The Open Letter The extract is from an open letter signed by 150 scientists urging governments to ban single-use plastics. Plastic pollution is not merely a...

(a) Two consequences of plastic pollution described in the letter [2]

The letter identifies several consequences of plastic pollution. Any two of the following earn 1 mark each:

• Microplastics have been detected in human blood, lung tissue, and placental samples, showing that plastic pollution has penetrated the human body.
• Approximately 1.8 million premature deaths per year worldwide are linked to exposure to plastic-derived chemicals.
• Endocrine disruption (interference with the body's hormone systems) results from chemical exposure.
• Respiratory illness is caused by plastic-derived chemicals entering the lungs.

These consequences demonstrate that the scientists are framing plastic pollution not just as an environmental issue but as a direct threat to human health. The letter deliberately selects consequences that affect people personally, making the case for urgent action more compelling.

(b) The line of reasoning from recycling failure to the proposed solution [6]

The scientists construct a three-step logical chain:

1. Establishing that the current solution has failed: They cite the statistic that only 9% of all plastic ever produced has been recycled. This is a powerful data point because it covers the entire history of plastic production, not just a single year, making it difficult to argue that recycling simply needs more time. [2 marks]
2. Shifting from downstream to upstream: Since managing plastic after it has been produced (recycling) demonstrably does not work, the scientists reason that the problem must be addressed at its source. If you cannot effectively clean up a pollutant, the logical alternative is to stop producing it. This is a shift from a reactive strategy (recycling) to a preventive one (production restriction). [2 marks]
3. Arriving at the specific policy demand: This upstream logic leads directly to their call for binding legislation to phase out single-use plastic items by 2030. The word "binding" is deliberate: voluntary programmes are what produced the 9% recycling rate, so the scientists argue that legal compulsion is necessary. [2 marks]

The underlying reasoning pattern is: if the downstream solution (recycling) is ineffective, then an upstream solution (restricting production) becomes necessary.

(c) Evaluation of whether the argument follows a sound line of reasoning [16]

Strengths of the reasoning:

• Logical coherence of the core argument: The progression from "recycling has failed" to "restrict production" is internally consistent. If the only current mechanism for dealing with plastic waste does not work, it is reasonable to argue for reducing the amount of waste created in the first place.
• Strong supporting evidence for health impacts: The Lancet study (a peer-reviewed medical journal with high credibility) and specific biological findings (microplastics in blood, lung tissue, and placentas) establish the seriousness of the problem. The evidence connects plastic pollution to measurable harm, not merely theoretical risk.
• Quantified recycling failure: The 9% figure is a concrete, verifiable statistic that directly supports the claim that voluntary recycling has failed. It addresses potential counter-arguments about incremental improvement by showing the cumulative outcome over decades.

Weaknesses in the reasoning:

• Correlation treated as causation: The 1.8 million deaths figure attributes causation from what is actually a correlation. "Exposure to plastic-derived chemicals contributes to" deaths does not prove that plastic is the sole or even primary cause. Other environmental or lifestyle factors may overlap.
• Scope mismatch: The letter calls for banning "single-use plastics," but the 9% recycling statistic refers to "all plastic ever produced." Single-use items are a subset of total plastic, so even a complete ban on single-use plastics would not address the 91% that remains unrecycled. The argument quietly narrows its target without adjusting its evidence.
• False dichotomy: The letter implies only two options exist: voluntary recycling (which failed) or a total ban on single-use plastics. This ignores intermediate policy tools such as extended producer responsibility schemes, deposit-return systems, plastic taxes, or mandatory recycled-content requirements. The reasoning jumps from "one approach failed" to "the most extreme alternative is necessary."
• Missing economic analysis: The 2030 deadline is presented as the logical outcome of the argument, but it is actually a policy choice with significant economic consequences (job losses in manufacturing, increased costs for businesses and consumers, need for alternative materials). The letter does not engage with whether 2030 is feasible or what the trade-offs would be.
• Appeal to authority without full transparency: The letter is signed by 150 scientists, which lends credibility, but their disciplines are unspecified. Experts in marine biology, for example, may not have the policy or economics expertise needed to assess whether a legislative ban is the most effective approach.

A thorough evaluation will recognise that the core argument is logically structured and supported by credible evidence, but that it contains a scope mismatch, a false dichotomy, and an unexamined causal claim. The strength of the reasoning lies in its diagnosis of the problem; its weakness lies in the jump to a single, extreme solution without considering alternatives or costs.

Award 13-16 for thorough analysis of reasoning structure identifying specific strengths and weaknesses; 9-12 for competent evaluation with some evidence; 5-8 for adequate but less developed points; 1-4 for superficial engagement.