Global climate is a top-of-mind issue for much of humanity. Will our planet become unlivable? What can we do to forestall that possibility? Can we play an active role in saving our planet without massive but inherently fragile globally coordinated action? While answering these questions is difficult, it is impossible without understanding the science. But we only have one world so how do we do that science in a meaningful and predictive way? This talk will lead us through atmospheric chemistry on Earth and beyond — where modern spectroscopy is allowing us to glimpse climate trajectories of our solar neighbors and what they might have to say about Earth’s future. Expanding our knowledge from our home planet to those within the habitable zone of the universe. Francisco will talk about how the synergy between experimental and theoretical approaches provides unprecedented insights into the fundamental chemistry shared between Earth and Venus, with a specific focus on chlorine—an important element on Venus, but an ozone depleting element on Earth. The talk unearths new chemistry involving chlorine and sulfur-containing species, forming novel molecules that influence observational chemistry in Venus's atmosphere. Detailed discussions on the structure and spectroscopy of chlorine and sulfur-containing intermediates shed light on their role in connecting sulfur and chlorine chemistry on Venus, offering valuable insights and lessons from chemistry on Venus to avoid on Earth.