H1 Biology 8876 · Nov 2023BiologyPaper 1Most challenging

Paper 1 Q28 — Reducing greenhouse gases needs net absorption

Ecology/climate — lowering atmospheric CO₂ requires net removal, not just lower emission

What the examiners said

“Option C… selected by a large proportion… These candidates had not noted that a reduction in greenhouse gases in the atmosphere requires net absorption of greenhouse gases rather than reduced emission.”

Try the question

Which action would actually reduce the amount of greenhouse gas already in the atmosphere?

Examiner report: “Candidates confused reduced emission with the net absorption needed to lower the amount present.”

Explore — the atmospheric CO₂ balance

Set the rate CO₂ is added and the rate it is absorbed. Only when absorption exceeds emission does the amount in the atmosphere actually fall.

Emission rate: 5 Absorption rate: 5

Lowering emission only slows the rise. The curve turns downward only when absorption overtakes emission — net removal.

Original reconstruction inspired by the misconceptions described in the Singapore-Cambridge GCE A-Level H1 Biology 8876 November 2023 Examiner Report. Not the actual examination question. For classroom exploration.

Made by lookang, using Claude Fable 5. More resources: iwant2study.org