There is a new ‘kid’ on the sustainable building ‘block’. Nobody knows much about her, few know where she has come from, but what we do know is that she is becoming increasingly popular and she’s turning heads!

Yes, we're talking about embodied carbon. In this blog post we want to introduce the topic, demystify some of the aspects of it to help you better understand what it means, and inform you as to what is involved in reducing its impact when it comes up in conversation.

What is embodied carbon?

Simply, embodied carbon is defined as the carbon footprint of a material. It considers how many greenhouse gases (GHGs) are released throughout the supply chain and includes the extraction of materials from the ground, transport, refining, processing & assembly, in use and end of life. So it includes the exhaust emissions of machines mining raw materials, drying, processing these, fuelling the trucks to move materials around, manufacturing emissions, replacement of materials on the building over 60 years (a typical building lifetime) and emissions associated with recycling or disposal and the like at the end of the building’s useful life.

Embodied carbon does not include carbon emissions associated with heating, lighting, ventilating, etc of a building when it is in use but specifically carbon emitted when producing materials that the building is made from. I’d like to think that most readers could get their heads around this bit but how you actually measure and calculate embodied carbon in a development is a whole new headache.

How do we reduce embodied carbon and by how much?

There are a few ways that allow embodied carbon to be reduced. The top 4 ways are:

1. Repurpose or reuse existing buildings
2. Reuse, re-manufacture and recycle materials
3. Build with low carbon, healthy materials
4. Offset emissions (renewable tech or woodland planting)
   
   

At the top of the list and the most obvious way to reduce embodied carbon is to not manufacture materials, use less and retrofit or repurpose existing buildings where possible. A lot of discussion has been had recently about the push for new eco buildings, but these often involve knocking down existing structures and starting from scratch. It's much better to use the ones we have!

Where materials need to be brought to site, a focus on circular economy thinking comes in. Think reuse, re-manufacture or recycle if possible and again reduce manufacture from scratch.

If new materials must be used, then use low-carbon, healthy materials such as wood, sheep’s wool, cellulose, slate, adobe and other lightly processed materials.

Finally, as a last resort, offset emissions by funding UK offsite renewable energy projects or woodland planting.

The question of by how much we should reduce embodied carbon is a tricky one. This answer has been helped in part by professional frameworks such as the RIBA 2030 Climate Challenge which has set out an aggressive target of 70% embodied carbon reduction by 2030 to help meet the UK’s commitment to reaching net zero carbon by 2050. Whilst this seems like a big leap to take, it is only because we don’t fully understand embodied carbon yet and don’t realise that with a better and more intelligent design and construction process we can quickly get there.

So, there you go. You're now hopefully a little more informed and better prepared to embrace embodied carbon with peers and on your next project. We’ll be writing many more articles on this subject so please stay tuned!