This lecture discusses the relationship between population, economic activity, and carbon emissions, emphasizing the Kaya identity. It explores various levers for decarbonization, including personal engagement, efficiency improvements, and systemic transformations. The instructor highlights the importance of sobriety in consumption and the need for collective action from individuals, businesses, and governments. The lecture also examines Switzerland's climate policy instruments, such as carbon taxes and incentives for energy efficiency. The impact of migration on emissions and the necessity of transitioning to renewable energy sources are addressed. The discussion includes the challenges posed by rebound effects in efficiency gains and the importance of comprehensive strategies to achieve emission reduction targets. The instructor concludes by stressing the need for a multifaceted approach to effectively combat climate change, integrating individual actions with broader systemic changes.