El plan de la ONU promete recortes masivos de emisiones en el sector de la construcción, el más contaminante y el más difícil de descarbonizar

Nairobi, 12 de septiembre de 2023 – Rapid urbanisation worldwide means every five days, the world adds buildings equivalent to the size of Paris, with the entorno construido sector already responsible for 37 per cent of global emissions. A report published today by the UN Environment Programme (UNEP) and the Yale Center for Ecosystems + Architecture (Yale CEA), under the Global Alliance for Buildings and Construction (GlobalABC), offers solutions to decarbonize the buildings and construction sector and reduce the waste it generates.

El informe, Materiales de construcción y clima: construyendo un nuevo futuro, offers policy makers, manufacturers, architects, developers, engineers, builders and recyclers a three-pronged solution to reduce “embodied carbon” emissions and the negative impacts on natural ecosystems from the production and deployment of building materials (e.g., cement, steel, aluminium, timber, biomass):

• Evitando waste through a circular approach: building less by repurposing existing buildings is the most valuable option, generating 50-75 per cent fewer emissions than new construction; promote construction with less materials and with materials that have a lower carbon footprint and facilitate reuse or recycle.
• Shift a materiales de construcción de origen biológico renovables de origen ético y sostenible, incluida la madera, el bambú y la biomasa. El cambio hacia materiales de base biológica gestionados adecuadamente podría conducir a un ahorro de emisiones compuesto en muchas regiones de hasta el 40 por ciento en el sector para 2050. Sin embargo, se necesita más apoyo político y financiero para garantizar la adopción generalizada de la construcción de base biológica renovable. materiales.
• Mejorar Descarbonización de los materiales convencionales que no se pueden sustituir. Esto afecta principalmente al procesamiento de hormigón, acero y aluminio (tres sectores responsables del 23% de las emisiones globales en la actualidad), así como al vidrio y los ladrillos. Se debe dar prioridad a la electrificación de la producción con energía renovable sources, increasing the use of reused and recycled materials, and scaling innovative technologies. Transformation of regional markets and building cultures is critical through building codes, certification, labelling, and the education of architects, engineers, and builders on circular practices.

El triple Evitar-cambiar-mejorar solution needs to be adopted throughout the building process to ensure emissions are slashed and human health and biodiverse ecosystems are protected. The solution also requires, in its implementation, sensitivity to local cultures and climates, including the common perception of concrete and steel as modern materials of choice.

“Until recently, most buildings were constructed using locally sourced earth, stone, timber, and bamboo. Yet modern materials such as concrete and steel often give only the illusion of durability, usually ending up in landfills and contributing to the growing climate crisis,” said Sheila Aggarwal-Khan, Director of UNEP’s Industry and Economy Division.

“El cero neto en el sector de la edificación y la construcción se puede lograr para 2050, siempre y cuando los gobiernos establezcan las políticas, los incentivos y la regulación adecuados para lograr un cambio en la acción de la industria”, añadió.

To date, most climate action in the building sector has been dedicated to effectively reducing “operational carbon” emissions, which encompass heating, cooling, and lighting. Thanks to the growing worldwide decarbonisation of the electrical grid and the use renewable energies, these are set to decrease from 75 per cent to 50 per cent of the sector in coming decades.

Dado que los edificios contienen materiales producidos en regiones dispares de todo el mundo, reducir las emisiones de “carbono incorporado” provenientes de la producción y el uso de materiales de construcción requiere que los tomadores de decisiones adopten un enfoque de ciclo de vida completo. Esto implica medidas armonizadas en múltiples sectores y en cada etapa del ciclo de vida del edificio: desde la extracción hasta el procesamiento, la instalación, el uso y la demolición.

También se requiere regulación y aplicación gubernamental across all phases of the building life cycle – from extraction through end-of-use – to ensure transparency in labelling, effective international building codes, and certification schemes. Investments in research and development of nascent technologies, as well as training of stakeholders in the sectors, are needed, along with incentives for cooperative ownership models between producers, builders, owners, and occupants to the shift to circular economies.

“The decarbonisation of the buildings and construction sector is essential for the achievement of the goal of limiting global warming to 1.5°C. By providing cutting-edge scientific insights as well as very practical recommendations to reduce embodied carbon, the study ”Building materials and the climate: Constructing a new future” advances our joint mission to decarbonise the sector holistically and increase its resilience”, said Dr. Vera Rodenhoff, Deputy Director General for International Climate Action and International Energy Transition of the German Federal Ministry for Economic Affairs and Climate Action (BMWK), which together with the German Federal Ministry for Economic Cooperation and Development (BMZ) has funded the study.

Case studies from Canada, Finland, Ghana, Guatemala, India, Peru, and Senegal, demonstrate how decarbonisation takes places using “Avoid-Shift-Improve” strategies: developed economies can devote resources to renovating existing ageing buildings, while emerging ones can leapfrog carbon-intensive building methods to alternative low-carbon building materials.

Cities worldwide can drive the implementation of decarbonisation. Many are already integrating vegetated surfaces, including green roofs, façades, and indoor wall assemblies to reduce urban carbon emissions and cool off buildings, increase urban entre otros.

NOTA A LOS REDACTORES

Acerca del Programa de las Naciones Unidas para el Medio Ambiente (PNUMA)

PNUMA es la voz líder mundial en materia de medio ambiente. Proporciona liderazgo y fomenta la colaboración en el cuidado del medio ambiente inspirando, informando y permitiendo a las naciones y los pueblos mejorar su calidad de vida sin comprometer la de las generaciones futuras. 

Acerca de la Alianza Global para la Edificación y la Construcción (GlobalABC)

Fundada en la COP21, organizada por el PNUMA y con 289 miembros, incluidos 40 países, la ABC global es la plataforma global líder para todas las partes interesadas en la construcción comprometidas con una visión común: un sector de la construcción y edificios eficiente, resiliente y sin emisiones.

Acerca del Centro de Ecosistemas + Arquitectura de Yale (Yale CEA)

Yale CEA unites researchers and practitioners across multiple fields, synthesising innovations in science, art and humanities towards ecosystems that prioritise the requirements of living organisms and ecologies. Our mission is to transform the DNA of the Built Environment, which is currently the sector responsible for the largest real-time climate change impacts and the consumption/production of toxic, non-renewable resources.