Chapter 13 examines climate change in depth. This first lesson tackles the foundational question: what does the data actually show? Not why it is happening (that's 13.2) or what it does (13.3), but the observed pattern itself — where (spatial) and when (temporal) the planet is warming. Getting these two dimensions straight is the backbone of every response you'll write on climate change, because markers want the pattern described precisely and quantified with real figures — not just “it's getting hotter.”
By the end you can:
Climate scientists overwhelmingly agree that Earth is warming and that human activity is the main cause: repeated surveys of the peer-reviewed literature put the consensus at over 97% of actively publishing climate scientists. Australia's own authorities — the Bureau of Meteorology and CSIRO, in their biennial State of the Climate report — reach the same conclusion. The scientific question is settled; the political and public argument about what to do about it is a separate thing. Don't confuse the two in an exam.
The headline figure: about 1.1–1.2 °C of warming since the late 1800s, and the pace has accelerated — most of it has come in the last ~40 years. The graph plots the temperature anomaly — the difference from a late-19th-century baseline, not the absolute temperature. The record is maintained by NASA's GISTEMP and confirmed independently by other teams.
Reliability comes from independent agreement. At least five separate teams process the raw temperature records using their own methods — different corrections, different handling of gaps — and every one of them reaches the same trend. That convergence is itself powerful evidence: a mistake in one method would show up as disagreement, not as five graphs that lie almost on top of each other. You can rebuild the global series yourself from NOAA's Climate at a Glance tool.
The ocean is the planet's great heat store, absorbing more than 90% of the extra energy that greenhouse gases trap. That's why sea-surface temperature has climbed steadily since 1880, tracked in NOAA's ocean records. Warmer surface water is the fuel for storms: it feeds more energy into tropical cyclones, hurricanes and typhoons, making them more intense — heavier rain, stronger winds — even if they don't grow more frequent.
Anomaly maps — like those from NASA — show the warming is near-global: almost every region is warmer than its 20th-century average, and vanishingly few areas have cooled. But it is uneven. Land warms faster than ocean, and the Arctic warms fastest of all — roughly three to four times the global rate (“Arctic amplification”, from 12.1), as reflective sea ice melts and exposes dark, heat-absorbing water.
Australia has warmed about 1.5 °C since national records began in 1910 — faster than the global average — according to the Bureau of Meteorology and CSIRO. The trend is both temporal (a clear rise) and spatial (virtually the whole continent), and it brings more dangerous fire weather (→ Chapter 14).
Numbers on a page can feel abstract. This short NASA visualisation animates the global temperature record from 1880 to 2022, painting each year's anomaly onto a world map. Watch the colours shift from blue (cooler than average) to deep red — and notice how the reddening speeds up, and where it bites hardest.
▶▶ Watch: Global Warming from 1880 to 2022 — ARCHIVED - NASA Climate Change (click → opens on YouTube)As you watch, note: (1) roughly which decade the map tips from mostly blue to mostly red; (2) which region reddens fastest and deepest; (3) how the animation shows a temporal and a spatial pattern at the same time.
Every figure in this lesson comes from a primary dataset — an official temperature record you can open and read yourself. Being able to name and cite the source of your data is exactly what separates a Band 5–6 response from a Band 3–4 one. Bookmark these for your research task.