Le cours permet d'apprendre les bases de la planification urbaine à travers ses dimensions techniques, environnementales, sociales, économiques et symboliques. Le cours parle uniquement des villes africaines et même si celles-ci ont valeurs d'exemple pour les ville du Sud, voire toutes les villes, nous nous efforçons à remettre les problématiques dans un contexte africain.
Changement climatique
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Из курса от партнера École Polytechnique Fédérale de Lausanne
Villes africaines I: Introduction à la planification urbaine
32 оценки
École Polytechnique Fédérale de Lausanne
32 оценки
Из урока
Le futur des villes ou comment planifier
Faire face au défi climatique qui change nos manières de faire la ville.
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Jérôme ChenalDr
Faculté de l'Environnement Naturel, Architectural et Construit - ENAC
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.
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