Climate Change and Managed Ecosystems - Chapter 1 pps

© 2006 by Taylor & Francis Group, LLC
Climate Change and Managed Ecosystems
© 2006 by Taylor & Francis Group, LLC
Climate Change
and
Managed Ecosystems
Edited by
J.S. Bhatti
R. Lal
M.J. Apps
M.A. Price
Published in 2006 by
CRC Press
Taylor & Francis Group
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Boca Raton, FL 33487-2742
© 2006 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group
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10987654321
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Climate change and managed ecosystems / edited by J.S. Bhatti [et al.].
p. cm.
Includes bibliographical references and index.
ISBN-10: 0-8493-3097-1 (hardcover)
1. Climatic changes. 2. Ecosystem management. I. Bhatti, J. S. (Jagtar S.)
QC981.8.C5C5113823 2006
333.95 dc22 2005028910
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© 2006 by Taylor & Francis Group, LLC
Preface
The idea for this book arose during the planning phases of an International Confer-
ence in Edmonton, Canada in July 2004 entitled “The Science of Changing Climates
— Impacts on Agriculture, Forestry and Wetlands.” The conference was organized
jointly by the Canadian Societies of Animal Science, Plant Science and Soil Science
with support from Natural Resources Canada/Canadian Forest Service because they
saw climate change as one of the most serious environmental problems facing the
world. The United Nations Convention on Climate Change (UN 1992, article 2)

called for a “ stabilization of greenhouse gas concentrations in the atmosphere at
a level that would prevent dangerous anthropogenic interference with the climate
system ” For agriculture, forestry and wetlands, these potentially dangerous
interferences include changes in ecosystems boundaries, loss of biodiversity,
increased frequency of ecosystem disturbance by fire and insects, and loss and
degradation of wetlands. Regional temperature increases, precipitation increases and
decreases, change in soil moisture availability, climatic variability and the occurrence
of extreme events are all likely to influence the nature of these impacts. The book
is organized into five main parts.
Part 1: Climate Change and Ecosystems (Chapters 1–3). We discuss the fragility
of ecosystems in the face of changing climates, particularly through human-caused
increases in atmospheric GHGs. Chapter 2 details how and why the climate has
changed in the past; and what can be expected to occur in the foreseeable future.
The implications of climate change to agriculture, forestry and wetland ecosystems
in Canada are discussed in Chapter 3, and potential adaptation responses to reduce
the impacts of a changing climate are identified.
Part 2: Managed Ecosystems — State of Knowledge (Chapters 4–15). We
explore what is known about the impacts of climate on our agricultural, forested
and wetland ecosystems. This section illustrates the importance of terrestrial eco-
systems in the global carbon cycle and focuses on discussions of the potential
interaction between terrestrial and atmospheric carbon pools under changing climatic
conditions. Our current understanding of the impact of climate change on food and
fiber production as well as the potential role of the different ecosystems in carbon
source/sink relationships has been discussed in detail here.
Part 3: Knowledge Gaps and Challenges (Chapters 16–18). We attempt to iden-
tify what needs to be known and done to ensure continued stability in these ecosys-
tems. This part includes a description of some of the activities that have been
undertaken in the past to identify gaps in our understanding of GHGs emissions
from agriculture, forest and wetland and their mitigation, as well as current research
initiatives to address these gaps.

Part 4: Economics and Policy Issues (Chapter 19). This provides an overview
of economic reasoning applied to climate change and illustrates how terrestrial
© 2006 by Taylor & Francis Group, LLC
carbon-uptake credits (offset credits) operate within the Kyoto Protocol framework.
Attention is focused on the potential of terrestrial carbon sinks to slow the rate of
CO
2
buildup in the atmosphere.
Part 5: Summary and Recommendations (Chapters 20–21). We give an overall
view of the knowledge gained from the conference and identify research needs to
achieve reduced atmospheric carbon levels. The first chapter (Chapter 20) synthe-
sizes the major findings of all the previous chapters and examines the implications
for different ecosystems. The second chapter (Chapter 21) identifies key knowledge
gaps relating to climate and climate-change effects on agriculture, forestry, and
wetlands. It further points toward the needs to make management of these ecosys-
tems part of a global solution, by identifying gaps in the current understanding of
adaptation or mitigation strategies for terrestrial ecosystems.
While we are confident that the material contained in this book will be helpful
to anyone seeking up-to-date information, we are also aware that in such a rapidly
evolving field it is inevitable that material will quickly become dated. With that in
mind we encourage you, the reader, to contact the chapter authors for their current
views and information on the topics covered.
J.S. Bhatti
R. Lal
M.J. Apps
M.A. Price
© 2006 by Taylor & Francis Group, LLC
Acknowledgments
This book would not have been possible without the assistance of a great many
people and organizations. We would like to acknowledge in particular our Platinum

Sponsors: Alberta Agriculture, Food and Rural Development; Canadian Adaptation
and Rural Development Fund; Canadian Climate Impacts and Adaptation Research
Network; National Agroclimate Information Service; Natural Resources Canada,
Canadian Forest Service; Poplar Council of Canada; Prairie Adaptation Research
Collaborative; and University of Alberta; our Gold Sponsor: Ducks Unlimited; and
our Silver Sponsors: Agrium and MERIAL/igenity. We also want to gratefully
acknowledge the thorough work of our anonymous group of reviewers, who helped
to ensure that the manuscripts met the highest scientific standards. Thanks, too, to
Cindy Rowles for her invaluable clerical assistance and advice. And finally, thanks
are due to the managers and staff of Taylor & Francis Group for their careful attention
to detail in publishing this book.
© 2006 by Taylor & Francis Group, LLC
About the Editors
J.S. Bhatti, Ph.D., is a research scientist and project leader with Natural Resources
Canada, Canadian Forest Service, Northern Forestry Centre, in Edmonton, Alberta.
He received his Ph.D. in soil science from University of Florida and started working
for Natural Resources Canada, where he concentrated on nutrient dynamics in boreal
forests under various harvesting practices and moisture regimes.
Dr. Bhatti’s interest in climate change moved him to Northern Forestry Centre
in 1997, where his focus has been on carbon dynamics under changing climate and
disturbance regimes both in upland and low land boreal forest ecosystems. His
scientific publications deal with improving the precision of carbon stock and carbon
stock estimates, changes in forest carbon dynamics in relation to disturbances,
moisture, nutrient and climate regimes, and understanding the influence of bio-
physical processes on forest dynamics. He is coordinating a national effort to monitor
forest carbon dynamics to understand and quantify the prospective impacts of climate
change on Canadian forests.
R. Lal, Ph.D., is a professor of soil physics in the School of Natural Resources and
Director of the Carbon Management and Sequestration Center, FAES/OARDC at
The Ohio State University. He was a soil physicist for 18 years at the International

Institute of Tropical Agriculture, Ibadan, Nigeria. In Africa, Professor Lal conducted
long-term experiments on land use, watershed management, methods of deforesta-
tion, and agroforestry. Since joining The Ohio State University in 1987, he has
worked on soils and climate change. Professor Lal is a fellow of the Soil Science
Society of America, American Society of Agronomy, Third World Academy of
Sciences, American Association for the Advancement of Sciences, Soil and Water
Conservation Society and Indian Academy of Agricultural Sciences.
Dr. Lal is the recipient of the International Soil Science Award, the Soil Science
Applied Research Award and Soil Science Research Award of the Soil Science
Society of America, the International Agronomy Award and Environment Quality
Research Award of the American Society of Agronomy, the Hugh Hammond Bennett
Award of the Soil and Water Conservation Society, and the Borlaug Award. He is
the recipient of an honorary degree of Doctor of Science from Punjab Agricultural
University, India, and of the Norwegian University of Life Sciences, Aas, Norway.
He is past president of the World Association of the Soil and Water Conservation
and the International Soil Tillage Research Organization. He was a member of the
U.S. National Committee on Soil Science of the National Academy of Sciences
(1998–2002). He has served on the Panel on Sustainable Agriculture and the Envi-
ronment in the Humid Tropics of the National Academy of Sciences. He has authored
and co-authored more than 1100 research publications. He has written 9 books and
edited or co-edited 43 books.
© 2006 by Taylor & Francis Group, LLC
M.J. Apps, Ph.D., retired as senior scientist, carbon and climate change, from
Natural Resources Canada, Canadian Forest Service in 2005, but continues to work
part time on various international projects. He obtained his Ph.D. in physics from
the University of Bristol, and continued in solid state physics as a research associate
at Simon Fraser University before moving to the University of Alberta to take a
research position in the Faculty of Pharmacy and Pharmaceutical Sciences, where
he set up the Neutron Activation Analysis system for trace element analysis at the
Slowpoke Nuclear Reactor. His interest in environmental issues led him to join the

Canadian Forest Service in 1980, where he initiated research on trace pollutants and
radionuclides in the terrestrial environment. He moved into climate change and
carbon cycling as a focus for his work in forest ecosystem modeling in 1990, and
spearheaded the development of the Carbon Budget Model of the Canadian Forest
Sector, now used for Canada's reporting under the Kyoto Protocol.
Dr. Apps is the author or co-author of more than 200 published manuscripts,
has served as lead or convening lead author on many reports of the Intergovernmental
Panel on Climate Change, and sits on several international and national scientific
steering committees on global change issues. He has received significant national
and international recognition, including the International Forestry Achievement
Award presented at the World Forestry Congress, an honorary diploma issued by
the International Boreal Forest Research Association in St. Petersburg, designated
Leader of Sustainable Development by the five natural resource departments of the
government of Canada, and the 2005 Award of Excellence by the Public Service of
Canada.
M.A. Price, Ph.D., P.Ag., FAIC, is professor emeritus of livestock growth and meat
production at the University of Alberta and was, until his retirement in 2004, research
director at the university’s Beef Cattle Research Ranch at Kinsella, Alberta. He was
born and raised on the family farm in the U.K., and farmed there after high school.
He received his post-secondary education at the University of Zimbabwe (B.Sc.,
agriculture), University of New England, Australia (M.Rur.Sc. and Ph.D. in livestock
production) and University of Alberta, Canada (NRC post-doctoral fellowship in
animal science).
Dr. Price served as chairman of the Department of Animal Science at the
University of Alberta from 1987 to 1995. His areas of research concentrate mainly
on sustainable methods of increasing efficiency and decreasing costs of production
in meat production systems. He has published more than 115 scientific papers in
peer-reviewed journals, and more than 130 extension articles in trade and industry
magazines. He is the editor of the Canadian Journal of Animal Science.
© 2006 by Taylor & Francis Group, LLC

CONTRIBUTORS
M.J. Apps
Canadian Forest Service
Natural Resources Canada
Pacific Forestry Centre
Victoria, BC, Canada
T. Asada
Wetlands Research Centre
University of Waterloo
Waterloo, ON, Canada
J.K.A. Atakora
Department of Agricultural, Food
& Nutritional Science
Agriculture/Forestry Centre
University of Alberta
Edmonton, AB, Canada
R.O. Ball
Department of Agricultural, Food
& Nutritional Science
Agriculture/Forestry Centre
University of Alberta
Edmonton, AB, Canada
V.S. Baron
Crops & Soils Research Station
Agriculture and Agri-Food Canada
Lacombe, AB, Canada
I.E. Bauer
Canadian Forest Service
Northern Forestry Centre
Edmonton, AB, Canada

P.Y. Bernier
Canadian Forest Service
Natural Resources Canada
Saint-Foy, PQ, Canada
J.S. Bhatti
Natural Resources Canada
Canadian Forest Service
North Forestry Centre
Edmonton, AB, Canada
D. Burton
Nova Scotia Agricultural College
Truro, NS, Canada
J. Casson
Alberta Agriculture, Food & Rural
Development
Agriculture Centre
Lethbridge, AB, Canada
O.G. Clark
Department of Agricultural, Food
& Nutritional Science
Agriculture/Forestry Centre
University of Alberta
Edmonton, AB, Canada
W.A. Dugas
Texas Agricultural Experiment Station
Texas A&M University
College Station, TX, USA
I. Edeogu
Technical Services Division
Alberta Agriculture, Food & Rural

Development
Edmonton, AB, Canada
J.J. Feddes
Department of Agricultural, Food
& Nutritional Science
Agriculture/Forestry Centre
University of Alberta
Edmonton, AB, Canada
© 2006 by Taylor & Francis Group, LLC
H. Hengeveld
Environment Canada
Scientific Assessment and Integration
Downsview, ON, Canada
G. Hoogenboom
Department of Biological &
Agricultural Engineering
The University of Georgia
Griffin, GA, USA
B.C. Joern
Department of Agronomy
West Lafayette, IN, USA
C. La Bine
Campbell Scientific (Canada) Corp.
Edmonton, AB, Canada
R. Lal
School of Natural Resources
College of Food, Agricultural
& Environmental Sciences
The Ohio State University
Columbus, OH, USA

D.B. Layzell
BIOCAP Canada Foundation
Queen’s University
Kingston, ON, Canada
J.J. Leonard
Department of Agricultural, Food
& Nutritional Science
University of Alberta
Edmonton, AB, Canada
P.C. Mielnick
Blackland Research Center
Texas A&M University
Temple, TX, USA
S. Moehn
Department of Agricultural, Food
& Nutritional Science
University of Alberta
Edmonton, AB, Canada
B. Morin
Technical Services Division
Alberta Agriculture, Food & Rural
Development
Edmonton, AB, Canada
L.D. Mortsch
Adaptation and Impacts Research
Group
Meteorological Service of Canada
Environment Canada
University of Waterloo
Waterloo, ON, Canada

K.H. Ominski
Department of Animal Science
University of Manitoba
Winnipeg, MB, Canada
J.D. Price
Technical Services Division
Alberta Agriculture, Food & Rural
Development
Edmonton, AB, Canada
M.A. Price
Department of Agricultural, Food
& Nutritional Science
University of Alberta
Edmonton, AB, Canada
B.T. Richert
Department of Animal Sciences
Purdue University
West Lafayette, IN, USA
M.A. Sanderson
USDA-ARS
Pasture Systems & Watershed
Management Research Unit
University Park, PA, USA
W.C. Sauer
Department of Agricultural,
Food & Nutritional Science
University of Alberta
Edmonton, AB, Canada
© 2006 by Taylor & Francis Group, LLC
J. Sauvé

Alberta Agriculture
Food & Rural Development
Edmonton, AB, Canada
R.H. Skinner
USDA-ARS
Pasture Systems and Watershed
Management Research Unit
University Park, PA, USA
J. Stephen
BIOCAP Canada Foundation
Queen’s University
Kingston, ON, Canada
J.M.R. Stone
Environment Canada
Meteorological Service of Canada
Hull, PQ, Canada
A.L. Sutton
Department of Animal Sciences
Purdue University
West Lafayette, IN, USA
G.C. van Kooten
Department of Economics
University of Victoria
Victoria, BC, Canada
D.H. Vitt
Department of Plant Biology
Southern Illinois University
Carbondale, IL, USA
G.C. Waghorn
Dexcel Ltd.

Hamilton, New Zealand
B.G. Warner
Department of Geography
University of Waterloo
Waterloo, ON, Canada
K.M. Wittenberg
Department of Animal Science
University of Manitoba
Winnipeg, MB, Canada
S.L. Woodward
Dexcel Ltd.
Hamilton, New Zealand
D.G. Young
Crops & Soils Research Section
Agriculture & Agri-Food Canada
Lacombe, AB, Canada
Y. Zhang
Department of Agricultural, Food &
Nutritional Science
University of Alberta
Edmonton, AB, Canada
R.T. Zijlstra
Department of Agricultural, Food
& Nutritional Science
University of Alberta
Edmonton, AB, Canada
© 2006 by Taylor & Francis Group, LLC
Contents
PART I Climate Change and Ecosystems
Chapter 1

Interaction between Climate Change and Greenhouse Gas Emissions
from Managed Ecosystems in Canada 3
J.S. Bhatti, M.J. Apps, and R. Lal
Chapter 2
The Science of Changing Climates 17
H. Hengeveld
Chapter 3
Impact of Climate Change on Agriculture, Forestry, and Wetlands 45
L.D. Mortsch
PART II Managed Ecosystems — State of Knowledge
Chapter 4
Anthropogenic Changes and the Global Carbon Cycle 71
J.S. Bhatti, M.J. Apps, and R. Lal
Chapter 5
Plant/Soil Interface and Climate Change: Carbon Sequestration from the
Production Perspective 93
G. Hoogenboom
Chapter 6
Carbon Dynamics in Agricultural Soils 127
R. Lal
Chapter 7
Plant Species Diversity: Management Implications for Temperate
Pasture Production 149
M.A. Sanderson
© 2006 by Taylor & Francis Group, LLC
Chapter 8
Net Ecosystem Carbon Dioxide Exchange over a Temperate, Short-Season
Grassland: Transition from Cereal to Perennial Forage 163
V.S. Baron, D.G. Young, W.A. Dugas, P.C. Mielnick, C. La Bine,
R.H. Skinner, and J. Casson

Chapter 9
Forests in the Global Carbon Cycle: Implications of Climate Change 175
M.J. Apps, P.Y. Bernier, and J.S. Bhatti
Chapter 10
Peatlands: Canada’s Past and Future Carbon Legacy 201
D.H. Vitt
Chapter 11
Linking Biomass Energy to Biosphere Greenhouse Gas Management 217
D.B. Layzell and J. Stephen
Chapter 12
Ruminant Contributions to Methane and Global Warming —
A New Zealand Perspective 233
G.C. Waghorn and S.L. Woodward
Chapter 13
Strategies for Reducing Enteric Methane Emissions in Forage-Based Beef
Production Systems 261
K.H. Ominski and K.M. Wittenberg
Chapter 14
Mitigating Environmental Pollution from Swine Production 273
A.L. Sutton, B.T. Richert, and B.C. Joern
Chapter 15
Diet Manipulation to Control Odor and Gas Emissions from
Swine Production 295
O.G. Clark, S. Moehn, J.D. Price, Y. Zhang, W.C. Sauer, B. Morin,
J.J. Feddes, J.J. Leonard, J.K.A. Atakora, R.T. Zijlstra, I. Edeogu,
and R.O. Ball
© 2006 by Taylor & Francis Group, LLC
PART III Knowledge Gaps and Challenges
Chapter 16
Identifying and Addressing Knowledge Gaps and Challenges Involving

Greenhouse Gases in Agriculture Systems under Climate Change 319
D. Burton and J. Sauvé
Chapter 17
Knowledge Gaps and Challenges in Forest Ecosystems under Climate
Change: A Look at the Temperate and Boreal Forests of North America 333
P.Y. Bernier and M.J. Apps
Chapter 18
Knowledge Gaps and Challenges in Wetlands under Climate Change
in Canada 355
B.G. Warner and T. Asada
PART IV Economics and Policy Issues
Chapter 19
Economics of Forest and Agricultural Carbon Sinks 375
G.C. van Kooten
PART V Summary and Recommendations
Chapter 20
Impacts of Climate Change on Agriculture, Forest, and Wetland Ecosystems:
Synthesis and Summary 399
J.M.R. Stone, J.S. Bhatti, and R. Lal
Chapter 21
Climate Change and Terrestrial Ecosystem Management: Knowledge Gaps and
Research Needs 411
I.E. Bauer, M.J. Apps, J.S. Bhatti, and R. Lal
© 2006 by Taylor & Francis Group, LLC
Part I
Climate Change and Ecosystems
© 2006 by Taylor & Francis Group, LLC
3
1
Interaction between

Climate Change and
Greenhouse Gas Emissions
from Managed Ecosystems
in Canada
J.S. Bhatti, M.J. Apps, and R. Lal
CONTENTS
1.1 Introduction 3
1.2 Past and Future Climate Change 5
1.3 Greenhouse Gas Emissions from Agriculture, Forestry,
and Wetland Ecosystems 7
1.4 Climate Change in Relation to Agriculture, Forestry, and Wetlands 9
1.4.1 Agricultural Ecosystems 9
1.4.2 Forest Ecosystems 9
1.4.3 Wetland/Peatland Ecosystems 11
1.5 Purpose of This Book 12
1.6 Summary and Conclusions 13
References 14
1.1 INTRODUCTION
The world’s terrestrial ecosystems are being subjected to climate change on an unprec-
edented scale, in terms of both rate of change and magnitude. Understanding the ability
of terrestrial ecosystems to adapt to change requires fundamental knowledge of the
response functions. The changes under consideration in this book include not only the
climatic change from increased concentration of greenhouse gases (GHGs) and con-
sequent warming trends especially in the north, but also land use, land-use changes,
and alterations in disturbance patterns, both natural and human induced. The interactive
nature of climate change is complex and nonlinear because the variables of change
are strongly interactive (Figure 1.1) and not independent. To remain viable, agricultural
© 2006 by Taylor & Francis Group, LLC
4 Climate Change and Managed Ecosystems
and forest production systems will need to change rapidly to meet the challenge of

the inevitable changes in the mosaic of ecosystems across the landscape.
Agricultural ecosystems (including crop and animal production, pastures and
rangelands), forest ecosystems, and wetlands (including peatlands) can be regarded as
one dimension of the problem, and climate change as another. This book synthesizes
our current understanding of the processes of climate change and its impacts on
different managed ecosystems. From a human perspective the impacts of climate
change lie in the interactions among these different ecosystems: vulnerability must be
assessed in terms of the collective impact on these terrestrial ecosystems that supply
essential goods and services to society. Humans depend on these ecosystems for food,
fiber, and clean air and water, and the adverse impacts of climate change are likely to
have far-reaching effects on human lives and livelihoods.
An important indicator of the human interaction with the global climate system
is the human perturbations to global carbon cycle. Carbon is exchanged between
terrestrial ecosystems and the atmosphere through photosynthesis, respiration, decom-
position, and combustion. Terrestrial ecosystems have the capacity for either acceler-
ating or slowing climate change depending on whether these systems act as a net
source or a net sink of carbon. This source or sink status is, however, not a static
characteristic of the ecosystem, but will change over time as a result of changes in the
physical, chemical, and biological processes of these systems,
1
all of which are influ-
enced by human activity. Data on global carbon stocks in major biomes are presented
in Table 1.1. Response to climate change will alter these carbon stocks, changing the
fluxes among terrestrial ecosystems and the atmosphere differently in different geo-
graphical regions. There is a strong need to quantify these fluxes both in relation to
different management options and to different environmental pressures. The basic
challenge is the detection of very small changes relative to the size of the pools. Thus,
it is important to understand the dynamics of these different pools, and identify factors
that make these pools either sinks or sources of GHGs.
FIGURE 1.1 Linkage between various climate change issues and different ecosystems.

Agriculture, Forest and
Wetlands/Peatlands
Land Degradation
Climate Change
Food and Fiber
Supply
© 2006 by Taylor & Francis Group, LLC
Interaction between Climate Change and Greenhouse Gas Emissions 5
1.2 PAST AND FUTURE CLIMATE CHANGE
Changes in climate are not new: Earth has long been subjected to sequential
glacials, interglacials, and warm periods, and all parts of Canada have been warmer,
cooler, wetter, and drier at various times in the past. A number of natural factors
control climatic variability, including Earth’s orbit, changes in solar output, sunspot
cycles, and volcanic eruptions (Chapter 2). However, the present climatic change
is unprecedented in character: it cannot be explained by these factors alone. The
recently observed increase in global temperature is strongly related to increases
in the concentration of GHGs in the recent past,
2
increases that are directly
attributable to human activities. Over the course of the 20th century global mean
temperature has risen by about 0.6°C, and is projected to continue to rise at an
average rate of 0.1 to 0.2°C per decade for the next few decades then increase to
a rate of warming of between 1.4 and 5.8°C per decade by 2100.
2
Average
temperatures across Canada are expected to rise at twice the global rate. In general,
Canadian temperatures have been increasing steadily over the last 58 years, with
winter temperatures above normal between 1985 and 2005 (Figure 1.2). At the
same time, in general, over the last 58 years, winter precipitation has been decreas-
ing (Figure 1.3) across Canada. In southern Canada, surface temperatures have

increased by 0.5 to 1.5°C during the 20th century. The greatest warming has
occurred in western Canada, with up to 6°C increase in the minimum temperature.
In addition, the frequency of days with extreme temperature, both high and low,
is expected to increase, snow and ice cover to decrease, and heavy precipitation
events to increase.
3
During the second half of the 21st century, heat sums, measured
in growing degree days, across southern Canada are expected to increase by
between 40 and 100%.
TABLE 1.1
Global Carbon Stocks and Net Primary Productivity of the
Major Terrestrial Biomes
Biome
Area
(109 ha)
18
Carbon Stock
(Pg C)
18
Total C NPP
(Pg C yr
–1
)
19
Tropical forests 1.76 428 21.9
Temperate forests 1.04 159 8.1
Boreal forests 1.37 290 2.6
Northern peatlands 0.26 419 —
Arctic tundra 0.95 127 0.50
Crops 1.60 131 4.1

Tropical grasslands 2.25 330 14.9
Temperate grasslands 1.25 304 4.4
Deserts 4.55 199 3.5
© 2006 by Taylor & Francis Group, LLC
6 Climate Change and Managed Ecosystems
FIGURE 1.2 Canadian winter temperature deviation with weight running mean between 1948
and 2005. (Courtesy of Environment Canada.
7
)
FIGURE 1.3 Canadian winter precipitation deviation from weight running mean between
1948 and 2005. (Courtesy of Environment Canada.
7
)
Environment Canada
Meteorological Service of Canada
Climate Research Branch
Environment Canada
Service meteorologique du Canada
Direction de la recherche climatologique
4
3
2
1
0
-1
-2
-3
-4
°C
1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year/Année
Environment Canada
Meteorological Service of Canada
Climate Research Branch
Environment Canada
Service meteorologique du Canada
Direction de la recherche climatologique
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
%
1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
Year/Année
© 2006 by Taylor & Francis Group, LLC
Interaction between Climate Change and Greenhouse Gas Emissions 7
1.3 GREENHOUSE GAS EMISSIONS FROM AGRICULTURE,
FORESTRY, AND WETLAND ECOSYSTEMS
Natural processes such as decomposition and respiration, volcanic eruptions, and
ocean outgassing are continuously releasing greenhouse gases such as water vapor,
carbon dioxide (CO

2
), methane (CH
4
), and nitrous oxide (N
2
O) into the atmosphere.
Molecule for molecule, CO
2
is a weak GHG in terms of global warming potential
(GWP); most other GHGs have a stronger GWP. Compared to CO
2,
on a 100-year
timescale, the GWP is 21 times greater for CH
4
, 310 times greater for N
2
O, and 900
or more times greater for chlorofluorocarbons and hydrochlorofluorocarbons.
4
How-
ever, the net contribution of each gas to the greenhouse effect depends on four
factors: the amount of the gas released into the atmosphere per year, the length of
time that it stays in the atmosphere before being destroyed or removed, any indirect
effect it has on atmospheric chemistry, and the concentration of other GHGs. In
taking into account all these factors, the net contribution of CO
2
to the greenhouse
effect is two to three times higher than that of CH
4
and about 15 times higher than

that of N
2
O.
4
Over the 20th century there has been a significant increase in GHGs
in the atmosphere due to human activities such as fossil fuel burning and land use
change. For example, there has been about a 30% increase in the concentration of
CO
2
since the pre-industrial era: from 280 ppm in the late 18th century to 382 ppm
in 2004.
5
A global CO
2
emission rate of approximately 23.9 gigatonnes (Gt) has recently
been estimated by the Carbon Dioxide Information and Analysis Centre.
6
Defores-
tation, land use, and ensuing soil oxidation have been estimated to account for about
23% of human-made CO
2
emissions. CH
4
emissions generated from human activi-
ties, amounting to ~360 Mt per year, are primarily the result of activities such as
livestock and rice cultivation, biomass burning, natural gas delivery systems, land-
fills, and coal mining. Total annual emissions of N
2
O from all sources are estimated
to be within the range of 10 to 17.5 Mt N

2
O, expressed as nitrogen (N).
4
While
Canada contributes only about 2% of total global GHG emissions, it is one of the
highest per capita emitters, largely the result of its resource-based economy, climate
(i.e., energy demands), and size.
7
The change in Canada’s GHG emissions between
1990 and 2002 by a number of different sectors (specifically, energy, transportation,
industrial processes, agriculture, land-use change and forestry, and waste and land-
fills) is presented in Figure 1.4.
7
Total Canadian emissions of all GHGs in 2002
were 20.1% more than the 1990 level of 609 Tg of C. This growth in emissions
appears to be mainly the result of increased energy production and fossil fuel
consumption for heating in the residential and commercial sectors, as well as
increases in the transportation, mining, and manufacturing sectors. The average
annual growth of emissions over the 1990–2002 period was 1.7%.
Historically, agricultural activities have been a source of atmospheric enrichment
of GHGs. In 2002, agriculture-related GHG emissions totaled 59 Tg of C, repre-
senting 8% of total Canadian emissions.
7
This sector accounted for 66% of Canada’s
total emissions of N
2
O and 26% of CH
4
emissions. On a category basis, agricultural
soils contributed 50% of the sector’s emissions (29.6 Tg of C) in 2002 with the other

half coming from domestic animals (32% or 18.8 Tg) and manure management
© 2006 by Taylor & Francis Group, LLC
8 Climate Change and Managed Ecosystems
(17% or 10.2 Tg of C). While total sector emissions rose 2% between 1990 and
2001, emissions from manure management rose 22% and enteric fermentation emis-
sions increased by 18%. Net CO
2
emissions from agricultural soils partially offset
these increases, changing from a net source of 7.6 Tg of C in 1990 to a net sink of
0.5 Tg of C in 2002. The N
2
O emissions from soils, however, rose 15% over the
same period.
7
The profile of GHG emissions from the agricultural sector is very different from
other sectors. For this sector, N
2
O emissions associated primarily with N sources
(fertilizer and animal manure) represent 61% of GHG emissions, CH
4
from rumi-
nants and other sources represent another 38%, while net CO
2
emissions account
for less than 1% of agricultural GHG emissions. N
2
O is released during the biological
process of denitrification, and CH
4
is released from enteric fermentation by rumi-

nants, most specifically cattle, grazing the forage produced on these grasslands
(Chapter 12). Digestive processes involving the breakdown of plant materials under
conditions that are oxygen free, or oxygen limited, result in CH
4
production and
account for 28% of agricultural emissions. Indirect emissions from livestock oper-
ations such as handling, storage, and land application of farm manure account for
14% of agricultural emissions. Microbial decomposition of manure can result in
CO
2
, CH
4
, and N
2
O emissions, with their relative contributions dependent on factors
such as manure dry matter, C and N contents, as well as temperature and oxygen
availability during storage.
The forest sector, limited to productive managed forest lands in Canada, was a
net sink in 2002, as it removed 15 Tg of C from the atmosphere.
7
This estimate
represents the sum of the net CO
2
flux and non-CO
2
(CH
4
and N
2
O) emissions. The

net CO
2
flux alone amounted to a sink of 21 Tg, which reduced total Canadian
FIGURE 1.4 Change in GHG emissions and sinks for Canada between 1990 and 2002 for
different sectors. (Courtesy of Environment Canada.
7
)
GHG emissions and removals (Mt CO
2
eq)
300
250
200
150
100
50
0
-50
-100
-150
-200
Electricity
and
Petroleum
Industries
Transportation
Other
Industries
Agriculture
Land-use

Change and
Forestry
(non-CO
2
only)
Waste and
Landfill
Land-use
Change and
Forestry
1990 2002
© 2006 by Taylor & Francis Group, LLC
Interaction between Climate Change and Greenhouse Gas Emissions 9
emissions in 2002 by 3%. Non-CO
2
emissions were about 6.0 Tg in 2002. However,
the source/sink relationship for the forest sector is strongly influenced by distur-
bances, especially fire and insect outbreaks, which makes the GHG uptake or emis-
sions of Canadian forests in a given year hard to predict
8
(Chapter 9).
In terms of greenhouse gases, wetlands can either be sources or sinks. Due to
the complex biogeochemistry of peatlands/wetlands, they may function as sinks for
one gas while acting as sources for others (Chapters 4 and 10). Peatland/wetlands
may also change from sinks to sources due to anthropogenic impacts such as
increased nutrient loading, drainage, flooding, burning, and vegetation change.
1.4 CLIMATE CHANGE IN RELATION TO
AGRICULTURE, FORESTRY, AND WETLANDS
1.4.1 A
GRICULTURAL

E
COSYSTEMS
Arable agriculture occurs on only 7% of Canada’s landmass due to climatic and soil
limitations, and about 70% of Canada’s arable acreage is located in Alberta and
Saskatchewan.
9
Even under current conditions, climate has a major influence on the
year-to-year variation in agricultural productivity in this region. Climate change can
be expected to lead to more extreme weather conditions (i.e., conditions outside the
range of previous norms), increases in weed and pest problems, and severe water
shortage. On the other hand, these impacts will vary on a regional basis,
10
and some
Canadian agricultural regions will benefit from a warmer climate and longer growing
season, while others will be adversely affected.
With agricultural intensification to meet increases in food demand, soil degra-
dation emerges as a major threat under climate change
11
(Chapters 4 and 6). Deg-
radation of soil quality under climate change could result from decreases in soil
organic matter (SOM), nutrient leaching, and soil erosion. Soil erosion is a major
threat to agricultural productivity and sustainability as well as having adverse effects
on air and water quality (Chapters 4 and 6). Wind and water erosion may increase
significantly in agricultural soils due to increases in extreme weather condition such
as heavy precipitation events or prolonged droughts.
12
Warmer winters may result
in lower snow cover, and the reduction in soil moisture content could further increase
the risk of wind erosion. Land-use change from natural vegetation to croplands
potentially exacerbates these impacts due to increased vulnerability of the landscape

to erosion.
1.4.2 F
OREST
E
COSYSTEMS
Forests cover more than one third of the land surface of the Earth. Almost half
(410 Mha) the total landmass of Canada is forestland.
9
Boreal forests are the
dominant forest type, spanning the complete width of the country (Figure 1.5).
About 51% of Canada’s forests are deemed suitable for timber production. The
productivity of forest ecosystems largely depends upon the climate, nutrient, and
moisture regimes.
13
Climate affects the distribution, health, and productivity of
the forest and has a strong influence on the disturbance regime. The realization
© 2006 by Taylor & Francis Group, LLC
10 Climate Change and Managed Ecosystems
of the potential increase in plant productivity due to climate change depends on
a variety of factors such as changes in species and competitive interactions, water
availability, and the effect of temperature increase on photosynthesis and respira-
tion (Chapter 16). In addition to the direct influence of climate change, other
variables such as land-use change and existing land cover have profound influences
on the forest distribution and productivity.
The future C balance of the forest will largely depend on the type and frequency
of disturbances, changes in species composition, and alterations to the nutrient and
moisture regimes under changing climate conditions (Chapter 9). It will also depend
on forest management practices that affect both the disturbance regime and nutrient
status. Projected climate change scenarios for the boreal forest generally predict
warmer and somewhat drier conditions, posing questions about regeneration as well

as productivity. In addition, the disturbance patterns are also expected to change.
With more frequent disturbances (Figure 1.6), more of the stands will move into
younger age classes where the uptake by regrowth is initially more than offset by
CO
2
efflux from the decomposition of soil pools and elevated detritus left by the
disturbance. This situation is expected to worsen as climatic change proceeds,
especially if the conditions for successful regeneration are adversely altered. Altered
boreal forest disturbance regimes — especially increases in frequency, size, and
severity — may release CO
2
from vegetation, forest floors, and soils at higher rates
than the rate of C accumulation in the regrowing vegetation.
8
FIGURE 1.5 Land cover map of Canada. (Courtesy of Natural Resources Canada.
9
)
© 2006 by Taylor & Francis Group, LLC
Interaction between Climate Change and Greenhouse Gas Emissions 11
The precise balance of C uptake and release depends on the detailed processes,
and especially the outcome of interactions among climate, site variables, and vege-
tation over the changing life cycles of forest stands. Quantifying life-cycle dynamics
at the stand level is essential for projecting future changes in forest level C stocks
(Chapter 9). Forest management options to enhance or protect C stocks include
reducing the regeneration delay through seeding and planting, enhancing forest
productivity, changing the harvest rotation length, the judicious use of forest prod-
ucts, and forest protection through control and suppression of disturbance by fire,
pests, and disease.
1.4.3 W
ETLAND

/P
EATLAND
E
COSYSTEMS
Canada contains the world’s second largest area of peatlands (after Russia). In
Canada these peatlands cover approximately 13% of the land area and 16% of the
soil area (Figure 1.7).
14
The largest area of peatlands (96%) occurs in the Boreal
and Subarctic peatland regions. The dominant peatland types are bogs (67%) and
fens (32%), with swamps and marshes together accounting for less than 1% of the
Canadian peatlands. Overall, the most important controls of the carbon cycle in
peatlands are plant community, temperature, hydrology, and chemistry of plant
tissues and peat.
15
Limited data and understanding of the influence of changing
environmental conditions and disturbance (including fires and permafrost melting)
on the carbon cycle of peatlands over short and medium timescales (10 to 100 years)
FIGURE 1.6 Boreal forest under fire. (Courtesy of Canadian Forest Service.)
© 2006 by Taylor & Francis Group, LLC
12 Climate Change and Managed Ecosystems
hinder predictions of the changes in the carbon sink/source relationships under a
changing climate. The projected warming and associated changes in precipitation
will influence both net primary production and decomposition in peatlands, but how
global warming will directly influence peatland carbon dynamics remains uncertain
(Chapters 10 and 17). Melting of permafrost tends to increase peatland carbon stocks
through increased bryophyte productivity but also appears to increase heterotrophic
respiration.
16
Peatland fires result in decreased net primary production and elevated

post-fire decomposition rates, but little is known about the recovery of the carbon
balance after peatland fires (Chapters 10 and 17).
1.5 PURPOSE OF THIS BOOK
The major objective of this book is collation and synthesis of the current state-of-
knowledge of the impacts of climate change on agriculture, livestock, forestry, and
wetlands. Although many of the specific examples draw on Canadian studies, these
examples have lessons that are useful in other parts of the world, especially in the
Northern Hemisphere. The sustainable management of northern regions is a critical
objective in terms of human needs for food and fiber. Climate change, along with
land-use change and increased disturbance regimes, will be a significant threat to
meeting this objective, and will require significant improvements in understanding
and modification to present management practices.
Another objective of global importance is to help policy makers and land man-
agers to reach informed choices regarding the relationships between carbon sources
FIGURE 1.7 Land-use change from natural peatlands to agricultural activities. (Courtesy of
Steve Zoltai, Canadian Forest Service.)
© 2006 by Taylor & Francis Group, LLC