The concentration of water vapor, Earth’s most abundant greenhouse gas, is rising as our climate warms. But water vapor isn’t causing human-produced global warming. Instead, it’s amplifying it. Learn why: https://climate.nasa.gov/ask-nasa-climate/3143/steamy-relationships-how-atmospheric-water-vapor-supercharges-earths-greenhouse-effect/ Video: Water vapor in the atmosphere during the summer and fall of 2005. Credit: NASA/JPL-Caltech | NASA Climate Change