5.3.10Unit 5: Respiration, Internal Environment, Coordination and Gene Technology
Contentious Issues in Environmental Science — IAL Edexcel Linear Revision Notes & Topical Questions
5 min read 5 parts Lesson 24 of 36 Unit quiz
Section 1 of 5Scientific Consensus
Most scientists agree on the main conclusions about climate change.
Agreement
- There is a strong consensus that greenhouse gas concentrations are rising and cause warming.
Human cause
- The consensus view is that human activities, mainly burning fossil fuels, are the main reason.
Dissent
- A few individuals argue that natural factors, such as solar activity, explain the warming.
Testing claims
- Claims are judged by how well they fit all of the evidence, not by who makes them.
Public debate
- Scientific agreement does not guarantee agreement in politics, where values and costs are also debated.
Section 2 of 5Evaluating Evidence
A careful evaluation follows a sequence of questions.
1
Does the statement take account of all of the available evidence, or only part of it?
2
Is the data reliable, from several independent studies, and are the results statistically significant?
3
Has the work been published in a peer-reviewed journal, so that other scientists have checked it?
4
Is the source free from bias, or does the author have a financial or political interest in the outcome?
5
A claim is more credible if other scientists can repeat the work and get similar results.
Section 3 of 5Why Issues Are Contentious
Why Issues Are Contentious
Uncertainty
- Models contain assumptions, and predictions have ranges rather than single answers.
Economics
- Reducing emissions has costs, and countries disagree on who should pay.
Ethics
- Decisions affect future generations and people in low-lying or poor regions.
Media
- News reports may simplify results or give equal weight to unequal evidence.
Section 4 of 5Making Judgements
Correlation
- A relationship in data does not prove cause, so look for a mechanism.
Mechanism
- Greenhouse gases absorb infrared radiation, which supplies a physical explanation.
Risk
- The precautionary principle supports action even when some uncertainty remains.
Balance
- A good answer states both the strengths and limitations of the evidence.
Section 5 of 5Exam Checklist & Tips
5.3.10 – Key Points for the Exam
- Consensus A general agreement among most experts in a field.
- Peer review Checking of a scientific report by independent experts before publication.
- Bias Influence of personal, financial or political interests on a conclusion.
- Reliability How consistently a result can be repeated.
Common Mistakes
- Rejecting a result simply because of who produced it; judge the evidence.
- Treating one outlier year as evidence against a long-term trend.
- Saying that a model is useless because it contains uncertainty.
- Confusing correlation with causation or ignoring the mechanism.
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