On Earth Day 2021, the HBS Business and Environment Initiative and AMP199 Energy Circle co-hosted a conversation between Joan MacNaughton, Chair of the Climate Group and of the Advisory Board of the New Energy Coalition of Europe, and Professor Richard Vietor, Baker Foundation Professor of Business Administration at the Harvard Business School, about how governments, businesses, and society must act together—now—to cut global emissions in half by 2030 to keep temperature rises under 1.5°C and avoid the disastrous effects of climate change.