Achieving the Paris Agreement goals of keeping the increase in global temperature well below 2°C, pursuing efforts to limit it to 1.5°C, requires rapid reductions in greenhouse gas emissions. This effort is directly This contrasts with the continued growth of the global population, which is expected to reach 9.7 billion by 2050. Most of this growth is concentrated in cities, which puts high pressure on the need for additional housing and infrastructure.

New analysis has shown that the global carbon footprint of the construction sector has increased over the past three decades has doubled and is projected to more than double by 2050The built environment embodies significant emissions, which is a significant obstacle to meeting climate goals.

Dominance of materials in the emission profile

The construction industry is widely considered one of the hardest sectors to decarbonize. In 2022, the sector was responsible for 33 % global carbon footprintOver three decades (1995-2022), the construction sector's share of total emissions increased from 20 % to 33 %. This growth is primarily driven by material-related inputs.

In 2022, more than half of the sector's emissions came from cementitious materials, bricks and metals. Cement itself is the main contributor, accounting for more than a quarter (28 %) of the total carbon footprint of construction. Cement, clinker, bricks and clay together contribute 40 %. Metals (mainly steel) add another 15 %. The total contribution of these five categories (considered unsustainable construction materials) has increased from 39 % in 1995 to 57 % in 2022.

The remaining emissions came from transport, services, machinery and construction site activities (37 %), while glass, plastics, chemicals and bio-materials contributed approximately 6 %.

The impending depletion of the carbon budget

If current trends continue within the scenario business-as-usual (SSP2), cumulative emissions from the construction sector will reach 440 Gt CO₂ between 2023 and 2050. The analysis highlights that the carbon footprint of construction alone exceed the annual carbon budget for the 1.5°C and 2°C targets over the next two decades.

The cumulative emissions estimate shows that the construction industry will exhaust the entire remaining carbon budget with an 83% probability of limiting warming to 1.5°C by 2030Even in a scenario where emissions from all other sectors were reduced to zero, construction activity alone would be enough to consume all remaining 1.5°C budgets by 2050.

Regarding the 2°C target, the sector will exceed the annual carbon budget between 2040 and 2045 (with an 83% probability).

Regional differences and the need for revolution

The structure of the global contribution has changed dramatically over the past three decades. While in 1995 50 % of the global carbon footprint came from high-income countries (e.g. the US and the EU), in 2022 emerging economies dominateChina alone accounted for 49.% of the global footprint in 2022, while India was second. China's contributions to the carbon footprint increased about sixfold between 1995 and 2022.

It is important to note that different regions show unique footprint patterns. For example, India, Africa and the Middle East are the regions where the carbon footprint of the building sector is projected to grow the fastest in the future. In contrast, projections for the EU, North America and China assume stagnation or decline (in the case of China due to population decline). These differences suggest that policy "One size fits all" is not effective and decarbonization strategies must be tailored to unique regional needs.

Structural transformation is urgently needed to reverse this trajectory. Authors advocate a material revolution, such as replacing traditional materials with bio-based products that exploit economies of scale and pave the way for a sustainable future in construction. Part of the solution is investing in infrastructure for bio-materials and updating building codes to recognize the safety and durability of these low-emission alternatives. Inaction will not only accelerate global warming, but also undermine efforts for a sustainable future. JRi

The study was published in the journal Nature