 the number of people who are displaced annually because of disasters, that means the number of people who are brutally displaced, but we don't know all along there are displaced, we don't know whether they return or not, and perhaps most importantly, we don't know how many people are displaced by slow onset events, such as the certification or sea level rise, so the short answer is, we don't know, which opens the door wide open to speculations, to inflated numbers, and also to many uncertainties. People that are moving in the context of, let's say, environmental change, people that are migrating due to environmental degradation, we need to know what are their needs, there will be different needs of different people, you can think of people that are older, people that are disabled, so we need to know who's moving, and we probably also need to know what kind of capacities, what are their vulnerabilities, and the protection needs. So once we need to know why people are moving and where they are, and what are their plans for future movement. The number of people who are displaced and will be displaced in the future depend a lot on our policies, on climate policies, to what extent are we gonna reduce or greenhouse gas emissions, adaptation policies, of course, and also migration policies, are we going to encourage people to move, or are we gonna try and keep them in the same place? We can figure out the number of people at risk because of the impacts of climate change, but it's much more difficult to figure out the number of people who will actually decide to move in relation to these impacts, and then also there is an issue with regard to data collection. Most of these movements are internal movements, and typically they are not recorded in statistical apparatuses. But very often we see that responders or governments do not collect data on displacement in disaster situation, and that's a challenge both for the immediate response to the needs of these people, but also when public policy needs to look into solution to the displacement situation. Movement or migration can also present challenging for public planning, let's say, urban planning, urban settlement planning, health services, school services. So public policy and decision-making also need data, trying to understand what are the dynamics of people moving in the context of environmental change and migration. We've made a lot of headway over the last few years in that regard, and we've developed new methods like, for example, agent-based modeling, which holds a lot of promises. We've also used new types of data, for example, data provided by mobile phone, which also holds a lot of promises. The challenge is now to put these new methods together and see how we can aggregate them in a kind of meta-analysis that could give us more indications about the number of people who are displaced now and the number of people who will be displaced tomorrow. It will always be difficult to provide a global figure, and probably it is more interesting to provide local or national figure that can actually inform local and national policies.