Fires, drought and warmer temperatures were to blame for excess carbon dioxide in the atmosphere during the 2015-2016 El Niño, scientists with NASA’s Orbiting Carbon Observatory-2 say. The findings, part of five papers published in the journal Science, shed light on the mechanisms through which Earth “breathes” carbon dioxide, a potent greenhouse gas, and reveal how those mechanisms affect climate change. Global temperatures have been on the rise, thanks largely to the human-driven increase in greenhouse gases like carbon dioxide. But not all of the carbon dioxide produced each year ends up in the atmosphere. Some of it gets trapped in the ocean, or locked on land thanks to plants that use the gas during photosynthesis.