A new report from a Canadian climate change think tank concludes that excess carbon dioxide from large-scale development of shale gas--which is just vented into the air--is potentially a very large source of greenhouse gas emissions. The researchers found that natural gas extracted from shale in the Horn River Basin contains approximately 11-12% CO2, "considerably higher than the average content of only 2-4.5% for British Columbia’s conventional natural gas reservoirs." They conclude that this will make it extremely difficult for the province to achieve its CO2 reduction targets.