Humanity has been grappling with environmental challenges that have grown in number and severity ever since the Stockholm Conference in 1972. The scientific assessments synthesized in this report show that those challenges now represent a planetary emergency. While tackling the emergency is demanding, the report lights a path to a sustainable future marked with new possibilities and opportunities. Chapter 1. Tackling the planetary emergency and lighting a path to a sustainable future with new opportunities -- Part 1. Transforming nature puts human well-being at risk -- Chapter 2. The current mode of development degrades the Earth‘s finite capacity to sustain human well-being -- Chapter 3. Society is failing to meet most of its commitments to limit environmental damage -- Chapter 4. The achievement of the Sustainable Development Goals is threatened by environmental risks -- Part 2. Transforming humankind’s relationship with nature is the key to a sustainable future -- Chapter 5. Human knowledge, ingenuity, technology and cooperation can transform societies and economies and secure a sustainable future -- Chapter 6. Earth’s environmental emergencies must be addressed together to achieve sustainability -- Chapter 7. Transforming economic, financial and productive systems can lead and power and the shift to sustainability -- Chapter 8. Keeping the planet healthy is key to providing health and well-being for all -- Chapter 9. All actors have a part play in transforming humankind’s relationship with nature -- Annex 1. Assessment Reports Used in this Synthesis Report.