This lecture covers the challenges and potential solutions for mitigating CO2 emissions, focusing on energy supply, economics, and transition. It discusses the world population growth projections, energy use per person, primary energy consumption, CO2 capture and storage methods, cost of direct carbon sequestration, and the impact of agriculture and meat production on GHG emissions. The lecture also explores the role of renewable energies, net zero energy buildings, the use of wood as a building material, and the potential of a vegan diet in reducing environmental impact.