Changement climatique

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Из курса от партнера École Polytechnique Fédérale de Lausanne

Villes africaines I: Introduction à la planification urbaine

34 оценки

École Polytechnique Fédérale de Lausanne

Villes africaines I: Introduction à la planification urbaine

34 оценки

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.

Из урока

Le futur des villes ou comment planifier

Faire face au défi climatique qui change nos manières de faire la ville.

Agriculture urbaine6:17

Changement climatique5:52

Познакомьтесь с преподавателями

Jérôme Chenal
Dr
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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