Year 10 Science · Unit 4 · Lesson 9
Challenge Worksheet
Learning Goals
Read the graph
Study the chart of the nine planetary boundaries. A bar that crosses the dashed "safe boundary" line means that boundary has been exceeded. Answer the question below using the data shown.
Planetary Boundaries, How Far Each Is Pushed (2023 assessment)
Data: Richardson et al. (2023), planetary boundaries update. Bar length is a simplified indication of how far each boundary is pushed, not an exact value.
(a) Using the chart, state how many of the nine boundaries have been exceeded and name the two that the graph shows are pushed the furthest. Which two boundaries remain within the safe zone?
(b) Stratospheric ozone is the only boundary that has recovered after once being in danger, thanks to the Montreal Protocol (a global agreement to phase out ozone-destroying chemicals). What does this single success story suggest about whether other boundaries could also be brought back within safe limits? Justify your answer.
(c) The Stern Review (2006) found that acting on climate change costs about 1% of GDP per year, while inaction costs 5 to 20% of GDP permanently. Use these figures to explain why economists describe climate action as an "investment" rather than a "sacrifice."
Evaluate the claim
Someone claims...
"The whole idea of a 'personal carbon footprint' was invented by BP, an oil company, in a 2004 advertising campaign. It was a trick to blame ordinary people for climate change instead of the corporations causing it. So recycling, cutting your flights, and changing your diet are all pointless. Only governments and big companies can fix this, so there is no reason for me to change anything I do."
(a) What part of this claim is accurate? Explain the real concern about how the "personal carbon footprint" idea has been used.
(b) Where does the argument go wrong? Give two reasons why individual action still matters, even though systemic change is essential.
(c) Write a balanced one-paragraph response to the claim that explains how individual and systemic action reinforce each other rather than compete. Use the term intergenerational equity in your answer.
Wrap Up
In one sentence, what was the main idea of this lesson?
For teacher or self-marking use. Accept answers with the same meaning.
Read the graph
(a) Six of the nine boundaries have been exceeded. The two pushed furthest on the graph are biogeochemical flows (nitrogen and phosphorus cycles) and biosphere integrity (biodiversity loss). The two that remain within the safe zone are stratospheric ozone depletion and atmospheric aerosol loading. (Ocean acidification is near the boundary but not yet across it.)
(b) The ozone recovery shows that boundaries can be brought back within safe limits when there is coordinated global action: the Montreal Protocol phased out CFCs worldwide and the ozone layer is healing. This suggests other boundaries could improve too, but only with comparable international agreement and enforcement. Students should note it is harder for boundaries like climate change, because fossil fuels are far more central to the global economy than CFCs were, so the change required is much larger. Award marks for a justified position either way.
Stern Review
(c) Spending about 1% of GDP each year now is a small, upfront cost that avoids a much larger permanent loss of 5 to 20% of GDP from climate damage (extreme weather, sea-level rise, lost agriculture and health costs). Because the money spent now prevents far greater future losses, it behaves like an investment that "pays back" by avoiding damage, rather than a sacrifice that simply makes people poorer. Reward use of the actual figures to compare the cost of action with the cost of inaction.
Evaluate the claim
(a) The accurate part: BP did popularise the "personal carbon footprint" in a 2004 advertising campaign, and the genuine concern is that focusing only on personal footprints can shift blame away from the corporations and policies that produce most emissions, making individuals feel solely responsible for a systemic problem.
(b) The argument goes wrong by treating individual action as pointless. Two valid reasons it still matters: (1) individual choices add up at scale and send market signals, e.g. rising demand for electric vehicles and plant-rich diets drives investment and lowers prices; (2) visible individual action shifts social norms and tends to come with voting for stronger climate policy, helping enable systemic change. Accept other valid reasons such as direct emissions reductions.
(c) A strong paragraph explains that individual and systemic action are not a real choice between two options but reinforce each other: individuals who act normalise sustainable behaviour, create demand for clean technology, and vote for stronger policy, while systemic changes (carbon pricing, renewable standards, right-to-repair) make low-carbon choices the easy default for everyone. It should connect this to intergenerational equity, the idea that decisions made today should leave future generations an environment and resource base at least as good as our own, so both levers are needed to protect their right to a liveable planet. Award up to 4 marks for a balanced, well-linked argument that correctly uses the term.