Carbon storage in peatlands what is the potential

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Carbon storage in peatlands what is the
potential?
Fred Worrall

• Dept. of Earth Sciences
• University of Durham

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Why should I care about peatlands?

• Peat soils are the largest soil store of carbon
  in the World
• Northern peats contain 450000 Mt C, 30 of the
  Worlds terrestrial carbon
• The UK has 8 of the Worlds peat
• UK peat is the countrys largest terrestrial
  carbon store
• More carbon stored than the forests of Britain
  and France combined
• The amount of carbon is equivalent to 35 years of
  total UK output of CO2
• UK peat is a major water source in Northern
  Britain
• Water colour is major water quality limitation

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At equilibrium Net emissions 0
Carbon absorbed over time
Carbon poor
At equilibrium Net emissions 0
A transitionary sink
Carbon rich
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Restore
Net source
Pristine
Net sink
Net sink
Avoided loss
Transitionary sink
Peat grows mineral soils dont
Perpetual sink
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Modelling uptake/release pathways

• Based around water balance in peats
• Model includes
• Primary productivity
• Soil CO2 respiration
• Methane
• Wet and dry deposition
• DOC
• POC
• Dissolved CO2

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Modelling uptake/release pathways

• Based upon 725 km2 of the Peak District National
  Park
• Daily to monthly time step
• Spatial resolution only restricted by topographic
  or climatic data
• Typically 1 km2
• Has been run upto 12 years in the past and 75
  years into the future
• Includes
• Grazing
• Drainage
• Burning

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Present carbon budget

• Average areal budget
• 51 tonnes C/km2/yr
• Total budget
• 26 Ktonnes C/yr

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Best case scenario

• If there was no gullies, no burning
• Model becomes dominated by altitude variation
• Areal average budget
• 80 tonnes C/km2/yr
• Total C budget
• 41 Ktonnes C/yr
• Even under best case scenario there are areas
  that are still losing carbon
• Does this mean that some areas are unsustainable?

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Targetting action?

• Comparison of reality with best-case
• Red areas indicates areas of high potential
  perpetual gain
• Green areas no potential perpetual gain
• Are some areas unsustainable?
• Areas that are large sources converted to areas
  of that are small sources
• Cuts losses and protects against further change

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What could this mean?

• There are 3568 km2 of peat in England and Wales
  (Milne and Brown, 1997)
• Presently assumed to be storing 88 tonnes CO2
  equivalent/km2/yr 315 Ktonnes CO2 equivalent/yr
• If England and Wales were Moor House
• Worst case scenario
• Heavily drained 1306 ktonnes CO2
  equivalent/km2/yr
• Over burnt and grazed 92 Ktonnes CO2
  equivalent/yr
• Best case scenario
• Pristine bog 150 Ktonnes CO2 equivalent/yr
• Potential gain 1546 ktonnes CO2 equivalent/yr

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Transitionary sinks?

• This modelling does not estimate transitionary
  sinks
• How much carbon is missing from a gully?
• How quickly can we fill a gully?

1.8m
Courtesy of Natural England
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If you dont think the capacity is massive
1km
There are 10000km of grips in the N. Pennines AONB
If all of that volume could be re-filled it would
be worth 6 million
Courtesy of Natural England
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What about lowland peat soils?

• Considered the Chat Moss complex
• Projected budgets 20 years ahead, 2007-2026
• Scenarios considered
• Cutover peat
• Pristine peat
• Transitionary sink

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How much carbon is stored?

• The transitionary sink is so large that the
  pristine sink can be discounted
• The total carbon saving of restoration would be
• -609 to -1128 tonnes of equivalent CO2/km2/yr
• This is equivalent to
• 240 cars/km2/yr
• 22400 passengers from Manchester to Amsterdam/km2
• 1 MW wind turbine/km2/yr

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How much is this carbon worth?

• The shadow price of carbon is 6 - 18 / tonne of
  CO2 equivalent
• The cost of restoration is 150 - 450 /ha
• The cost of
• Carbon capture and storage - 25 /tonne of CO2
  equivalent
• UK woodland based scheme - 10 /tonne of CO2
  equivalent

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The profit from peatland restoration?
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Equivalent cost of carbon stored
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So?

• The case for the massive and ongoing potential of
  peat soils is clear
• If we do nothing more areas will becomes net
  sources of carbon and add to the problem
• The Yorkshire/Humber region has damaged peatlands
  in both upland and lowland settings

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What do we need to do?

• Survey
• Including the fringes and former peat areas
• Model
• Calculate present and possible budgets
• Maps can identify targets sites
• Calibrate/validate
• Gather local information to improve confidence
• Risk analysis
• Perform both stochastic and sensitivity analysis
• Intervene
• Make changes and monitor them