2005, Hurricane Katrina: the flooding of New Orleans killed 18,000 people.2008, Hurricane Nargis: 150,000 people killed in the Irrawaddy Delta region, also because of flooding. While floods caused by extreme weather are occurring more and more often and are growing stronger, the rise of sea level is a phenomenon impacting all the coastlines across the world. Over the last decades, the sea level rose by 2 mm per year, which is 20 times faster than it did for the two past centuries. This rise has two explanations: the melting ice and the thermal expansion of water amplified by climate change. IPCC feared a sea-level rise of 98 cm by the end of the century but NASA just reported that a rise of 1meter by 2100 is now inevitable. Half of the world population currently lives at less than 200km from the coastline and one in ten people lives at less than 10 meters above sea-level. In France 24% of the coastline is now under the threat of erosion. A phenomenon with many consequences: soil salinization, contamination of drinking water, agricultural land loss, reduction in biodiversity. According to a study published in Nature Climate Change, floods alone could cost up to a trillion dollars every year. In addition to the efforts made to prevent the sea level from rising, it is now fundamental to implement adaptation policies. In Bangladesh, 40% of the lands could be flooded, Netherlands has to build new dikes and populations living on islands in the Pacific Ocean may have to flee. All countries will be impacted by this phenomenon but some more than others. Once again the most vulnerable countries are the one which will have to face the most severe consequences. This situation will have to be addressed by the international community at the next COP21 which will take place in Paris.