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India Currents gave me a voice in days I was very lost. Having my articles selected for publishing was very validating – Shailaja Dixit, Executive Director, Narika, Fremont

At the Front Door: Cement’s Carbon Footprinta column on climate change in our lives.

One of Santa Clara County’s most notable cement production facilities, the Lehigh Southwest quarry and plant, recently sued the County for failing to process their permit to expand mining operations. The proposed expansion would increase mining production by 600,000 tons per year and result in an additional 500 daily truck trips through Cupertino.

A concrete distribution center is also currently being considered in Milpitas and is expected to expose residents to worse air pollution.

Santa Clara County and the City of Cupertino are concerned about the impact of this expansion on the environment and on the quality of life of their residents.

Cement produces a whopping 4 billion tons of CO2 per year

This conflict of interest between the cement industry and the residents of communities where they are located is in no way localized to the SF-bay area. Quite the opposite — the cement industry impacts the health of our entire planet. It accounts for 8% of the total man-made carbon emissions — which is a whopping 4 billion tons of CO2 per year. In the United States alone, we produce about 90 metric tonnes of cement each year and California is the second-highest producer of cement in the country. Reducing the carbon emissions from cement production, therefore, must be included as a part of the solution to combat climate change.

There are two major reasons behind cement’s high carbon footprint. The manufacturing process of cement involves heating limestone to very high temperatures of over 1500 degrees Celsius. The chemical reaction that occurs in this process releases carbon dioxide.  Secondly, cement manufacturing requires a significant amount of energy, which is often obtained by burning fossil fuels. This further increases cement’s carbon footprint.  In addition to increased carbon emissions, cement production also leaves in its wake swathes of arid land from limestone mining and deposition of cement on the topsoil.

Concrete Jungles create hotspots

Once built, our concrete buildings and roads form urban heat islands making the heat waves even more difficult to live through. In line with the theme of racial and class inequality, both the cement-producing factories and the urban heat islands tend to disproportionately affect poor communities and communities of color. People who work in construction can also be exposed to wet cement, which is highly alkaline and can cause severe skin burns.

The excess production and consumption that plagues our modern lifestyle also show up in our cement-construction industry. We are building more than we need just for the sake of economic growth. This is epitomized by the ghost cities in China and India, with forests being replaced at a rapid pace by unoccupied concrete jungles. These are the same parts of the world where billions of people cannot afford a roof over their heads.

Are there low-emission alternatives to cement?

Innovative, low-emission alternatives to cement do exist. Some of these options reduce emissions by eliminating the high-temperature heating step from cement production.  Others reduce the amount of cement used in concrete replacing it with substitutes such as fly ash, which is a waste product from coal combustion. Switching to clean energy sources for cement production would also have an impact on cement’s carbon footprint. However, due to a lack of awareness and market demand, these solutions remain expensive and underutilized compared to traditional cement.

Most major cement-producing companies have acknowledged their environmental impact and stated commitments to reduce their carbon footprint. However, we need regulation to hold them accountable and to promote the adoption of lower-emission cement alternatives. For example, the Paris Agreement on climate stipulated that the annual carbon emission from the cement industry should fall by 16% by 2030.

Pushing clean energy bills in California

Senate Bill 596 Greenhouse Gasses: Cement Sector, is currently moving through the California Legislature. Sponsored by Senator Josh Becker, who represents parts of San Mateo and Santa Clara Counties, this bill would direct the Air Resources Board (ARB) to create a strategy to reach carbon neutrality in the cement industry by 2045. The limits set by the ARB would be enforceable.

Adding concrete to California’s Buy Clean program would also help reduce its carbon footprint. Senate Bill SB 778 would give preference to contractors who use low-carbon materials for state contracts. Since public agencies are the largest purchasers of concrete in the state, this bill would go a long way toward mainstreaming low-carbon concrete options. Additional legislation strives to update the specifications to improve the durability and reliability of concrete.

You can help in the fight to reduce cement’s carbon footprint by reaching out to your elected representative and communicating your support for the bills above. The contribution of cement to climate change does not get as much public attention as it deserves. Your input on this matter is, therefore, likely to have an outsized impact!

Vaibhav Karkare is a Climate Reality Leader who works in the tech industry.

Erin Zimmerman is trained as a Climate Reality Leader in 2019 by the Climate Reality Project, but has been active in the environmental movement for over a decade. Erin holds a Ph.D. in Political Science from the University of Adelaide, where she focused on environmental degradation and its impacts on the country and regional stability in Asia. She is currently the Chair of the Speakers’ Bureau of the Santa Clara Chapter of the Climate Reality Project and an active member of the Legislative and Policy team.

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Erin Zimmerman

Erin Zimmerman is trained as a Climate Reality Leader in 2019 by the Climate Reality Project, but has been active in the environmental movement for over a decade. Erin holds a PhD in Political Science...