Climate Change and Forestry

Allan L. Carroll, Ph.D.

Senior Research Scientist Natural Resources Canada Canadian Forest Service Pacific Forestry Centre Victoria, Canada

Overview

   Global forests and forestry Forests and the carbon cycle Climate change and forests: • Impacts • • Mitigation Adaptation

Global forests Forest Other wooded land Other land Water   Forests comprise  4 billion ha (30% of land surface, 434 billion m 3 ) 89% natural (36% primary and 53% modified) Source: FAO Global Forest Resource Assessment 2005

Global forests: recent changes Change 2000 – 2005    Greatest forest loss in low-income, low-latitude countries Average annual net loss: Brazil – 3.1 million ha Indonesia - 1.9 million ha Average annual net gain: China – 4.0 million ha >0.5% decrease per year >0.5% increase per year Change rate <0.5% per year   Forest loss due to: • • Forest gain due to: • • Expansion of settlements, infrastructure, unsustainable logging practices Sources of carbon Afforestation, landscape restoration, natural forest expansion Sinks of carbon Source: FAO Global Forest Resource Assessment 2005

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 3.2 ± 0.1 GtC/yr Airborne fraction Atmosphere Biosphere 6.4 ± 0.4

Fossil fuel 1.6 ± 0.9

Land-use change 2.6 ± 0.1

Land uptake (esp. forests) Reduce emissions

Data from IPCC AR4 WG1 2007

2.2 ± 0.4

Ocean uptake Increase sinks  Less than half of human emissions stay in atmosphere  Mitigation = reduced emissions and/or increased sinks  Forests/forestry can have significant impacts on future atmospheric C concentrations

Climate change and forests: impacts Projections of surface temperatures (relative to 1980-1999) 2020 – 2029 (short term) 2090 – 2099 (long term) Emission scenario: B1 A2 Increasing GHGs Climate change Increasing temperatures Feedbacks?

Impacts on forests

From IPCC AR4 WG1 2007

Climate change and forests: impacts (short term) Increased productivity   CO 2 fertilization Higher temperature (inc. growth rate)    Nitrogen mineralization Longer growing season Range expansion Increased disturbance  Size/severity of forest fires, wind damage, floods    Rate/severity/range of native insect and disease impacts Invasive species Feedbacks

Climate change and forests: impacts (long term) Restricted distributions, esp. northern hemisphere Current 2 x CO 2

IPCC 1995, GFDL + MAPSS models

Temperate grasses Grasslands Deserts Savanna Tropical seasonal forests Tropical moist forest Wetland, mangrove etc Agricultural land Ice Tundra Boreal forests

  Forests and mitigation 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: 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

Adaptation = adjustments in ecological, social, and economic systems in response to the effects of climate change. (Smit et al. 2000) 1 st assessment report 2 nd assessment report 3 rd assessment report Observed Emissions scenarios Constant from 2000    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

Forests and adaptation

“…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) Opportunities?

    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) A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change.