effort to reduce methane emissions, and has been advancing technology to detect leaks. ♪ ♪ as sharon wilsonumber of scientists were waking up to the dangers of methane. including the man who'd helped pioneer the process of fracking. >> i became very much more concerned about climate change when i realized what shale gas and oil was going to unleash. that's the right word, unleash. (chuckling): this is trite. unleash a tsunami of oil and gas, yes. that's what it did. that's when i started feeling contradictory regret and pride. (chuckles) pride that we had done good engineering work to help somebody eventually figure out how to do it, regret that we had figured, we had helped somebody figure out how to do it. (chuckles) by going to shale, we're going to prolong the fossil fuel industry, and by prolonging the fossil fuel industry, we're going to exacerbate climate change. >> narrator: by now, tony ingraffea was a civil engineering professor at cornell university, and had spent years advising oil and gas companies. in 2011, he and colleagues published a critical report on the climate impact of