Climate_Change_101 - Eco-Efficiency Centre

Climate change 101

Over the past several years, the term “climate change” has become an inescapable mainstay in the popular press. As such, a simple review of greenhouse gases and their role in climate change is an important starting point in your carbon footprinting initiative.

Our atmosphere contains naturally occurring concentrations of heat-trapping greenhouse gases like carbon dioxide, methane, water vapour and ozone; without them, the average temperature of the earth would be a chilly -18 degrees and would be relatively uninhabitable.

However, since the industrial revolution, the concentration of these greenhouse gases, of which carbon dioxide is the most prevalent, has risen sharply. Everything from our daily car commute to the production of this workbook produces emissions, either directly, through vehicle exhaust, or indirectly, through generated the electricity needed to run our lights and motors. Because these gases retain heat, as their concentrations have increased, so too has the average temperature of the earth.

As mentioned, carbon dioxide is the most prevalent greenhouse gas, but a number of other gases contribute to climate change. When evaluating quantities of greenhouse gas emissions, we often see volumes measured in carbon dioxide-equivalent, or CO_2e. This unit takes into account the warming potentials of the anthropogenic greenhouse gases named in the Kyoto Protocol: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride¹.

Six greenhouse gases included in carbon footprint calculations^{1, 2}

Greenhouse gas	Common anthropogenic sources	Warming potential
Carbon dioxide (CO₂)	Energy, deforestation and land-use change	1
Methane (CH₄)	Fossil fuel combustion, landfills, and agriculture	21
Nitrous oxide (NO_x)	Fossil fuel combustion and fertilizers	310
Hydrofluorocarbons (PFCs)	Substitutes for chlorofluorocarbons and semiconductor production	140 – 11,000 (Average: 2,441)
Perfluorocarbons (HFCs)	Substitutes for chlorofluorocarbons and semiconductor production	7,400 – 9,200 (Average: 7,614)
Sulphur hexafluoride (SF₆)	Magnesium production, electrical transmission equipment	23,900

This phenomenon of human-caused climate change is the result of an elevated concentration of greenhouse gases in the atmosphere, and many scientists predict it will result in a variety of environmental complications, such as a dwindling Arctic ice sheet, more frequent extreme weather events like hurricanes, and droughts. But in spite of these forecasts, a growing number of practical strategies to fight climate change, many of which can bring valuable financial benefits to your organization.

A note on air pollutants

Oftentimes, the terms “air pollutants” and “greenhouse gases” are used interchangeably. In fact, air pollutants are those compounds that contribute to local air pollution, which can lead to smog and acid rain, and include nitrogen oxide, sulphur oxide, ground-level ozone, carbon monoxide and particulate matter.³ Air pollutants can include (common source in parentheses):

Nitrogen oxide (fuel combustion, such as gasoline or diesel),
Sulphur oxide (combustion of coal, for example)
Carbon monoxide (fuel combustion)
Particulate matter (electricity generation).³

(For more information, please visit the cited reference.)

Greenhouse gases, such as those listed above, contribute to global climate change. Although the environmental impact of air pollutants and greenhouse gases in our atmosphere is different, by managing one, we often realize reductions in the other, minimizing the local consequences of pollution and global consequences of climate change.

References

¹World Business Council for Sustainable Development & World Resources Institute. (2007, December). The Greenhouse Gas Protocol: Measuring to manage: A guide to designing GHG accounting and reporting principles.

²Environment Canada. (2008a, December 17). Environment Canada - Greenhouse Gas Emissions 1990-2000 - Chapter 1 Introduction.

³Environment Canada. (2006, August 18). Clean Air Online - 5.2 - Criteria Air Contaminants.