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This chapter builds on AR5, assessing new evidence on climate change impacts with a focus on risks associated with 1.5°C versus 2°C global warming. It emphasizes the increased impacts at the higher warming threshold and revisits major risk categories. Human-induced warming has led to increased temperatures, heatwaves, and precipitation events, with significant impacts on natural and human systems.

Global warming of 1.5°C leads to severe but less drastic impacts than 2°C, affecting ecosystems, weather extremes, sea levels, and human health. Overshooting 1.5°C poses long-term risks, emphasizing the need for urgent mitigation efforts. Sea level rise, ocean acidification, and impacts on marine and terrestrial ecosystems are projected to be less severe at 1.5°C. Land use changes are critical in mitigation pathways.

Human systems are at less risk at 1.5°C concerning food security, health, and economic growth. Coastal regions and small islands face compounded risks, with adaptation crucial to managing impacts. Changes in the risk levels since AR5 for "Reasons for Concern" show increased risks at lower temperatures, urging immediate action to limit warming.