Transcript Climate Change Theme - Sustainable Development Commission

Policy options to achieve the 80% cut
Land Management, Sequestration and Sinks
Robin Matthews
Climate Change Theme Leader
Macaulay Institute
Aberdeen AB15 8QH
Presentation at Scottish Parliament, November 19, 2008
Structure of the talk
1.
2.
3.
4.
Background
Contribution to overall Scottish GHG emissions made by
the land use sector
Trends in GHG emissions from the land use sector
Scope for the use of land for sequestration and sinks
Emissions from the land use sector
• N2O: N-fertiliser, wet acid
soils, animals
• CH4: livestock, natural peat
bogs
• CO2: cultivation, fuel
consumption
• However, Scotland’s soils contain:
– Shallow organic soils: ~1400 Mt C
– Peat soils: 2000-4500 Mt C
• Forests and soils have considerable capacity to store carbon
Carbon sequestration
Effect of land use change on soil C
New Zealand
-1.15 t C ha-1 y-1 in first 3 years
Geescroft Wilderness: converted from
arable to woodland in 1880s
average 0.33 t C ha-1 y-1
Scale of the contribution
62% of UK’s removals is by
Scottish forests (2003)
Scotland’s total emissions: 59 Mt CO2e yr-1
Land use emissions: 11.8 Mt CO2e yr-1
From ‘Changing Our Ways: Scotland’s Climate Change Programme’, SEERAD, 2006.
Trends in main GHG source/sinks
Forestry
Livestock
Land use change
N fertiliser application
LULUCF source/sink trends
10
Scotland
Agriculture
decline in cattle and
sheep numbers
8
Mt CO2e yr-1
6
60% reduction
4
Net emissions from land use sector
2
0
1985
-2
1990
1995
2000
2005
2010
increase in sink
size by 78%
-4
Land use, land use change, forestry
-6
From AEA (2008), Greenhouse Gas Inventories for England, Scotland, Wales & Northern Ireland: 1990 - 2006
Agricultural management
• alternative ‘carbon-neutral’
energy crops
• increased C sequestration
through different ground
covers and land management
• reducing CH4 emissions from
livestock
• more efficient use of organic
and inorganic fertilisers
• Initial calculations suggest
abatement potential of 1.57
MtCO2e
Land use change: arable to grassland
Scotland: 600,250 ha
Land use change: arable to grassland
Abatement potential
Ignoring land suitability for the moment
–
–
–
–
y-1
setaside: 0.97 MtCO2e
beef: 0.11 MtCO2e y-1
sheep: 0.40 MtCO2e y-1
dairy: -8.12 MtCO2e y-1
2
abatement potential (MtCO 2e)
• 600,250 ha of cropland in
Scotland
• Assume all is converted
into grassland
• Sequestration rate:
~1.5 t CO2 ha-1 y-1
• Abatement potentials:
1
0.11
0.40
beef
sheep
0.97
0
-1
dairy
-2
-3
-4
-5
-6
-7
-8
-9
-8.12
setaside
Land use change: forestry
Options
• afforestation of abandoned
agricultural lands
• forest management to
increase carbon density at
the stand/landscape level
–
–
–
–
–
maintaining forest cover
minimising soil C loss
increasing rotation lengths
increasing growth
managing drainage
• increasing off-site carbon
stocks in wood products
• enhancing product and fuel
substitution
Land use change: forestry
Forestry Strategy: Increase of forestry from 17-25%
• Current forest area: 1,347,001 ha
• 2050 target: 1,969,300 ha
(+622,299 ha)
• Assume sequestration rate is
11 t CO2 ha-1 yr-1
• Abatement potential:
6.8 Mt CO2e yr-1 (12.5%)
• ‘Changing Our Ways’ (2006): The
forestry sector should deliver
annual carbon savings of
– 2.2 Mt CO2e by 2010 (4.0%)
– 2.9 Mt CO2e by 2015 (5.4%)
– 3.7 Mt CO2e by 2020 (6.7%)
Forest planting rates
Tradeoffs for landuse
• As climates warm,
more marginal areas
will become suitable
for agriculture
• What will be the
implications for:
–
–
–
–
–
–
–
food production
bioenergy
timber
water quality, quantity
soils
carbon storage
biodiversity
Land use change: peat restoration
•
•
•
•
•
•
•
•
total peat area: 1,096,000 ha
degraded basin peat: ~24,000 ha
eroded blanket peat: ~9,000 ha
functioning peat-bog sequesters
~730 kg CO2 ha-1 y-1
degraded bog could lose
~730 kg CO2 ha-1 y-1
one-off cost of £400-1000 per ha
abatement potential:
1460 × 33,000 × 10-9
= 0.048 Mt CO2e y-1
0.09% of Scotland’s emissions of
55 Mt CO2 yr-1
Summary
Abatement
potential
Fraction of
AFOLU
Fraction of total
(MtCO2e yr-1)
(%)
(%)
Agriculture
1.57
13.3
2.7
Cropland to
grassland
0.97
8.2
1.6
Forestry
6.80
57.6
11.5
Peatland
0.05
0.4
0.1
TOTAL
9.39
79.5
15.9
•
•
•
Proviso: Very ‘ballpark’ figures – indicative only!
Many assumptions that need to be tested
More detailed UK study to be published by Office of Climate Change in December
Marginal abatement cost curves
Expensive options,
small emission savings
Financial
savings
Cheap option, big
emission savings
• Options ranked in
decreasing order of
cost-effectiveness
• Width of each bar
(x-axis): abatement
potential (AP)
• Height of each bar
(y-axis): costeffectiveness (CE)
• Comparing the
abatement scenario
with a baseline