An essential tool for decarbonizing the built


CarbonStar  is a government-backed quantification method for calculating the embodied carbon of concrete. 


Concrete's Carbon Problem

Share of Global Emissions

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Concrete is the most-used building material on the planet. It is also the most polluting, accounting for 8% of global emissions. 

That huge amount of embodied carbon is because cement, the key ingredient of concrete, is one of the most carbon-intensive materials on earth, as it requires heating limestone to 1000°C / 1800F.

Components of Concrete

Decarbonizing Concrete

Until recently, the focus of decarbonizing concrete has been on cement – decreasing the amount of cement to decrease the embodied carbon. This has led to concrete mixes containing up to 70% Supplementary Cementitious Material (SCM) in place of cement. But this approach can only go so far. 

Technology is offering a new path: carbon sequestration. By capturing CO2 in the components of concrete - or in the mix itself - the embodied carbon of cement can be entirely offset, allowing concrete to become carbon neutral, or even carbon negative.

Counting the Carbon

With the rapidly growing number of techniques and technologies being used to reduce the embodied carbon of concrete, a method for counting that carbon is required – and that is where CarbonStar comes in.

Commissioned by the Standards Council of Canada (SCC) and written by the Canadian Standards Accreditation (CSA) along with a committee of 30 experts in the field, CarbonStar shifts the paradigm from simply green or not green, to quantifying the exact climate impact of concrete.

To learn more about the CarbonStar Rating System, please click the button at right to open your free CSA account.