prize1-8, Exercise 3: Questioning a chart

Model answer:

Any four of: What period does it cover, and does it start or end at an unusual peak or trough? Is it global or about one place? What is the source of the data, and can I find the original? What baseline is it compared with? Is it a long-term average (climate) or a short run (weather)? Does the chart state any uncertainty? Do other independent records agree with it?