Cement, the Unheralded Polluter
by Lloyd Alter, Toronto 
on 10.16.07
It is time again for the Green Building Festival in Toronto, and like last year, it is sponsored by St. Lawrence Cement. We did a rant last year at this time about why concrete isn't green and won't repeat it; instead we will note a column by David Adam in the Guardian.
"There were no climate change protesters waiting to jeer as the chief executives and other senior figures of one of the world's biggest industries gathered on Wednesday. Yet they represented a business that produces more than 5% of mankind's carbon dioxide emissions. And they were in Brussels to discuss climate change.
These chief executives deal in a more down-to-earth commodity: cement. It is the key ingredient in concrete, and one that is rapidly emerging as a major obstacle on the world's path to a low-carbon economy.
No company will make carbon-neutral cement any time soon. The manufacturing process depends on burning vast amounts of cheap coal to heat kilns to more than 1,500C. It also relies on the decomposition of limestone, a chemical change which frees carbon dioxide as a byproduct. So as demand for cement grows, for sewers, schools and hospitals as well as for luxury hotels and car parks, so will greenhouse gas emissions. Cement plants and factories across the world are projected to churn out almost 5bn tonnes of carbon dioxide annually by 2050 - 20 times as much as the government has pledged the entire UK will produce by that time."
Dimitri Papalexopoulos, managing director of Titan Cement, Athens, who attended the meeting, said: "No matter what you do, cement production will always release carbon dioxide. You can't change the chemistry, so we can't achieve spectacular cuts in emissions.
"Cement is needed to satisfy basic human needs, and there is no obvious substitute, so there is a trade-off between development and sustainability."
Concrete is the second most used product on the planet, after water, and almost half of it is produced in China. The booming Chinese economy has created such a demand for building materials that cement production there last year released 540m tonnes of carbon dioxide - just short of Britain's total output from all sources. Cement's weight and low value mean it is almost always made close to where it is needed, and China's demand helped it to overtake the US as the world's leading polluter last year.
Like the aviation industry, the expected rapid growth in cement production is at severe odds with calls to cut carbon emissions to tackle global warming. " ::Guardian
Treehugger has noted lots of ways of making eco-cement, Pollution eating concrete, and nano-engineering. But as the man said, "You can't change the chemistry" -we need concrete for a lot of things that can't be built with anything else, we should keep working to improve it, but we can't call it green.
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Please fix links
LA: Done. Thanks.
St. Lawrence Cement is a notorious polluter, which has paid millions of dollars in fines for polluting in Canada and the U.S.
They are currently appealing a ruling in Quebec by their former neighbors in Beauport, who won a major judgment against the company for ruining their quality of life.
The company is controlled by the Swiss giant Holcim (formerly Holderbank) which in addition to a horrendous environmental track record, used slave labor during World War II, was cozy with the South African apartheid regime, and led a cement cartel which paid the largest anti-competitive fine in European history.
Nasty company, all around.
This company spent $60 million in New York's Hudson Valley on a failed plant proposal, which the company tried to pass off as "state of the art," but would have been a massive polluter. The doctors of the main hospital serving the area of the proposal did an independent study and found that the company's plans would increase asthma, cancer and heart attacks if built.
So it is frankly astonishing and rather sick for anyone to hold a "green" conference and let SLC sponsor it.
Cement production has other impacts on the environment, such as destroying habitats for numerous species. Case in point: in the UAE, voracious demand for cement has put many mountain species at risk of extinction. http://www.ameinfo.com/134368.html
Let's keep in mind however that cement/concrete can be used to build thermally massive buildings that minimize the use of heating and cooling (thus avoiding CO2 emmissions). Yes, I know, you could use natural stone to achieve the same effect, but I assume that mining large quantities of rock would have similar negative effects as the production of cement that John previously addressed in his comment. I'm not a huge defender of cement, per say, but I wanted to remind people that it is a balance in building design between many environmental and performance related factors.
5% of CO-2 emissions by the 2nd most used product on the planet, doesn't necessarily seem that far off, and I wonder what would be the environmental implications of using stone, wood or steel or synthetics instead at our rate of building. Glass and steel also need furnaces, and so does brick, And I doubt we can grow trees fast enough. If used properly not only does cement allow for building thermal mass, and is ideal for radiant floor heating, it doesn't leach or off-gas, rot, or rust and is non-chemically mold resistant - it can last for ages (reducing the energy req'd to rebuild). It is also one of the only ways to achieve the kind of density required to sustainably support our exploding population.
What we should be considering is not why use cement, but why use unnecessary amounts of it. Why allow urban sprawl that requires xtra miles of road, sidewalks and parking lots. Why allow buildings that in 20 years will be torn down because they were ugly and poorly planned, and poorly built. Why are we then hauling the rubble to the dump while we dig more gravel pits for aggregate... Why do we still believe in growth for growths sake?