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Cement is the Source of About 8% of the World's Carbon Dioxide Emissions (bbc.com)

Posted by msmash on from the concrete-proof dept.

Concrete is the most widely used man-made material in existence. It is second only to water as the most-consumed resource on the planet. But, while cement -- the key ingredient in concrete -- has shaped much of our built environment, it also has a massive carbon footprint. From a report: Cement is the source of about 8% of the world's carbon dioxide (CO2) emissions, according to think tank Chatham House. If the cement industry were a country, it would be the third largest emitter in the world -- behind China and the US. It contributes more CO2 than aviation fuel (2.5%) and is not far behind the global agriculture business (12%). Cement industry leaders were in Poland for the UN's climate change conference -- COP24 -- to discuss ways of meeting the requirements of the Paris Agreement on climate change. To do this, annual emissions from cement will need to fall by at least 16% by 2030.

3 of 185 comments (clear)

  1. Re:That's a trade I'm willing to make. by Headw1nd · · Score: 4, Interesting

    It is far from a given that cement production has to release as much CO2 as it does now. I am in the building world, I will assure you nobody is giving up concrete, but there is a lot of research going into reducing the carbon footprint of cement, along with increasing its strength and decreasing its weight. Most concrete in this world is used to support other concrete, affordably reducing weight would go a long way to reducing demand.

  2. Use Geo-polymer concrete instead by F34nor · · Score: 3, Interesting

    https://en.wikipedia.org/wiki/...

    It is what the pyramids were made from, pour-able limestone.

  3. How much of that 8% is from energy production? by jcochran · · Score: 3, Interesting

    Because the cement itself is carbon neutral.

    Reactions
    CaCO3 ==> CaO + CO2
    CaO + H2O ==> Ca(OH)2
    Ca(OH)2 + CO2 ==> CaCO3 + H2O

    So for each molecule of cement you make, you do produce 1 molecule of carbon dioxide. Then to use the cement, you add a molecule of water. And then over time, the result reacts with carbon dioxide (removing the carbon dioxide that was released when the lime was made) and releases a molecule of water.

    The only non-neutral production of CO2 from making cement is that from whatever source of energy you use to heat up the calcium carbonate to produce the lime.

    Doing a bit of research, it looks like 60% of the carbon dioxide released is from the chemical reaction and 40% from the heat used to drive the reaction. Since the 60% from the reaction will be reabsorbed by the cement, we can ignore it. So the actual amount of CO2 due to cement production isn't the 8% the article mentions, but something closer to 3.2%.