In our video, we'll take another look at climate change. Another look, since we have already mentioned this issue. We'll talk about how this issue can be planned. We'll take a certain number of items that we have mentioned previously. Climate change summons up two words: adapting and mitigating. Either we adapt to the changes: the higher the sea level, the more we'll factor it in in our buildings. Or we mitigate, which means we'll fight against the effects of climate change. So, either I adapt to rising sea levels, or I prevent sea levels from rising more. Then, from the perspective of populations, there is a capacity for people to adapt, but also from the perspective of governments there are financial, social capacities to adapt to climate change. At the other end of the spectrum is vulnerability, being unable to adapt. These are the four elements to keep in mind when discussing climate change and urban planning. What are the effects? Let's take an example: there are the effect itself, the problem it poses, and the the measures at our disposal in terms of urban planning. Example: rising temperatures. The problem are the heat spots, everywhere in the city. the measures to be considered are planting trees, the shaping of public spaces, air currents in the streets, parks. Another example: the rising number of insects as a result of rising temperatures. These are issues that are not well-known yet but that will be more widespread. What is there to do? We can fight against insects, with chemicals, but there is also the option to drain certain wetlands. Mitigating the effect of the change, in terms of urban planning, means to make some important decisions. We mentioned compact cities that are less energy-consuming than spread-out cities, with all the caveats I mentioned and the several other factors that need to be monitored, but let's say that compact cities would produce less green house gas and, as a result, urban planning is a way to mitigate. On the other side, the problem of heat spots is a direct consequence of the effect of climate change. There is not much to be done apart from adapting with a series of measures in terms of urban planning. Let's take an example of adaptation: I'm going to draw three coastlines. The water is here, and we have three options. If my house is right here, I can move it, or ban construction on this land, thus saying: for now on, future houses will be built there and we'll take this out. I can also decide that future houses will be above ground, on stilts, so that in case of floods the water will be at stilt level. Third option: there is a house here and I build a dyke so that if the sea level rises, I won't face the consequential floods. So, three examples of possible adaptations. I don't want to pass judgments, yet some are more expensive than others and some are more sustainable than others. For the millions or billions of people living along the coast, throughout the world, at risk of rising sea levels and who are very vulnerable indeed, we need to start thinking about solutions. In a previous video, we talked about the relation between abundant tropical rains leading generally to a spread-out city pattern, whereas, when in the heart of Sahel, we'll rather find compact city patterns. That brings us again to compact versus spread-out. Then comes this dual judgment call we are faced with between urban patterns and between adaptation and mitigation. Will I choose to adapt my situation to the problem ? If so, to what extent can my populations adapt and how vulnerable are they ? If I choose not to adapt but to fight against the effects, what are the elements I implement to truly work against these effects and substantially reduce the effects of climate change in the coming years ? Today we have these dual questions. There is, probably, a dual constraint, too. In other words, it's either working on adaptation or working on mitigation, because the effects or demands to work in one direction or the other are often two totally opposite directions. There will be choices to make over the coming years, drastically so. We should bear in mind all the different elements that we have mentioned in previous videos, with the competing needs for a transportation system, for urban agriculture, for climate change issues, for housing, for infrastructure, all of which requires choices based on needs but also on what we want to develop in terms of city pattern. The final decision on the pattern is yours to make, of course. What we're doing here is showing the mechanisms and means of action that can be used, or not used, in order to change the situation of cities today.
