Graph: A line graph representing how global temperatures have deviated from a baseline temperature defined as the average of global temperatures recorded between 1961 and 1990. Though the global temperature has been at or below this baseline level during the period roughly between 1860 and 1980, since 1980 global temperatures have been above this average.
More specifically, between 1860 and 1910 the global temperature held at approximately 0.4 celcius below the baseline level. In the period between 1910 and 1940, however, the global temperature rose steadily, before reaching the baseline level around 1940. Then, from 1940 to 1980 the global temperature held at approximately the baseline level. Since 1980 the global temperature has been rising steadily. In the early 2000s, global temperature was approximately 0.4 celcius above the baseline level.