April 15, 2024

Reducing Carbon Emissions, Increasing Adequate Housing: How the Buildings and Construction Sector Can do Both

Ariana Karamallis

Global Advocacy & Development Associate

Nearly 40 percent of global CO2 emissions result from the buildings and construction sector, and nearly 40 percent of the world’s population is living in substandard, unsafe housing. To keep up with demand, at least 96,000 new housing units would need to be built every day, but in order to meet global climate ambitions set out in the Paris Agreement, the sector would need to almost completely decarbonize by 2050.  Achieving these two goals – reducing carbon emissions, increasing adequate housing – will require new thinking, dialogue, and collaboration as well as new policies and financing.


Housing accounts for at least 17 percent of total global CO2 emissions, so the need to decarbonize the sector–while also meeting the staggering housing needs of almost 3 billion people living in inadequate housing worldwide–is urgent, and will continue to grow over the coming decades. That’s why at Build Change we believe that climate and disaster resilient housing should not merely be a part of the climate discourse–it should be at the forefront of it. 

Despite the statistics, there is good reason to be optimistic

To a great extent, the tools and experience to make resilient housing available to all in a way that benefits both people and the planet have already been proven in low-income and informal communities around the globe: things like incremental loans for home strengthening, improved construction materials and practices, and retrofitting existing homes.  

We illustrated the opportunity in Saving Embodied Carbon through Strengthening Existing Housing, a publication informed by 355 cases from six countries, that we released at COP 28.  This data shows that improving existing housing significantly avoids carbon emissions in the housing construction value chain, indicating substantial implications for achieving net zero in the built environment. In fact, strengthening existing housing presents an opportunity to save 4.8 gigatons of CO2 emissions compared to building new while making 268 million houses safe and resilient worldwide. Each retrofitted house contributes to an 18-metric-ton reduction in embodied carbon—equivalent to 18 flights from London to New York.

Not only is retrofitting existing housing better for the environment, it is also more affordable, roughly only 23 percent of the cost of new construction, and presents significant social benefits as well–especially when implemented using a homeowner-driven approach like ours. Retrofitting presents a path to financial resilience by saving governments and low-income communities millions in costs and safeguarding homes—often a family’s most valuable asset. It is an adaptation and mitigation solution that builds the resilience of entire communities, empowering families to adapt to the changing climate while reducing overall carbon emissions. And by retrofitting homes preventatively—before disaster strikes—we can get ahead of the next disaster and save millions of lives and assets. 

Policy and finance: driving from global agendas to local impact 

If we are serious about achieving net zero emissions in the buildings and construction sector, we must focus tremendous global effort on creating policy, financing, and technology solutions that reach the billions living in self-built, informal homes and include increasing access to resilient housing as a key mitigation and adaptation priority. We are looking forward to working with UN Habitat, who co-hosted this event, and other stakeholders to take forward the Housing for All resolution, adopted at the 2023 UN Habitat Assembly, to push these key issues forward.

The key outcome of the UN Environmental Program’s first Buildings & Climate Global Forum, which Build Change joined, is the Declaration de Chaillot. Adopted by 70 member states, it is a foundational document for international cooperation in the built environment sector. While the focus remains largely on mitigation efforts, the Declaration mentions housing throughout–noting the increasingly critical global housing shortage, particularly for adequate, sustainable, and affordable housing; the growth of informal settlements; and the resulting increasing exposure of those most vulnerable to risks and deepened vulnerability. It also encourages international actors to “specifically address…the sustainable construction needs, mitigation potential and adaptation needs of the real estate, housing, and building sector.” It is also heartening to see the Declaration note that solutions to housing challenges must be context-specific, energy-efficient, climate-adaptive and resilient. It is not either/or but rather both/and, with policies to adapt existing housing a key piece of the puzzle. 

As always, there are big picture items required to take these recommendations forward. Build Change is thrilled to support the Buildings Breakthrough Agenda as a key mechanism to strengthen international collaboration to decarbonize the building sector. But we recognize the tremendous political will required to channel both public- and private-sector financing towards effective adaptation and mitigation measures. We are calling on ministers and government leaders from rapidly growing countries of the Global South to heed the call to invest more in disaster-resilient housing policies and programs, while urging signatories from the Global North to channel foreign aid toward resilient housing and to enact policy frameworks that mainstream to production of safe, resilient, sustainable construction materials to be incorporated across the value chain. 

In these events and discussions, it can be so easy to forget what it really means for the billions of people living without a safe foundation beneath their feet or roof over their heads. The needs of those most vulnerable to climate change must be at the center of every finance mechanism we create, every policy decision our governments take, and every new technology we develop. We need to continually raise the call for climate and disaster-resilient housing, using momentum of these events to ensure that the right to safe, resilient, adequate housing is made a central item of the post-2030 global development agenda. 

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