Land Use, Land-Use Change and Forestry

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EXECUTIVE SUMMARY

The chapter addresses the implications of including-as adjustments to assigned amounts under the Kyoto Protocol-the effects of activities related to land use, land-use change, and forestry (LULUCF) other than those covered by Article 3.3. It derives a set of core questions from Article 3.4 of the Protocol and arranges these questions in a sequence designed to help decisionmakers work through issues such as which additional human-induced activities should be included and how those activities should be defined, measured, reported, monitored, and verified.

Although Article 3.4 of the Kyoto Protocol applies only to Parties listed in Annex I, examples and estimates that are relevant to current Annex I and non-Annex I countries are included because the list of countries interested in controlling greenhouse gas (GHG) emissions is likely to grow in the future. The numerous potential practices are summarized in broad activity groups, and "Fact Sheets" presenting the details of individual practices are included after the reference section.

The potential global impact of these additional LULUCF activities in Annex I countries in the first commitment period is estimated to be up to 0.52 Gt C yr-1. The combined Annex I and non-Annex I impact could reach 2.5 Gt C yr-1 in 40 years (Table 4-1). These estimates include only on-site carbon stock changes; reductions of CO2 emissions caused by the increased use of bioenergy or wood products are not included. The estimates are based on reviewed studies and the assumption that economic, social, and technical constraints will limit the land that is actually available for these activities to a small percentage of the land that is theoretically available. The main component of the large uncertainty associated with these estimates relates to where, and to what extent, LULUCF activities may occur. Once those facts are known, the estimates of GHG impacts of a given activity in a given location are far less uncertain.

Table 4-1: Potential net carbon storage of additional activities under Article 3.4 of the Kyoto Protocol. Increases in carbon storage may occur via (a) improved management within a land use, (b) conversion of land use to one with higher carbon stocks, or (c) increased carbon storage in harvested products. For (a) and (b), rates of carbon gain will diminish with time, typically approaching zero after 20-40 years. Values shown are average rates during this period of accumulation. Estimates of potential carbon storage are approximations, based on interpretation of available data. For some estimates of potential carbon storage, the uncertainty may be as high as 50%.

 
Areab
(106 ha)
Adoption/
Conversion
(% of area)
Rate of
Carbon Gain Areab
Potential
(Mt C yr-1)
Activity (Practices)
GroupAreaa
2010
2040
(t C ha-1 yr-1)
2010
2040

a) Improved management within a land use
Cropland (reduced tillage, rotations and cover crops, fertility management, erosion control, and irrigation management)
AI
NAI
589
700
40
20
70
50
0.32
0.36
75
50
132
126
Rice paddiesAreac (irrigation, chemical and organic fertilizer, and plant residue mgmt.)
AI
NAI
4
149
80
50
100
80
0.10
0.10
<1
7
<1
12
AgroforestryAread (better management of trees on croplands)
AI
NAI
83
317
30
20
40
40
0.50
0.22
12
14
17
28
Grazing land (herd, woody plant, and fire management)
AI
NAI
1297
2104
10
10
20
20
0.53
0.80
69
168
137
337
Forest land (forest regeneration, fertilization, choice of species, reduced forest degradation)
AI
NAI
1898
2153
10
10
50
30
0.53
0.31
101
69
503
200
Urban land (tree planting, waste management, wood product management)
AI
NAI
50
50
5
5
15
15
0.3
0.3
1
1
2
2

b) Land-use change
Agroforestry (conversion from unproductive cropland and grasslands)
AI
NAI
~0
630
~0
20
~0
30
~0
3.1
0
391
0
586
Restoring severely degraded landAreae (to crop-, grass-, or forest land)
AI
NAI
12
265
5
5
15
10
0.25
0.25
<1
3
1
7
Grassland (conversion of cropland to grassland)
AI
NAI
602
855
5
2
10
5
0.8
0.8
24
14
48
34
Wetland restoration (conversion of drained land back to wetland)
AI
NAI
210
20
5
1
15
10
0.4
0.4
4
0
13
1

c) Off-site carbon storage
Forest products
AI
NAI
n/ae
n/a
n/a
n/a
n/a
n/a
n/a
n/a
210
90
210e
90

Totals
AI
NAI
Global
497
805
1302
1063
1422
2485

a AI = Annex I countries; NAI = non-Annex I countries.
b Areas for cropland, grazing land, and forestland were taken from IGBP-DIS global land-cover database derived from classification of AVHRR imagery (Loveland and Belward, 1997). Each land-use/land-cover type was subdivided by the climatic regions defined in Table 4-4, using a global mean climate database (Schimel et al., 1996) of temperature and precipitation, with additional calculations of potential evapotranspiration (Thornthwaite, 1948). Each climatic region was further subdivided by Annex I and non-Annex I countries. Modal rate estimates from Table 4-4 were then weighted by the relative area of each land use by climatic region for Annex I and non-Annex I countries to derive a global area-weighted mean rate for each land use.
c Riceland area was subtracted from cropland area.
d Of the 400 Mha presently in agroforestry, an estimated 300 Mha are included in the land-cover classification for cropland; the remaining 100 Mha are included in forestland cover. These areas were subtracted from the respective totals for cropland and forestland.
e Assumes that severely degraded land is not currently classified as cropland, forestland, or grassland.
f Estimates for 2040 are highly uncertain because they will be significantly affected by policy decisions; n/a = not applicable.

Change in management within a land use or change in land use to one with a higher potential carbon stock can increase carbon stocks in an ecosystem, leading to a net removal of CO2 from the atmosphere. The carbon is stored as soil carbon, wood, leaf, root, and litter biomass. These different carbon pools have mean residence times that range from days to millennia. The stable carbon pools remain virtually unchanged over very long periods if management, climate, and disturbance regimes do not change. The rate at which ecosystems can accumulate carbon, the ultimate size of the pools, and the rate at which the carbon can be lost again under altered circumstances all depend on the form of the newly stored carbon, the magnitude of the land-use or management change, the inherent biological productivity of the site, and the type and depth of the soil.

The net effect of LULUCF activities on the atmosphere depends not only on changes in on-site carbon stocks but also on:

These non-CO2 effects can add to, or reduce, the effects from CO2. In several important cases, the non-CO2 effects are sufficiently large that failure to include them in the accounting procedure would lead to substantially misleading conclusions. For example, changes in CH4 and N2O emissions resulting from management changes in wetlands, rice crops, or dryland crops can offset a large portion of changes in the carbon stock.

The capacity to store on-site carbon through LULUCF activities is finite because the land area available for this purpose has competing uses and is limited and because the carbon pools have practical upper limits. Although the rates suggested in Table 4-1 will eventually decline, they are considered to be applicable for a 30- to 50-year period.

The potential contribution of these additional LULUCF activities to the reduction of global radiative forcing is therefore a substantial portion of the total human-induced effect, though it is too small to balance current fossil fuel emissions by itself. Including major LULUCF activities as adjustments to the assigned amounts under the first commitment period of the Kyoto Protocol could potentially reduce the degree to which many countries may need to alter energy use and energy production technology in the short term.

The opportunities for reducing the net flux of GHGs to the atmosphere through the application of these activities is large because of the extensive areas of cropland, agroforests, grazing lands, and forests that exist. The associated impacts-in terms of altered crop, animal, and tree production; water yield; biodiversity; energy use; and socioeconomic effects-are in many cases significant; these impacts can be negative or positive (frequently a mixture of both), depending on the specific activity and the environment in which it is applied. In deciding whether to develop policies or programs to encourage these activities, the associated non-climate benefits and tradeoffs of the activities are usually very important factors and may dominate over climate considerations at a local or national scale (Section 4.7).

Decisions about how additional activities will be implemented under the Protocol will significantly affect the cost and difficulty of implementation by the Parties, as well as the choice of reporting methods that will be used (particularly in the initial years). Carbon stocks in agricultural soils and forests can be measured, monitored, and verified by a range of methods with varying precision. The cost of measurement increases with the required precision. The methods continue to improve in accuracy and cost-effectiveness. One impact of including additional activities will be accelerated development and improved cost-effectiveness of new methods.

There are two basic options for inclusion of additional LULUCF activities: include a limited list of activities, or include essentially all LULUCF activities that affect carbon pools and/or GHG fluxes. Choosing to include a very limited list of additional activities may reduce short-term demands on a Party's accounting system, but it may fail to encourage activities and practices that have important impacts on the atmosphere and benefits for environmental quality and sustainable development and may result in displacement of emissions into areas or activities that are not included. A reporting regime in which a large number of small land areas must be monitored and tracked far into the future may make some practices (particularly those that tend to shift from place to place over time) very expensive to monitor and verify operationally. In that case, accounting for the main carbon stock changes over the entire land area of the country-as is done by some current national inventory systems-may be a more cost-effective approach in the long run. Such full-area accounting may simplify accounting procedures by allowing one set of rules to apply everywhere, making the precise definition of different land uses and LULUCF activities less critical and enabling a statistical sampling approach rather than spatially explicit recordkeeping.

For many LULUCF activities-particularly those that involve land-use change or widespread adoption of new management systems-measuring the direct human-induced effects independently of the background of indirect effects and natural variability is difficult or impossible. Where a single or well-defined change in management (such as the addition of fertilizer, a switch to conservation tillage, or a change in forest harvesting technique) can be identified and there are comparable areas nearby where that management is not undertaken, estimating the fraction of the total effect from the activity may be possible through the use of control plots, models, or predicted baselines. The decisions taken on these aspects will be important in affecting measurement and accounting difficulty.

Some agricultural practices (e.g., excessive soil disturbance, nutrient depletion, planting varieties with low biomass production, crop residue removal, inadequate erosion control practices) have caused reductions in soil organic carbon (SOC) estimated at 55 Gt C globally. The application of best-practice crop management-which may include conservation tillage, frequent use of cover crops in the rotation cycle, agroforestry, judicious use of fertilizers and organic amendments, site-specific management, soil water management that involves irrigation and drainage, and improved varieties with high biomass production-can recover a substantial part of this loss over a period of several decades. In rice agriculture, careful water and fertilizer management can lead to increased carbon storage, but calculation of the net effect must consider simultaneous changes in CH4 and N2O emissions. In general, carbon-enhancing cropland management will increase the capacity of croplands to feed the world's growing population (Section 4.4.2).

Forest management can create a significant increase in the standing stock of forest biomass and produce positive associated benefits such as improved water quality, reduced soil erosion, increased biodiversity, and enhanced rural income. Forest management includes all of the practices relating to the regeneration, tending, use, and conservation of forests. All aspects that are not included as afforestation, reforestation, and deforestation (ARD) activities under Article 3.3 could be covered by Article 3.4. Examples of the main forestry practices likely to alter carbon stocks include forest regeneration, including sub-practices such as human-induced natural regeneration, enrichment planting, less grazing of savanna grassland, change of tree provenances or species to include short-rotation forestry; forest fertilization; pest management; forest fire management; harvest quantity and timing; low-impact harvesting; and reducing forest degradation (Section 4.4.4).

The carbon impacts of forest management usually can be measured best as a net result of the complete suite of practices applied to a given forest area, as well as the end-use of the forest products. End use is important for two reasons: First, wood products provide a carbon sink, the size of which depends on the lifetime of the product; second, greater use of wood allows reduced use of fossil fuel (either by using the wood directly for energy production or indirectly to replace energy-intensive products such as steel, aluminum, and concrete). Including forest products as an activity under Article 3.4 will require decisions about how to report credits because the products will come from ARD and non-ARD forests (Chapter 3), and their original sources will be hard to trace once they are in use. Such products are widely traded between countries, requiring decisions about where and how to assign credits (Section 2.4.2.2).

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