What is the horizontal scale of your graph? How many years does it show?
The x axis is years counting by 20 years and from 1960 to 2000.

What is the vertical axis showing? What are the units? What is the total range shown?
The y axis shows temperature, and the temperature ranges from -0.6 to 0.6 and it counts by 0.2 per a unit.

Can you tell from the picture's host page where the data came from? If so, where?
They don't specifically say where the data came from.