Implications of future disturbance regimes on the carbon balance of Canada’s managed forest (2010–2100)

J M Metsaranta,W A Kurz,E T Neilson,G Stinson

doi:10.1111/j.1600-0889.2010.00487.x

J M Metsaranta, W A Kurz + Show 2 more

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https://doi.org/10.1111/j.1600-0889.2010.00487.x

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Abstract

Recent increases in fire and insect disturbances have contributed to a transition of Canada’s managed forest carbon balance from sink to source. Further increases in area burned could contribute positive feedback to climate change. We made probabilistic forecasts of the recovery of C sinks in Canada’s managed forest between 2010 and 2100 under two assumptions about future area burned by wildfire: (1) no increase relative to levels observed in the last half of the 20th century and (2) linear increases by a factor of two or four (depending on region) from 2010 to 2100. Recovery of strong C sinks in Canada’s managed forest will be delayed until at least the 2030s because of insect outbreaks, even if predicted increases in area annually burned do not occur. After 2050, our simulations project an annual probability of a sink near 70% with no increase in area burned and 35% with increasing area burned. All simulations project a cumulative C source from 2010–2100, even if annual area burned does not increase. If the sink strength of terrestrial ecosystems is reduced because of increasing natural disturbances, then it will become more difficult to achieve global atmospheric CO2 stabilization targets.

Highlights

The strength and dynamics of carbon (C) sinks in terrestrial and ocean systems affect the residual airborne fraction of fossil fuel emissions remaining in the atmosphere
We conducted our simulations with the CBM-CFS3 (Kurz et al, 2009), an empirical model of stand- and landscape-level C dynamics that implements Tier 3 standards of the Intergovernmental Panel on Climate Change (IPCC) good practice guidance for reporting on C stocks and stock changes resulting from land use, land-use change and forestry (Penman et al, 2003)
Our simulations project that the probability of an annual C sink is around 70% in the last half of the 21st century if there is no increase in area burned and only 35% if area burned increases

Summary

Introduction

The strength and dynamics of carbon (C) sinks in terrestrial and ocean systems affect the residual airborne fraction of fossil fuel emissions remaining in the atmosphere. Possible climatic and global change feedbacks (Field et al, 2007; Luo, 2007; Kurz et al, 2008c), could affect the time frame over which this recovery will occur. We examine the potential impact of these forecast increases in area burned on the C balance of Canada’s managed forest over the course of the 21st century. Determining if such an increase will delay or prevent the recovery of the C sink in Canada’s managed forest is of both scientific and policy interest because it will affect the level of mitigation effort needed to reach future atmospheric CO2 stabilization targets

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