Researchers created the first bottom-up approach to estimate national carbon uptake. They found the cement in U.S. structures sequesters over 6.5 million tons of CO2 a year; in Mexico the same structures sequester about 5 million tons.
  • Nomecks@lemmy.ca
    English
    60·
    19 hours ago

    This corresponds to roughly 13 percent of the process emissions — the CO2 released by the underlying chemical reaction — in U.S. cement manufacturing.

  • A_A@lemmy.worldEnglish
    20·
    18 hours ago

    Numbers here are misleading :
    (13% and 25% of CO2 produced during manufacturing)

    These percentage are based on what is produce during the year while existing cement things that are picking up CO2 were fabricated in the span of many decades.

    trivial example to illustrate what i am saying here

    …
    supposed we are making each year one new building for 100 years in a row.
    After that time, we have 100 buildings picking up CO2 from the air but in that year we create only one new building.
    Now, we calculate total amount of CO2 picked up by 100 building divided by CO2 emitted to build this new single building.

    This is how misleading this calculation is.

    in fact if we were to make new buildings at a steady pace for long enough, we would eventually reach “kinetic equilibrium” in which the rate of CO2 picked up is equal to the rate of CO2 emitted : so we would reach 100% of annual CO2 production. (equilibrium)