Acid deposition, commonly referred to as acid rain, continues to damage Canadian ecosystems.  Acidification of lakes and streams makes the water unsuitable to support some fish and other biota.  Acid deposition also damages forest soils by stripping the soil nutrients and increasing the release of toxic chemicals such as aluminium, as well as directly damaging some sensitive tree species.  Acids corrode buildings, statues and sculptures, speeding the decay of these structures that are part of our national heritage.

In recognition of the continuing acid deposition problem, on October 19, 1998, all 26 Energy and Environment Ministers signed The Canada-Wide Acid Rain Strategy for Post-2000.  The Strategy is a framework to resolve the acid deposition problem in eastern Canada and ensure that new acid deposition problems do not occur elsewhere in Canada.  The long-term goal of The Strategy is "to meet the environmental threshold of critical loads for acid deposition across Canada."  Critical loads are the maximum amount of acid deposition that an ecosystem can receive without significant damage.  They vary substantially from one region to another depending on the local soil and bedrock conditions.

The Strategy calls for a number of actions towards achieving the long-term goal:

• development of further controls on acidifying emissions in Canada and the United States;
• implementation of pollution prevention measures so that new facilities are built clean;
• governments taking steps to minimize emissions (keeping-clean-areas-clean); and
• maintaining active roles in acid rain science and monitoring, including reviewing the adequacy of science and monitoring programs, and assessing the role of nitrogen in acidification.

Commencing with the 2006/07 report, progress will be reported biennially, alternating with the biennial Canada – United States Air Quality Agreement progress report which presents similar information.  Acid Rain progress reports were becoming increasingly delayed due to difficulties in the collection and development of emissions inventories, forecasts and backcasts. Biennial reporting will reduce the time lag between the available actual emissions information and the reporting period.