OBJECTIVES OF THIS REPORT

Agriculture occupies a larger portion of global land area (about 35%) than any other human activity. Because of its scale and intensity, agriculture emits a lot of gases into the atmosphere. For example, agriculture is a main source of greenhouse gases, accounting for about 25% of the CO₂, 50% of the CH₄, and 70% of the N₂O released via human activity globally. As well, agriculture accounts for more than 50% of ammonia released into the air.

But because farmlands are managed so intensively, farmers can control, at least partly, the amounts of gases released. Various ways of farming produce different emissions; and by choosing new practices, it may be possible to reduce emissions. For some gases, farmlands may, in fact, even be made to absorb more than they emit, thereby helping to restore air quality.

In this report, we focus on the effect of Canadian agriculture on the atmosphere. Specifically, we try to answer three questions:

• How do farming practices affect the composition of the atmosphere?
• What is the amount of agriculture's emissions to the air?
• How can we reduce these emissions?