Exercises: The environmental impact of technology

Explain in your own words what the life cycle of a product is and put its four stages in order: use, raw material extraction, end of life, and manufacturing. Give an example of what happens in each stage of a T-shirt's life.

The figure shows the life cycle ring of a product, but one of the stages is covered.

Find out which stage is covered (what happens to the product when we stop using it) and describe what can happen to its materials in that stage: the two possible outcomes (landfill or recovery) and why it matters which of the two occurs.

The environmental footprint of a product is everything it "costs" the planet: materials, energy, water, transport, and waste. Explain this idea using the analogy of footprints in the sand (what we leave behind even if we don't see it) and name three invisible footprints left by a simple pencil before it reaches your hand.

A mobile phone contains dozens of different materials: metals such as copper and gold, rare earths, plastics, and glass. Explain what it means that these materials are "extracted" (mining, energy, distant places) and why that makes manufacturing a new mobile phone cost much more to the planet than using it for a year.

During the use stage, the impact does not stop: appliances consume electricity, water, or consumables. Choose three appliances in your home and describe what each one consumes while in use (and what hidden consumables it has, such as coffee pods or ink cartridges).

At the end of its life, a broken toy can end up in the normal bin, at the recycling centre, or repaired and passed down to your cousin. Compare these three outcomes: what happens to its materials in each case and which of the three truly extends the life of the product.

Eco-design means designing products with their impact in mind right from the start: ensuring they last, can be repaired, taken apart, and recycled. Explain the concept and give two specific eco-designed decisions for a school backpack (materials, replaceable zips, colours, and dyes...).

Planned obsolescence is designing a product so that it stops working prematurely (batteries that cannot be replaced, lack of spare parts). Explain the idea with a well-known example and reason out who benefits and who suffers (users, manufacturers, and the planet).

The figure shows a rough diagram of how a mobile phone's environmental footprint is distributed across the stages of its life cycle.

Interpret the graph: which stage accounts for the largest share of a mobile phone's footprint and why (mining and manufacturing), what this means for our choices (what pollutes more: changing mobile phones every year or charging it every day), and which stage we can extend to improve the overall total.

Compare the life cycle of a reusable steel bottle with that of $200$ single-use small bottles per year: materials and energy used to manufacture each, how many times each is used, and what waste they generate. At what point does the reusable bottle start to "win"? Reason your conclusion.

Perceived obsolescence does not break the product: it makes us feel that it is old (fashion, the latest model, this year's colour). Explain the difference between this and planned obsolescence, give an example of each, and analyse what mechanisms advertising and sales use to fuel perceived obsolescence.

A cloth bag must be manufactured (using more material and energy than a plastic one), but it is used hundreds of times. Explain what it means to "offset" the manufacturing impact over multiple uses and calculate: if manufacturing the cloth bag has $20$ times more impact than manufacturing a plastic one, how many uses are needed to offset it? And what happens if you forget it in the wardrobe?

Responsible consumption starts before making a purchase. Write down five questions you should ask yourself before buying something (Do I need it?, How long will it last?, Can it be repaired?, Where does it come from?, What will I do with the old one?) and apply them to a real-life scenario: changing headphones because "new ones have come out".

Trace the global footprint of a mobile phone: minerals from several continents, component factories in Asia, assembly, transport by ship and lorry to your shop. Explain why this journey is also part of its footprint and how it relates to the price you pay (and to what you do not pay: the environmental costs).

Repairing extends useful life and avoids manufacturing a new product. Describe three simple repairs that extend the life of items in your house (replacing the battery, sewing on a button, replacing a scooter wheel) and estimate how many extra years of use each achieves compared to throwing the item away.

Energy labels on household appliances classify their efficiency using letters and colours. Explain what information they provide (how much energy the appliance consumes while operating) and how to use them when shopping: compare two similarly priced washing machines with different energy ratings and reason which one turns out cheaper overall after ten years of use.

A clothing brand sells a cotton T-shirt for just $5\ \text{€}$ with the slogan: "Low prices so you can renew your style every month at no cost to the environment".

Analyze the following production data sheet for the garment:

• Cultivation: requires $2700\ \text{litres}$ of water and $150\ \text{g}$ of pesticides per T-shirt.

• Dyeing: discharges wastewater with untreated toxic dyes in the country of origin.

• Transport: travels $9500\ \text{km}$ by cargo ship and lorry from Southeast Asia to Spain.

• Durability: loses its shape and deteriorates after $5$ washes.

1. a) Refute the advertising slogan by identifying which "hidden costs" (environmental and social) are not reflected in the sale price of $5\ \text{€}$.
2. b) If one person buys $8$ T-shirts of this type per year compared to another who buys $2$ fair trade organic cotton T-shirts (designed to last $50$ washes for $20\ \text{€}$ each), compare the annual water impact (assuming the same cultivation water consumption per T-shirt) and total economic expenditure of both consumers.
3. c) Justify two ecodesign measures that the brand should apply to the garment to extend its lifespan and facilitate its recycling at the end of its life cycle.

A car manufacturer advertises its new model with the message: "Zero emissions from the very first kilometre". You have the following average data from its life cycle assessment (LCA):

• Vehicle manufacturing: the petrol car generates $6\ \text{t}$ of $\text{CO}_2$; the electric car generates $10\ \text{t}$ of $\text{CO}_2$ (due to the mining and processing of lithium and cobalt for its battery).

• Use: the petrol car emits $130\ \text{g}$ of $\text{CO}_2$ per kilometre travelled. The electric car consumes $16\ \text{kWh}$ every $100\ \text{km}$.

1. a) If the electric car is recharged in a country whose electricity grid emits $0,25\ \text{kg}$ of $\text{CO}_2$ per $\text{kWh}$, calculate how many grams of $\text{CO}_2$ it emits per kilometre and from what total mileage it offsets the initial manufacturing impact compared to the petrol car.
2. b) What would happen to that threshold if the electricity comes from a coal-fired power station emitting $0,80\ \text{kg}$ of $\text{CO}_2$ per $\text{kWh}$? Carry out the calculation and predict whether the electric car would still be greener after travelling $100\,000\ \text{km}$.
3. c) Based on the results, refute the manufacturer's claim and justify what factors the sustainability of the electric vehicle actually depends on.

A smartphone manufacturer seals the casing and glues the battery with structural adhesive, without selling official spare parts to the public. Facing criticism, the company claims: "It is an essential technical decision to make the phone submersible (IP68 resistance) and achieve a thickness under $8\ \text{mm}$".

1. a) Refute this technical argument by analyzing how other designs resolve this trade-off (for example, the use of watertight rubber gaskets, micro-screws, and clean-release stretch adhesive strips).
2. b) Explain the impact that this design decision has on the product's repairability index and on the generation of electronic waste (WEEE) when the battery degrades after two years of use.
3. c) Within the framework of the "right to repair", design a proposal for technical regulations that obliges manufacturers to guarantee repairability without forcing them to sacrifice water protection.

Analyze the environmental and economic impact of two mobile phone consumption habits over a period of $10\ \text{years}$ using these average data:

• Manufacturing a new smartphone: generates $60\ \text{kg}$ of $\text{CO}_2$, produces $180\ \text{g}$ of electronic waste when discarded, and costs $300\ \text{€}$.

• Replacing the degraded battery with an official one: generates $3\ \text{kg}$ of $\text{CO}_2$, produces $35\ \text{g}$ of battery waste, and costs $40\ \text{€}$ including labour.

• User A: buys a new phone every $2\ \text{years}$ (never repairs).

• User B: buys a new phone every $5\ \text{years}$ and replaces its battery at mid-life (at year $2,5$ and year $7,5$).

1. a) Calculate for each user, at the end of the $10\ \text{years}$, how many phones they have consumed, the total economic expenditure, the accumulated kilograms of $\text{CO}_2$, and the total mass of waste generated.
2. b) Interpret the results: what percentage of $\text{CO}_2$ emissions and how much money does User B save compared to User A?
3. c) Justify why many consumers act like User A by identifying at least one technical barrier of the product and one mechanism of psychological obsolescence.

A fast fashion brand manufactures a hoodie made of $65\ \%$ cotton and $35\ \%$ polyester (a synthetic fibre derived from petroleum). The garment costs $12\ \text{€}$ and its design follows a microtrend meant to last only a single season.

1. a) Analyze the life cycle of this garment: explain what happens during the use phase in domestic washes with synthetic fibres (microplastics) and what impact they cause on aquatic ecosystems.
2. b) From a materials perspective, justify why blending cotton and polyester in the same fabric cheapens manufacturing but turns the garment into waste that is technically almost impossible to recycle compared to a monomaterial garment ($100\ \%$ cotton or $100\ \%$ polyester).
3. c) Propose two specific ecodesign criteria that a textile manufacturer should apply so that clothing enables a real circular economy without losing functionality.

In your secondary school, computers, peripherals, and small household appliances are thrown away every school year because they stop working or become slow. Design a technical plan for the school titled "Extend the life of your devices" that addresses the following points:

1. a) Triage protocol: describe the logical steps that students should follow in the Technology workshop to diagnose whether a device that does not turn on has a simple and repairable fault (cables, connections, fuses, dirt) before sending it to the recycling centre, bearing in mind that all checks are carried out with the device unplugged and under the teacher's supervision.
2. b) Maintenance and reuse workshop: design two specific technical actions that can be applied to discarded equipment (for example, installing lightweight open-source software distributions on old computers, repairing connectors through supervised soldering (with safety glasses and fume extraction), or creating a spare parts bank).
3. c) Impact measurement: define a formula or method with concrete data (number of recovered devices, mass of WEEE avoided in kilograms, or estimated economic savings) to demonstrate to the management team at the end of the school year whether the plan has been successful.

Evaluate a real product from your home using eco-design criteria: materials (recycled or recyclable?), repairability (does it come apart?, are there spare parts available?), packaging (necessary?, recyclable?) and expected durability. Give it a justified mark for each criterion and propose two design improvements that would raise its mark.

A lighting company designs an LED light bulb whose capacitors fail after $2000\ \text{hours}$ of use, even though the LED diodes can emit light for $25\,000\ \text{hours}$. The company claims that installing more durable components would raise the bulb's price from $1,50\ \text{€}$ to $2,30\ \text{€}$ and that "consumers prefer to pay less."

1. a) Show with a calculation which option is more cost-effective for a user: buying $1,50\ \text{€}$ bulbs that last $2000\ \text{hours}$ or $2,30\ \text{€}$ bulbs that last $25\,000\ \text{hours}$ to cover a total of $50\,000\ \text{hours}$ of lighting.
2. b) Justify why it is so difficult to prove in court that this design constitutes an intentional case of planned obsolescence rather than a simple cost-reduction decision.
3. c) Design a legislative proposal with two mandatory technical measures (for example, a visible repairability index, warranties proportional to the declared lifespan, or mandatory availability of spare parts) that prevent these practices without the need to internally audit the circuitry of each device.