Uploaded August 2026 | Updated September 2026, 2 weeks ago
Up to 98% of one major contractor’s emissions sit in its supply chain.That makes construction decarbonisation a procurement and materials problem as much as an energy problem.
My guest is Keith O’Flynn, Group Supply Chain Sustainability Manager at John Sisk & Son, one of Ireland’s largest construction contractors. Keith works directly on the difficult part of corporate emissions reduction: Scope 3, where companies depend on suppliers, materials, standards and credible carbon data to turn targets into physical change.
Construction operates on notoriously thin margins, while clients are demanding lower-carbon projects and companies are working towards increasingly ambitious emissions targets. The tension is obvious. Concrete and steel remain deeply carbon-intensive, cleaner alternatives are not always available at scale, and even when lower-carbon products work, established standards, insurance requirements and procurement practices can slow adoption.
Several points changed how I framed the problem. At Sisk, Scope 1 and 2 together account for only around 2% of company emissions; up to 98% are supply-chain based. Around 80% of the relevant purchased-goods emissions come from concrete and steel. Yet a low-carbon concrete demonstrator using ACT cement delivered around a 70% reduction in embodied carbon against the cited baseline. The surprising barrier was not simply price. Standards can be harder to move than technology.
We also get into a less comfortable issue: carbon accounting itself. If companies rely on broad emissions factors or spend-based calculations, how accurately do they really know what their Scope 3 footprint looks like? And if the data is weak, are they directing capital and procurement pressure at the right problems?
This isn’t about easy fixes. It’s about concrete, steel, suppliers, carbon data, standards, electrification and the commercial realities that determine whether decarbonisation gets built.
If you work in construction, procurement, sustainability, climate strategy, industrial decarbonisation or Scope 3, this conversation should give you a sharper view of where the practical leverage sits.
If you’re tackling these issues in the real world, I’d be interested in what is proving hardest to change.
Climate Confident: tomraftery.com/Subscribe on YouTube and follow Climate Confident on your preferred podcast platform.
Chapters:
00:00 Supply Chain Emissions Shock
00:26 Show Intro and Guest Setup
02:14 Meet Keith and Sisk
04:37 Construction Net Zero Reality
08:24 Where Emissions Really Sit
11:00 Low Carbon Concrete Breakthroughs
21:59 Low Carbon Steel and Circularity
25:21 Bringing Suppliers Along
27:39 Targets Lessons and Wrap Up
Up to 98% of one major contractor’s emissions sit in its supply chain.That makes construction decarbonisation a procurement and materials problem as much as an energy problem.
My guest is Keith O’Flynn, Group Supply Chain Sustainability Manager at John Sisk & Son, one of Ireland’s largest construction contractors. Keith works directly on the difficult part of corporate emissions reduction: Scope 3, where companies depend on suppliers, materials, standards and credible carbon data to turn targets into physical change.
Construction operates on notoriously thin margins, while clients are demanding lower-carbon projects and companies are working towards increasingly ambitious emissions targets. The tension is obvious. Concrete and steel remain deeply carbon-intensive, cleaner alternatives are not always available at scale, and even when lower-carbon products work, established standards, insurance requirements and procurement practices can slow adoption.
Several points changed how I framed the problem. At Sisk, Scope 1 and 2 together account for only around 2% of company emissions; up to 98% are supply-chain based. Around 80% of the relevant purchased-goods emissions come from concrete and steel. Yet a low-carbon concrete demonstrator using ACT cement delivered around a 70% reduction in embodied carbon against the cited baseline. The surprising barrier was not simply price. Standards can be harder to move than technology.
We also get into a less comfortable issue: carbon accounting itself. If companies rely on broad emissions factors or spend-based calculations, how accurately do they really know what their Scope 3 footprint looks like? And if the data is weak, are they directing capital and procurement pressure at the right problems?
This isn’t about easy fixes. It’s about concrete, steel, suppliers, carbon data, standards, electrification and the commercial realities that determine whether decarbonisation gets built.
If you work in construction, procurement, sustainability, climate strategy, industrial decarbonisation or Scope 3, this conversation should give you a sharper view of where the practical leverage sits.
If you’re tackling these issues in the real world, I’d be interested in what is proving hardest to change.
Climate Confident: tomraftery.com/Subscribe on YouTube and follow Climate Confident on your preferred podcast platform.
Chapters:
00:00 Supply Chain Emissions Shock
00:26 Show Intro and Guest Setup
02:14 Meet Keith and Sisk
04:37 Construction Net Zero Reality
08:24 Where Emissions Really Sit
11:00 Low Carbon Concrete Breakthroughs
21:59 Low Carbon Steel and Circularity
25:21 Bringing Suppliers Along
27:39 Targets Lessons and Wrap Up
