Hundreds of thousands of non-producing oil and gas wells exist in Canada with millions more around the world. These wells have the potential to contaminate water supplies, degrade ecosystems, and emit methane and other air pollutants. Thus, non-producing wells present risks to climate stability and to environmental and human health, which can be reduced by plugging. To quantify methane emissions reduction potential and environmental risks and opportunities of well plugging, we have measured more than 500 wells in Canada alone. In this presentation, I will present an overview of available methane emission measurements with a focus on Canada and factors linked to high-emitting non-producing wells. I will also present estimates of methane emissions from non-producing wells at the national scale, including uncertainties. I will end with the implications of these findings on orphaned oil and gas wells in Canada and elsewhere.