The temperature-time graph from https://globalwarmingindex.org/ shows how the Earth’s global average monthly temperatures have varied from the year 1880. Throughout this question, monthly global temperatures refer to the difference between the temperature in a particular month and the average temperature for that calendar month over the period 1850-1879.

a) Which year contained the month in which global temperatures first exceeded 0.5°C above the 1850-79 average?
[1 mark]
b) Estimate a value for the highest recorded monthly global temperature since 1880 and
give the year in which it was recorded.
[1 mark]
c) Estimate a value for the average monthly global temperature between 1980 and 2000.
[2 marks]
d) What is the lowest monthly global temperature recorded since 2000?
[1 mark]