According to recent global data, the amount of heat-trapping carbon dioxide emissions from cement production, a less well-known but significant source of carbon pollution, has doubled in the past 20 years.
According to emissions expert Robbie Andrew of Norway’s CICERO Center for International Climate Research and the Global Carbon Project, worldwide emissions from producing cement for buildings, roads, and other infrastructure reached nearly 2.9 billion tonnes (2.6 billion metric tonnes) of carbon dioxide in 2021, or more than 7% of the world’s carbon emissions. Around 1.4 billion tonnes (1.2 billion metric tonnes) of carbon dioxide were emitted by cement in 2002, 20 years ago.
Global cement emissions have increased by more than three times since 1992, and are currently expanding at a pace of 2.6 percent annually, largely due to China. Not merely that there is more cement being produced and consumed. Cement has really been moving in the opposite way at a time when all businesses are supposed to be streamlining their procedures. According to the International Energy Agency, China is mostly to blame for the 9.3 percent increase in the carbon intensity of cement from 2015 to 2020, which measures how much pollution is emitted per tonne.
Rob Jackson, a climate scientist at Stanford University who directs the Global Carbon Project, a team of researchers that analyse global climate pollution and publish their findings in peer-reviewed journals, stated that cement emissions have increased more quickly than most other carbon sources. The fact that cement emissions were constant during COVID was also unusual. They didn’t expand as much, but they also never saw a fall like coal, gas, and oil did. Since the Chinese economy never actually shut down entirely, in my opinion, it explains it.
When compared to other important materials like steel, cement is unusual because, in addition to requiring a lot of heat to manufacture, which results in emissions, the chemical process used to make cement also generates a significant amount of carbon dioxide, which is the main long-term heat-trapping gas due to human activity.
Clinker, the crumbly binding agent in the entire combination, is a crucial component in the recipe for cement and is needed in large quantities. When limestone, or calcium carbonate, is excavated from the ground and heated to 2700–2800 degrees (1480–1540 degrees Celsius), calcium oxide is produced. However, as Andrew pointed out, the process releases carbon dioxide from the limestone into the atmosphere.
According to Portland Cement Association senior vice president for sustainability Rick Bohan, ‘in the US, 60% of our CO2 is a chemical reality of life… Concrete is a universal building material, which is the truth. Concrete is used in every single building project in some capacity.’
Buildings, roads, and bridges all contain cement, the main component of concrete.
According to Steve Davis, an Earth systems scientist at the University of California, ‘each human on the earth is eating on average more than a kilogramme (2.2 pounds) of cement per day.’ ‘It goes without saying that you won’t go to Home Depot every day and buy a sack of cement. But the bridges, buildings, and roads outside are consuming more than a kilogramme on your behalf. And that kind of boggles my head.’