The United Nations plans to decarbonize the polluting construction industry.

idly mushrooming urban environments pose a serious challenge to coping with climate change and the destruction of life-sustaining ecosystems. The construction sector, the most polluting and most difficult to reduce carbon emissions, must reduce the number of buildings, use more sustainable materials and clean up traditional materials to lower carbon emissions,

the United Nations said on Tuesday. The industry is responsible for 37% of global carbon dioxide emissions, and the growth of urbanization is driving the use of carbon-heavy materials, especially concrete and steel, in new buildings. Rap

idly mushrooming urban environments, where a building the size of Paris is added every five days, destroy life-sustaining ecosystems and pose a serious challenge to combating climate change. A report released Tuesday by the United Nations Environment Programme (UNEP) and the Yale Center for Ecology and Architecture calls on the industry to prioritize "circular" approaches that avoid waste. Sheila Agarwal-Khan, director of UNEP's

industry and economy department, said it was feasible to achieve net zero emissions in the construction sector by 2050 if "the government puts in place the right policies, incentives and regulations to drive a shift in industry action.". Building less and reusing existing buildings produces 50-75% fewer emissions than new construction,

the report said. Switching to renewable bio-based materials, such as wood and biomass, could achieve up to a 40% reduction in emissions in some regions by 2050, the report added. Traditional materials that cannot be replaced (concrete, steel, aluminum, glass, and brick) must be further decarbonized,

the report States. Efforts to clean up these carbon-intensive materials can be accelerated

by electrifying production, scaling up innovative technologies, and using more recycled materials. Concrete, aluminium and steel alone account for 23% of total global emissions.

The report suggests that in order to effectively decarbonize the sector, the global construction industry should reduce the share of concrete used by half between 2020 and 2060. Two-thirds of this should be "recycled" concrete , that is, concrete that is recycled, reused, or made with low-carbon cement. The rest is new low-emission cement. One of the

report's co-authors, Anna Dyson, a professor at the Yale School of Architecture in the United States, said the industry needed a "revolution" that included a "dramatic reduction" in new concrete production. "But it will be a gradual process," she told AFP. Steel and concrete "often just give the illusion of permanence" and often end up in landfills and contribute to the growing climate crisis, said Sheila Agarwal-Khan, director of UNEP's

industry and economics department.

Until the middle of the 20th century, building materials were often obtained locally and from renewable or organic sources, such as stone and wood. Mr Dyson said buildings were designed for climate conditions and until recent decades had mainly used "extractive, toxic and non-renewable methods" to obtain materials.

The construction industry must work with the forest and agriculture sectors to manage wood and biomass resources and materials needed for future cities, she added. Dyson also said that biomass on walls or roofs could be an important low-carbon material for future cities. Naomi Keener, one of the co-authors at McGill University in

Canada, said there was no "magic bullet" to decarbonize the industry and that "new materials" and "transformation processes" needed to be added.

The report brings together contributions from researchers and architects from around the world and will be presented next week at a conference of climate ministers and business leaders in New York.

According to UN sources, the report will also play an important role at the Paris International Conference in March 2024, which will bring together government ministers responsible for building and climate.

The source added that some countries are likely to make "breakthrough" commitments at the UN climate talks in Dubai starting in November, as they did in 2021 in areas such as transport, energy, steel, agriculture and hydrogen.