climate change and forestry allan l. carroll, ph.d. natural resources canada canadian forest service...

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?