Transcript Outline

The Carbon Cycle - Policy Nexus
Robert T. Watson
IPCC, Chair
COP-6bis
Bonn, Germany
July 17th
Global Carbon Cycle
 Key Messages
Human activities (combustion of fossil fuels and land-use
changes) have and are continuing to perturb the carbon cycle -increasing the atmospheric concentration of carbon dioxide
The terrestrial biosphere has historically been a source of carbon
to the atmosphere - it is currently a net sink
The current terrestrial carbon sink is caused by land management
practices, higher carbon dioxide, nitrogen deposition and possibly
recent changes in climate
This uptake by the terrestrial biosphere will not continue
indefinitely. The question is when will this slow down, stop or
even become a source?
LULUCF activities will result in the sequestration of carbon in three
main pools -- above and below ground biomass and soils for
decades to centuries
Global Carbon Cycle
 Key Messages
some of the LULUCF sequestered carbon could be released back
to the atmosphere due to changes in climate, but unlikely for
many decades -- even then there would still be more carbon in
the three pools than without the LULUCF activities
there may be a few instances, e.g., Boreal forests at high
latitudes, when the benefits of carbon sequestration may be
partially or fully offset by changes in albedo
slowing deforestation has multiple environmental and social
benefits
monitoring systems can be put in place to monitor all three pools
of carbon
LULUCF activities buy time to transform energy systems to lower
GHG emitting systems, but will allow more fossil carbon to
transferred to the more labile biological pools, hence avoiding a
tonne of carbon emissions is better than creating a tonne of sinks
Indicators of the Human Influence
on the Atmosphere during the Industrial Era
Carbon emissions and uptakes since 1800
(Gt C)
140
Land use
change
115
Oceans
110
265
Fossil
emissions
Terrestrial
180
Atmosphere
The Global Carbon Cycle - 1990s
Units Gt C and Gt C y-1
Atmosphere
…are leading to a
build up of CO2
in the atmosphere.
3.2
750
63
500 Plants
6
0
Soil
2000
6.3
About
16,000
1.6
Fossil emissions ...
91.7
9
0
…and land clearing
in the tropics...
The KP seeks to reduce net
carbon emissions by about
0.3 Gt C below 1990 levels
from industrial countries
Fossil Deposits
Oceans
39,000
Current Role of the Terrestrial Biosphere
 During the 1990s the net global uptake of carbon by the
terrestrial biosphere was about 1.4 Gt C per year --assuming emissions from tropical deforestation in the 1990s
were about 1.6 Gt C per year (the same as in the 1980s) -then the gross uptake of carbon by the terrestrial biosphere
was about 3 Gt C per year
 Inverse modeling suggests that about 50% of the global
uptake is occurring in the tropics and the other 50% in the
mid- and high-latitudes of the northern hemisphere
 The primary cause of the current uptake (about 1.5 Gt C per
year) in N. America, Europe and Asia is, as said earlier,
thought to be re-growth due to management practices, with
carbon dioxide, nitrogen fertilization and climate change
contributing, but to smaller extent
Global Net Ecosystem Productivity
Net ecosystem productivity, Gt C yr –1
4
Sink
2
0
Source
–2
1900
1950
2000
2050
2100
Predicted effects of changes in climate and atmospheric CO2 on
the global net uptake of carbon by terrestrial ecosystems -this model shows the sink maximizing in about 2050 and
declining to zero by 2100 -- other models tend to show
constant or less of a decline after 2050
The Kyoto Protocol
The Challenge of Mitigation
 The near-term challenge is to achieve the
Kyoto targets
 The longer-term challenge is to meet the
objectives of Article 2 of the UNFCCC, i.e.,
stabilization of GHG concentrations in the
atmosphere at a level that would prevent
dangerous anthropogenic interference with
the climate system
food security
ecological systems and
sustainable economic development
The Long-term Challenge
Carbon emissions and stabilization scenarios
The Challenge of Stabilization of Atmospheric
Concentrations of Carbon Dioxide
 If governments decide to stabilize the atmospheric
concentration of carbon dioxide at 550ppm (about twice
the pre-industrial level), global emissions would have to
peak by about 2025 and fall below current levels by
2040 to 2070.
 This would mean that all regions would have to deviate
from most “business-as-usual”scenarios within a few
decades
Key Conclusions of IPCC
 In the absence of trading, Annex B costs of complying with
the Kyoto Protocol, range from $150-600/tC (i.e., 0.2 - 2%
loss of GDP), where-as with full Annex B trading the costs
are reduced to $15-150/tC (i.e., 0.1 - 1% loss of GDP)
 These costs could further reduced with use of:
the Clean Development Mechanism
sinks
mixture of greenhouse gases
ancillary benefits and
efficient tax recycling
 If all cost reduction activities could be realized then
GDP growth rates would only have slow by a few hundreds
of a percent per year
Key Issues for the Kyoto Protocol
Article 3.3
Which stock changes? All, or only those
directly human induced - what is included?
Article 3.3 The net changes in greenhouse gas emissions from sources and
removals by sinks resulting from direct human-induced land-use change
and forestry activities, limited to afforestation, reforestation, and
deforestation since 1990, measured as verifiable changes in stocks in
each commitment period shall be used to meet the commitments in this
Article of each Party included in Annex I. The greenhouse gas emissions
from sources and removals by sinks associated with those activities shall
be reported in a transparent and verifiable manner and reviewed in
accordance with Articles 7 and 8.
Can we separate the growth increment due to “normal” forest
growth from that due to carbon dioxide, nitrogen fertilization
and climate change or year-year climate variability? -- IPCC
Potential net emissions from forests
Art. 3.3 Annex 1 Countries
-1
Mt C
yr
IPCC definitions
Annex 1
AR
26
D
-90
Note the qualifications about these estimates.
•Based on assumption that current rates of
ARD continue through to 2012
•Assumptions about the shape of the growth
curve greatly affect the outcome
Potential emissions reductions
from forests under CDM (using Art.
3.3 rules) in non-Annex 1 Countries
Mt C yr-1
IPCC definitions
Non-Annex 1
AR
D
373
-1600
Avoided deforestation not eligible under current
Pronk text
-
concern about baselines, leakage, permanence
-
multiple benefits, including biodiversity, water
resource management
Key Issues for the Kyoto Protocol
Article 3.4
Contrasts with Article 3.3 refers
to “direct human-induced
activities
Article 3.4 … Such a decision shall apply in the second and
subsequent commitment periods. A Party may choose to apply
such a decision on these additional human-induced activities for
its first commitment period, provided that these activities have
taken place since 1990.
The key issue is whether these activities must commence after
1990 or whether activities initiated before 1990, but that are
continued after 1990, are eligible -- a key issue with respect
to the current net terrestrial uptake -- Pronk text finesses this
issue by discounting for the first commitment period
Interpretations of Article 3.4
Narrow definition
Broad definition
Forest Management
Cropland Management
Grazing land Management
USA definition
Full carbon accounting
 All stocks across all carbon pools
 If applied to all land in all countries then the
accounting would produce the “Net terrestrial uptake”
of about 1.4 GtC y-1 (IPCC TAR) without any additional
effort to reduce emissions or increase sinks
 Assuming emissions from tropical deforestation are
1.6 GtC y-1, this suggests a global uptake of about 3
GtC y-1
Assuming 50% of the uptake is at mid- and high latitudes, this
would allow Annex I Parties to claim an annual credit of between
about 1.5 GtC y-1 due to the residual uptake because of improved
management practices pre-1990, carbon dioxide and nitrogen
fertilization effect and climate change. Current text would limit this
credit by discounting by 85%.
Maximum USA & Japan purchases
The current text
60
M t C / yr
50
40
30
20
10
0
70%
75%
80%
85%
90%
95%
100%
discounts credits for
forest management
under Article 3.4 by
85%, and
Forest mgmt discount (Pronk = 85%)
limits the use of sinks
to 50% of total
reductions
60
Mt C / yr
50
40
30
20
10
0
20%
30%
40%
50%
60%
70%
Cap on the use of sinks (Pronk 50%)
80%
Accounts for pre-1990
activities, does not separate
direct from indirect human
activities, and accepts
broad definitions
Annual C sequestration potential (GtC/y)
improvement of management within cover type new activities since 1990
I
Annex 1
Urban land management
Global
Rice Paddies
Agroforestry
Grazing land management
Cropland management
Forest management
0
0.1
0.2
0.3
Contains a best estimate of the rate of uptake of these
activities by 2010 (varies between 3% to 80%) -- current text
would inhibit investment in forest management under Article
3.4 because of the 85% discounting
Annual C sequestration potential (GtC/y) - change
in cover type - new activities since 1990
Annual C sequestration potential (GtC/y)
Transformation between cover types
Annex 1
Degraded land restoration
Global
Wetland restoration
Degraded agriculture to agroforest
Cropland to grassland
0
0.1 0.2
0.3
0.4
0.5
Can the Direct and Indirect Human-induced
sequestration be separated??
 “For activities that involve land-use changes (e.g., from
grassland/pasture to forest) it may be very difficult, if not impossible,
to distinguish with present scientific tools that portion of the observed
stock change that is directly human-induced from that portion that is
caused by indirect and natural factors.”
 Emissions and removals from natural causes such as El Niño may be
large compared with commitments - year to year natural global carbon
uptake varies by as much as 2-4 Gt C per year - terrestrial systems do
not sequester efficiently during El-Nino events - the climate is
predicted to become more El-Nino-like
 For activities that involve land-management changes (e.g., tillage to
no-till agriculture), it should be feasible to distinguish between the
direct and indirect human-induced components through control plots
and modeling, but not to separate out natural factors
Permanence
 “Sinks” are potentially reversible
through human activities, disturbances, or environmental
change, including climate change.
 This is a more critical issue than for activities in other
sectors, e.g., the energy sector.
 A pragmatic solution … ensure that any credit for
enhanced carbon stocks is balanced by accounting for
any subsequent reductions in those carbon stocks,
regardless of the cause.
Monitoring Carbon
 Technical methods sufficient to serve the requirements of
the Protocol exist for above ground stocks and most likely
for below ground stocks.
 Annex 1 Parties generally have the technologies available,
but few currently apply them routinely for monitoring
 Non Annex 1 Parties may require assistance to develop the
necessary capacities and cover costs
 Methods and research results are highly transferable
between Parties, and rapid improvement should be expected
Conclusion
LULUCF activities can play a critical role in
limiting the build-up of carbon dioxide in the
atmosphere, especially in the near-term, but to
stabilize the atmospheric concentration of carbon
dioxide (Article 2 of the Convention) will require
significant emissions reductions globally, which
can only be achieved by either reducing energy
emissions or by capture and storage of energy
emissions