UN Reports Buildings Sector Emissions Are Slowing - But Not Fast Enough

Last week the United Nations Environment Programme (UNEP) and the Global Alliance for Buildings & Construction (GlobalABC) released their latest Global Status Report for Buildings and Construction 2024-2025, providing critical insights into the sector's progress in curbing emissions globally. While one encouraging takeaway was that overall emissions from the sector appear to have stalled for the first time since 2020, the report made one thing abundantly clear – we need to do much more, and faster.

Latest figures indicate that buildings still consume a staggering 32% of global energy and contribute 34% of global CO₂ emissions, with operational emissions alone reaching a record 9.8 gigatonnes in 2023. And while gradual improvements are a promising indicator that efforts being made to decarbonise the sector are beginning to yield results, the scale of action is nowhere near on the level required to achieve the targets outlined by the Paris Agreement. This is particularly concerning, given we have already exceeded the 1.5 °C temperature limit for more than a calendar year.

Key findings from the report show that:

• Energy intensity from buildings has declined by 9.5% since 2015, but remains far from the targeted 18.2%.
• Total CO₂ emissions from building operations actually rose by 5.4%, significantly lagging behind the 28.1% reduction target.
• Renewable energy's share in final energy demand rose by 4.5 percentage points, below the 17.8 percentage point goal.
• Cumulative energy efficiency investments grew, but a $1.1 trillion gap still remains.

These are worrying shortfalls which will make the ultimate goal of decarbonising by 2050 significantly more difficult to achieve. The longer we lag behind, the more ambitious these targets will need to become year on year. Add to this the increasing global risk of buildings being destructed by extreme climate events, such as wild fires, hurricanes and floods, or war, then we could potentially be facing an even greater emissions challenge in order to rebuild and repair the damage caused by these events.

Bold action is clearly required to address these shortfalls and close the emissions gap. The report calls for greater ambition across six key areas, namely:

• Building Codes
  Including recommendations that major carbon-emitting countries adopt mandatory zero-carbon building energy codes by 2028; countries with existing codes make zero carbon ready standards mandatory by 2030; and those without codes should establish a pathway to mandatory adoption by 2035.
• Retrofit
  The rate of building energy efficiency retrofits should be tripled by 2030 to achieve a 35% reduction in energy intensity.  (Of course, efforts to monitor the performance of these retrofits once the building is in use must also be prioritised, to prevent operational drift and performance reductions over time).
• Renewable energy adoption
  Should be scaled up to reflect global goal of tripling renewable energy in buildings. 
• Nationally Determined Contributions (NDC) integration
  Major emitters should include detailed building code reform plans in their NDC submissions.
• Embodied carbon
  Embodied carbon limits should be adopted in building codes by 2030, with clear guidance on reporting.
• Finance
  Global building energy efficiency investments need to double from $270 billion to $522 billion by 2030.

We need to start acting on each of these challenges now, as delay will only compound the problem for future generations. Ensuring that there are adequate policies and financing in place to enact these changes, will undoubtedly be a key factor.

Of course, it is vital that efforts to accelerate progress in these areas is supported by reliable, data-driven insights. Buildings are complex entities and there are a multitude of factors to consider to ensure that the right strategies are implemented to deliver the optimum outcomes across a range of factors encompassing energy use, carbon emissions, costs and occupant needs.

Stabilising emissions, while significant, is only just the first step. The built environment must move swiftly from maintaining current levels to driving down emissions across a rapidly expanding global footprint. The technologies to support this shift already exist, but to succeed they need to be backed by adequate policies, upskilling and investment to ensure they are utilised to their full potential.

Advanced building performance simulation tools, such as ours, can replicate real-world building conditions to test the outcome of multiple scenarios, from early-stage design or retrofit decisions through to operational energy reduction and optimisation strategies. Such insights enable AEC professionals, building owners, operators and policymakers alike to prioritise interventions, direct investments wisely, and track measurable outcomes to help deliver the scale of change that is required.

Through the many projects delivered by our software users around the world and our consulting teams over the past three decades, we know that significant energy and carbon savings can readily be achieved. We are committed to continuing to playing our part by delivering the software tools our sector needs to build on and accelerate progress on a much wider scale.

IES has proven its capability of incorporating many global building codes and regulations into our software, and are well placed to support the recommendations of this report to increase the adoption zero carbon ready building standards. We will continue to develop our capability in support of the most credible building codes available, leveraging our vast international experience in this arena to help countries around the world implement these codes much more quickly and effectively.

This report should serve as a pivotal call to action - one that galvanises further commitment to innovative solutions on the path to zero carbon buildings. By working collaboratively, adopting the right tools and policies, and championing a whole building lifecycle approach to decarbonisation, let’s make it our duty to ensure that the next status report presents a far more positive outlook for our sector, and the future of our planet.