The graph, from the IPCC 1.5 Report, shows how the rate of carbon dioxide emissions could
fall between 2020 and 2040, or between 2020 and 2055.
In 2020, the rate of carbon dioxide emissions is 42 billion tonnes/year
a) Convert 42 billion tones to kilograms, giving your answer in standard form.
b) If the emissions follow a straight line from 2020 to 2040, estimate the predicted
emissions in 2030, giving you answer in billions of tonnes.