The chart above shows the annual temperature change comparing to the mean between 1951-1980.
The data is taken from the
GISTEMP site annual mean from January to December.
The X axis represent the Year between 1880 to 2015.
The Y axis represent the temperature change in Degrees Celsius.
A line chart represents the change where the blue dots show the actual points measured.
Hovering the mouse over a dot shows a tooltip with the Year and Annual Temperature.
Selecting "absolute" shows the temperature in absolute value by adding the 1951-1980 mean which is 14.0 Degrees Celsius.
It's shown clearly that the temperature is increasing over the years.
The average between 1951 to 1980 (
A) is around zero which is what the change compared against.
Before that period (
B) the average was colder in around -0.2 degrees
while after that period (
C) there's a small decrease followed by a linear increase of the global temperature.
There's an interesting peak between years 1939 to 1946 (
D) and the question is whether the second world war
that took place over these years had any effect on the global warming?
You might find an answer
here