AMERISKA: Analysis of Multivariate Extremes and RISKs Assessment. An international research network on food and environmental risks assessment. The project AMERISKA aims at encouraging interactions of people of different backgrounds and from different countries to assess risks of different kinds. In particular, the project focuses on the assessment of risks in the contexts of food, hydrology and climatology which are major issues of concern for society. • Food risks assessments: The use of chemical products and the degradation of the natural environment are responsible for the presence of contaminants in food usually accumulated by human body. The degree of toxicity of the products and the consequences for human health require better stochastic modeling of the accumulation process. • Environmental risks assessments: modeling accurately the spatio-temporal structures of some atmospheric extreme variables like heavy rainfall, storms, still remains a statistical challenge. This is due to the complex multivariate structure within and between rare events. Inferring in space and time will be at the core of this environmental applications. To assess the aforementioned risks, a careful use of statistics is required. One major difficulty is that extremal events are often not well modeled due to the lack of observations. It is a major challenge for applied mathematicians to understand heavy tail phenomena observed. In particular, it appears that the importance of the events requires a global point of view, involving many researchers form different disciplines. It seems possible to use more information on extremal events because of the emergence of bigger mass of data. A major problem is to deal with the interaction (dependence) of extremes which necessarily leads to a multivariate context. Suitable mathematical tools have been developed only recently: multivariate regular variation processes are suitable new concepts for dealing with extremes and dependence in space and time. The literature on stochastic models for spatio-temporal extremal phenomena is still rather sparse. Statistical inference on these phenomena has just started and convincing applications are still missing. It is necessary to bundle the working forces of various researchers to face the challenges. AMERISKA will be a project where applied mathematicians concerns on issues of extremal risks will met; they will discuss the problems mentioned and and collaborate on their solution. One of the goals is the organization of a semester on risks that could be partly funded by Labex MME-DII. The research will be coordinated and led by 4 principal investigators: Olivier Wintenberger, Patrice Bertail, Philippe Naveau and Thomas Mikosch. They will manage a team of 8 experts from different countries, 12 french professors with strong experiments, 9 young french researchers and 2 PhD students, all working in the domain of quantitative risk analysis.