China uses as much cement in two years as the US did over the entire 20th century
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China uses as much cement in two years as the US did over the entire 20th century
Finally, a viral statistic that is close to being true.
“China used as much cement in three years as the US did in the entire 20th century” is a headline that has been repeated over and over.
I’m skeptical of most statistics that go viral, so had to double-check and calculate the numbers myself.
This number is still close to being true, except China consumes as much cement every two years as the US did over the 20th century.
We see this comparison in the chart below. Here I’m using data published by the US Geological Survey (USGS).
From 1900 to 1999, the US produced 4.2 billion tonnes of cement.
It consumed 4.4 billion tonnes.China produced 2.4 billion tonnes in 2020, and 2.5 billion tonnes in 2021. This means it produced 4.9 billion tonnes in these two years.
That’s production, not consumption, but based on trade numbers that I could find, China exports very little cement – only around 5 million tonnes. That means production and consumption are basically the same.
China produces more than half of the world’s cement
China now dominates global cement production, and has done for more than a decade.
In the charts below we see it in the context of the world’s cement output.
In 2014 it produced 60% of the world’s cement, and it has fallen only slightly since then to 56% in 2019.
Why do we care about the scale of cement production?
This comparison might be an interesting fact, but why does it actually matter?
Two key reasons.
The first simply shows the scale and speed that China is industrialising. On a human level, this is a good thing: living standards in China have improved rapidly in recent decades; poverty rates have plunged; and it has been building cities and infrastructure at breakneck speed.
The second is environmental. Cement production emits CO2 – not only from using energy in its production but from the chemical reactions that take place too.
It accounts for about 4.5% of global CO2 emissions from fossil sources – that’s the emissions from coal, oil, gas, cement, and flaring.Unsurprisingly given how much cement it produces, China dominates global emissions from cement. It emits around 852 million tonnes, which is equal to almost double the total fossil emissions of South Africa.
The problem with cement is that it’s an industry that we can’t just decarbonise by switching to renewable or nuclear energy. We need innovations to eliminate CO2 production from the direct process itself.
Export data is sourced from the UN Comtrade database.
To make cement we heat limestone (CaCO₃) at high temperatures.
This produces a compound called 'clinker' (CaO) and CO₂ as a byproduct.
CaCO₃ + Heat ➙ CaO + CO₂.
Andrew, R. M. (2019). Global CO 2 emissions from cement production, 1928–2018. Earth System Science Data, 11(4), 1675-1710.
You can also calculate this from the latest CO2 emissions data from the Global Carbon Project.
It estimates that global fossil emissions in 2021 were 37.12 billion tonnes.
Cement emissions were 1.67 billion tonnes.
That means cement emissions were 4.5% of the total.
China uses as much cement in two years as the US did over the entire 20th century
We can't eliminate all concrete use in construction, but we can replace part of it with mass timber, which has a much lighter carbon footprint. (See https://www.mdpi.com/2071-1050/14/1/144 )
Mass timber is rapidly growing in popularity in Europe, North America and Japan, and is now being explored in China as well.
"We need innovations to eliminate CO2 production from the direct process itself."
Yes! Thankfully there are a host of great companies innovation on cement and concrete production. We need a wartime-level effort to scale these ASAP. But hope is on the horizon.