Quantifying terrestrial ecosystem carbon stocks for future GHG mitigation, sustainable land-use planning and adaptation to climate change, Québec, Canada Michelle Garneau, Professor Simon van Bellen, Associate professor Geotop Research Center Université du Québec à Montréal, Montréal, Canada Global Symposium on Soil Organic Carbon FAO, Rome – 22 March 2017
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Quantifying terrestrial ecosystem carbon stocks for future GHG mitigation, sustainable land-use planning and adaptation to climate change, Québec, Canada
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Michelle Garneau, Professor Simon van Bellen, Associate professor
Geotop Research CenterUniversité du Québec à Montréal, Montréal, Canada
Global Symposium on Soil Organic Carbon FAO, Rome – 22 March 2017
Distribution of peatlands in the Canadian boreal beltafter Tarnocai, 2011
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Sask
atch
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Ont
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bec
New
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nsw
ick
Nov
a-Sc
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Prin
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Yuko
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Nun
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0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000 Area (km²)Frozen Fens
Frozen Bogs
Unfrozen Fens
Unfrozen Bogs
• 2nd largest country (9.9 million km2) • Peatlands: 13-17% of terrestrial surface • ≥ 150 Gt of carbon (Tarnocai, 2011)• 64% in the boreal and 33% in the
Global boreal forests store ~272 Gt C (Pan et al., 2011)
• Carbon accumulation is mostly cyclic
• Large emissions of CO2 and CH4 linked with natural disturbance (fires) and human intervention
Northern peatlands represent 500-600 Gt C or ~30% of the terrestrial carbon stock (Yu, 2012; Turetsky et al., 2015)
• Accumulation mostly since the last glaciation
• Sinks of carbon, but sources of methane (CH4)
Peatlands have had a net cooling effect on the global climat during the Holocene, removing CO2 from the atmosphere: -0.22 to -0.56 W m-2 (Frolking & Roulet, 2007)2007)
O2CO2
C
CC
C
Photosynthesis
CO2
C
Forest stand
CH4CC
C
C CC
Forest stand life cycle = decades to a few centuries
Longer growing seasons and positive moisture balance: increased potential for carbon sequestration
Warming and negative moisture balance: decreased potential for carbon sequestration
Soil moisture balance (P-ET) Temperature
+2.5ºC
Projected changes in summer climate and peatland carbon dynamics (2041-2070)
Ouranos, 2016
+3ºC
+1,5 - 2ºC +0,3 mm jr-1
-0,3 mm jr-1
Soil moisture balance (P-ET) Temperature
+2,5ºC
Climate change and permafrost peatlands
Permafrost degradation:
• Palsa collapse• Increased emission of CH4
• Gradual drying, return of xerophilous Sphagnum moss
• Return of net accumulation
~50-70 years until return of net carbon accumulation (Turetsky et al., 2007, Sanderson, 2016, Lamarre et al., 2012)
Ouranos, 2016
+6ºC
Hiver
Warming and negative moisture balance: increased fire severity, especially in western Quebec
Projected changes in summer climate and forest soil carbon (2041-2070)
+3ºC
+1,5 - 2ºC +0,3 mm jr-1
-0,3 mm jr-1
Soil moisture balance (P-ET) Temperature
+2,5ºC
Ouranos, 2016
The total carbon stock is the
equivalent of a total sink of 51.7 Gt
CO2 –eq.
In 2014, anthropogenic emissions in
Quebec were 82.1 Mt CO2-eq., or
1.6‰ of the total carbon stock
Peatland carbon density (kg C m-2) is 7 to 8 times higher than those of the forest soil: 85.5 kg C m-2 vs. 10.9 kg C m-2
The total boreal forest soil and peatland carbon stock is estimated at 14.1 Gt C
(MDDELCC, 2016)
Carbon stocks vs. anthropogenic emissions
• The Quebec boreal forest soil and peatland carbon stock is estimated at 14.1 Gt C• At 7.9 Gt C, peatlands represent more than half of this stock
• Boreal forest soils store around 6.2 Gt C, with 79% in managed forest soils (vs. 21% in unmanaged forest soils) and 57% in mineral horizons (vs. 43% in organic horizons)
• Future GHG mitigation policies and sustainable land-use planning should be supported by an increase in investments in peatland, wetland and forest conservation, management and rehabilitation to limit greenhouse gas emissions