The environmental impact of the oil sands is an issue that has been extremely divisive. As with the extraction and use of any fossil fuel, negative environmental effects arise as a result of the extraction, upgrading, and processing of bitumen from the oil sands. Although some steps are being taken to reduce the severity of these impacts - such as reclamation - there are still associated climate, air, and water effects. Since there are so many environmental impacts that can be discussed, the main concerns have been broken down into several core issues including:
- Tailings Ponds Impacts: Tailings ponds are settling ponds that contain the waste byproduct of oil sands extraction and upgrading. They are a mix of water, sand, silt, clay, unrecovered hydrocarbons, and other contaminants.
- Climate Impacts: The greenhouse gas emissions for oil sand extraction and processing are significantly larger than for conventional crude oil. These emissions contribute to global warming and the enhanced greenhouse effect.
- Water Impacts: The extraction of bitumen from oil sands requires a large amount of water, and thus water use is a concern when looking at oil sands extraction. Water used in the oil sands can be recycled, but only small amounts of this water are returned to the natural cycle.
- Air Quality Impacts: Along with greenhouse gases, other pollutants are released into the air during oil sands operations. These pollutants are harmful to the environment and human health, and include gases such as NOx and SOx.
- Reclamation: Reclamation is the attempt to return previously used land - whether it is old surface mines, or more frequently tailings ponds - to their natural state. The chemicals in the tailings are factor that can make reclamation difficult.