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The value of peatland rewetting for reducing GHG emission Hlynur Óskarsson Agricultural University of Iceland
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Page 1: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

The value of peatland rewetting for reducing GHG emission

Hlynur Óskarsson Agricultural University of Iceland

Page 2: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

- Extent of peatland draining in Iceland- GHG emissions and the feasibility of restoration- Our research at Mávahlíð, Western Iceland

Outline

Page 3: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Icelandic peatlands

- Original coverage estimated as 9000 km2

- Minerotrophic and dominated by vascular plants

- By far the largest ecosystem carbon reservoir

Page 4: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Peatland draining

Page 5: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Length of drainage ditches excavated yearly during the period 1942-1993

Page 6: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Length of drainage ditches excavated yearly during the period 1942-1993

Page 7: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 8: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Length of drainage ditches excavated yearly during the period 1942-1993

Page 9: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 10: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 11: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Estimate of wetland drainage

• Drained for cultivation = 576 km2 (~15%)• Drained and never cultivated = 3.424 km2 (~85%)

• > 75% disturbed• ~ 45% fully drained

Less than 80% of the drained areas are cultivated, some areas are used for grazing but a large fraction is currently not in use

Page 12: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

349 Gg eq-CO2 / yr (N2O)

1615 Gg CO2 / yr (Fossil fuel use in 2010 = 1992 Gg CO2 )

440 Gg C / yr

400.000 ha drained

UN default value: 1,1 ton C / ha / yr

1. Negative greenhouse gas balance

Drained, but not in use – is that acceptable?

Page 13: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

2. Peat erosion taking place

Page 14: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

3. Water quality issues

Page 15: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

4. Areas declining in fertility

Page 16: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

5. Loss of habitat for wetland species

Page 17: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Drained, but not in use – is that acceptable? - No

Rewetting possible?

Page 18: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Hestur rewetted siteSmall GHG study 2000-2

• Comparative study of three sites – undrained, drained and rewetted

• Simultaneous measurement campaigns (8) – CO2, CH4, N2O

Page 19: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

y = 500,43Ln(x) - 2135

R2 = 0,5679

y = 404,29Ln(x) - 1506,2

R2 = 0,7127

y = 412,29Ln(x) - 1585,9

R2 = 0,7432

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

PAR

mg

CO

2 m

-2 h

r-1

Endurheimt

Framræst

Óraskað

Log. (Endurheimt)

Log. (Framræst)

Log. (Óraskað)

Page 20: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

CH4 efflux

y = 0,4783e0,2186x

R2 = 0,4464

y = 0,59e0,2035x

R2 = 0,5756

y = 0,0143x + 0,0316

R2 = 0,0248

-5,0

0,0

5,0

10,0

15,0

20,0

-2 0 2 4 6 8 10 12 14 16 18

Soil temperature

mg

CH

4 m

-2 h

r-1

Restored

Drained

Intact

Expon. (Restored)

Expon. (Intact )

Linear (Drained)

Page 21: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

y = 96,513e0,1801x

R2 = 0,7551

y = 29,315e0,2306x

R2 = 0,7741

y = 45,078e0,1898x

R2 = 0,6739

0

200

400

600

800

1000

1200

1400

1600

1800

2000

-2 0 2 4 6 8 10 12 14 16

Soil temperature (-10cm)

mg

CO

2/m

2 /hr

DrainedIntactRestored

Page 22: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

GHG Flux g / m-2 / yr-1 Natural mire Drained site Restored site

CO2 respiration 1154,1 2525,8 1211,1

CO2 uptake -1677,6 -1613,0 -1541,8

CO2 NEE -523,5 912,8 -330,7

CH4 (CO2-eq) 382,9 17,0 357,1

N2O (CO2-eq) 4,4 33,2 1,6

SUM total CO2-eq -136,2 963,0 28,1

Page 23: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Restoration holds promise because in most areas no alteration has taken place other than the excavation of the ditches and research indicates that peatland restoration establishes the former GHG balance of the peatland

Page 24: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

A recent report from the Ministry of the Environment on options for reducing GHG emissions concludes that wetland restoration is a feasible option and that large areas (~ 1000 km2) could be restored without having negative effects on other land-use, such as agriculture

Page 25: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

In 2007 Iceland and Belarusproposed to the UNFCCC thatwetland restoration be acceptedas “new activity” under the Kyotoprotocol.

At the climate summit in Cancún2010 / Durban 2011 negotiatorsagreed that in a future climateagreement it should be possiblefor countries to reduce theiremissions by rewetting drainedpeatlands

Page 26: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 27: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Mávahlíð research site

DitchRoad

Thanks to: Rannveig Ólafsdóttir, Guðrún Óskarsdóttir, Stefanía L. Bjarnadóttir Snorri Þorsteinsson and Jón Guðmundsson

Funded by: ISAL Iceland

Page 28: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Mávahlíð research site

DitchRoad

• ~ 3 ha in size• Drained in 1977• Never ploughed• 936 mm & 3,3°C

• Ave. depth 2,45 m• % C 31,3• C/N 17,3• Bulk density 0,24

Page 29: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Mávahlíð research site

DitchRoad

Weekly measurements of:

• GHG• Soil water table• Soil temperature• NDVI

Page 30: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Mávahlíð research site

DitchRoad

Continuous measurements of:

• Soil water table• Soil moisture• Soil temperature• PAR• Air temperature• Precipitation

Page 31: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Mávahlíð research site

DitchRoad

Weekly samples for measurements of:

• POC• PON• DOC• DON• (CO2 )• (CH4)

Page 32: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

y = 44,372e0,263x

R² = 0,8347

0

500

1000

1500

2000

2500

0 2 4 6 8 10 12 14 16

Soil temperature

mg

CO

2m

-2hr

-1

Page 33: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

y = -735ln(x) + 2961,1

R² = 0,8075

-2500

-2000

-1500

-1000

-500

0

500

0 100 200 300 400 500 600 700 800 900

mg

CO

2m

-2hr

-1

PAR

Page 34: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

-35000

-25000

-15000

-5000

5000

15000

25000

35000

0 50 100 150 200 250 300 350 400

Day of Year

GPP

ER

NEE

Page 35: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

DitchRoad

Mávahlíð research site - July, 2012

Page 36: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 37: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands
Page 38: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

CO2 respiration flux 2012

2012

0 50 100 150 200 250 300 350

mg

m-2

h-1

0

200

400

600

800

1000

1200

1400

1600

1800

Drained Rewetted

Page 39: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

CH4 flux - 2012

DOY - 2012

0 50 100 150 200 250 300 350

mg

m-2

h-1

-0,2

-0,1

0,0

0,1

0,2

0,3

0,4

0,5Drained Rewetted

Page 40: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

CO2 respiration flux 2012-13

2012 2013

0 100 200 300 400 500 600 700

mg

m-2

h-1

0

500

1000

1500

2000Drained Rewetted

Page 41: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

CH4 flux 2012-13

2012 2013

0 100 200 300 400 500 600 700

mg

m-2

h-1

-2

0

2

4

6

8Drained Rewetted

Page 42: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Reduction in emission following rewettingCO2-eq - 2012

2012 - DOY

160 180 200 220 240 260 280 300 320

mg

m-2

h-1

0

100

200

300

400

500

Page 43: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Reduction in emission following rewettingCO2-eq - 2013

2013 - DOY

140 160 180 200 220 240 260 280

mg

m-2

h-1

-200

0

200

400

600

800

Page 44: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Photosynthetic CO2 flux vs PAR

PAR

0 200 400 600 800 1000 1200 1400

mg

m-2

h-1

-3500

-3000

-2500

-2000

-1500

-1000

-500

0

Drained Rewetted

Page 45: The value of peatland rewetting for reducing GHG emission · -GHG emissions and the feasibility of restoration-Our research at Mávahlíð, Western Iceland Outline. Icelandic peatlands

Conclusions• Rewetting the site was successful – WTL at the surface • Almost immediately some reduction in soil respiration – increased with time• CH4 efflux slower to respond but very significant increase in in second season• Photosynthetic uptake of CO2 approx.15% less on rewetted site


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