Helen Cleugh_Near-real-time measurement of carbon dioxide, water and energy fluxes: determining the best available estimates of ecosystem carbon and water fluxes at continental scales
This document discusses using flux tower and other observational data to constrain land surface models and determine carbon and water budgets across Australia. It describes how the OzFlux network provides carbon dioxide and water flux measurements from different ecosystems. These flux measurements have been used to test and improve land surface models and reduce uncertainty in estimates of net primary production for Australia. Integrating these observational constraints into the BIOS2 modeling framework has provided insights into Australia's dynamic carbon and water cycles at continental scales.
Heterojunctions of halogen-doped carbon nitride nanosheets and BiOI for sunli...Pawan Kumar
A fluorine-doped, chlorine-intercalated carbon nitride (CNF-Cl) photocatalyst has been synthesized for simultaneous improvements in light harvesting capability along with suppression of charge recombination in bulk g-C3N4. The formation of heterojunctions of these CNF-Cl nanosheets with low bandgap, earth abundant bismuth oxyiodide (BiOI) was achieved, and the synthesized heterojunctions were tested as active photoanodes in photoelectrochemical water splitting experiments. BiOI/CNF-Cl heterojunctions exhibited extended light harvesting with a band-edge of 680 nm and generated photocurrent densities approaching 1.3 mA cm-2 under AM1.5 G one sun illumination. Scanning Kelvin probe force microscopy (KPFM) under optical bias showed a surface potential of 207 mV for the 50% BiOI/CNF-Cl nanocomposite, while pristine CNF-Cl and BiOI had surface photopotential values of 83 mV and 98 mV respectively, which in turn, provided direct evidence of superior charge separation in the heterojunction blends. Enhanced charge carrier separation and improved light harvesting capability in BiOI/CNF-Cl hybrids were found to be the dominant factors in increased photocurrent, compared to the pristine constituent materials.
Noble Metal Free, Visible Light Driven Photocatalysis Using TiO2 Nanotube Arr...Pawan Kumar
Bulk g‐C3N4 is an earth‐abundant, easily synthesizable, and exceptionally stable photocatalyst with an electronic bandgap of 2.7 eV. Herein, the concepts of P‐doping and size quantization are combined to synthesize highly fluorescent P‐doped carbon nitride quantum dots (CNPQDs) with a bandgap of 2.1 eV. CNPQDs are hosted on anatase‐phase and rutile‐phase TiO2 nanotube array scaffolds, and examined as photoanodes for sunlight‐driven water‐splitting and as photocatalysts for surface catalytic reactions. Square‐shaped rutile phase TiO2 nanotube arrays (STNAs) decorated with CNPQDs (CNPQD‐STNA) generate 2.54 mA cm−2 photocurrent under AM1.5 G simulated sunlight. A champion hydrogen evolution rate of 22 µmol h−1 corresponds to a Faradaic efficiency of 93.2%. In conjunction with Ag nanoparticles (NPs), the CNPQD‐STNA hybrid is also found to be an excellent plexcitonic photocatalyst for the visible light‐driven transformation of 4‐nitrobenzenethiol (4‐NBT) to dimercaptoazobenzene (DMAB), producing reaction completion at a laser power of 1 mW (532 nm) while Ag NP/TNA and Ag NP/STNA photocatalysts cannot complete this transformation even at 10 mW laser power. The results point the way forward for photochemically robust, noble metal free, visible light harvesting photoacatalysts based on nanostructured heterojunctions of graphenic frameworks with TiO2.
Water-splitting photoelectrodes consisting of heterojunctions of carbon nitri...Pawan Kumar
Quinary and senary non-stoichiometric double perovskites such as Ba2Ca0.66Nb1.34-xFexO6-δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba2Ca0.66Nb0.68Fe0.33Co0.33O6-δ (BCNFCo), exhibited an optical absorption edge at ~ 800 nm, p-type conduction and a distinct photoresponse upto 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C3N4 (CN) was prepared via a facile solvent assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C3N4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskite and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm-2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ~ 88%.
A copy of the presentation given to the University of Utrecht (geological department). The first part is about the sense of urgency for options to lower the CO2 emissions. And that mineralization was millions of years sufficient fast to handle the natural CO2 emissions.
The second part describes three methods of using this principle.
- Ambient Weathering
- Product replacement (use Olivine instead of another product)
- Process Intensification (high pressure, high temperature process for increased reaction rate).
Pol Knops
Bio-physical impact analysis of climate change with EPIC
Presented by Christine Heumesser at the AGRODEP Workshop on Analytical Tools for Climate Change Analysis
June 6-7, 2011 • Dakar, Senegal
For more information on the workshop or to see the latest version of this presentation visit: http://www.agrodep.org/first-annual-workshop
Heterojunctions of halogen-doped carbon nitride nanosheets and BiOI for sunli...Pawan Kumar
A fluorine-doped, chlorine-intercalated carbon nitride (CNF-Cl) photocatalyst has been synthesized for simultaneous improvements in light harvesting capability along with suppression of charge recombination in bulk g-C3N4. The formation of heterojunctions of these CNF-Cl nanosheets with low bandgap, earth abundant bismuth oxyiodide (BiOI) was achieved, and the synthesized heterojunctions were tested as active photoanodes in photoelectrochemical water splitting experiments. BiOI/CNF-Cl heterojunctions exhibited extended light harvesting with a band-edge of 680 nm and generated photocurrent densities approaching 1.3 mA cm-2 under AM1.5 G one sun illumination. Scanning Kelvin probe force microscopy (KPFM) under optical bias showed a surface potential of 207 mV for the 50% BiOI/CNF-Cl nanocomposite, while pristine CNF-Cl and BiOI had surface photopotential values of 83 mV and 98 mV respectively, which in turn, provided direct evidence of superior charge separation in the heterojunction blends. Enhanced charge carrier separation and improved light harvesting capability in BiOI/CNF-Cl hybrids were found to be the dominant factors in increased photocurrent, compared to the pristine constituent materials.
Noble Metal Free, Visible Light Driven Photocatalysis Using TiO2 Nanotube Arr...Pawan Kumar
Bulk g‐C3N4 is an earth‐abundant, easily synthesizable, and exceptionally stable photocatalyst with an electronic bandgap of 2.7 eV. Herein, the concepts of P‐doping and size quantization are combined to synthesize highly fluorescent P‐doped carbon nitride quantum dots (CNPQDs) with a bandgap of 2.1 eV. CNPQDs are hosted on anatase‐phase and rutile‐phase TiO2 nanotube array scaffolds, and examined as photoanodes for sunlight‐driven water‐splitting and as photocatalysts for surface catalytic reactions. Square‐shaped rutile phase TiO2 nanotube arrays (STNAs) decorated with CNPQDs (CNPQD‐STNA) generate 2.54 mA cm−2 photocurrent under AM1.5 G simulated sunlight. A champion hydrogen evolution rate of 22 µmol h−1 corresponds to a Faradaic efficiency of 93.2%. In conjunction with Ag nanoparticles (NPs), the CNPQD‐STNA hybrid is also found to be an excellent plexcitonic photocatalyst for the visible light‐driven transformation of 4‐nitrobenzenethiol (4‐NBT) to dimercaptoazobenzene (DMAB), producing reaction completion at a laser power of 1 mW (532 nm) while Ag NP/TNA and Ag NP/STNA photocatalysts cannot complete this transformation even at 10 mW laser power. The results point the way forward for photochemically robust, noble metal free, visible light harvesting photoacatalysts based on nanostructured heterojunctions of graphenic frameworks with TiO2.
Water-splitting photoelectrodes consisting of heterojunctions of carbon nitri...Pawan Kumar
Quinary and senary non-stoichiometric double perovskites such as Ba2Ca0.66Nb1.34-xFexO6-δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba2Ca0.66Nb0.68Fe0.33Co0.33O6-δ (BCNFCo), exhibited an optical absorption edge at ~ 800 nm, p-type conduction and a distinct photoresponse upto 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C3N4 (CN) was prepared via a facile solvent assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C3N4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskite and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm-2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ~ 88%.
A copy of the presentation given to the University of Utrecht (geological department). The first part is about the sense of urgency for options to lower the CO2 emissions. And that mineralization was millions of years sufficient fast to handle the natural CO2 emissions.
The second part describes three methods of using this principle.
- Ambient Weathering
- Product replacement (use Olivine instead of another product)
- Process Intensification (high pressure, high temperature process for increased reaction rate).
Pol Knops
Similar to Helen Cleugh_Near-real-time measurement of carbon dioxide, water and energy fluxes: determining the best available estimates of ecosystem carbon and water fluxes at continental scales
Bio-physical impact analysis of climate change with EPIC
Presented by Christine Heumesser at the AGRODEP Workshop on Analytical Tools for Climate Change Analysis
June 6-7, 2011 • Dakar, Senegal
For more information on the workshop or to see the latest version of this presentation visit: http://www.agrodep.org/first-annual-workshop
Colin Prentice_What better modelling of ecosystems could achieve - TERN's e-M...TERN Australia
Similar to Helen Cleugh_Near-real-time measurement of carbon dioxide, water and energy fluxes: determining the best available estimates of ecosystem carbon and water fluxes at continental scales (20)
This publication was endorsed by the National Soils Advocate, The Hon. Penny Wensley AC, on the 8th of December 2022 during the launch of the TERN Australia Soil & Herbarium Collection.
The publication contains the results of 33 interviews with people who, in 2022, have jobs relevant to soils. It is intended for use by secondary and tertiary students who are perhaps wondering what to study or which career might be satisfying - or maybe they have already chosen a soils-related career and are keen to learn something about others who they may meet as lecturers, coworkers or employers.
The booklet will also hopefully be a useful resource for those that assist students with such decisions, including teachers, careers counsellors, guidance officers, librarians, and parents.
Summary of TERN monitoring plots in the Pilbara WA, Apr2015 - Jun2021TERN Australia
This report provides a snapshot of the data collected by TERN in the Pilbara, Western Australia. Also included in this report is how to access the data, descriptions of data types, panorama photos and examples of research using TERN data. Plots on the Pilbara were first surveyed by TERN from April 2015 to August 2016. The surveys collected vegetation and soil, data and samples following the AusPlots Rangelands methodology, with 37 plots completed. Some of the plots were revisted in 2021. An updated version of this report will be provided as this data becomes available.
Summary of TERN plots on Kangaroo Island, SA, Oct 2018 - Oct 2021TERN Australia
In October 2018, TERN undertook a survey on Kangaroo Island, South Australia. The survey involved vegetation and soils work following the AusPlots Rangelands methodology, with 13 plots completed. The plots are part of over 800 plots completed nationally. The plots were revisited following the fires in 2020
and again in 2021. This report will be updated as that data becomes available.
Evaluating ecological outcomes in the Regional Land Partnerships Program: A pilot monitoring, evaluation and research (MER) network.
This three-year project will trial Australia’s first MER network by implementing a pilot network – to promote national-scale learning about bushfire recovery across different ecosystem types, and the
ecological effectiveness of post-fire interventions.
Australia's Environmental Predictive CapabilityTERN Australia
Federating world-leading research, data and technical capabilities to create Australia’s National Environmental Prediction System (NEPS).
Community consultation presentation.
3-12 February 2020
Dr Michelle Barker (Facilitator)
(Presentation v5)
Biodiversity Management in Tasmania's Temperate Native ForestsTERN Australia
Sustainable Timber Tasmania's Dr Marie Yee's entry to the ILTER Most Striking Case competition on using the research from TERN's Warra Tall Eucalypt SuperSite to facilitate innovative biodiversity management in Tasmania's temperate native forests.
Observing Environmental Change in Australia: Conversations for SustainabilityTERN Australia
A comprehensive and engaging review of how the past decade of Australian Government research infrastructure investment has transformed our understanding of the environment.
Observing Environmental Change in Australia – Conversations for Sustainability covers the monitoring of environmental change, urbanisation and land-use changes, biodiversity, extreme events, climate, carbon and water.
Chapters detail the importance of Indigenous knowledge, the use of satellite remote sensing and drones, and managing ‘big data’. The book concludes with descriptions of visualising environmental information, emerging technologies, and the importance of engaging the community.
Observing Environmental Change in Australia: Conversations for SustainabilityTERN Australia
A comprehensive and engaging review of how the past decade of Australian Government research infrastructure investment has transformed our understanding of the environment.
Observing Environmental Change in Australia – Conversations for Sustainability covers the monitoring of environmental change, urbanisation and land-use changes, biodiversity, extreme events, climate, carbon and water.
Chapters detail the importance of Indigenous knowledge, the use of satellite remote sensing and drones, and managing ‘big data’. The book concludes with descriptions of visualising environmental information, emerging technologies, and the importance of engaging the community.
Yuxia Liu Phenology 2018 poster on tracking grass phenologyTERN Australia
University of Technology Sydney Yuxia Liu's Phenology 2018 conference poster on tracking grass phenology with phenocams and remote sensing over victorian pastures.
Report outlining the University of Adelaide and TERN's mapping of the ecological facets for continental Australia using globally consistent methods. The new maps capture the three major factors driving ecosystem formation-macroclimate, lithology and landform-with multiple spatial indicators. Vegetation structure has also been mapped and combined with the three indicators of ecosystem formation to produce 'ecological facets'.
TERN Ecosystem Surveillance Plots Roy Hill StationTERN Australia
A summary of TERN ecosystem observing plots on Roy Hill Station. The report also contains a list of the data and soil and plant samples openly available via TERN.
TERN Ecosystem Surveillance Plots Kakadu National ParkTERN Australia
A summary of TERN ecosystem observing plots in Kakadu National Park. The report also contains a list of the data and soil and plant samples openly available via TERN.
TERN Ecosystem Surveillance Plots Kakadu National Park
Helen Cleugh_Near-real-time measurement of carbon dioxide, water and energy fluxes: determining the best available estimates of ecosystem carbon and water fluxes at continental scales
1. Near-real-time measurement of CO2, water
and energy fluxes: Determining the best
available estimates of continental carbon and
water fluxes
Helen Cleugh, Eva van Gorsel and Vanessa Haverd
CSIRO Marine and Atmospheric Research
2. Some climate policy questions and
the research needed to provide the
answers
What is the role of natural land and ocean sinks in
sequestering greenhouse gas (GHG) emissions and what will
happen to these sinks in the future?
• Carbon cycle observations that track the uptake and release of
greenhouse gases in land, air and oceans
• How does climate change and variability affect Australia’s carbon
budget (sources and sinks; anthropogenic and biogenic)?
• Climate models (such as ACCESS) include coupled carbon and water cycle
3. Some climate policy questions and
the research needed to provide the
answers
How can we use our natural land sinks to mitigate Australia’s
GHG emissions?
What is the impact of natural disturbance regimes; how are
they changing?
• Investigate how climate and land management affect the stability of
Australia’s land-based carbon sinks
• How will carbon dioxide fertilisation affect Australian vegetation?
• Ensuring global and regional climate simulations represent Australian
terrestrial ecosystem processes
4. A capability to determine carbon and water
budgets at ecosystem to continental scales
• Uptake and release of CO2 and other GHG [fluxes]
• Carbon stocks in soil, plants and air [stores]
• Water and carbon
• Measurements and models
…. the TERN infrastructure “ecosystem”
6. AusPlots and
OzFlux Australian
Network Supersites Network
Site characteristics
CO2 and H2O Fluxes Biomass
Radiation Soil carbon & nutrients
Meteorology
Leaf-level photosynthesis
AusCover eMAST
Data assimilation and
Vegetation type
integration into
GPP
Veg indices (NDVI, EVI)
Knowledge of modelling applications
Leaf area index ecosystem exchange
Fire of carbon, water &
Canopy properties .....
energy
…. the TERN infrastructure “ecosystem”
7. OzFlux: a continental network of flux
stations to measure ecosystem fluxes
using nationally-consistent approaches
Flux towers measuring vineyard
and forest CO2 and water H
fluxes
ET
Q • CO2 (NEE) and water use (ET)
• Energy: Radiation (Q) and heat (H, G)
Q
NEE • Spatially-averaged at canopy-scale
• Continuous: hourly to multi-annual
G
10. OzFlux: carbon and water fluxes
available via a data portal for a range of
Australian climates and ecosystems
See OzFlux Data
Portal demo. by
Peter Isaac this
afternoon
11. What is Australia’s net carbon balance?
• How does climate change and variability affect
Australia’s carbon budget (sources and sinks;
anthropogenic and biogenic)?
• How much water is required for an ecosystem to
sequester CO2?
12. Determining Australia’s net biogenic carbon & water
balance by combining models and observations
• Haverd et al (2012) Using multiple observation types to
reduce uncertainty in Australia’s terrestrial carbon and water
cycles, Biogeosciences Discuss., 9 (2012)
• BIOS2 modelling environment
• Multiple observations
13. BIOS2 Model Environment
(Haverd et al, 2012)
BIOS2 = CABLE-SLI-CASAcnp in AWAP operational framework
CABLE = Community SLI = Soil-Litter-Iso CASAcnp =
Atmosphere-Biosphere-Land • Soil hydrology, evaporation Biogeochemical model
Exchange model • Soil & plant C, N, P
Haverd et al. (2011)
• Water, energy, carbon fluxes dynamics
Wang et al. (2011) Wang et al. (2007)
AWAP = Australian Water Availability Project
• Meteorology and soil data
• Continental processing framework
• Model-Data Fusion
Raupach et al. (2009)
14. Determining Australia’s net biogenic carbon & water
balance by combining models and observations
• Haverd et al (2012)
• BIOS2 modelling environment = CABLE + CASAcnp + SLI
• Multiple data sets:
• OzFlux carbon, water and energy fluxes
• Streamflow from gauged catchments
• Litterfall (leaf NPP)
• Carbon pools (above ground biomass, soil carbon)
15. Including OzFlux data to constrain
BIOS2 simulations of NPP (Net Primary
Production) for Australian continent
Prior estimate
Eddy fluxes
Streamflow
Litterfall
Eddy fluxes + Litterfall
error bars = uncertainty
Streamflow + Litterfall from propagated parameter
Streamflow + Eddy fluxes uncertainties (1 std. dev.)
Eddy fluxes + Litterfall + Streamflow
0 1 2 3 4
Net Primary Production (NPP) =y2.1 GT carbon per year
NPP (GtC )
-1
Including OzFlux flux data yields the greatest reduction in
uncertainty in NPP and ET
16. A reality check - comparing OzFlux
measured GPP and BIOS2 simulations
OzFlux = ensemble
annual cycle
BIOS2 = long-term
mean annual cycle
17. A reality check - comparing OzFlux
measured ET and BIOS2 simulations
OzFlux = ensemble
annual cycle
BIOS2 = long-term
mean annual cycle
18. A reality check - comparing OzFlux
measured ET and BIOS2 simulations
Monthly Annual
Monthly Annual
19. Australia’s water and carbon balance
from BIOS2, constrained by data
Soil Evaporation
• Energy, carbon, water budgets
• 1990 – 2009 (monthly)
• 5 km resolution
• Using BIOS2 (CABLE + SLI + CASAcnp)
Total NPP
Transpiration
20. NPP (g m-2 d-1)
3pg
3 i AussieGrass
BiosEquil
Century
2 CenW
dLdP
Miami-oz
12 mean NPP estimates 1
Miami
Olson
for Australia RFBN
TMS
(Roxburgh et al 2004) 0 Vast
ET (mm y-1)
ii AWAP
7 mean ET estimates for 1000 AWRA
Guerschman
Australia NDTI
etlook
(King et al 2012) MODIS
500
0
Australia
Savanna
Tropics
Warm Temp
Cool Temp
Mediterr
Desert
1 2 3 4 5 6 A
21. Concluding Comments (1)
• Climate mitigation and adaptation policy drivers requires a
capability to determine carbon and water budgets at ecosystem
to continental scales
– TERN provides model – data research infrastructure needed
– OzFlux + AusCover + Supersites + AusPlots + Soils
• OzFlux data have been used to:
– Test and improve the land surface model [CABLE] for Australian
ecosystems.
– CABLE is part of Australia’s newly developed global climate model [ACCESS]
– Significantly reduce the uncertainty in estimated NPP for Australia, using
CABLE as part of BIOS2
22. Concluding Comments (2)
• Insights into the dynamic
carbon and water budgets
for the Australian
continent, e.g.:
– Large inter-annual
variability in NPP driven by
variation in available
moisture
– And larger than
anthropogenic greenhouse
gas emissions
Editor's Notes
Q1: Under the Mitigation science deliverables
Q2: Under the Mitigation science deliverables
Quantify ecosystem carbon and water fluxes, and their consequences in terms of primary productivity and carbon storage, can now expand from beyond the local scale to regional, ecosystem and continental-scales
Shows range in climates
Shows range in climates
Currently, there is significant uncertainty about Australia’s net primary productivity - the difference between carbon that is taken up by vegetation from the atmosphere and carbon respired by plants and microbes. There is corresponding significant uncertainty about rates of water loss through transpiration from plants and evaporation from soil and water bodies. This obviously limits our understanding of and capacity to manage Australia’s interlinked carbon and water cycles.
Note that each obs. type has different space and time scales
Currently, there is significant uncertainty about Australia’s net primary productivity. There is corresponding significant uncertainty about rates of water loss through transpiration from plants and evaporation from soil and water bodies. This obviously limits our understanding of and capacity to manage Australia’s interlinked carbon and water cycles. Long-term continental Carbon balance (RHS) using BIOS2, constrained by data including OzFlux dataPrior parameters and their uncertainties lead to a continental NPP of 2.5±1.1 PgCyr−1, while the estimate constrained by all three data sets is2.1±0.4 GtCyr−1,->including eddy fluxes reduces uncertainty considerably (strongest effect). The impact of each of three data sets (leaf –NPP (litter-fall), streamflow and eddy flux data) and combinations thereof on the long-term mean Australian continental NPP estimate and its uncertainty. Each data set individually leads to a reduction in uncertainty compared with the prior estimate, although with quite different values, reflecting possible biases in the model and/or observations for the particular observable. The estimates are more convergent when 2 data sets are used simultaneously, and the estimate constrained by all three is a compromise between the results obtained using each data set individually.The error bars in Figure 3 indicate that eddy flux data provide a stronger constraint than leaf-NPP, even though leaf NPP observations more widely distributed (Figure 2). This reflects the high precision of the eddy flux measurements, compared with disparate litterfall observations which do not share a common methodology and are subject to large errors from fine scale heterogeneity. Long-term evaporation from streamflow provides a relatively weak constraint because in most regions of Australia, it is largely driven by rainfall (continentally, evaporation accounts for 90% of precipitation).
Verification – using allConstraints - Tumba, HS and Daly’s – see map at Slide 20
Long-term continental water balance (LHS) and Carbon balance (RHS) using BIOS2, constrained by data including OzFlux data
Here, the top two panes of the previous slide (NPP and ET) are shown with all elements greyed out. Superimposed in colour on the NPP pane are the various Roxburgh results. Superimposed on the ET pane are most of the WIRADA ET estimates. The old CABLE results from WIRADA will be removed for publication. Also left out of the WIRADA results are those of Yongqiang, which have some problems. All ET results are for the period Jan 2000-Dec 2005, except etlook which is for 2002/07-2005/06.
Net primary production is slightly larger (uptake) than heterotrophic respiration, largely because of the CO2 fertilisation effect. This leads to a small positive net ecosystem production (uptake), which is negated by fire and land use change emissions to give a small net biome production that is an emission. The interannual variability of net biome production is driven largely by variation in net ecosystem production due to moisture availability. This interannual variability is significantly larger than the entire greenhouse gas emissions (in GT C(eq) y-1).NBP = 0.056 Pg C year – emission; interannual variability about 0.4 Pg C, cf 0.15 CO2 emissionsNEP (NEE) Uptake about 0.1; cf 0.15 for anthropogenicTotal land atmopshere exchange for Australia is 0.15 + 0.0506 = 0.205 Pg C year.