3.1 Product Life Cycle

Carbon Footprint

• Carbon footprint refers to the total amount of carbon dioxide released into the atmosphere as a result of the activities of an individual, event, organisation, community or products which are used in daily life.
• Processes and activities which influence carbon footprint include:
  • use of water and electrical energy;
  • transportation and personal activities;
  • use of gas and fuel;
  • release of greenhouse gases;
  • generation of waste;
  • recycling and offset.
• Offset refers to processes that can reduce the release of greenhouse gases, such as planting green plants.
• The carbon footprint study of an individual begins by breaking down the products used in a day.
• The impact of a daily-use product is influenced by its use of electrical energy, water, transport and food, the waste and greenhouse gases it produces, and its frequency of use.
• An energy-efficient electrical appliance has a smaller carbon footprint because it uses less electrical energy.
• A carbon footprint label states the mass of carbon dioxide released by a product; for example, a label may show 900 g of CO₂ released for every 500 ml of a food product.

Breaking Down Products Used in Daily Life

For an electrical lighting device such as a filament lamp, energy-saving lamp or LED lamp:

1. Record its power in kilowatts (kW).
2. Record its frequency of use in a day in hours (h).
3. Calculate the electrical energy used in kilowatt-hours (kWh).
4. Calculate the mass of carbon dioxide released:

• Assumption: the use of 50 kWh of electrical energy produces 39 g of carbon dioxide.
• Example for an LED lamp:
  • power = 0.009 kW;
  • use = 5 h per day;
  • electrical energy used = $0.009\times 5=0.045\text{ kWh}$;
  • carbon dioxide released = $\frac{0.045}{50}\times 39=0.0351\text{ g}$.

Evaluate a daily-use product by asking:

• Is the product environmentally friendly?
• What are the negative impacts of its manufacturing process?
• Is the product safe to be used?
• How much waste is produced after it is used?
• What other products can be produced from its waste? For example, coffee waste can be used as a fertiliser.

Carbon Footprint and Carbon Handprint of a Product

• The carbon footprint of a product refers to the negative impacts on environmental sustainability caused by the product throughout its life cycle.
• The carbon handprint of a product refers to the positive impacts on environmental sustainability caused by the product throughout its life cycle.
• A carbon handprint aims to reduce the carbon footprint of a product and increase its positive impacts on environmental sustainability.

Carbon handprint measures

1. Use materials with a low carbon footprint in product manufacturing

   • Replace non-renewable building materials which emit large amounts of greenhouse gases with renewable materials which emit less greenhouse gases.
   • Example: replace cement with timber.

2. Extend the life cycle and increase the efficiency of a product

   • Examples: rechargeable batteries and solar panels.

3. Use energy that emits less greenhouse gases and highly-efficient energy converters

   • A hydroelectric power station uses a renewable energy source and does not emit greenhouse gases into the atmosphere during electricity generation.
   • Using electrical appliances with a 5-star energy efficiency label reduces electrical energy consumption and is a carbon handprint measure.

4. Manage waste efficiently towards environmental sustainability

   • Apply the 5R concept:
     • Refuse unnecessary products.
     • Reduce the quantity of products used.
     • Recycle products.
     • Reuse products.
     • Rot waste through composting.

5. Eliminate greenhouse gases and store carbon dioxide in carbon sinks

   • Carbon sinks are natural places such as forests and oceans that remove carbon dioxide from the air.
   • Carbon dioxide decreases when it dissolves in seawater and is absorbed by green plants in forests.
   • Carbon accumulated in biomass also helps to reduce carbon dioxide in the air.

Life Cycle of a Product

The common life cycle of a product starts from its source and ends at disposal:

Source → Manufacturing → Transportation → Usage → Disposal

• Cradle-to-cradle life cycle: disposal is followed by recycling, so the material becomes a resource for another product.
• Cradle-to-grave life cycle: disposal is followed by decay, ending the product’s useful cycle.

Efficient Management of Plastic Waste

• Plastic pollution is the accumulation of plastic products that has adverse effects on the environment, wildlife, wildlife habitats and humans.
• The chemical structure of most plastics allows them to withstand natural decomposition; therefore, they take a long time to decompose.
• Upcycle is a recycling process that produces a new product of higher value than the original product.
  • Example: used plastic bottles → plastic broom.
• Efficient plastic-waste management includes:
  • conducting a study on plastic pollution;
  • gathering data on the impact of plastic use;
  • raising awareness in the school and local communities;
  • reducing plastic waste and the use of plastic products;
  • generating creative and innovative reuse or upcycle solutions.

Microplastics in the food chain

• Microplastics are plastic pieces less than 5 mm in length which can become hazardous inside the body of aquatic organisms.

• Main sources: discarded bottles, man-made textiles, paint and electronic devices.

• Microplastics are transferred between organisms through feeding in a food web involving plankton, larvae, molluscs, fish, turtles, marine mammals and humans.

• Reduce this transfer by reducing plastic waste and the use of plastic products, including plastic bags and plastic straws.