Fig. 4 Changes in amount of atmospheric aerosol and of solar energy at Earth’s surface after nuclear exchange. Changes in amount of atmospheric aerosol and of solar energy at Earth’s surface after nuclear exchange. Visible wavelength aerosol optical depth versus time (A) and the change in shortwave surface energy relative to normal as a function of time (B) for varying amounts of BC emitted in the nuclear exchange. Color coding designates the BC injection. Owen B. Toon et al. Sci Adv 2019;5:eaay5478 Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).