Why Earth Optimism?

A focus on conservation in this issue of Science appears on the eve of Earth Day, which is being celebrated by scientists in meetings and public events worldwide. Conservation professionals, who have long condemned attacks on the environment, will gather for Earth Optimism events to highlight conservation achievements. Separately, but simultaneously, marches for science will highlight science's achievements but also decry that science, scientists, and evidence-based policy-making are under attack. Although distinct in emphasis, these events speak with the same voice.