Why regional carbon budgets scientific and policy background
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Why regional carbon budgets? Scientific and Policy Background. Scientific and policy requirements for comprehensive and dynamic carbon budgets. Mike Apps GCP Scientific Steering Committee & Natural Resources Canada Canadian Forest Service. Two Overarching Questions.

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Why regional carbon budgets scientific and policy background

Why regional carbon budgets?Scientific and Policy Background

Scientific and policy requirements for comprehensive and dynamic carbon budgets

Mike Apps

GCP Scientific Steering Committee

& Natural Resources CanadaCanadian Forest Service


Why regional carbon budgets scientific and policy background

Two Overarching Questions

How will rates of atmospheric C accumulation change?

  • Impacts

  • Adaptation measures

    Can the fluxes causing theatmospheric accumulation be controlled?

  • Mitigation: what can be done to reduce sources and or increase sinks

  • Can these be monitored effectively?

  • How long will they last?


Why regional carbon budgets scientific and policy background

Provocativeinsight: Kleidon Climatic Change 2004

Active Carbon Cycle

Exchange of 120 GtC/yr (land), and 90 GtC/yr (ocean)

C is cycled, not permanently stored

A natural cycle that has operated for at least 4 glacial cycles


Why regional carbon budgets scientific and policy background

Today

Future?

A stable mode of behaviour for at least the past ½ million years

Petit et al., 1999

Variation in T and CO2 over last 4 glacial cycles

CO2

Temperature

Falkowski et al., 2000


Why regional carbon budgets scientific and policy background

Human activity alters mechanisms of the cycle

And adds additional carbon to the active cycle

Fossil deposits

Perturbed Active Carbon Cycle

Perturbed Active Carbon Cycle

  • How the Earth system handles these perturbations will determine the impacts

    • How human activities are modified will influence the magnitude and timing of the perturbation


Global budget top down perspective

Net: 0.7

1990s

Global Budget: Top Down Perspective

Data for 1990s

from Houghton 2003

Re-analyses of Ocean (Plattner) and LUC data

Atmospheric accumulation rate

3.2 GtC per year 1990s

Atmosphere

Surface biosphere

6.3

F Fuel,

Cement

2.2

Land-Use

Change

2.9

Land Uptake

2.4

Ocean

Uptake

6 GtC/yr - equivalent to burning all of Canada’s trees every two years.


Global budget main questions

Global Budget: Main questions

Atmospheric accumulation rate

3.2 GtC per year 1990s

Atmosphere

Surface biosphere

6.3

F Fuel,

Cement

2.2

Land-Use

Change

2.9

Land Uptake

2.4

Ocean

Uptake

How good are estimates?

Where are the release occurring?

How will they change over time?

Can human behavior be modified?


Global budget main questions1

Similar set of questions

Global Budget: Main questions

Atmospheric accumulation rate

3.2 GtC per year 1990s

Atmosphere

Surface biosphere

6.3

F Fuel,

Cement

2.2

Land-Use

Change

2.9

Land Uptake

2.4

Ocean

Uptake


Global budget main questions2

Global Budget: Main questions

Atmospheric accumulation rate

3.2 GtC per year 1990s

Atmosphere

Surface biosphere

6.3

F Fuel,

Cement

2.2

Land-Use

Change

2.9

Land Uptake

2.4

Ocean

Uptake

What are the mechanism responsible?

Where is the uptake occurring?

How will it change over time?

Can management influence?


Global budget scoping mitigation opportunities

Activities are undertaken within regions at local levels

Comprehensive REGIONAL budgets are needed for guidance

REDUCE SOURCES

INCREASE SINKS

Global Budget: Scoping mitigation opportunities

Atmospheric accumulation rate

3.2 GtC per year 1990s

Atmosphere

Surface biosphere

6.3

F Fuel,

Cement

2.2

Land-Use

Change

2.9

Land Uptake

2.4

Ocean

Uptake


Mitigation regional c budget requirements

Mitigation: carried out at local to regional scales

Mitigation: Regional C Budget requirements:

  • Comprehensive/sectoral perspective

    • Implementation and accuracy

  • Spatially complete

    • Resolution appropriate for decision making or reporting

  • Appropriate time scales

    • Resolution years, horizon 10-100 yrs

  • Forecasting/scenario ability

    • Planning strategies

  • Tracking/monitoring ability with uncertainties

    • Evaluating, assessing, and adaptive management. Reporting

  • Transparency, credibility, explicit uncertainty

    • Accountability and comparability


Global perspective reconciling top down and bottom up

Global Perspective: reconciling top-down and bottom up

Land uptake currently inferred as residual.

  • Bottom up estimates are incomplete – limited by sectors, regions, and data

    Houghton reviewed the recent top down and bottom up estimates and attempts to reconcile.

    Houghton concludes

  • global land net uptake : net tropical source and a net northern sink,

  • magnitudes depend on accuracy of estimates of tropical LUC

    and

  • Both net tropical source and net northern sink appear to change over time

R.A.Houghton, 2003.Global Change Biology 9: 500-509,


Importance of mechanisms for land uptake

Importance of mechanisms for land uptake

What we now know:

  • No single region is responsible

  • No single mechanism is responsible

    Rather

  • Spatial mosaic of sources and sinks – at many scales, across landscapes, across biomes, across regions

  • Biological sources and sinks are often autocorrelated (but with time delays)

  • The spatial mosaic changes with time

Gaining a quantitative understanding of the processes underlying the land uptake is INTRINSICALLY a REGIONAL AND LOCAL problem, with scaling up challenges  REGIONAL CARBON BUDGETS


Importance of mechanisms for land uptake1

Importance of mechanisms for land uptake

  • Different mechanisms  different mitigation approaches

    • policy interest, scientific challenge

  • Different mechanisms  different future trajectories (climate implications)

    • scientific challenge, policy need – though not always appreciated!

  • Ability to factor out directhuman interventions from indirect responses and natural variability

    • policy request, strong scientific challenge


Two broad mechanisms for land uptake

Site Ci

  • Examples

  • Disturbed soils

  • Forest Stand

age

Biomass+ detritus +soils

Increased Site fertility(Carrying capacity)

Increased growth rate, decreased decomposition

Different factors important for different regions

Deceased site fertility, growth rate, …

Two broad mechanisms for land uptake

  • Changes in productivity (stimulated NPP, reduced respiration) in response to CO2, climate, nutrient, management …


Why regional carbon budgets scientific and policy background

Two broad mechanisms for land uptake

Site level

Ci

stand age

  • Shift of average age to right increases C (i.e., landscape becomes a sink)

  • Shift to left decreases C (i.e. source)

  • Changes in demographics (age distribution) due to change in mortality (LUC or natural distrubances)

  • At landscape or regional scale, must take into account age distribution


Why regional carbon budgets scientific and policy background

But, significant time before C released during/after disturbance is recaptured

Must be very careful when scaling up site to regional

stand Ci

stand age

Source

Sink

Net loss

Net removal

Contribution to landscape

remains deficit for much longer than instantaneous measurement suggests

Subtle scaling issue: Site to Landscape

Site scale accumulation

Biomass+ detritus +soils

Local Tower


Need for comprehensive system perspective

Carbon balance at a regional scale

Carbon balance at a global scale

Carbon balance at an ecosystem scale

e.g., Janssens et al (2004) (Europe)

e.g., Houghton (2003)

Need for comprehensive system perspective

At any scale, net flux to atmosphere is a complex balance of many individual time varying fluxes each having different controls

  • Two basic approaches to carbon balance:

  • Flux estimates

  • Pool (stock) change

Equivalent/complementary results (conservation of mass)

IFF all significant fluxes, and all significant stock changes are accounted

e.g., Barford et al (2001)(Harvard )


Need for comprehensive system perspective1

3.2 ± 0.1 GtC/yr

Atmosphere increase

>8Gt/yr?

Atmosphere

Surface biosphere

Ocean Circulation

?

Forests

?

6.3 ± 0.4

F Fuel,

Cement

2.2 ±0.8

Land-Use

Change

2.9 ± 1.1

Land uptake

2.4 ± 0.7 Oceans

Need for comprehensive system perspective

Especially important in predicting future atmospheric carbon if some of the present feedbacks fail …

Balance will be altered by

global change

  • Cox et al 2000

  • Kurz &Apps 1999

  • Sarmiento et al 1998

  • Peterson et al 2001


Betts future changes global region scale

Ignoring climate change

Uptake

Including climate change

Release

Regional changes with global significance

Betts: Future changes (?) global & region scale

  • Carbon feedbacks from dieback in Amazon

Betts et al 2004


Why regional carbon budgets scientific and policy background

With large C consequences

Note Change after 1970

Kurz and Apps, Ecol. Appl. 1999

Kurz and Apps: Contemporary, regional scale

Stand replacing disturbances in Canadian forests have changed over last 50 years

MJA IOS Mar 2004 23


Why regional carbon budgets scientific and policy background

Summary: Policy issues and challenges

Policy and decision makers focus on:

  • Likely impacts (party/country level and globally)

    • Of not doing anything (impacts and adaptation potential)

    • Of mitigation measures (cost/benefit)

    • Timing of these impacts

  • Feasible mitigation opportunities

    • Within country

    • Globally

  • Robust analysis of party (country) level budgets

    • Trade and negotiations

    • Planning and monitoring


Why regional carbon budgets scientific and policy background

Summary: Science issues and challenges

Quantitative understanding the spatial and temporal dynamics of the perturbed carbon cycle:

  • Reconciling top-down and bottom-up estimates of the global carbon budget

  • Understanding the mechanisms that control the major fluxes (anthropogenic and biospheric) making up the budget

  • Predicting how the budget will change over time

  • Observation and measurement challenges posed by the above needs


Why regional carbon budgets scientific and policy background

The way forward?

‘Better’ regional carbon budgets

  • Data, comprehensive (processes, sectors, pools), spatial representation, dynamic

    that can be used

  • to constrain and augment global budgets

  • to inform decision makers at regional scales

  • to enable implementation of carbon management strategies

  • to monitor progress at relevant scales and facilitate adaptive management


Why regional carbon budgets scientific and policy background

Think globally,

analyze locally


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