Climate Change and Agriculture

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 What is climate change? | Sources and sinks of Agricultural greenhouse gases | Greenhouse gases and Alberta’s agricultural industry | Opportunities for Alberta's agricultural sector | Greenhouse gas factsheets | Current initiatives | Carbon offsets | GHG research | Cropping | Livestock | Climate change adaptation | Energy | Contacts

Why is Climate Change Important?

The Earth’s climate is constantly changing as a result of natural processes. The atmosphere has an effect like a greenhouse on the Earth’s temperature. The energy from the sun reaching the earth is balanced by the energy the Earth emits to space. Greenhouse gases (GHG) trap some of the energy the Earth releases to space. The GHG in the atmosphere act as a thermostat controlling the Earth’s climate. Without this natural greenhouse effect, the average temperature on Earth would be -18˚C instead of the current +15˚C. Therefore, life as we know it would be impossible.

The majority of the world’s scientists studying this topic agree that the current rate of climate change is faster than at any time in the last 10,000 years because of human activity. Human activities affect GHG levels by introducing new sources of emissions or by removing natural sinks, such as forests. Sources are processes or activities that release GHG; sinks are processes, activities or mechanisms that remove GHG. The levels of GHG are determined by a balance between sources and sinks.

Since the industrial revolution, concentrations of GHGs have been increasing steadily as a result of industrialization (increasing sources of emissions), as well as cultivation and deforestation (declining sinks). In its fifth assessment report since 1990, the Intergovernmental Panel on Climate Change (IPCC) concluded that climate change is already happening and can be primarily attributed to human activity.

Global climate change is expected to have substantial impacts on the environment including water resources, fisheries, forests, wildlife and ecosystems. Regional climate changes, particularly temperature increases, are already affecting different natural systems on all continents and in some oceans. Scientists also predict that climate change will increase climate variability.

Canada has committed to reducing GHG emissions to 17% below 2005 levels by 2020 and 30% below 2005 levels by 2030. Canada pledged to take action and reduce GHGs on an industry-by-industry basis. For example, regulations in the transportation industry have been put in place that require an average of 5 percent renewable fuel content in gasoline. Provinces and territories have been taking steps to address climate change according to their specific circumstances. Businesses and individuals are also reducing emissions by using resources more efficiently and adopting new, cleaner technologies. In order to achieve significant reductions, all GHG emitters will need to do their part.

Alberta was the first jurisdiction in North America that passed a law requiring reduced GHG in 2007. Facilities that release more than 100,000 tonnes of carbon dioxide equivalent (T CO2e) per year must either:
i) reduce their emissions intensity by 12% below a baseline level
ii) pay $15 / T CO2e into a Climate Change Emissions Management (CCEMC) Corporation fund, or
iii) buy carbon offset credits from others who make voluntary practice changes that reduce GHG
emissions, based on criteria outlined in government approved carbon offset protocols.

Farmers in Alberta have participated in this new carbon market through reduced tillage and conservation cropping and by generating renewable biogas energy from manure, described later in this document. Table 1 shows how both targeted reductions and carbon prices will increase by 2017. Alberta is also developing a new climate change action plan to transition to a low-carbon future.

Table 1. Upcoming changes to reduction requirements in Alberta’s Specified Gas Emitter’s Regulation.

YearReduction Required*Cost per tonne of Carbon Dioxide
2007 – 201512%$15
*As compared to a baseline of average emission intensity between 2003-2005

Attention to climate change has brought new focus to agriculture. Agriculture affects GHG levels and it is also vulnerable to the predicted impacts of climate change. The agricultural industry already has many ‘beneficial management practices’ that can reduce GHG emissions or capture and store carbon. By showing leadership and initiative, farmers and ranchers in Alberta can remain competitive, increase efficiencies and resilience to a changing climate and may be able to capture emerging market opportunities.

Additionally, the agricultural industry will need to prepare for and adapt to climate change. For more information on adaptation to climate change in Alberta see factsheets listed below entitled “Climate Change in Alberta” and “A Changing Climate for Agriculture - How Can We Prepare?”

Sources and Sinks of Agricultural Greenhouse Gases

Although carbon dioxide is the major GHG released by other sectors, agricultural GHG have special characteristics. Methane and nitrous oxide are the primary agricultural emissions. As illustrated in Fig. 1 methane is released by livestock through enteric fermentation (digestive processes) and decomposing manure, while nitrous oxide is released by fertilizer, tillage and manure. Some carbon dioxide emissions occur from fuel and energy use in agricultural operations. Carbon dioxide can also be emitted from soils through mechanical soil disturbance and land use change, or it can be stored or sequestered as a carbon sink in soils by management such as conservation tillage. The United Nation’s Intergovernmental Panel on Climate Change estimates that soil carbon sequestration, through improved cropland and grazing land management, as well as the restoration of degraded lands, offers great potential in agriculture for climate change mitigation.

Figure 1. Greenhouse gas sources and sinks in Canadian agricultural systems. Source: Agriculture and Agri-Food Canada.

In order to compare emissions from different sources, the global warming potential of each type of greenhouse gas is compared to the global warming potential of carbon dioxide. For example, the global warming potential of one tonne of methane is 25 times more potent than one tonne of carbon dioxide over a 100 year period (Table 2).

Table 2. Global Warming Potentials - Source IPCC, 2007*
Relative Warming Potential
(CO2 equivalents or CO2e)
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
* IPCC published the Global Warming Potentials for CH4 and N2O as 23 and 296 in 2001, and 25 and 298 in 2007; however the above GWPs are still used to be consistent with the National Accounting Frameworks.

In Canada, the GHGs emitted by the various industry sectors are calculated and recorded annually in the National GHG Inventory. According to Environment Canada, agricultural emissions in 2013 accounted for 60 megatonnes (Mt) or 8 percent of the total GHG emissions for Canada (Figure 2). Emissions from fossil fuel production, processing, transmission, and distribution within the energy industry in Canada accounted for 81 percent of the total GHG emitted. In 2013 the agricultural industry contributed about 70 percent of total Canadian nitrous oxide emissions and about 27 percent of total Canadian methane emissions.

Figure 2. Canada’s Greenhouse Gas Emissions by Industry Sector for 2013 in carbon dioxide equivalents (CO2e). Source: Environment Canada 2015

Greenhouse Gases and Alberta’s Agricultural Industry

Figure 3 illustrates agricultural sources and sinks of GHG emissions in Alberta in 2013 that totalled 22 Mt CO2e. This represented 8 per cent of Alberta’s total emissions and 30 per cent of Canada’s agricultural emissions. In Alberta, methane from digestion by livestock, predominantly cattle) accounted for just under 50% of agricultural emissions or 10 MT CO2e. Emissions from soil management practices, including irrigation, tillage and applications of fertilizer and manure account for almost half or 9 MT of Alberta’s agricultural emissions and are the fastest growing emission source in agriculture. Carbon dioxide from off road fuel use accounted for 14 percent of totals. Net changes in GHG emissions removals due to emission sequestration by soil carbon in Alberta’s cropland totaled close to 17 per cent of Alberta’s agricultural emissions in 2013.

Figure 3. Alberta's agricultural GHG sources and sinks in 2013 in carbon dioxide equivalents (CO2e). Data from: Environment Canada 2015.

Opportunities for Alberta's Agricultural Sector

There are many opportunities to improve efficiencies while reducing emission rates, removing emissions thorough soil carbon storage and replacing fossil fuel based products with renewable biological materials.
Management improvements that reduce GHG emissions, or that captures and stores carbon, such as direct seeding, will also increase production efficiencies and farmers’ ability to adapt.

Productivity improvements are associated with reductions in GHG emissions in Canada. Between 1981 and 2006 the following reductions in emissions from dairy decreased from 1.23 to 0.98 kg CO2e per kilogram of milk produced, emissions from beef decreased from 16.4 to 10.5 kg CO2e per kilogram of beef cattle live weight and emissions from pork decreased from 3.0 to 1.9 kg CO2e per kilogram of pork live weight. The main reason for these emission declines were dramatic increases in productivity, including a doubling of crop productivity in the last 50 years. In addition, better genetics, better feed formulation, better animal housing, and better animal health more than tripled dairy production in last 50 years. Feed to food conversion has also improved, e.g. from 3. 4 to 1. 4 kg of feed per dozen eggs.

Alberta produces about 40% of Canada’s cattle. Ruminants like cattle emit methane through a process called enteric fermentation in their extra digestive organ. Management of livestock emissions addresses an important source since methane has a higher greenhouse warming effect than carbon dioxide. Alberta researchers are international leaders in selecting genetic traits to improve feed efficiency in beef cattle. Emissions are lowered when cattle eat less, which lowers costs. Lower feed and manure requirements also mean fewer emissions from spreading manure and field passes to grow and transport feed, so there are additional savings of fuel and time. Feeding strategies that focus on feed quality, or use edible oils or other additives to lower emissions are also effective, but have associated costs. Manure also emits methane when it decays under low oxygen such as liquid manure storages or poorly aerated stockpiles, as well as nitrous oxide. Amounts of emissions depend on the storage method, application method and rate, manure type and soil conditions.

Nitrous oxide emissions from Alberta cropping systems tend to be lower than in other areas since lower rates of fertilizer are used and there are fewer occurrences of wet conditions that promote nitrous oxide emissions in sub-humid and semi-arid climates. Management to increase nitrogen use efficiency reduces emissions and also chances of loss in runoff, while offering opportunities to increase yields at lower input costs by optimizing timing, placement, product and rate.

Agriculture is in a unique position to lower emissions because of its ability to ‘capture’ atmospheric carbon in growing crops and store a portion of that carbon in soil organic matter. Conservation farming practices, such as direct seeding, no-till farming and good fertilizer placement, have increased soil organic carbon levels helping to ‘offset’ GHG emissions and reduce the industry’s net contribution. Reducing GHG emissions simply means that crops and livestock are raised more efficiently, thus reducing wasteful input losses like nitrogen and energy. Adoption of conservation practices will not only help to reduce GHG emissions but can also benefit water quality, increase the resilience of soils to climate change and air quality.

Greenhouse Gas Factsheets
Two new factsheets are now available for download, as follows:
Current Initiatives
Carbon offsets
Carbon credits or offsets generated from voluntary practice improvements in the agriculture sector are a compliance option for large GHG emitters in Alberta under the Specified Gas Emitters Regulation. To facilitate the offset investment in Alberta, Agriculture and Forestry (AF), industry and other government departments are collaborating to develop carbon offset quantification protocols. These government approved quantification protocols describe the:
i) policy basis for identifying practice improvements that are "above and beyond business as usual",
ii) science basis for GHG emission reduction and/or removal from a particular practice change as well as
iii) verifiable records required to prove that the practice improvement has occurred.

AF has actively been developing and supporting a number of standardized offset protocols for producers who want to create offset credits for sale in the carbon market. For an update on opportunities in the Alberta Carbon Market about offset sales of over $140 M for emission reductions of 11 Mt of CO2e from reduced tillage, conservation cropping and biogas from manure, click here.

GHG Management Practices Booklets for Cow Calf and Hog Producers
These booklets provide information on different management strategies associated with the reduction and removal of GHGs from the atmosphere on the farm. Reducing a farm’s GHG production can help to reduce the farm’s environmental footprint, improve production efficiencies, and may offer a return on investment.

Cow/Calf Operations and Greenhouse Gases
This booklet examines herd health, grazing management, feed management and manure management. The booklet highlights current research and the greenhouse gas reduction benefit to various management strategies in a cow/calf operation. This document can be downloaded as a whole here (pdf file size 6 MB) or by section:

Introduction Part 1 (pdf file size 165 KB)
Introduction Part 2 (pdf file size 149 KB)
Figure 1 - Farm GHG Sources and Sinks (pdf file size 385 KB)
Section 1 Herd Health (pdf file size 88 KB)
Section 2 Grazing Management (pdf file size 1,376 KB)
Section 3 Feed Management (pdf file size 109 KB)
Section 4 Manure Management (pdf file size 355 KB)
References (pdf file size 40 KB)

Hog Operations and Greenhouse Gases
This booklet examines pig herd health, feed management, the barn, manure handling and storage, manure application and odour control in order to highlight their impacts on greenhouse gas management. This document can be downloaded as a whole here (pdf file size 6.28 MB) or by section:

Introduction Part 1 (pdf file size 168 KB)
Introduction Part 2 (pdf file size 521 KB)
Figure 1-Farm GHG sources and sinks (pdf file size 384 KB)
Section 1 Herd Health (pdf file size 107 KB)
Section 2 Feed Management (pdf file size 638 KB)
Section 3 Greenhouse gases and the barn (pdf file size 211 KB)
Section 4 Manure Handling and Storage Systems (pdf file size 449 KB)
Section 5 Manure Application and Management (pdf file size 135 KB)
Section 6 Controlling Odours and Greenhouse Gases (pdf file size 239 KB)
References (pdf file size 78 KB)

Paper copies of these free booklets can be ordered by contacting the Environmental Stewardship Division of AF. You may call from anywhere in Alberta toll-free by dialing 310-0000 followed by 780-422-4385.

GHG Research
Since 2000, AF has been actively conducting agricultural related GHG research. Some of this research has been studying GHGs from livestock and GHGs from various crop and tillage management practices. See below for a description of projects and publications that AF staff and partners are currently involved in related to GHGs and climate change.

In 2003, AF and the University of Alberta published a report titled Development of a Farm-Level Greenhouse Gas Assessment: Identification of Knowledge Gaps and Development of a Science Plan. The first chapter of this report focuses on the current state of knowledge of agricultural GHG research and identifies preliminary gaps in our knowledge. The second chapter contains an Alberta-based agricultural GHG inventory for 2001, while the third chapter describes the Agricultural Science Plan which prioritized research in the areas of soil and crops, livestock, land use and energy and whole farm systems. All of these three chapters clearly identify agricultural GHG research gaps and recommend there is currently not enough information available to produce on-farm assessments that will accurately reflect the GHG emissions of a typical farm within a reasonable range of error. Although this plan is not current, it is still very relevant due to the time and resources that are needed to address agricultural GHG emissions. This report is available for download here as a pdf file (size 1.46 MB).

Study to evaluate the response of wheat, barley and canola with two nitrogen fertilizers. Len Kryzanowski, Environmental Stewardship Division and Ross McKenzie, Research Division of AF are jointly conducting a province wide study to evaluate the effects of response of wheat, barley and canola with two nitrogen fertilizers including urea (46-0-0) and Environmentally Smart Nitrogen (ESN; a polymer coated slow release urea; 45-0-0) at 9 different agro-ecological locations across Alberta for five years. The fertilizers are applied at five different rates ranging from 0 to 120 kg/ha, banded in fall, and side banded and seed-placed at seeding, with each crop. The objectives of the study are to examine nitrogen fertilizer use, nitrogen fertilizer use efficiency and to develop nitrogen fertilizer response curves for each crop, in each major agro-ecological area of Alberta. The study is examining nitrous oxide emissions from the two fertilizer forms and the effects of time of fertilizer application and placement at the various N rates. The intensive gas monitoring takes place in all treatments from time of application to after crop harvest. The intensive sites monitored for gas emission are an irrigated site at Lethbridge in the Dark Brown soil zone, and dryland sites at Lacombe in the Black soil zone and near Westlock in the Gray Wooded soil zone.

Germar Lohstraeter taking a gas sample for nitrous oxide (N2O) flux measurements by using a gas chamber and syringe.

Craig Sprout taking a soil sample to measure available nitrogen beside a GHG sampling chamber.


Energy Efficiency
Increasing energy efficiency is one of the best ways for agriculture to address climate change. AF is using energy assessments to increase energy efficiency on farms. Energy assessments make producers aware of their farms power consumption and where the largest economic benefits are gained by increasing energy efficiency. Energy assessments consist of spreadsheets, protocols and information on energy saving technologies that assessors use for various farming operations. In 2005 Climate Change Central and AF started developing an energy assessment for livestock barns. AF has set a goal to expand the assessment program to the entire farm. Assessments have recently been developed for irrigation, greenhouses, seed cleaning, feed mills and feedlots. One of the gaps in energy assessments on a farm is separating the power use for various operations. AF encourages producers to meter separate operations for both natural gas and electricity so energy assessments can be performed and potential energy savings discovered. To address energy use in field operations, the Alberta Farm Carbon Calculator was developed. The calculator assists producers in saving diesel fuel during field operations.

New lighting technologies have been thoroughly investigated at the Agricultural Technology Centre. These new lighting technologies are demonstrated in a storage building at the Agricultural Technology Centre. New energy saving technologies that are currently under investigation include variable frequency drives for fans and pumps, infrared heating, tank-less hot water heater, solar air heater, LED lights and a written pole motor. The information found on energy savings with the technologies will also be used in the Growing Forward On-Farm Energy Management Program for possible future incentives.

Renewable Energy
On farm power generation should only be developed once all energy efficiencies are realized. The micro generation legislation in Alberta states that producers can only generate enough energy to offset the energy they use on farm. Wind energy shows great potential for on farm power generation. AF collaborated with the Farmer’s Advocate and the Pembina Institute to develop the Landowner’s Guide to Wind Development. The guide is a resource to producers who are approached with wind development proposals or producers thinking of developing their own wind power micro generation. Solar energy also has great potential for on farm power generation but capital costs are still high. The Agricultural Technology Centre developed an off grid solar powered system for a storage building using photo voltaic panels. The system generates power for a light system and is used for research and demonstration. AF organizes conferences to address the knowledge gap in renewable energy. Energy Options behind the Farm Gate conferences were held in Taber in 2009 and in Grande Prairie and Stettler in 2010.

Click here to view the Landowners’ Guide to Wind Energy in Alberta.

Greenhouse gas emissions from calf-fed and yearling-fed beef production systems, with and without the use of and growth promotants. Research is being conducted by J.A. Basarab, V.S. Baron, O. Lopez-Campos, J.L. Aalhus, and E.K.Okine. The objective of this study are to:

  1. Conduct a primary scope life cycle assessment of beef cattle production for GHG emissions using actual inputs and outputs from calf-fed vs. yearling-fed production systems with and without aggressive growth implant and feed additive strategies (e.g., β-adrenergic agonist);
  2. To compare GHG reductions with those generated from the equations in the “Reduced Days at Harvest in Beef Cattle” protocol. This report will be available in January 2012.

A collaborative research project between Agriculture and Agri-Food Canada, Agriculture and Rural Development and XY-Green Carbon Inc. on anaerobic digestion of animal manure. Anaerobic digestion (AD) of animal manure has become an environmentally attractive technology to meet the world’s increasing demand for energy. Anaerobically digested manure (ADM), often referred as digestate, is one of the final by-products of the biogas energy industry. The ADM is a nitrogen-rich material and its application increases crop yields, but could also increase soil nitrous oxide (N2O) emissions, which is an environmental concern. The objectives of this study were to investigate the N2O emissions from soil receiving various forms of ADM application. Two field sites were selected, one near Lethbridge, Southern Alberta, and another near St. Albert, Central Alberta. A complete randomized block design with six treatments, two application rates and four replications was used. The six treatments were: (1) control: no amendment (CK), (2) fresh manure (M), (3) ADM, (4) liquid removed from ADM to produce separated solids (SS), (5) SS processed into pellets (PE), and (6) urea-enriched SS processed into N:P balanced pellets (PEU). All amendments were applied at rates of 100 and 200 kg N per ha per yr. Barley was grown and harvested at the soft dough stage as forage for making silage feed. During the growing season, the rate of N2O emission was collected weekly using a vented static chamber at the Lethbridge site and every two weeks at the St. Albert site. Analysis of preliminary data indicates that crop yield and N2O emission from the ADM treatment were generally higher than from all other treatments, reflecting the higher water soluble N in the ADM and increases in soil moisture content following the amendment application. Two more years of field work is planned for much needed additional field data before meaningful conclusions can be drawn.

Click here to view a presentation.

Climate Change Adaptation
Working with Alberta Environment’s Alberta Climate Change and Adaptation Team (ACCAT), AF developed one of the first studies done in Alberta to examine whether the recent global climate patterns and more extreme weather events across the Canadian landscape were concerning producers. Producers from different agricultural sectors within the Taber, Red Deer, St Paul and Fairview area were asked to describe the ways they historically and currently deal with risks and opportunities arising from changing climate and what they intend to use as longer term strategies. The report outlines several strategies that producers could implement to adapt to climate change in order to be sustainable. This report is available for download here as a pdf file (size 374 KB).

Climate in Alberta has changed in the past and is projected to in the future. For a two-page factsheet summarizing past and expected changes go here.

How can farmers prepare for climate change? For a two-page factsheet summarizing options go here.

Click here to go to the Environment and Sustainable Resource Development’s page to view Alberta’s Climate Change Strategy current initiatives in Adapting to Climate Change.


For more information about GHGs and climate change in agriculture please contact:

Sheilah Nolan
Climate Change Specialist
Environmental Strategy & Research Branch
Phone: 780-427-3719
Tom Goddard
Senior Policy Advisor
Environmental Strategy & Research Branch
Phone: 780-427-3067

For more information about lowering agricultural GHG and climate change related research and activities, please contact:

Dr. Vern Baron
Research Scientist
Agriculture and Agri-Food Canada
Phone: 403-782-8109

Dr. John Basarb
Beef Research Scientist
Livestock Research Branch
Roger Bryan
Manager, Environmental Innovation
Environmental Strategy & Research Branch
Phone: 780-427-3616
Richard Heikkila
Senior Economic Analyst
Economics Branch
Phone: 780-422-4088
Len Kryzanowski
Environmental Strategy & Research Branch
Phone: 780-422-1252
Kerrianne Koehler-Munro
Environmental Program Specialist
Environmental Strategy & Research Branch
Phone: 780-427-3628

Paul Jungnitsch
Carbon Offsets Agrologist
Environmental Strategy & Research Branch
Phone: 780-427-3801
Jason Price
Project Manager, Energy Program
Environmental Extension and Programming Branch
Phone: 780-427-4181
Bob Riewe
Irrigation Modeling Specialist
Water Resources Branch
Phone: 403-381-5868

Brent Swallow
Department Chair, Environment and Development Economist
University of Alberta
Dr, Susan Markus
Beef Research Scientist
Livestock Research Branch
Phone: 403-742-7570
Jeff Bell
Industry Development Officer
Bio-Industrial Opportunities Branch
Phone: 780-638-3158

Asgedom H. and E. Krebab. 2011. Beneficial management practices and mitigation of greenhouse gas emissions on the agriculture of the Canadian Prairie: a review. 2011. Agronomy Sust. Developm. 31:433-451,

Beauchemin, K. A., Janzen, H.H., Little, S.M., McAllister, T.A. and McGinn, S.M. 2011. Mitigation of greenhouse gas emissions from beef production in western Canada – Evaluation using farm-based life cycle assessment. Animal Feed Science and Technology. 166-167: 663-667

Desjardins, R.L. 2013. Climate Change—A Long-term Global Environmental Challenge. Procedia - Social and Behavioral Sciences, 77 pp. 247 – 252.

H.H. Janzen, R.L. Desjardins, P. Rochette, M. Boehm and D. (eds.) 2008. Better Farming Better Air: A Scientific Analysis of Farming Practices and Greenhouse Gases in Canada. WorthAgriculture and Agri-Food Canada.

Environment Canada. 2015. National Inventory Report 1990-2013: Greenhouse Gas Sources and Sinks in Canada. Available online at

Environment Canada. News Release June 23rd, 2010. Government of Canada Makes Major Investment to International Climate Change.

Lemmen, D.S., Warren, F.J., Lacroix, J., and Bush, E., editors (2008): From Impacts to Adaptation: Canada in a Changing Climate 2007; Government of Canada, Ottawa, ON, 448p.

Liebig, M.A., Morgan, J.A., Reeder , J.D., Ellert, B.H., Gollany, H.T., and Schuman, G.E. 2005. Greenhouse gas contributions and migitaiton potential of agricultural practices in northwestern USA and Western Canada. Soil and Tillage Research, 25-52.

United Nations Framework on Climate Change (UNFCC). 2009. Fact sheet: Climate change science. Available online at

Intergovernmental Panel on Climate Change (IPCC), 2007, Summary for Policymakers, in Bert Metz et al. (eds) Climate change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (New York, NY: Cambridge University Press, 2007). Available online at

IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis.
Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)].Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Available online at
For more information about the content of this document, contact Sheilah Nolan.
This document is maintained by Nicole Huggins-Rawlins.
This information published to the web on March 2, 2005.
Last Reviewed/Revised on September 22, 2015.