climate change and forestry allan l. carroll, ph.d. natural resources canada canadian forest service...
TRANSCRIPT
Climate Change and Forestry
Allan L. Carroll, Ph.D.
Natural Resources CanadaCanadian Forest ServicePacific Forestry Centre
Victoria, Canada
Senior Research Scientist
Overview Global forests and
forestry Forests and the carbon
cycle Climate change and
forests:
• Impacts
• Mitigation
• Adaptation
Forests comprise 4 billion ha (30% of land surface, 434 billion m3) 89% natural (36% primary and 53% modified)
Source: FAO Global Forest Resource Assessment 2005
Global forests
ForestOther wooded landOther landWater
Global forests: recent changes
Forest loss due to:• Expansion of settlements, infrastructure, unsustainable logging practices• Sources of carbon
Forest gain due to:• Afforestation, landscape restoration, natural forest expansion• Sinks of carbon
Source: FAO Global Forest Resource Assessment 2005
>0.5% decrease per year >0.5% increase per year Change rate <0.5% per year
Change 2000 – 2005
Greatest forest loss in low-income, low-latitude countries
Average annual net loss:Brazil – 3.1 million haIndonesia - 1.9 million ha
Average annual net gain:China – 4.0 million ha
Carbon implications of global forest cover change
Forests: both large sources and sinks of carbon The global forest sector:
• Emissions from deforestation 1.6 Gt C/yr
• Equivalent to 20% of anthropogenic GHGs
Forests affect and are affected by climate change• Outcome determines mitigation/adaptation
potential
How forest affect the carbon cycle
Less than half of human emissions stay in atmosphere
3.2 ± 0.1 GtC/yr Airborne fraction
Atmosphere
Biosphere
6.4 ± 0.4
Fossil fuel
2.2 ± 0.4Ocean uptake
1.6 ± 0.9Land-use change
2.6 ± 0.1Land uptake(esp. forests)
Data from IPCC AR4 WG1 2007
Reduce emissions Increase sinks
Mitigation = reduced emissions and/or increased sinks
Forests/forestry can have significant impacts on future atmospheric C concentrations
Climate change and forests: impacts
From IPCC AR4 WG1 2007
Projections of surface temperatures (relative to 1980-1999)
Emission scenario:
B1
A2
2020 – 2029 (short term) 2090 – 2099 (long term)
IncreasingGHGs
Climatechange
Impacts onforests
Increasingtemperatures
Feedbacks?
Climate change and forests: impacts (short term)
CO2 fertilization
Higher temperature(inc. growth rate)
Nitrogen mineralization Longer growing season Range expansion
Size/severity of forest fires, wind damage, floods
Rate/severity/range of native insect and disease impacts
Invasive species Feedbacks
Increased productivity Increased disturbance
Current
IPCC 1995, GFDL + MAPSS models
Temperate grasses
Grasslands
DesertsSavannaTropical seasonal forestsTropical moist forestWetland, mangrove etcAgricultural landIceTundraBoreal forests
2 x CO2
Climate change
Restricted distributions, esp. northern hemisphere
Climate change and forests: impacts (long term)
Forests and forestry cannot solve the problem of fossil C emissions, but they can contribute to the solution
Reduced deforestation, increased afforestation could more than offset global carbon emissions from the transportation sector (Stern 2006)
Forests and mitigation
Forests and mitigation: management options
Maintain (or increase) forest area• Reduce deforestation, increase
afforestation
Increase stand-level carbon density• Partial harvest systems, reduce residue
burning, reduce regeneration delays, species selection
Increase landscape-level carbon density• Lengthen rotations, inc. conservation areas,
protect against disturbance
Increase stored C in wood products, reduce fossil C emissions through product substitution and bioenergy• Longer-lived products, recycling, biofuels,
salvage
Forests and adaptation
Continued warming even with emissions held at 2000 levels
Impacts greatest at higher latitudes
Increasing need for adaptation to accompany mitigation efforts
From IPCC AR4 WG1 2007
1st assessment report2nd assessment report3rd assessment reportObserved
Constant from 2000
Emissions scenarios
Adaptation = adjustments in ecological, social, and economic systems in response to the effects of climate change. (Smit et al. 2000)
Forests and adaptation
Technological(e.g. assisted migrations, increased resilience)
Behavioral(e.g. altered ecosystem service requirements)
Managerial(e.g. altered forest practices)
Policy(e.g. planning regulations)
“…more extensive adaptation than is currently occurring is required to reduce vulnerability to future climate change. There are barriers, limits and costs, but these are not fully understood.” (IPCC AR4 WG2 2007)
A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change.
Opportunities?