James Pardo commented on a recent Harvard University study which found much higher levels of methane emissions from natural gas extraction than U.S. EPA estimates suggest. Mr. Pardo said that methane leakage has been widely overstated and misunderstood, especially compared with the long-term climate effects of carbon dioxide, which stays in the atmosphere for decades longer than methane. Energy companies already have plenty of incentive to minimize fugitive methane emissions. “For a well operator, it's money in the bank,” Mr. Pardo said. “You don't want to leak it.” As far as methane leaks during transport, “It probably needs to be looked at, but I'm confident that the technology exists to address those issues if they are actually issues,” Mr. Pardo said.