Modelisation, Ville & Changement climatique

Consortium

Colette Marchadier — 2010-05-05T07:13:45Z

The aim of the project is to investigate an interdisciplinary problem. The research consortium needs, therefore, to include all the component of the problem. This is why it includes :

- The CIRED, which develops a urban-transportation model that will be used to create long-term scenarios for cities, and assess adaptation strategies.

This model is the only published model able to capture the effect of transitions from one city structure to another. Moreover, CIRED has a long experience of managing interdisciplinary projects with partners from natural and social sciences.

- The GAME laboratory, which will be involved through two different work groups.

The GAME, from Météo-France, which is developing a top-of-the-art model of urban weather and carried out several observation campaigns in urban areas (CAPITOUL in Toulouse, ESCOMPTE in Marseille), and the GMGEC team, which is developing a global climate model (ARPEGE-Climat) that will be used to assess the possible future evolution of heat wave risks.

- The CSTB, which will provide its competency on building characteristics, building engineering, present and future building design, construction, maintenance and exploitation conditions which are likely to change in order to adapt both the existing and the future built environment to a new climatic deal.

A specific attention will be taken concerning the consistency of adaptation measures as regard to green house gases emission mitigation.

Main tasks

Colette Marchadier — 2009-05-06T16:18:49Z

WORK BREAKDOWN STRUCTURE

In order to reach the above objectives, VURCA project will be split into 5 main tasks and few subtasks as summarized in the table below .

Task 0	Project coordination
Task 1	Improve the TEB urban climate model -1a Modelling the urban green space in TEB -1b The air conditioning module -1c The thermal index of human body
Task 2	Improving the NEDUM-1D urban development economic model
Task 3	Assessing city vulnerability to heat waves events -3a Simulating Paris urban climate for several synthetic heat waves -3b Building the urban heat wave seriousness indicator -3c Analyzing the path of the urban heat wave indicator in the future climate
Task 4	Defining city adaptation strategies -4a Building adaptation measures -4b Urban structure adaptation strategies -4c Economic and structural characteristics of the adaptation scenarios
Task 5	Evaluating the benefits from development and adaptation strategies -5a Simulating heat waves according to adaptation strategies -5b Defining an indicator for the city vulnerability to heat waves -5c Key insights and policy implications

WORKFLOW

VURCA WBS

Abstract

Colette Marchadier — 2009-05-06T15:34:15Z

To what extent are spatial planning policies that lead to alternative urban configurations effective in matching energy consumption scenarios for climate change adaptation? And what is the economic cost of effective spatial planning scenarios that involve the spatial re-adjustment of agents, activities, services and settlements?

– How to consider the specific interactions that exist between global and regional climate change, and urban climate at city-scale?

– How to translate in a relevant and physically-based way the impact of an altered climate on comfort and vulnerability of urban population?

– How to realistically assess the possible adaptation strategies by taking into account environmental benefits, costs, and socio-economic consequences? .

These questions are crucial as they address the issue of whether urban planning and spatial policies can lead to effective strategies in response to climate change. Modeling and analysis of climate change have been long dominated by aggregate approaches with a national and international perspective. This has gone along with a neglect of local spatial organization.

Our analysis aims to shed light on the potential contribution of the spatial dimension of an economy to local adaptation strategies to climate change and focuses its attention on a complementary local–urban scale of analysis which can inform the design of spatial planning and policy for adapting to climate change. The relevance of this is underlined by empirical evidence and data.

Cities bring together 50% of the world population, and this share exceeds 80% in developed countries. Such population concentration gives rise to social, economic, and environmental concerns. Among these, the issue of the specific micro-climate characterizing the urban areas is of particular interest in that the so-called Urban Heat Island (UHI) effect could create serious consequences on public health when it comes
to considering the overall temperature increase due to climate change. Particularly, the vulnerability of urban areas to an expected increase in the frequency and intensity of heat waves is what is raising the public and institutional concern and pushes them to search for solutions.

In this context, the Vulnérabilité URbaine aux épisodes Caniculaires et stratégies d'Adaptation (VURCA) project proposes an interdisciplinary approach where both environmental, technical and socio-economic aspects are considered, in order to provide first insights on the complex interaction between city economies and climate change and on the viability and effectiveness of identified adaptation options. From a methodological perspective, this is expected to be achieved by integrating in a unique investigation framework the outcomes from three
different analytical methods:

– a climate model,

– a urban-weather model

– and a coupled housing-transportation model.

The work program aims to develop the two indicators from such an integrated framework. The heat-wave seriousness indicator, which links large-scale
climate information to local seriousness of the event (defined from comfort index and energy consumption at city- and neighbourhood-scale).
climatique. La modélisation et l'analyse de ce dernier

The innovation is that this indicator will take into account the specifics of urban weather. Second, urban climate simulations will be performed
for a given heat wave – the 2003 event in Paris – and a large range of stylized cities based on simple socio-economic scenarios taking into
account population change, economic development, and various urban development strategies (including urban planning strategies to adapt
to climate change and to mitigate future emissions, e.g., compact city, city with parks, etc.

The second indicator, namely the heat-wave
urban-vulnerability indicator, that relates the characteristics of urban morphology to the vulnerability to a 2003-like event. Finally, the
economic costs of several adaptation strategies (e.g. influence on housing prices (including quality index) or transportation demand) and the
benefits (in terms of comfort and energy consumption) will be assessed to inform on the overall efficiency of these adaptation strategies.

We see the application mainly in the policy area, to support the view that the spatial planning is relevant not only in the mitigation strategies,
but also to adaptation measures in response to global warming

Objectives

Colette Marchadier — 2009-05-05T15:36:29Z

The project aims, first, at evaluating the level of urban structure vulnerability (in terms of comfort losses ) and energy demand sensitivity (in terms of air cooling). due to heat waves

The second objective is the evaluation of potential adaptation strategies efficiency in response to these vulnerabilities.

For both issues, we will develop a systemic analysis based on strong interdisciplinary exchanges between climatologists, experts of the urban climate, building experts, urban planners and economists. In the conventional approach developed to study socio-economic impacts of global change, social sciences are often considered as “end-of-pipe” disciplines, only supposed to interpret results from natural sciences from a social-science standpoint-of-view. This project, on the opposite, aims at making natural and social scientists work together on a common issue. This is to be done through:

– project rationales and objectives that have been developed from the beginning by an interdisciplinary team;

– the use of modelling frameworks as a “tool” that supports the communication across different disciplines.

Since the systemic approach will be develop through a core of models, an important effort will concern the improvement of our models in order to make them match together. For example, new modules will be implemented in actual urban-weather model TEB in order to be able to assess indoor and outdoor thermal comfort or evaluate how adaptation strategies are efficient (air conditioning, greening of urban areas). Nevertheless, it is important to mention that the project does not aim at being as innovative in each discipline as a specific project could be in a single discipline, but rather at investigating a complex problem by coupling the tools (possibly in a simplified version) of each discipline within a systemic framework.

In the end, the project will integrate the results of a climate model, an urban-weather model, and a coupled housing-transportation model, into a unique investigation framework. The work program is built as a systematic sensitivity analysis, according to three main stages:

– First, we will carry out urban climate simulation for a given city – Paris – under meteorological conditions of large-scale heat waves. A large range of heat wave events, varying in intensity and duration, will be tested in order to develop a heat-wave seriousness indicator, that links large-scale climate information to local seriousness of the event (defined from comfort indicators and energy consumption at city- and neighbourhood-scale). The innovation is that this indicator will take into account the specifics of urban weather.

– Second, we will carry out urban climate simulations for a given heat wave – the 2003 event in Paris – and a large range of idealized stylized cities based on simple socio-economic scenarios taking into account population change, economic development, and various urban development strategies (including urban planning strategies to adapt to climate change and to mitigate future emissions, e.g., compact city, city with parks, etc.). Other scenarios such as the sprawling of the residential areas at the rim of the idealized stylized cities will also be considered so as to take into account the inertia of the decision mechanisms and their potential impact on the vulnerability of the built environment. Scenarios on the expected quality of buildings will be introduced. This sensitivity study will make possible to determine a heat-wave urban-vulnerability indicator, that links the characteristics of urban morphology to the vulnerability to a 2003-like event.

– Finally, we will compare the economic costs of several adaptation strategies (e.g. influence on housing prices (including quality index) or transportation demand) and the benefits (in terms of comfort and energy consumption), to assess the overall efficiency of these adaptation strategies.