How many times larger is the co2 concentration in 2018 compared to Pre-industrial times?

The concentration of carbon dioxide (CO2) in Earth's atmosphere is approaching 397 ppm (parts per million) by volume as of May 2012 and rose by about 2.0 ppm/yr during 2000â€"2009. This current concentration is substantially higher than the 280 ppm concentration present in preindustrial times, with the increase largely attributed to anthropogenic sources.