What Decarbonization Means for Cows, Steel and Cement

(Bloomberg) -- What is “decarbonization”? It’s an approach to climate change both sweeping and incremental: working industry by industry, process by process, to bring greenhouse gas emissions down as close to zero as possible. Some challenges are familiar: switching power plants to renewable sources and filling roads with electric vehicles. A look at agriculture, which accounts for 25% of emissions, along with cement and steel, which combined account for 14%, gives a sense of less well-known tasks.


  • Sources: Producing cement’s main ingredient, called clinker, involves heating limestone in a kiln, where carbon trapped in the stone combines with oxygen and is released as CO2. More carbon is released if the heat comes from fossil fuels.
  • Solutions: Some companies are working to reduce the amount of clinker used, while others are testing substitutes including fly-ash, the residue left in chimneys of coal-burning furnaces; slag from iron production; and hemp mixed with lime.
  • Hurdles: Regulators are very cautious about approving alternatives to a substance holding together most of the world’s buildings. Some options may be three times as expensive as regular cement.
  • Long-range prospects: Cement production is expected to increase by as much as a quarter by mid-century. Reducing the amount of carbon released hinges on improving energy efficiency and shifting to cleaner fuels. But those steps would only make a dent: The International Energy Agency says that a decarbonized cement industry would rely mostly on carbon capture technologies that are currently too expensive for mass use.
  • Bright spot: Brazil’s cement is among the world’s cleanest, thanks to the availability of pozzolan, a volcanic material that can take the place of clinker.
What Decarbonization Means for Cows, Steel and Cement


  • Sources: Iron ore is purified in traditional blast furnaces by being heated along with coke, a refined form of coal. Coke releases carbon monoxide that absorbs oxygen from the iron ore, creating pig iron and carbon dioxide.
  • Solutions: European steelmakers are testing a switch to hydrogen as the bonding agent. Hydrogen produced by renewable power could also be used to fire furnaces. Increasing the use of recycled steel is seen as critical to reducing emissions as it’s far less energy-intensive.
  • Hurdles: The chief technology officer of ArcelorMittal, the world’s biggest steelmaker, estimates that switching to hydrogen could double the cost of steel. The upfront investment needed for the change could require large amounts of government aid.
  • Long-range prospects: Global demand for steel is expected to rise by 50% between 2019 and 2050 as cities grow. The IEA says the carbon intensity of steel -- the energy needed to produce a given amount -- needs to fall 1.9% each year through 2030; between 2010 and 2016 the average decrease was 1.4%.
  • Bright spot: A pilot project called Carbon2Chem by the German steelmaker Thyssenkrupp AG uses carbon dioxide and other gases released in the steel production process as raw materials for making chemicals, reducing overall emissions.
What Decarbonization Means for Cows, Steel and Cement


  • Sources: The widespread practice of burning stubble after harvests releases carbon dioxide, while heavy use of inorganic fertilizers releases methane and nitrous oxide. The destruction of rainforests for ranching and farming, including growing animal feed, is part of why livestock accounts for 60% of agricultural emissions.
  • Solutions: Steps on the supply side include improving soil management and developing livestock with digestive systems that produce less methane. On the demand side, advocates hope to persuade people to eat less meat and dairy and to pressure food companies to buy only from environmentally friendly sources.
  • Hurdles: Brazilian President Jair Bolsonaro has been hostile to measures to reduce deforestation in the Amazon, while food production in Asia is dominated by poor, small-scale farmers, including many reluctant to give up traditional methods.
  • Long-range prospects: With the world’s population growing and consumers in China and other emerging markets eating more meat as they grow more affluent, consumption of animal products is forecast to rise 60% by 2050.
  • Bright spot: In the developed world, meat consumption is dropping faster than expected, while substitutes such as Beyond Meat have drawn investor interest.

The Reference Shelf

  • An academic paper on the impact of livestock on climate change.
  • Bloomberg Businessweek: Peas, soy and mung beans are on the rise.
  • Greener cement is a hard sell for the building industry: Bloomberg.
  • The long road to “greener” steel, from Deutsche Welle.

©2019 Bloomberg L.P.

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