drainage wetting wet peatland subsidence ⦠the âdevil's cycleâ of mainstream peatland utilisation⦠Page 13. Bava
A review of current and potential climate responsible peatlands management practices Hans Joosten Greifswald University
[email protected]
Kalimantan
When drained, peatlands become vigorous sources of carbon dioxide (and nitrous oxide)
Clear relation between water level and GHG emissions (example: total CO2, CH4 and N2O, temperate zone)
Western agriculture originated in the ‘semi-desert’
…inciting the idea that productive land must be dry…
…and soils must be continuously moved…
…ideas that we also apply to wet, organic soils…
… growing desert plants on peat: Aloe vera…
… growing arid plants on peat: mays/corn…
Why peatland drainage? • • • •
To cultivate dryland plants (main food plants) To improve bearing capacity / trafficability To improve microclimate (less early and late frosts) To increase nitrate availability from peat oxidation
In the first decades, this works out fine On the longer-term severe problems occur (next to GHG emissions) that frustrate productivity
Germany Drained peatland subsides, becomes wetter and requires ever deeper drainage, leading to further subsidence
… the “devil’s cycle” of mainstream peatland utilisation…
wet peatland
wetting
drainage
subsidence
Bavaria: 3 m loss since 1836
UK: 4 m loss since 1870
…Nether-lands: bogged down: 1000 yr of peatland drainage, Nether-lands now half the country deep under sea level…
1000 yrs x 1 cm = 1000 cm = 10 m!
…Nether-lands: bogged down: 1000 yr of peatland drainage, Nether-lands now half the country deep under sea level…
In tropics subsidence 10 times faster!
Many tropical peatlands are coastal and will - with continuous drainage and >2000 mm of rainfall - become undrainable …
Sumatra, Indonesia
Aljosja Hooijer
…and unusable…
Germany
In Germany, ten thousands of hectares of agricultural peatland have already been given up as they could no longer be drained
Ukraine … In continental climates the peat soil degrades irreversibly and does not provide water for plants anymore…
Mongolia
Desertification after peatland overgrazing
…peatlands are difficult to cultivate …
Jilin, China …give often bad harvests …
Heilongjang, China …and are consequently often neglected and abandoned…
Drained peatland use destroys its subsistence base That thing with the Three gears cannot work. Can it, daddy?
fodder fuel
food security productivity
No girl, It can‘t…
fiber
salt intrusion
land loss
subsidence acid sulphate soils
flooding
haze ghg emissions
drainage biodiversity loss
fire
Jakutien, RF
FAO: Causes → peatlands → consequences Climate change mitigation ↔ food security
FAO report: Decision support tree Do you have organic soils?
Start
NO
Are you sure?
YES Choose the relevant type(s)
6
Use chapter ´4.1
7
9
Is productive use necessary?
YES
NO Is the ecosystem pristine?
Paludiculture chapter 2.2
Can a near-nature state be restored?
YES
YES
Conservation chapter 2.1
Restoration chapter 2.3
Drained organic soils
8
Check paludiculture options
Is productive use necessary? NO
YES
NO
NO
This report is not relevant for you
NO
Wet organic soils
8
YES
Rewetting chapter 2.3
Is rewetting possible?
YES NO
Check restoration options
Best practice chapter 2.4
NO
10
Hazard control chapter 2.5
FAO report: Decision support tree Wet organic soils Is productive use necessary?
YES
Paludiculture chapter 2.2
NO
NO
Is the ecosystem pristine?
Can a near-nature state be restored?
NO
YES
YES
Conservation chapter 2.1
Restoration chapter 2.3
Kenya
Non-used peatlands are not use-less: they provide vital ecosystem services and biodiversity…
FAO report: Decision support tree Wet organic soils Is productive use necessary?
YES
Paludiculture chapter 2.2
NO
NO
Is the ecosystem pristine?
Can a near-nature state be restored?
NO
YES
YES
Conservation chapter 2.1
Restoration chapter 2.3
soil degradation oceanic climate
soil degradation continental climate.
subsidence
Management options for productive use
emissions
Alternatives management practices Costs on short-, middle- and longterm S-T M-T L-T
Draining and ‘black culture’ Draining and mixing with mineral subsoil Draining (deep) and covering with sand (30 cm) Draining and removal of peat (undeep/usable) Draining (shallow) and covering with sand (10 cm) Draining (shallow) and covering with sand (30 cm) Paludiculture (=undrained land use)
Paludiculture seems to be an optimal option (but must be developed)
Poland If you need to use them, use them wet: paludicultures!
Poland
Paludiculture is agriculture/grazing/forestry on wet peatland
Neimongol, China
Reed mat making at Wuliangsuhai Lake
FAO report: Decision support tree Drained organic soils
Check paludiculture options
Is productive use necessary?
YES Rewetting chapter 2.3
YES
Is rewetting possible?
NO Check restoration options
NO
Best practice chapter 2.4
NO Hazard control chapter 2.5
Indonesia
Rewetting with paludiculture reduces peatland emissions and produces renewable biomass resources: Jelutung rubber tree
FAO report: Decision support tree Drained organic soils
Check paludiculture options
Is productive use necessary?
YES Rewetting chapter 2.3
Is rewetting possible?
NO Check restoration options
NO
Best practice chapter 2.4
NO Hazard control chapter 2.5
Used and not rewet-able • • • • •
Minimize drainage as far as possible Choose crops adapted to high soil moisture Cultivate permanent crops Avoid land clearing by fire Limit fertilization
Malaysia
i.e.: no oil palm for „biofuel“ on drained peatland
FAO report: Decision support tree Drained organic soils
Check paludiculture options
Is productive use necessary?
YES Rewetting chapter 2.3
YES
Is rewetting possible?
NO Check restoration options
NO
Best practice chapter 2.4
NO Hazard control chapter 2.5
Peatlands burn if drained, abandoned and easily accessible. Better prevent this!
Brunei
• • • •
Secure undrained peatlands Rewet drained peatlands Develop paludicultures Adapt management of peatlands that cannot be rewetted
Peatlands must be wet: for climate, for people, for ever…
