This statistic represents the average level of carbon dioxide in the atmosphere worldwide between the 1880s and 2011, and gives a forecast for 2016. The level of 400 parts per million has already been measured in Barrow, Alaska in April 2012. According to the source, average global levels of CO2 are estimated to reach 400 parts per million in 2016. Since the beginning of the first measurements in 1959, there has been a constant increase in concentration of CO2. In the early 1960s, the greenhouse gas rose about 0.7 parts per million per year. Over the last ten years, it has been rising at about 2 parts per million per year. Before the Industrial Revolution began in the 19th century, the global average level of carbon dioxide was around 280 parts per million.