2-1: Graph Reading
This is a graph with an x axis along the bottom and a y axis that runs vertically. The x axis on this graph shows the years,
from 1900 to the present. The y axis shows temperature variations measured in degrees celsius.
Scientists used a thirty year period from 1961 to 1990 to establish that they call normal. That 30 year average is the comparison point and is represented by
a horizontal line at zero degrees.
For example, the year 1900 was 0.8°C cooler than the 1961 to 1990 average.