The Carbon Cycle - Policy Nexus Robert T. Watson IPCC, Chair COP-6bis Bonn, Germany July 17th
Global Carbon Cycle
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
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)
The Global Carbon Cycle - 1990s Units Gt C and Gt C y -1 The KP seeks to reduce net carbon emissions by about 0.3 Gt C below 1990 levels from industrial countries Atmosphere Fossil Deposits 6.3 63 91.7 60 90 3.2 Plants Soil Oceans 750 500 2000 39,000 About 16,000 1.6 … are leading to a build up of CO 2 in the atmosphere. Fossil emissions ... … and land clearing in the tropics...
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
1900 1950 2000 2050 2100 Predicted effects of changes in climate and atmospheric CO 2 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 Global Net Ecosystem Productivity Net ecosystem productivity, Gt C yr –1 Sink Source 4 2 0 – 2
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
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
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
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. Which stock changes? All, or only those directly human induced - what is included? 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 may be asked to assess this possibility Key Issues for the Kyoto Protocol Article 3.3
Potential net emissions from forests Art. 3.3 Annex 1 Countries Mt C yr -1 AR D IPCC definitions 26 -90 Annex 1
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 AR D IPCC definitions 373 -1600 Non-Annex 1 Avoided deforestation not eligible under current Pronk text - concern about baselines, leakage, permanence - multiple benefits, including biodiversity, water resource management
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 Contrasts with Article 3.3 refers to “direct human-induced activities Key Issues for the Kyoto Protocol Article 3.4
Interpretations of Article 3.4 Forest Management Cropland Management Grazing land Management Narrow definition Broad definition 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%.
The current text discounts credits for forest management under Article 3.4 by 85%, and limits the use of sinks to 50% of total reductions Accounts for pre-1990 activities, does not separate direct from indirect human activities, and accepts broad definitions
I 0 0.1 0.2 0.3 Forest management Cropland management Grazing land management Agroforestry Rice Paddies Urban land management Annex 1 Global 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) improvement of management within cover type - new activities since 1990
Annual C sequestration potential (GtC/y) - change in cover type - new activities since 1990
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
“ 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.
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
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