Methane (CH4) is a potent greenhouse gas whose concentration in the atmosphere has risen sharply in recent decades. Wetlands are the largest natural source of methane to the atmosphere, but large uncertainties remain about how much methane comes from wetlands and how these emissions may increase in response to a changing climate. Tropical wetlands, including those in the Amazon, produce substantial amounts of methane, but accurately estimating their emission sources and magnitudes remains difficult. One reason is the lack of measurement data, especially in the tropics, where extensive cloud cover interferes with satellite observations and ground-based measurements are sparse.