In Dec 2015, National Review published an interesting tweet that showed visibly no major change in the annual global temperature from 1880-2015.
This graph makes global warming look like a myth. The temperature has been shown as almost constant with no significant change over time. Then why is everyone so worried? What are they saying when they talk of rising temperatures and its harm to the planet earth?
Lets take a closer look –
This is a classic example of how not using the right scale can distort data and deceive people. What Graph 1 ignores to mention or highlight is that even a change of one degree in average global temperature is important and by starting the y axis from 0, the scale is making the temperature change look irrelevant. Misleading visualizations having skewed axes results in misinterpretation of data.
Graph 2 on the other hand, by starting the y axis at a higher number shows the pattern accurately and thereby will help in making informed and correct decisions.
Hence it is very important to choose the right y- axis and it is perfectly acceptable to not start your axis at 0 because at times, like in this case even the minutest fluctuations matter.
Source – https://qz.com/580859/the-most-misleading-charts-of-2015-fixed/