The graph shows satellite measurements of global sea level rise since 2000 plotted relative to 1993. (sea level rise measured in mm = millimetres)

a) Draw a line of best fit through the data and write an equation for your line in the form y = mx + c, to show how sea level is rising through time.

[3 marks]

b) What are the units of your value for mx, and c?

[1 mark]

c) Using your equation, work out how much higher sea level will be in 50 and 100 years’ time.

[2 marks]

Some scientists think that sea level isn’t rising with a constant rate, but is in fact accelerating.

Fitting a quadratic curve to this data gives the equation, y = 0.05x ^{2} + 2.6x + 21.3.

d) What are the units of the value for 0.05x^{2}?

[1 mark]

e) Use this equation to calculate how high sea level will be in 50 and 100 years’ time.

[2 marks]

f) What is the difference between your answers in (c) and (e)?

[1 mark]