That means that over the course of decades, it takes smaller amounts of methane than carbon dioxide to heat up the planet to the same level. But the flip side of that math is that cutting methane emissions is one of the most effective ways to limit climate change. “Little or no measurement-based data is used to report methane emissions in most parts of the world,” according to the IEA. The United States, the world’s third largest methane-emitting country, has seen its methane emissions slowly decline over the past 30 years. That burned methane forms carbon dioxide, so the overall climate impact is lower than just letting the methane go free.