3.1 Product Life Cycle
Every product manufactured and used in our daily routine impacts the environment throughout its life cycle. This topic explores carbon footprint, carbon handprint, product life cycles, upcycling of plastic waste, and the threat of microplastics in food webs.
Learning Objectives
- Explain the meaning of carbon footprint and identify factors that influence it.
- Calculate the carbon footprint of an electrical appliance based on electrical energy usage.
- Distinguish between carbon footprint and carbon handprint of a product.
- Identify and describe carbon handprint measures taken to reduce greenhouse gas emissions.
- Describe the common life cycles of a product: cradle-to-cradle and cradle-to-grave.
- Explain the concept of upcycling in managing plastic waste.
- Explain the meaning of microplastics and their transfer through food webs.
Product Life Cycle Models and Carbon Footprint vs Handprint
A closed loop recovers materials through recycling, while an open loop ends in decay. Carbon handprint actions work against the carbon footprint of a product.
Short Explanation
What is a 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 used in daily life.
Every product we use leaves an environmental footprint from the moment its raw materials are extracted until its disposal. When a product is made, transported, and operated, it causes greenhouse gas emissions. However, sustainable choices can act as carbon handprints that offset and reduce environmental harm.
Processes that influence carbon footprint
Processes that increase carbon footprint
Water usage, release of greenhouse gases, electrical energy consumption, transportation, waste production, gas usage, fuel usage, and personal activities.
Processes that reduce carbon footprint
Recycling and carbon offset, for example planting green plants.
Calculating the carbon footprint of an electrical appliance
Electrical energy used (kWh) = Power (kW) × Frequency of use in a day (h)
Amount of carbon dioxide released (g) = (Electrical energy used (kWh) ÷ 50 kWh) × 39 g
A usage of 50 kWh of electrical energy produces 39 g of carbon dioxide.
Carbon handprint measures
1. Low carbon footprint materials
Non-renewable building materials emitting a lot of greenhouse gases are replaced with renewable building materials emitting less greenhouse gases. For example, cement is replaced with timber.
2. Extending product life and efficiency
Using products with extended lifespan and higher efficiency, such as rechargeable batteries and solar panels.
3. Low-emission energy and efficient converters
Using renewable energy sources like hydroelectric power stations that do not emit greenhouse gases, and adopting electrical appliances carrying a 5-star energy efficiency label.
4. Efficient waste management
Applying the 5R concept: Refuse, Reduce, Recycle, Reuse, and Rot.
5. Carbon sinks
Carbon sinks are natural reservoirs like forests and oceans that remove CO2 from the air. CO2 dissolves in seawater and is absorbed by green plants during photosynthesis.
Life cycle of a product
A product life cycle starts from source to disposal. There are two types of product life cycles:
Cradle-to-cradle
Product life cycle where materials from disposed products are recovered through recycling and reused as raw materials for manufacturing new products.
Source → Manufacturing → Transportation → Usage → Disposal → Recycle → Manufacturing
Cradle-to-grave
Linear life cycle where the product ends with disposal and decay in landfills without material recovery.
Source → Manufacturing → Transportation → Usage → Disposal → Decay
Upcycling and microplastics
Upcycling
Upcycling is an efficient management method representing a recycling process used to produce a new product of higher value or quality than its original product. For example, turning used plastic bottles into a plastic broom.
Microplastics
Microplastics are plastic pieces less than 5 mm in length. They can become hazardous when ingested by aquatic organisms.
Microplastics in the food web
| Food web pathway | Transfer sequence |
|---|---|
| Aquatic pathway 1 | Microplastics → Plankton → Larva → Fish → Human |
| Aquatic pathway 2 | Microplastics → Mollusc → Human |
| Marine pathway | Microplastics → Fish / Larva → Turtle / Marine mammal |
Try to Answer First
Answer in your mind, then press “Check Answer”.
What is the main difference between cradle-to-cradle and cradle-to-grave life cycles of a product?
Give one example of a carbon handprint measure in product manufacturing.
What size defines a microplastic, and why is it dangerous in marine ecosystems?
Common Mistakes
- Confusing carbon footprint with carbon handprint. Carbon footprint measures negative environmental impacts, whereas carbon handprint represents proactive positive actions taken to reduce the footprint.
- Confusing upcycling with ordinary recycling. Upcycling converts waste materials into a new product of higher value than the original discarded item, not just breaking down material for basic reuse.
- Assuming cradle-to-grave includes recycling. Cradle-to-grave ends strictly at waste disposal and decay.
- Misunderstanding the size limit of microplastics. Thinking microplastics are microscopic only, whereas scientifically they are any plastic particles less than 5 mm in length.
Concept Misunderstandings
Carbon sinks like oceans and forests release greenhouse gases into the air.
Carbon sinks actively absorb and store carbon dioxide from the atmosphere, for example via photosynthesis in plants and dissolution in seawater.
Any reduction in electricity use completely eliminates a product's carbon footprint.
Carbon footprint encompasses the entire life cycle, including raw material sourcing, manufacturing, and transport, not just the usage phase.
Summary
- Carbon Footprint: Total amount of CO2 emitted by an individual, organisation, or product life cycle.
- Carbon Handprint: Positive actions taken to decrease carbon footprint across product life cycles, such as using timber instead of cement, choosing 5-star energy appliances, 5R waste management, and preserving carbon sinks.
- Product Life Cycles: Cradle-to-grave: Source → Manufacturing → Transportation → Usage → Disposal → Decay. Cradle-to-cradle: Source → Manufacturing → Transportation → Usage → Disposal → Recycling → Manufacturing.
- Upcycling: Transforming waste plastic products into higher-value functional items.
- Microplastics: Plastic fragments under 5 mm that accumulate in aquatic organisms and transfer across trophic levels to humans.
Short Activity
A. Objective Quiz
1 Which of the following is an example of a carbon handprint measure in the manufacturing of a product?
2 What is the defining length criterion for microplastics according to NOAA?
B. Fill in the Blanks
3 Natural reservoirs such as oceans and forests that remove and store carbon dioxide from the atmosphere are known as carbon .
4 The process of turning waste plastic bottles into a new product of higher value, such as a plastic broom, is called .
C. Drag and Drop: Match the Concept to Its Description
Drag each concept to the description it matches. On a phone, tap an answer first, then tap a matching box. Tap the Answer Choices area to return a selected item.
C. Match the Concept to Its Description
Write the correct concept next to each description.
| Description | Concept |
|---|---|
| 1. Total amount of carbon dioxide released into the atmosphere by human activities or products | |
| 2. Positive impacts and measures aimed at reducing greenhouse gas emissions across a product's life cycle | |
| 3. A product life cycle that starts from source and ends with disposal and natural decay | |
| 4. A product life cycle where disposed materials are recovered and reused through recycling |
Answer choices: Carbon footprint • Carbon handprint • Cradle-to-grave • Cradle-to-cradle
