Slow decarbonisation of buildings, construction sector raise concerns

A new UN report warns that rising construction and slow adoption of green building solutions are driving up global emissions and deepening climate risks.[ iStock]

Decarbonisation of buildings in the construction sector has slowed globally, making them a major source of emissions.

This has increased their vulnerability to climate impacts and energy price shocks, according to a new report from the UN Environment Programme (Unep) and the Global Alliance for Buildings and Construction (GlobalABC).

The tenth edition of the Global Status Report for Buildings and Construction (2025-2026) assessed the progress across the sector using seven key indicators covering policies, finance, technologies, and investment aligned with global commitments towards a 2050 net-zero emissions pathway.

The report, published amid a global housing and energy affordability crisis, highlights how climate action in buildings can reduce energy bills, improve living conditions, and strengthen resilience to climate impacts, while cutting greenhouse gas emissions.

“From homes and schools to hospitals and workplaces, buildings play a fundamental role in our lives,” said Inger Andersen, executive director of Unep, during the report release in Nairobi.

“Buildings can either lock in climate risks or deliver safer, healthier and more affordable living conditions. With half of the world’s buildings yet to be built or renovated by 2050, governments have a critical opportunity to drive zero-emission, resilient construction through better policies, codes and investment.”

Every day, the world builds an estimated 12.7 million square metres of floor area – roughly the equivalent of adding the entire city of Paris in new floor space nearly every week. In 2024, the global building floor area expanded by 1.7 per cent, reaching 273 billion square metres. This rapid growth was driven largely by construction in emerging economies, including India and Southeast Asia.

 The buildings and construction sector now accounts for nearly 50 per cent of global material extraction, 37 per cent of global emissions, and 28 per cent of global energy consumption. The sector accounts for 21 per cent to 42 per cent of global greenhouse gas emissions (operational and embodied emissions), making it the largest emitting sector globally.

The operated emissions account for 27 per cent of global emissions and is generated by heating, cooling, lighting, and powering buildings.

Embodied emissions account for 15 per cent of global emissions and are generated by the extraction, manufacturing, and transportation of building materials like steel, concrete, and aluminium, as well as the construction process itself.

According to the report, since 2015, the global building energy intensity – measuring a building’s annual energy consumption relative to its size – has reduced by 8.5 per cent.

Green building certifications have nearly tripled. In 2024, renewables supplied just 17.3 per cent of buildings’ energy demand. This is far below what is needed for a net‑zero pathway.

Investments in energy efficiency reached $275 billion (Sh36 trillion) in 2024, contributing a cumulative investment of $2.3 trillion (Sh298 trillion) since 2015. Since 2020, however, the report says progress has slowed because the green transition has not kept pace with construction.

To align the sector with a net-zero pathway, the report urges policymakers to accelerate energy efficiency improvements and the fossil fuel phase-out, and to ensure that investment in building energy efficiency reaches $5.9 trillion (Sh764 trillion) by 2030, equivalent to $592 billion (Sh77 trillion) annually.

The report highlights positive examples across regions, including the European Union, which deployed policies tackling operational emissions embodied emissions improvements in building energy performance in Japan and Switzerland, and growth in on-site renewables in buildings in Australia, Germany, India, and Pakistan.

Others are national climate action plans (NDCs) covering building sector strategies in the Bahamas, Cambodia and Colombia, updated building energy codes in California, Kenya, Japan and Singapore, expansion of green building certification in China, Colombia, India and Türkiye. UNEP and GlobalABC said they will continue working to strengthen data, improve methodologies and support national policymaking.

In February this year, Kenya took a significant step towards combating climate change by launching the Kenya National Buildings and Construction Decarbonisation Roadmap (2026–2040). The roadmap aims to address the environmental impact of the country’s growing housing needs while aligning with global climate goals.

With an annual housing deficit of 200,000 units, Kenya’s carbon emissions have risen dramatically from 3.9 million tonnes in 1972 to 22.4 million tonnes in 2021. The built environment alone costs the country an estimated $2.3 billion (Sh300 billion) annually due to climate-related damages.

The roadmap launched in Nairobi by Works Secretary, State Department for Public Works, Nicholas Mutua, on behalf of the Principal Secretary Joel Arumonyang aims to reduce building sector emissions by 67 per cent by 2040.

It aligns with Kenya’s updated NDC, which commits to a 30 per cent reduction in emissions by 2030 through affordable, sustainable and resilient housing.

It aims to turn global climate commitments into actionable local solutions, positioning Kenya as a leader in decarbonisation efforts across Africa.