Concrete carbonation facts counter claims of investors hung up on cement plant emissions

The London-based Institutional Investors Group on Climate Change (IIGCC) has recently approached CRH Plc, HeidelbergCement AG and LafargeHolcim Ltd. about commitments to achieving net zero carbon dioxide emissions no later than 2050. The call to action aligns with strategies in the United Nations Conference of Parties’ (COP 21) 2015 Paris Agreement. The 150-plus signatory countries volunteer CO2 emission reductions whereby projected global temperatures rise no more than 1.5°C over this century.

“The cement sector needs to dramatically reduce the contribution it makes to climate change. Delaying or avoiding this challenge is not an option,” explains IIGCC CEO Stephanie Pfeifer. “Major economies are increasingly adopting net zero emission targets. The cement sector needs to get ahead of profound transformation by addressing barriers to decarbonization in the short- to medium-term if companies are to secure their future.”

The group engages the global cement, aggregate and concrete elite in “Investor Expectations of Companies in the Construction Materials Sector.” The document draws new parallels based on embellished versions of tired arguments: As the most widely used construction material the world over, cement is the source of 7 percent (what happened to the 5 percent or 6 percent benchmark?) of global man-made CO2 emissions. If it were a country, the cement industry would trail only China and the U.S. among global CO2 emitter. “Investor Expectations” takeaways center on greenhouse gas emission reduction and Paris Agreement fealty:

  • Companies should commit to achieving net zero carbon emissions over the next three decades with targets that are “science-based … in line with the decarbonization required to keep global temperatures well below 2°C warming.”
  • Investors expect companies to engage with policy makers to pursue cost-effective climate change mitigation and an orderly transition to a low-carbon economy.

Heavy-handed undercurrent aside, “Investor Expectations” cites cement and concrete producers’ strides in lowering the CO2 embodied in finished slabs and structures, and specifically calls out HeidelbergCement’s emissions-reduction strategies. IIGCC would strengthen its case if it acknowledged how CRH—as the world’s largest portland cement consumer—has a vested interest in optimizing the “clinker” or pure portland cement factor in every yard of ready mixed, 8-in. concrete masonry unit equivalent, and ton of precast it ships. And why not credit commitments, mirroring Paris Agreement terms, that a LafargeHolcim executive and technical staff delegation spelled out nearly four years ago in COP 21 sessions?

If they are true to their embrace of science and transparency, IIGCC members or allies need to look beyond CO2-intensive cement plant combustion and calcination processes. A team from CalPortland Co. weighs the effective emissions reversal or retrieval in a 10-page report, “Incorporating the Effect of Carbonation in Concrete Life Cycle Assessment.” (note “CalPortland documents glaring greenhouse gas accounting void,” pages 18-19).

“Considerable attention has been paid to quantifying the industrial process emissions from cement production, however the natural reversal process of the uptake of CO2 during concrete’s material life phases is just beginning to receive the consideration it deserves,” authors contend. “Carbonation occurs during the entire useful life of a concrete product, during its secondary salvaged or recycled life such as a crushed material for construction roadway base, or in its terminal life as landfill material. Every time concrete is crushed or reduced in particle size after its intended use, into its secondary use, or termination into a landfill, new opportunities to increase carbonation are created.”

“Incorporating the Effect of Carbonation” is a pertinent, timely contribution to the cement and concrete library. Its implications are sure to challenge the climate change crowd’s intellectual honesty.