Model of changes required to avoid more than 2 degrees Celsius of global warming
"To cut emissions drastically by mid-century and avoid more than 2°C of global warming, would require the 15 largest economies to cut their carbon-dioxide emissions in half over the next four decades (at the moment, emissions are growing each year and show no signs of dropping). The average person worldwide could emit no more than 1.6 tons of carbon per year by 2050 — less than one-tenth of what the average American currently emits."
Source: Brad Plumer, "Here's what the world would look like if we took global warming seriously," Vox, July 9, 2014, Accessed July 31, 2014, http://www.vox.com/2014/7/9/5883835/a-step-by-step-guide-to-avoiding-dra...