Top Pro & Con Arguments
Average temperatures on earth have increased at a rate far faster than can be explained by natural climate changes.
Average surface temperatures on earth have risen more than 2°F over the past 100 years.  According to NASA, “The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.” 
A 2008 study comparing data from tree rings, ice cores, and corals over the past millennium created the famous “hockey stick” graph showing a steady trend in the earth’s temperature over the last 1,700 years followed by a steep jump in the previous decade (forming a shape like a hockey stick).  Berkeley scientists found that the average temperature of the earth’s land increased 2.5°F over 250 years (1750-2000), 1.5°F of which “appears likely” to be attributable to humans over the past 50 years. Read More