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emissions reductions substantially reduce the probability of extreme seasonal temperatures in many regions in less than 20 years, implying that early mitigation action benefits societies, with climate damages reduced in the nearer future as well as the longer term. These are some examples of scientific findings to be assessed systematically by the IPCC’s special report on Global Warming of 1.5ºC. We will report its conclusions in September next year, just in time for the Facilitative Dialogue in 2018. The context of this special report will be strengthening the global response to the threat of climate change, sustainable development and efforts to eradicate poverty. We will examine linkages between achieving the SDGs and 1.5ºC warming in order to identify scientific underpinnings for climate-resilient development pathways. In so doing we will identify technological, environmental, socioeconomic and institutional opportunities and challenges related to 1.5ºC pathways. This includes among others: issues related to negative emission technologies, adaptation potential and limits to adaptive capacity, and potential overshoot. Our aim is to distil robust understanding on avoided impacts and reduced risks, and mitigation pathways at 1.5ºC compared with 2ºC. In addition to the special report on 1.5ºC, we are planning to provide you with two other special reports in two years’ time. Governments have asked us to look in particular at climate change questions around oceans and around land. First, the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. This has direct relations to SDG 14 – life below water, SDG 2 – food security, and SDG 11 – human settlements. Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90 per cent of the energy accumulated in the last 40 years. Oceans are continuing to warm, acidify and lose oxygen. This special report will assess the rapid changes in marine habitats, new knowledge related to sea-level risks and options for increasing coastal resilience in both human and natural systems. Our third special report is on climate change and land use. This has direct implications for SDG 15 – life on land. Climate change and land use are closely linked. This report will assess land-climate interactions, desertification, land degradation, and food security. We will analyze interlinkages between these four factors from the perspective of synergies, trade-offs and integrated response options. Of particular interest will be how the deployment of bioenergy relates to land use and food security – one of the few areas where there may seem to be a conflict between mitigating climate change and sustainable development. Science can offer policymakers valuable insights and understanding here. In 2021 we will deliver the outcomes of the main assessment, starting with the physical science base (Working Group I), then mitigation of climate change (Working Group III), and lastly impacts, adaptation and vulnerability (Working Group II). In 2022, the Synthesis Report will be completed, in good time for the Paris Agreement’s first global stocktake the following year. The overall thrust of the main assessment will consist of five elements:„„Scientific information relevant for the global stocktake (which will check progress towards achieving the aim of the Paris Agreement and its long-term goal). „„Presenting an integrated picture of emissions, climate, risks and development pathways. „„Enhancing the understanding of costs and benefits of mitigation and adaptation in the context of development pathways.„„Providing comprehensive understanding of adaptation and mitigation actions in the context of sustainable development. „„And last, providing scientific evidence for finance and means of support to strengthen the response and pursue climate resilient pathways. The result will be a solution-oriented integrated analysis linking climate futures and socioeconomic development pathways. We will close the loop between climate change, its impacts, adaptation and mitigation, and socioeconomic development. The result will be science for climate policy in the broader context of sustainable development. The result will be science for understanding the close link between decision-making in the short term and the consequences lasting through the long term. Actions today to overcome business as usual have positive impact on economic development and climate futures. ■ABOUT THE AUTHORDr Hoesung Lee is Chair of the Intergovernmental Panel on Climate Change (IPCC), elected in October 2015, and Endowed Chair Professor at the Korea University Graduate School of Energy and Environment, Seoul, Korea. His research encompasses the economics of climate change, energy and sustainable development. He is a member of the Board of Directors of the Korean Academy of Environmental Sciences, council member of the Global Green Growth Institute, and a member of the Asian Development Bank President’s Advisory Board on Climate Change and Sustainable Development. Pictured: Dr Hoesung LeeThis is an edited version of Dr Hoesung Lee’s address at the Opening Session of the 46th Plenary of the IPCC on 6 September 2017 in Montreal, Canada. For more information on IPCC’s work visit: http://www.ipcc.ch.CLIMATE SCIENCE 053