 All those things are all together in the same issues of should we spend more energy on facing the end of the month or the end of the world. This is a difficult issue. How much should we do for the future? Okay, there are many people who believe that the future will be brighter today, that we will have more wealth, that we will produce more goods and services and therefore future generation will be better off than us. So when we decide to invest for those generations, in fact we increase intergenerational inequalities and that's one bad aspect of sacrificing the present for the future. We ask the poor, the current generation to sacrifice consumption for the benefits of people who potentially will be much wealthier than us and therefore that would be compatible with the common good only if the benefits of those investments are large enough for the future generation. The problem with this general way of thinking of economics comes from the fact that we make the assumption that we will be more prosperous in the future, that we live in a growing economy. It has been true for the last two centuries but it's not necessarily true for the future. So one of the big things I did in my research over the last few years is to examine the role of risk and uncertainty and so that's why in our society we penalize investment that generates benefits for the very distant future and in the real world we speak about discounting. We discount the future, we penalize the future just because it's a future and the problem is how by how much we should or we do discount the future is the critical question I'm examining in my research. One application of this technology is in terms of when we apply that to climate change. Climate change is we must, we are asked to make sacrifice in the short run because the energy transition will be costly for the benefits of reducing emission and the reduced emission will be mostly beneficial for the for future generation, generation who will live on this planet in in 50 years, one century or two centuries from now. The question is how much should we be ready to give up in terms of purchasing power today to reduce emission by one ton to simplify when you eliminate one ton of CO2 emission today you reduce damages by something like 1,000 or 2,000 euros in 50 or 100 years from now and so the question is what would be the energy transition efforts that we should be ready to give up to do in order to eliminate those future damages. This debate can be summarized into the price of carbon. Typically we think that should be something between 50 euros per ton of CO2 and 200 euros per ton of CO2. I believe it should be something like 160 euros. That's one way of translating your question which is do we do enough for the future into a number I mean a number like a discount rate or like a level of the price of carbon and so when I say 160 euros per ton of CO2 I mean we should do all efforts of reducing emission that cost us less than 160 euros. If we think that's not enough we should increase the price of carbon. All those things are all together in the same issues of should we spend more energy on facing the end of the month or the end of the world. When one difficulty with this whole issue is whether people will accept to make those sacrifices and whether the politician will be ready to bear the political cost of imposing those sacrifices to the population. Anyway this is the kind of thing I've been studying with colleagues here over the last five years with the assistance and financial support of the Agence Nationale de la Recherche which I thank for their support.