This letter from the Acting Executive Director of UN Environment is structured around four main points: i) Where we Stand; ii) Opportunities; iii) Pathways; and iv) A Call to Action. The letter concludes with a challenge: "In Nairobi next month, and in New York in September, let us all prove that we are ready to hold ourselves to account. Our scientists have calculated that we need to increase five-fold, our ambition on climate change. So, I challenge you, as our window of opportunity gets smaller by the hour: What does ambitious climate action look like for you? For climate, for nature, for consumers? For people, for planet, for posterity? What are you ready to bring to the table?"