Fifth IPCC Assessment Report now out

The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) is now available. It provides policymakers with an assessment of information on climate change, its impacts and possible response options (adaptation and mitigation). Summaries for policymakers of three reports of IPCC working groups and of the Synthesis Report have now been approved by IPCC plenaries. This present paper reports on the most essential findings in AR5. It briefly informs on the contents of reports of all IPCC working groups. It discusses the physical science findings, therein observed changes (ubiquitous warming, shrinking cryosphere, sea level rise, changes in precipitation and extremes, and biogeochemical cycles). It deals with the drivers of climate change, progress in climate system understanding (evaluation of climate models, quantification of climate system responses), and projections for the future. It reviews impacts, adaptation and vulnerability, including observed changes, key risks, key reasons for concern, sectors and systems, and managing risks and building resilience. Finally, mitigation of climate change is discussed, including greenhouse gas emissions in the past, present and future, and mitigation in sectors. It is hoped that the present article will encourage the readership of this journal to dive into the AR5 report that provides a wealth of useful information.