Uploaded April 2026 | Updated September 2026, 2 weeks ago
Concrete alone accounts for roughly 7-8% of global emissions.
That means the real climate story in buildings is no longer just about energy.
I’m joined by Alexander Sexsmith, architect and founder of Sexsmith Architects, to look at a part of climate tech and decarbonisation that still gets far too little attention: the materials we build with, the health risks we tolerate, and the resilience gaps we keep designing in. Alex works at the intersection of regenerative architecture, building performance, and climate adaptation, with a focus on what actually holds up under heat, fire, water, and real-world deployment.
Why does this matter now? Because as grids get cleaner, embodied carbon matters more. Because standard construction still fails badly when climate impacts hit. Because the next construction boom is happening in fast-growing regions where the choices made now will shape emissions, resilience, and public health for decades. And because net zero becomes a slogan very quickly if the building sector keeps treating concrete, petrochemical foams, and weak materials as business as usual.
What changed my thinking here was how many assumptions still go unchallenged. Concrete alone carries a staggering share of global emissions. Standard drywall is so fragile that if it gets wet, it often has to be torn out. Indoor air can be dramatically worse than outdoor air, even though we spend most of our lives inside. And some of the materials many people still dismiss as niche, like straw bale and hemp-lime systems, are already proving surprisingly strong fire performance and real potential at larger scale.
We also get into the harder truth: better materials do not scale just because they exist. Cost matters. Code matters. Skills matter. Supply chains matter. Insurance matters. Policy matters. If you care about the energy transition, emissions reduction, climate policy, or climate innovation, this is where the argument gets real.
No silver bullets here. No hand-waving. Just the messy question of how to cut emissions from buildings without locking in the next generation of climate and resilience problems.
This is for business leaders, policymakers, investors, architects, developers, and climate professionals trying to decarbonise the built environment in the real world.
If you’re working on this directly, I’d be interested in your perspective in the comments.
Links:
Climate Confident podcast: climateconfidentpodcast.com
Follow the podcast for more conversations on climate tech, decarbonisation, clean energy, climate policy, and deployment.
Chapters/Timestamps:
00:00 - Concrete’s hidden climate cost
00:21 - Why Arizona became a resilience lab
01:21 - From sustainable to regenerative buildings
04:34 - Why buildings are becoming a materials problem
07:16 - Concrete emissions and the scale challenge
09:18 - Climate, health, and the indoor air argument
11:26 - Can hemp, straw, and cork scale?
14:28 - Fire ratings, thermal mass, and real performance
17:33 - Cost, pilots, and why better materials stay niche
21:30 - Fire, water, insurance, and resilience
24:02 - From farm-to-table architecture to passive cooling
29:12 - Lightning round: retrofit, toxic foam, thermal mass
Concrete alone accounts for roughly 7-8% of global emissions.
That means the real climate story in buildings is no longer just about energy.
I’m joined by Alexander Sexsmith, architect and founder of Sexsmith Architects, to look at a part of climate tech and decarbonisation that still gets far too little attention: the materials we build with, the health risks we tolerate, and the resilience gaps we keep designing in. Alex works at the intersection of regenerative architecture, building performance, and climate adaptation, with a focus on what actually holds up under heat, fire, water, and real-world deployment.
Why does this matter now? Because as grids get cleaner, embodied carbon matters more. Because standard construction still fails badly when climate impacts hit. Because the next construction boom is happening in fast-growing regions where the choices made now will shape emissions, resilience, and public health for decades. And because net zero becomes a slogan very quickly if the building sector keeps treating concrete, petrochemical foams, and weak materials as business as usual.
What changed my thinking here was how many assumptions still go unchallenged. Concrete alone carries a staggering share of global emissions. Standard drywall is so fragile that if it gets wet, it often has to be torn out. Indoor air can be dramatically worse than outdoor air, even though we spend most of our lives inside. And some of the materials many people still dismiss as niche, like straw bale and hemp-lime systems, are already proving surprisingly strong fire performance and real potential at larger scale.
We also get into the harder truth: better materials do not scale just because they exist. Cost matters. Code matters. Skills matter. Supply chains matter. Insurance matters. Policy matters. If you care about the energy transition, emissions reduction, climate policy, or climate innovation, this is where the argument gets real.
No silver bullets here. No hand-waving. Just the messy question of how to cut emissions from buildings without locking in the next generation of climate and resilience problems.
This is for business leaders, policymakers, investors, architects, developers, and climate professionals trying to decarbonise the built environment in the real world.
If you’re working on this directly, I’d be interested in your perspective in the comments.
Links:
Climate Confident podcast: climateconfidentpodcast.com
Follow the podcast for more conversations on climate tech, decarbonisation, clean energy, climate policy, and deployment.
Chapters/Timestamps:
00:00 - Concrete’s hidden climate cost
00:21 - Why Arizona became a resilience lab
01:21 - From sustainable to regenerative buildings
04:34 - Why buildings are becoming a materials problem
07:16 - Concrete emissions and the scale challenge
09:18 - Climate, health, and the indoor air argument
11:26 - Can hemp, straw, and cork scale?
14:28 - Fire ratings, thermal mass, and real performance
17:33 - Cost, pilots, and why better materials stay niche
21:30 - Fire, water, insurance, and resilience
24:02 - From farm-to-table architecture to passive cooling
29:12 - Lightning round: retrofit, toxic foam, thermal mass
