Atmospheric processes play important roles in shaping the Earth’s energy and water cycles. With the help of numerical models, observations and theories, GFDL scientists conduct cutting-edge research to advance the fundamental understanding of atmospheric processes in governing climate variability and change, with the goal of developing more accurate representations of them in climate models. This work makes it possible to quantify the key characteristics of natural and anthropogenic perturbations to the climate system (such as greenhouse gases, aerosols, land use, volcanoes and solar radiation), and to elucidate the mechanisms through which these perturbations influence global and regional climate.