts in the growing season and the associated rates of terrestrial
productivity. Changes in productivity will influence the ability of these ecosystems
to sequester atmospheric CO2. We use the Terrestrial Ecosystem Model
(TEM), which simulates the soil thermal regime, in addition to terrestrial
carbon, nitrogen and water dynamics, to explore these issues over the years
1960-2100 in extratropical regions (30˚-90˚ N).
Our results reveal noteworthy changes in snow, permafrost, growing
season length, productivity, and net carbon uptake, indicating that prediction
of terrestrial carbon dynamics from one decade to the next will require that
large-scale models adequately take into account the corresponding changes in
soil thermal regimes.
Filesize: 60.62 Kb Added on: 28-Jul-2005 Downloads: 127 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
MODELING THE HISTORY OF TERRESTRIAL CARBON SOURCES AND SINKS Description: We
report modeling experiments with a new global dynamic land model (LM3V), to
reconstruct possible causes of the terrestrial carbon sources and sinks over
the past century. The model is unique,
in that it is capable of representing the global history of land use, including
the management of secondary forests (those forests that have re-grown at least
once following harvest). Several published carbon inventories attribute the
majority of the carbon sink caused by land use in the temperate zone to the
management of secondary forests.
Filesize: 17.72 Kb Added on: 03-Aug-2005 Downloads: 127 Home Page | Comment on Proceeding | Details Category: Abstracts/Land Use and the Terrestrial Carbon Cycle
CH4 TOTAL COLUMNS FROM SCIAMACHY - COMPARISON WITH ATMOSPHERIC MODELS Description: A
detailed comparison of global atmospheric CH4 retrievals from the
space-borne spectrometer SCIAMACHY onboard the European environmental satellite
ENVISAT is presented with the atmospheric transport models TM4 and TM5. Filesize: 224.71 Kb Added on: 25-Jul-2005 Downloads: 126 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
WHAT CAN WE LEARN FROM INTENSIVE ATMOSPHERIC SAMPLING FIELD PROGRAMS? Description:
Intensive atmospheric
sampling field programs are envisioned as a key component of integrated
research programs such as the North American Carbon Program (NACP) [Sarmiento and Wofsy,
1999; Wofsy and Harriss, 2002]. The intensive
sampling provides unique information about the spatial distribution of CO2
as well as imposes tight constraints on regional budgets that are difficult to
obtain from other means. We summarize what we have learned from the numerous
COBRA (CO2 Budget and Rectification Airborne study) experiments [Gerbig et al.,
2003a] that have taken place in 2000, 2003, and 2004. We present the observed spatial variability
of CO2 [Gerbig et al., 2003a; Lin et al.,
2004a] and regional budgets derived from regional air
parcel-following experiments [Lin et al., 2004b]. These
observations are also used as a critical testbed for modeling frameworks [Gerbig et al.,
2003b]. We draw conclusions about ways to maximize the value
of intensive atmospheric sampling experiments and the role that such
experiments should play within programs like the NACP.
Filesize: 721.39 Kb Added on: 01-Aug-2005 Downloads: 123 Home Page | Comment on Proceeding | Details Category: Abstracts/The Fate of Fossil-Fuel Carbon Emissions
THE ROLE OF WATER RELATIONS IN DRIVING GRASSLAND ECOSYSTEM RESPONSES TO RISING ATMOSPHERIC CO2 Description:
While
rising atmospheric carbon dioxide (CO2) is known to be an important
contributor to radiative forcing of Earth’s climate, more direct effects of
this gas on photosynthesis and plant water relations have been underway for
more than a century, and likely have already contributed to important ecosystem
changes. Experiments conducted in native and semi-natural grasslands in which ambient
CO2 concentrations have been artificially increased have shown that
increasing CO2 often increases photosynthesis, results in higher
soil and plant water content, and can enhance plant water use efficiency, the
ratio of plant biomass produced per unit water transpired back to the
atmosphere. While these responses may appear beneficial, there are long-term
responses of ecosystems to CO2 such as alterations in the cycling
and availability of critical plant nutrients like nitrogen (N) which are likely
to change over time and may significantly alter CO2-enhanced
production and forage quality. Herein we discuss these phenomena and speculate
on the implications and the importance for world grasslands.
Filesize: 31.72 Kb Added on: 02-Aug-2005 Downloads: 122 Home Page | Comment on Proceeding | Details Category: Abstracts/Impacts of High CO2 on Land and Ocean Ecosystems
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Talk History | |
Friday, September 30 | · | Discussion Panel |
· | Nitrogen Regulation of Carbon Sequestration in Terrestrial Ecosystems in Respons |
· | The Role of Water Relations in Driving Grassland Ecosystem Responses to Rising A |
· | Unraveling the Decline in High-latitude Surface Ocean Carbonate |
Thursday, September 29 | · | Hazards of Temperature on Food Availability in Changing Environments (HOT-FACE) |
· | The Amazon and the Modern Carbon Cycle |
· | New Coupled Climate-carbon Simulations from the IPSL Model |
· | The Changing Carbon Cycle |
· | What are the Most Important Factors for Climate-carbon Cycle Coupling? |
· | CO2 Uptake of the Marine Biosphere |
· | European-wide Reduction in Primary Productivity Caused by the Heat and Drought i |
· | Persistence of Nitrogen Limitation over Terrestrial Carbon Uptake |
· | Atmospheric CO2, Carbon Isotopes, the Sun, and Climate Change over the Last Mill |
· | Proposing a Mechanistic Understanding of Atmospheric CO2 During the late Pleist |
· | Greenhouse Gas (CO2, CH4) and Climate Evolution since 650 kyrs Deduced from Anta |
Wednesday, September 28 | · | (In and) Out of Africa: Estimating the Carbon Exchange of a Continent |
· | Recent Shifts in Soil Dynamics on Growing Season Length, Productivity, and... |
· | Interannual Variability in the Carbon Exchange Using an Ecosystem-fire Model |
· | Photosynthesis and Respiration in Forests in Response to Environmental Changes |
· | Seasonal and Interannual Variability in Net Ecosystem CO2 Exchange in Japan |
· | Estimating Landscape-level Carbon Fluxes from Tower CO2 Mixing Ratio Measurement |
· | Monitoring Effects in Climate and Fire Regime on Net Ecosystem Production |
· | Radiative Forcing from a Boreal Forest Fire |
· | The Influence of Soil and Water Management on Carbon Erosion and Burial |
· | Spatial and Temporal Patterns of CO2, CH4, and N2O Fluxes in Ecosystems |
· | Modeling the History of Terrestrial Carbon Sources and Sinks |
· | The Age of Carbon Respired from Terrestrial Ecosystems |
· | Discussion Panel |
· | The Underpinnings of Land Use History |
Tuesday, September 27 | · | Regional CO2 Fluxes for North America Estimated from NOAA/CMDL Observatories |
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