Chapters 13.1–13.3 nailed the problem: the planet is warming, humans are the cause, and the impacts are already here. This final climate lesson asks the exam's hardest question — what do we do about it, and how do you evaluate whether a response actually works? The IPCC's AR6 Synthesis Report is blunt: to hold warming near 1.5°C, global emissions must roughly halve by 2030 and reach net-zero CO₂ by about 2050. Every response below is judged against that yardstick.
By the end you can:
Mitigation tackles the cause — cutting emissions and boosting carbon sinks. Adaptation tackles the harm we can no longer avoid — sea walls, drought-tolerant crops, early warnings. They are not rivals: almost every serious plan uses both, because even zero emissions tomorrow leaves decades of warming already locked into the system.
The Paris Agreement, adopted at COP21 in December 2015 and in force since November 2016, binds nearly 200 countries to hold warming well below 2°C and pursue 1.5°C. Each nation sets its own pledge — a Nationally Determined Contribution — and every five years the UN climate conferences (COP) take stock and ratchet ambition upward. The catch: targets are voluntary and self-set, enforcement is weak, and countries can leave — the USA withdrew in 2017 and rejoined in 2021.
Solar & wind.
Electric vehicles.
Reforestation, biochar.
Seaweed cattle feed.
Mitigation splits into cutting emissions (solar, wind, EVs) and removing carbon (reforestation, biochar, soil). The goal is net-zero — residual emissions balanced by removals. Australia has legislated this: a 43% cut below 2005 levels by 2030 and net-zero by 2050, with progress tracked in the National Greenhouse Gas Inventory (DCCEEW). Innovation counts too — feeding cattle a dash of Asparagopsis seaweed can cut their methane by up to 80%.
Tuvalu is home to about 11,000 people spread over nine coral atolls, with a highest point barely 4.5 m above the sea and most land under 3 m. Rising seas already contaminate freshwater and cropland, raising the prospect of the world's first climate refugees. Wealthy, flat nations like the Netherlands can adapt with dykes and floating homes — but Tuvalu cannot out-build the ocean. In 2023 the Australia–Tuvalu Falepili Union treaty opened a migration pathway for up to 280 Tuvaluans a year: adaptation as planned retreat.
electricity (hydro, wind at Tilarán, geothermal).
net-zero-by-2050 plan; electric buses.
reversed deforestation; ecotourism funds conservation.
Behind the cards: Costa Rica abolished its army in 1948 and redirected the savings into health, education and, later, the environment. Its national decarbonisation plan targets net-zero by 2050, and payments to landholders lifted forest cover from about 21% in the 1980s to over 50% today. The catch for the exam: a small, mountainous, hydro-rich nation of ~5 million is far easier to green than a large, coal-reliant industrial economy — so praise the achievement, but question how transferable it is.
Grist revisits the Paris Agreement five years on — what it promised, what it has and hasn't delivered, and why “voluntary” targets are both its genius and its weakness. Treat it as a model for how to evaluate a strategy: weigh ambition against delivery, then land a judgement.
▶▶ Watch: The Paris climate agreement, explained (5 years later) — Grist (click → opens on YouTube)As you watch, note: (1) what the agreement actually commits countries to; (2) why enforcement is the weak point; (3) one piece of evidence you could use to argue it is working — and one against.
Every claim in this lesson traces back to a primary source — a treaty text, an official inventory or an independent assessment. Use these to check the data yourself and to build a research task. Being able to name and cite a source is exactly what lifts a Band 5–6 response above a Band 3–4 one.