You have probably heard how such-and-such company has cut its carbon footprint by, say, 15% in the past three years. But, what is carbon footprint means? Global climate change is one of the greatest challenges of our time. With global warming dominating so many headlines today, it is no surprise that many companies are looking to reduce the amount of carbon dioxide and other greenhouse gases their activities produce. Greenhouse gas (GHGs) emissions are generally calculated as carbon footprint. Carbon footprint measures the total greenhouse gas emissions caused directly and indirectly by a person, an organisation, or a product. It is measured in tonnes of carbon dioxide equivalent (tCO2e).
Carbon footprint is calculated by considering the amount of greenhouse gas emitted/removed or embodied in the life cycle of a product. Life cycle includes all stages involved in the manufacture of a product right from bringing raw materials to final packaging, distribution, use, and to disposal. Life cycle assessment (LCA) produces a complete picture of inputs and outputs with respect to generation of air pollutants, water use and wastewater generation, energy consumption, GHGs emitted, or any other similar parameter of interest and cost–benefit initiatives.
Many companies in a variety of industries do not account for the entire supply chain that results in final goods and services, thus overlooking up to 75 percent of the greenhouse gas emissions involved. Many factories assess only carbon dioxide released directly and not from materials processing or production of parts done by suppliers, which contributes significantly to the ultimate footprints. However, downstream industries such as paints and coatings generally take into account gas emission from raw materials and paint manufacturing.
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The payoff for broadening the carbon footprint analysis is that companies will find new cost-effective ways to reduce greenhouse gas emissions. By looking beyond their own walls, businesses will uncover more ways to reduce the burden of looming carbon taxation and high fuel prices. Identifying more energy-conscious manufacturers, for example, could reduce emissions for retailers more dramatically than simply decreasing electricity use in stores.
Life cycle methodologies
Some of the well-known and widely used life cycle analysis methods are:
- Cradle-to-grave: It is the full Life Cycle Assessment from resource extraction ('cradle') to use phase and disposal phase ('grave'). It involves carbon footprint during raw material extraction/production, their transportation and storage, paint production, transportation to end user, its use and disposal.
- Cradle-to-gate: It is an assessment of a partial product life cycle from resource extraction ('cradle') to the factory gate (ie, before it is transported to the consumer). The use phase and disposal phase of the product are omitted in this case.
- Cradle-to-cradle: It is a specific kind of cradle-to-grave assessment, where the end-of-life disposal step for the product is a recycling process. It is a method used to minimize the environmental impact of products by employing sustainable production, operation, and disposal practices and aims to incorporate social responsibility into product development.
- Gate-to-gate: It is a partial LCA looking at only one value-added process in the entire production chain. Gate-to-gate modules may also later be linked in their appropriate production chain to form a complete cradle-to-gate evaluation.
Dealing with raw materials is the most difficult part of the carbon footprinting exercise. There are some databases such as ‘ecoinvent’ and ‘Plastics Europe” databases which give readymade carbon footprint value for number of chemicals. Others have to be collected from raw material suppliers. CO2e emissions associated with the release of solvents shall also be used. Data relating to energy consumption and wastes from production have to be collected. Packaging data are generally collected from the supplier of packaging materials, carbon foot printing varying depending upon the recycled content of the packaging materials. Collection of waste management data is another difficult task, since there are no databases available unlike some for raw materials.
Once the complete data on carbon footprints of raw materials and energy consumption data of different processes are available, GHG emission conversion factors are used to convert the energy data to CO2e and finally the carbon footprint of a product is calculated.
The author is an Independent Consultant based in Chapel Hill, NC, USA, and was recently Vice President - Technology at Asian Paints Ltd, Mumbai, India. He is a member of the American Chemical Society and Product Development Management Association. Email: firstname.lastname@example.org