What accounts for that jaw-dropping carbon footprint? To make cement, you have to heat limestone to nearly 1,500 degrees C. Unfortunately, the most efficient way to get a cement kiln that hot is to burn lots of coal, which, along with other fossil fuel energy sources, accounts for 40 percent of the industry’s emissions. Eventually, the limestone breaks down into calcium oxide (also known as lime) and releases CO2, which goes straight into the atmosphere, accounting for a further 60 percent of the industry’s emissions.
The good news is that there’s no shortage of ideas for how to slim down cement’s weighty carbon footprint. The bad news is that most of them are either in their infancy or face significant barriers to adoption. As our window of time for preventing catastrophic climate change grows ever smaller, we need major investments in new technologies and changes to how the cement industry works. But most of all, we need politicians need to wake up to the fact that the cement industry has a climate problem. (...)Developing new cement manufacturing technologies is only half the battle against cement’s carbon emissions. The other half is finding ways to use less cement.
Today the world churns out 4 billion tons of cement every year, or about 1,200 pounds for every human being alive. As more people move into cities, developing countries modernize their infrastructure, and the world transitions to new energy systems, our appetite for cement is only expected to grow. By 2050, we could be cooking up close to 5 billion tons of cement a year.
“As with everything in climate change, the most salient aspect of the problem is its scale,” said Rebecca Dell, an industry strategist with ClimateWorks. “If cement were a niche material this wouldn’t be a problem.”
by Maddie Stone, Grist | Read more:
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