Presented at the 3rd ICOS Science Conference in Prague, Czech Republic, 11-13 Sep 2018.

1. Connecting global & regional carbon
budgets to support policy-making
Ana Bastos
Contributions from: P. Ciais, F. Chevallier, J. Winckler, S. Sitch, P.
Friedlingstein, M. O‘Sullivan, M. Jung, M. Reichstein C. Rödenbeck,
W. Peters, I. van der Laan-Luijkx, N. Smith, P. Patra, J. Pongratz, J.
Nabel, P. Pickers, P. Canadell, C. Le Quéré

2. Motivation
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 2
“Parties aim to reach global peaking of
greenhouse gas emissions as soon as
possible [...]to undertake rapid reductions
thereafter in accordance with best
available science, so as to achieve a
balance between anthropogenic emissions
by sources and removals by sinks of
greenhouse gases in the second half of this
century [...]“

3. Motivation
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 3
“Parties aim to reach global peaking of
greenhouse gas emissions as soon as
possible [...]to undertake rapid reductions
thereafter in accordance with best
available science, so as to achieve a
balance between anthropogenic emissions
by sources and removals by sinks of
greenhouse gases in the second half of this
century [...]“

4. Motivation
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 4
“Parties aim to reach global peaking of
greenhouse gas emissions as soon as
possible [...]to undertake rapid reductions
thereafter in accordance with best
available science, so as to achieve a
balance between anthropogenic emissions
by sources and removals by sinks of
greenhouse gases in the second half of this
century [...]“
Demand for the scientific community:
• Track accurately anthropogenic emissions (fossil fuel and land-use
change) at regional/country scale and consistent with global budget;
• Quantify accurately the regional sinks (anthropogenic and natural) and
their changes consistent with global budget;
• Understand and quantify processes and feedbacks governing the GHG
sinks from local to global scale (present and future).

5. Motivation
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 5
Source: Le Quéré et al 2017; Global Carbon Budget 2017
Individual estimates from: Chevallier et al. (2005); Clarke et al. (2011); Guimberteau et al. (2017); Hansis et al. (2015); Haverd et al. (2017); Houghton and Nassikas (2017); Jain et al.
(2013); Kato et al. (2013); Keller et al. (2017); Krinner et al. (2005); Melton and Arora (2016); Oleson et al. (2013); Reick et al. (2013); Rodenbeck et al. (2003); Sitch et al. (2003); Smith et
al. (2014); Tian et al. (2015); van der Laan-Luijkx et al. (2017); Woodward et al. (1995); Zaehle and Friend (2010). Full references provided in Le Quéré et al. (2017).
Latest Global Carbon
Budget
(LeQuéré et al., 2018)
Top-down and bottom-up
estimates of land surface
CO2 fluxes agree quite well
at global scale

6. Motivation
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 6
Source: Le Quéré et al 2017; Global Carbon Budget 2017
Individual estimates from: Aumont and Bopp (2006); Buitenhuis et al. (2010); Chevallier et al. (2005); Clarke et al. (2011); ; Doney et al. (2009);
Guimberteau et al. (2017); Hauck et al. (2016); Haverd et al. (2017); Ilyina et al. (2013); Jain et al. (2013); Kato et al. (2013); Keller et al. (2017); Krinner
et al. (2005); Landschützer et al. (2016); Law et al. (2017); Melton and Arora (2016); Oleson et al. (2013); Reick et al. (2013); Rödenbeck et al. (2003);
Rödenbeck et al. (2014); Séférian et al. (2013); Schwinger et al. (2016); Sitch et al. (2003); Smith et al. (2014); Tian et al. (2015); van der Laan-Luijkx et
al. (2017); Woodward et al. (1995); Zaehle and Friend (2010). Full references provided in Le Quéré et al. (2017).
Latest Global Carbon
Budget
(LeQuéré et al., 2018)
Top-down and bottom-up
estimates of land surface
CO2 fluxes agree quite well
at global scale but still
show inconsistencies in
regional budgets, their
trends and
inter-annual variability.

7. RECCAP-1goals
• To establish the mean carbon balance of
large regions of the globe at the scale of
continents and large ocean basins,
including their component fluxes.
• To do it by comparing and reconciling
multiple bottom-up estimates with the
results of regional top-down
atmospheric inversions, with attribution
to main flux components.
• To evaluate the regional ‘hot-spots’ of
inter-annual variability and possibly the
trends and underlying processes over
the past two (or more) decades by
combining available long-term
observations and modeling.
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 7
https://www.biogeosciences.net/special_issue107.html
Haverd et al. 2013
Gloor et al. 2012
King et al. 2015
Patra et al. 2013
Ishii et al. 2014
Valentini et al. 2014
Sarma et al. 2013
Lenton et al. 2013
Schuster
et al. 2013
Dolman et al. 2012
Piao et al. 2012
Luyssaert et al. 2012
McGuire et al. 2012
Sitch et al. 2015
Ciais et al. 2014
Peylin et al. 2013
Khatiwala et al. 2013
Wanninkhof et al. 2013
Houghton et al. 2012
Peters et al. 2012
Enting et al. 2012
Andres et al. 2012
Chen et al. 2012

8. Opportunitiesfor2nd phaseRECCAP
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 8
In the meantime...
Consolidation of long-term CO2
monitoring networks / new RI

9. Opportunitiesfor2nd phaseRECCAP
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 9
New / long earth-
observation data
In the meantime...
Consolidation of long-term CO2
monitoring networks / new RI

10. Opportunitiesfor2nd phaseRECCAP
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 10
TRENDY
DGVMs
CO2 flux products and global
budget annually updated
In the meantime...
Consolidation of long-term CO2
monitoring networks / new RI
New / long earth-
observation data

11. • Which regions dominate trends and anomalies?
• Where and when do top-down and bottom-up
estimates agree/disagree? (... and why?)
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 11

12. Bridging scales: top-down and bottom-up
estimates of global and regional CO2 fluxes
• Inter-annual variability
• Long-term changes
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 12

13. ThebestobservedEl-Niñoonrecord
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 13
Chatterjee et al. 2017 Science
Liu et al. 2017 Science
Wang et al., 2018 ESSD
Special issue coming out Oct 08

14. El-Niño2015/2016
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 14
• GCB2017 residual sink
• 3 inversions (CAMS, CarboScope s76 & s04)
• 16 DGVMs from TRENDYv6 (bold MMEM)
• Shades: Multivariate ENSO index
Agreement is better at global scale, but
event dependent (e.g. 1997/98 vs 2015/16).
Disagreement is not necessarily bigger
between inversions vs DGVMs.
Bastos et al. 2018
(Phil.Trans.R.S.-B, in press)
Detrended anomalies
Do top-down and bottom up estimates of CO2 fluxes
agree on the C-cycle response to El-Niño?

15. El-Niño2015/2016
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 15
Seasonal evolution of the terrestrial sink during 2015-2016
Seasonal evolution: good agreement during onset,
peak and demise of El-Niño
DGVMs overestimate the response to
the onset of El-Niño (Q3 – JJA 2015)
Bastos et al. 2018
(Phil.Trans.R.S.-B, in press)
Lines: CAMS, CarboScope 04
Box-plots: TRENDYv6 models
Net CO2 uptake anomaly
Q1 (JFM 2015) to Q8 (OND 2016)

16. El-Niño2015/2016
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Evaluating the driving processes
Global and tropical decrease in terrestrial CO2 uptake mainly due to reduced
productivity rather than to increased respiration, especially in the tropics
Bastos et al. 2018
(Phil.Trans.R.S.-B, in press)
Component flux anomalies: GPP TER

17. Didtheland-sinkrecoverin2017?
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 17
Unpublished results not included. Updates can be found at
http://www.globalcarbonproject.org/carbonbudget/index.htm

18. Bridging scales: top-down and bottom-up estimates of
regional CO2 fluxes
• Inter-annual variability
• Long-term changes
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 18
Unpublished results not included. Updates can be found at
http://www.globalcarbonproject.org/carbonbudget/index.htm

19. Summary
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 19
• Societal demand to quantify accurately the sources and sinks of
CO2 (... and other GHGs) at spatial and temporal scales relevant
for policy-making
• Need to bridge global and local scales to understand processes
and feedbacks governing the GHG sinks

20. Summary
A. Bastos ::::::: 3rd ICOS Science Conference ::::::: 13.09.2018 20
• Societal demand to quantify accurately the sources and sinks of
CO2 (... and other GHGs) at spatial and temporal scales relevant
for policy-making
• Need to bridge global and local scales to understand processes
and feedbacks governing the GHG sinks
• State-of-the-art top-down and bottom-up approaches are now
quite consistent at the global scale...
• ... but still show disagreements in trends and variability in certain
regions
• Understanding such disagreements can be highly informative
though