[en] This article summarises key messages from the report of Group II on Impacts, Vulnerability and Adaptation of the 6. IPCC. After reviewing the facts established by Group I on climate science and presenting the risks of climate change in the world and in Europe, it examines the solutions and concludes on the possibilities for removing the barriers to change

[en] Sea level varies globally and regionally, on a broad range of temporal scales, in response to climate change and variability, as well as to solid Earth's deformations caused by land ice melt.This article consists of an overview of the most up-to-date results about past and present sea level variations and associated contributions (land ice melt, ocean thermal expansion,land water storage changes). Following a 130 m rise during the last deglaciation, the mean sea level remained almost stable during the last few millennia, until the beginning of the industrial era. During the 20. century, the rate of sea level rise amounted 1.7 ± 0.3 mm/yr on average. Since the early 1990's, the global mean sea level rise has reached 3.2 ± 0.4 mm/yr, as observed by altimeter satellites, but with high regional variations in sea level trends. Over the 1993-2010 time period, the contributions to the global mean rise are from ocean warming (30 to 40%), land ice melt (about 50%) and land water storage change (10 to 15%). The observed regional variability mostly results from non-uniform ocean thermal expansion.We then present future changes in sea level, both in terms of global mean and regional variability, using information from the IPCC 5. Assessment Report published in 2013 for different global warming scenarios. Projections show that for the period 2081-2100 (relatively to 1986-2005), the global mean elevation may range from 40 to 63 cm depending upon the warming scenario, with an uncertainty of ±15 cm due to model imperfection.High regional variability will be superimposed on the global mean rise. In a final section,we briefly discuss expected coastal impacts of sea level rise over the next decades. (authors)

[en] This report treats of the link between climate change and sea level. It was written in complement to volume 4 of the Jouzel's mission report 'Regionalized scenarios. France's climate in the 21. Century' published in August 2014. It updates volume 3 of this report already devoted to the sea level issue and published in February 2012. It aims at taking stocks of the knowledge about past and future sea level changes at the world and French coast scales, and about the main physical impacts of sea level rise (marine submersion, coastal erosion, saline influx into coastal aquifers and impacts on coastal and harbour infrastructures). However, the socio-economic impact and related risks management are not approached. It is based on the IPCC expertise and on results of works carried out by the French scientific community

[en] The coastline of France faces a range of highly specific challenges, in terms of demographics, urbanisation, socio-economic activities and the environment. The attractiveness of coastlines, and the ever-growing trend for soil sealing, is making these territories increasingly vulnerable to the impacts of climate change. The main impacts of climate change are rising temperatures, changing rainfall and cyclone patterns, the acidification of water and rising sea levels - an impact that is addressed in detail in this work. Data gathered since the early 20. century reveal a significant trend, namely that sea levels rose substantially and quickly during the last century, at a rate five times faster than in previous millennia. In statistical terms, the average sea level rose by 1.7 ± 0.2 mm per year between 1901 and 2010, and by 3.2 ± 0.4 mm per year between 1993 in 2014. All current climate models predict that average global sea levels will rise at a rate faster than that observed between 1971 and 2010 during the 21. century. This means that, in addition to the 20 cm rise in sea levels observed in the last 150 years, the sea is expected to rise by a further 26 to 82 cm by the end of this century. The exact rise will depend on the success of efforts to reduce greenhouse gas emissions. Although the rise in average sea levels in the last 150 years may seem insignificant when compared with the height of waves and tides, the IPCC's summary report (2014) suggests that an average rise in sea levels of 0.5 m would, without suitable adaptation and protection measures, result in flooding occurring between 10 and 100 times more often. This report presents: 1 - The main impacts of climate change on the coastline 2 - Climate change and sea level: from the planet to the French coastline 3 - Adaptation - from crisis management to planning: 'Waves and flooding' warnings; Cost of coastal natural disasters and the insurance mechanism; Regulating territories exposed to coastal flooding risks; A national coastal erosion anticipation strategy; Experimental relocation of activities and property: towards spatial reconfiguration of territories threatened by coastal risks; Scientific knowledge, today and tomorrow; The LiCCo project and the perspectives of elected officials on both sides of the Channel