Summary for Policymakers: Global Warming of 1.5 °C

The Summary for Policymakers presents the key findings of the Special Report of the Intergovernmental Panel on Climate Change on the impact of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways. An assessment of confidence is also indicated as to each of the findings. According to the findings, human activities are estimated to have caused approximately 1.0 °C of global warming above pre-industrial levels, with a likely range of 0.8 °C to 1.2 °C. At the current rate, global warming is likely to reach 1.5 °C between 2030 and 2052. According to the report, impacts on biodiversity and ecosystems on land, including species loss and extinction, are projected to be lower with a global warming of 1.5°C compared to 2°C. Furthermore, the report projects that limiting global warming to 1.5°C compared to 2°C lowers the impacts on terrestrial, freshwater and coastal ecosystems to retain more of their services to humans. Likewise, limiting global warming to 1.5°C compared to 2°C is projected to lower the increases in ocean temperature and associated increases in ocean acidity and decreases in ocean oxygen levels. Consequently, limiting global warming to 1.5°C will likely reduce risks to marine biodiversity, fisheries and ecosystems, and their functions and services to humans, as illustrated by recent changes to Arctic sea ice and warm-water coral reef ecosystems. Moreover, climate-related risks to health, livelihoods, food security, water supply, human security and economic growth are projected to increase with global warming of 1.5°C and increase further at 2°C. Most adaptation needs will be lower for global warming of 1.5°C compared to 2.0°C.