LETTER: Cement use adding to environment woes

Talk about it

To the Editor:

Tim Giago quoted an historic marker, “Buffalo Rock-Site where the last buffalo was killed … nearby is the site of the first lime kiln in the Black Hills.”

What’s a lime kiln and how does this relate to global warming?

The main ingredient in cement is limestone. But, they don’t just grind it up and call it cement. It must first undergo a chemical change. It is crushed, mixed with clay and heated to 1,450 degrees Fahrenheit. The result, called clinkers, is then ground into a powder.

In 1900, U.S. cement production was 2.68 million tons. Last year, 63 million tons. India’s 2010 production: 220 million tons. China: 1.8 billion tons.

That’s a lot of heat. But what is the chemical change? Limestone (CaCO3) is converted into lime (CaCO). For every 1,000 pounds of cement produced, nearly 900 pounds of CO2 is produced.

Last year, worldwide cement production was 3.325 billion tons. That’s nearly 3 billion tons of man-made CO2 that cement manufacturing put into the atmosphere, in addition to all that produced every year since that buffalo was killed.

We live on this ball in space. It is covered with a layer of insulation. Mankind lives between the layer of insulation and the sun. The surface of the earth and the atmosphere act like a solar collector. Global warming is caused by:

• Changes mankind has made to the surface of the earth, plus

• The ever-increasing amount of heat produced by mankind, plus

• The ever-increasing amount of CO2 produced by mankind exacerbated by

• The exploding world population.

Since the last Ice Age, our environment evolved and came into balance. Some called it an Eden. Look what mankind has done to it the last 200 years.

Tags: climate change, opinion, letters, cement