Methane is a major contributor to climate change behind CO2 — but it's been largely overlooked

Until now, methane has gone largely undetected as a contributor to climate change. The greenhouse gas is more potent than carbon dioxide.

The United States has joined with more than 30 countries in a pledge to tackle methane emissions.

Here & Now's Peter O'Dowd talks with Mark Brownstein, senior vice president of energy at the Environmental Defense Fund.