PEAT AND PEATLANDS PEATLANDS. Area of tropical peatland. Thickness of tropical peat: best estimate? Peat carbon pool

Transcription

1 Problems for sustainable management of tropical peatlands: case study of Indonesia Harri Vasander Jyrki Jauhiainen et al. from CARBOPEAT project PEAT AND PEATLANDS Peat is accumulation of partially decomposed organic matter, mostly of plant origin Decomposition may be inhibited by a combination of (a) Waterlogging (b) Oxygen deficiency (c) High acidity (d) Low temperature (e) Nutrient deficiency Peatlands are found in tropical, temperate, boreal and sub-arctic regions Department of Forest Sciences University of Helsinki, Finland harri.vasander@helsinki.fi HENVI-seminar P ASS TRO E PEATLANDS Peatlands: 4 million ha 4 % of all wetlands 3% of land & freshwater area They play a key role as Flood mitigation and control Climate regulation Carbon storage Maintenance of water quality Biodiversity Breeding and over-wintering grounds for waterfowl Food supply Supplies of fuel, fibre, peat Non-consumptive benefits Best estimate 368,51 km 2 Range 333, ,149 km 2 68% in Southeast Asia Area of tropical peatland Unpublished material of CARBOPEAT project Country Thickness of tropical peat: best estimate? Best estimate of mean thickness (m) Brunei 3 Indonesia 5 Malaysia 7 Comment Burma.3 Default value Papua New Guinea.3 Default value Philippines.5 Thailand.3 Default value Vietnam.3 Default value Other country specific data: Bangladesh, Belize, Cuba, Guiana, Jamaica, Liberia, Rwanda, Senegal, Sri Lanka, Trinidad & Tobago, Venezuela Best estimate 65.2 Gt Range Gt 94% in Southeast Asia Peat carbon pool Unpublished material of CARBOPEAT project 1

2 Distribution of lowland peatland in Southeast Asia Global and regional importance of tropical peatlands 1-11% of global peatlands by area* SE Asian peats % 14-2% of global peat carbon pool* SE Asian peats 13-19% Revised estimates for total forest carbon pools**: Indonesia : 11 Gt (from 4 Gt) (biomass + soil C) Malaysia : 15 Gt (from 1 Gt) (biomass + soil C) In both countries, peat component ~ 47% (* Immirzi et al.1992; Bridgham et al. 26) (** Brown et al. 1993) Tropical peat as a carbon store and ecosystem carbon dynamics 1 kg dry peat.5 kg carbon Global scale carbon storage 3% of terrestrial carbon is stored in peat globally 7% in northern climate zones / 3% in the tropics equivalent to 75% of all carbon in atmosphere equivalent to 1 years emission of fossil fuels Labile carbon storage in peat is very long-term Resource All peatlands Tropical peatlands Original peatland area in Finland 1.4 Mha = 1/3 land surface Area (Mha) (1-12% of the global reservoir) Carbon (t ha -1 ) Carbon total (Gt) 42-95, best estimate 65 (up to 1/3 all peat carbon reservoir) Ecosystem under destruction Land use change Drainage Logging Fires 2

3 Land cover change in Sebangau area Landsat MSS 1985 Landsat TM 1991 Landsat TM 1993 Landsat TM 1996 Landsat TM 1997 Landsat ETM 2 Aster 24 DMC 25 Block C Central Kalimantan Page et al. 28, Ecosystems Kevin Tansey, Agata Hoscilo & Sue Page Legal and illegal logging The principal recolonising tree species of degraded and fire-damaged peatlands in Central Kalimantan: Combretocarpus rotundatus in the left and Cratoxylon glaucum in the right. The fern in the foreground of both pictures is Stenochlaena palustris. Some mapped illegal logging canals in NE corner of Sabangau National park (25 survey). 3

4 Drainage for agriculture Relation between CO2 emission and water table depth Relation between CO2 emission and watertable depth CO2 emission (tonnes2co ha yr ) 12 y = 1,37x R2 = -, Series3 Linear (Series3) average watertable depth (cm) Compiled from available peer reviewed publications. Source: Henk Wösten, ALTERRA Jyrki Jauhiainen, University of Helsinki accumulated sub sid ence in cm 35 Average peat subsidence rate in relation to time in years. West Johor, Sarawak (1) Peat subsidence cm/ y 2.5 m 2. cm/y time in years Time (in years) until peat disappearance Peat depth (cm) Oil palm (drainage -5 cm) Shallow peat ( < 15 ) Time period for peat disappearance after drainage. Comparison between peat depth and drainage depth (2). < 1 Sago cultivation (drainage -25 cm) < 2 Anderson 1 ( 15 2 ) Anderson 2 ( 2 25 ) Anderson 3 ( >25 ): > 38 > 76 >2 27 (1) Wösten et al., Geoderma 78: (2) From personal communication with Henk Wösten 24. Managed peat problems (some) During land management; Water management Repeated renewing of drainage ditches (peat subsidence) Hydrological control in permeable peat is demanding Water catchment balance Unfertile soil needs a lot of fertilization Soft peat substrate demanding for top-heavy crop species Invading weed and pest species Fires Infrastructure maintenance on peat (roads, water ways, ) Fires Towards end of use increase problems connected to; Water management Salt water as ground water Salt water intrusion Former water catchment balance is lost Potential acid sulphate soil (PASS) activation leading to high acidity (H2SO4) and release of heavy metals from subsoil Loss of land Thousands hot spots have occurred in years 1997, 21, 22, 25, 26, 29? Oct

5 Reasons for reoccurring fires on Borneo peatlands Drainage Forest logging Land clearance Previous fire events OSM, Yogyakarta, 28. September 25 Bechteler, A., MSc, GeoBio Center LMU Munich Large scale fires are typical phenomenon in clear felled and selectively logged forests. Main cause for the fires is usually long dry period connected to land clearance in agricultural activities. Between 1997/98, within 6 months peat fires in Indonesia released Gt carbon ( * largely from burning peat (Page et al., 22). The total carbon loss for years 1997 to 26 is between 4.2 and 12.8 Gt (mean is 8.5 Gt). (F. Siegert) West-Europe annual carbon emissionsarelessthan.9 Gt (Pearce, 1997). Fires caused about 9.3 billion USD losses counted in money (The Jakarta Post ). ( *1 Gt = 1 kg Increase in CO2 Increase atmospheric CO Largest increase since 1957! The history of fire occurrence in Borneo between 1997 and / Between 1997 and 24 about 24% of Borneo has burned at least once (18 Mha). Indonesian side of Borneo covers 92 % of the fires, Malaysia and Brunei areas only 8 %. Year 26 More than 43, hotspots, more than 2 million hectares of peatland affected, in Borneo between 15 July and 15 October 26. The total hotspots in Sumatra and Kalimantan together in this period was more than 8, with 3.7 million hectares of peatland burned. OSM, Yogyakarta, 28. September 25 % of the burned area 45, 4, 35, 3, 25, 2, 15, 1, 5,, Brunei Darussalam Sabah Sarawak Kalimantan Barat Kalimantan Timur Kalimantan Tengah Bechteler, A., MSc, GeoBio Center LMU Munich Kalimantan Selatan Release of carbon from forest and peat fires in Indonesia (mostly Sumatra and Kalimantan) this year will be between.5 and 1.6 Gigatonnes. Florian Siegert and Andreas Langner Smoke haze map 19 Oct 26 Indonesian peat fires in in 1997/1998 caused also - hundred thousands of hospitalisations - millions of working & school days lost - natural resource base, business and prospects lost (USD 8.4 billion) - enhanced poverty, social & ethnic tensions 5

6 CO2 emission (Mt/y) Tropical peatlands & the carbon cycle : from sink to source present likely Minimum due to peat decomposition CO2 emissions due to peatland drainage (fires excluded), SE Asia PEAT-CO2 / Delft Hydraulics draft results Likely due to peat decomposition 1 Maximum due to peat decomposition Current (25): Mt CO2 yr-1 (1 24 Mt C yr-1 ) Projected ( ): Mt CO2 yr-1 (15-27 Mt C yr-1 ) Modelling C emissions from tropical peatland drainage fire emissions NOT included Current global emissions from fossil fuels ~25, Mt CO 2 yr -1 (in comparison, tropical peat drainage emissions equivalent to % of fossil fuel emissions) Indonesia and C loss from peat Annually, in Indonesia 2 million tonnes of CO 2 is emitted.6 Gigatonnes loss is caused by decomposition of dry peat (a process that will continue until all peat has disappeared) and 1.4 Gigatonnes are lost through the annual fires. In the ranking of countries based on their total CO 2 emissions Indonesia comes 21 st. if peatland emissions are included, Indonesia is ranked 3 rd. Because of peat carbon losses, Indonesia emits more than all the efforts of western countries to reduce greenhouse gases under the Kyoto Protocol. But all this ignores (significant) land use changes, drainage and fire Southeast Asian peatlands Loss of carbon through peat oxidation 3 (~26 Mt C yr -1 ) Carbon sequestration 1 (19 21 Mt C yr -1 ) Reduced carbon sequestration 2 (~1 Mt C yr -1 ) Release of carbon by fire 4 (~19 Mt Cyr -1 ) Vegetation carbon sink Reduced vegetation sink Pool: 61 Gt (& increasing?) Pool: < 61 Gt Natural overall carbon sequestration (& decreasing by 46 Mt C yr -1 ) Current situation overall carbon source Notes: 1 based on area of 252,229 km 2 and carbon accumulation rate of 8 g C m 2 yr -1 (Neuzil, 1997; Page et al., 24) 2 based on deforestation of 121, km 2 of peat swamp forest (Hooijer et al., 26; 29) 3 based on likely mean annual drainage depth of 6 cm and a resulting annual soil CO 2 emission of 81 t ha -1 (Jauhiainen et al., in prep.) 4 based on average fire-related C emissions over period (Page et al., 22; van der Werf et al., 28) Southeast Asian peatlands - from carbon sink to carbon source Estimated current annual loss ~46 Mt C England s total peat store is ~3 Mt C, Finland s ~ 53 Mt C!! 17 Mt CO 2 e yr -1 = 5.6% global fossil fuel emissions!! Indonesian peat losses alone ~ Mt C yr -1 Restoration, rehabilitation, mitigation? World Institutions & Indonesian Govt. now starting to recognise the scale of the problem Small-scale hydrological restoration & reforestation projects underway Pilot projects to implement improved water management in plantations Larger-scale REDD demonstration, CDM & VCS projects in planning will require huge investment in fire control Fire hotspots, Sept 29 ( 6

7 Reducing the contribution mismanaged tropical peatlands make to C emissions Peat fires grab the headlines but emissions from peat oxidation same order of magnitude! Stopping one but not the other merely means it will take a longer time until exhaustion of the peat C store 23 cm in 28 yrs Summary Global area of tropical peatlands ~37, km 2 ; 68% in SE Asia Pre-disturbance carbon pool ~65 Gt; 94% in SE Asia Uncertainty but importance of SE Asian region is clear Peat carbon comprises 47% of the total soil carbon pools in Indonesia & Malaysia Emphasises importance of including peat carbon in national and regional assessments of terrestrial carbon stocks Scale of GHG emissions from tropical peatlands now being recognised emissions reduction is being addressed... Too little, too late? Terima kasih Kiitos Photo: Maija Lampela Thank you 7