World's Carbon Dioxide Level Surpassed 400 Parts Per MillionThis September

Global climate continues to be warmer as the amount of carbon dioxide (CO2) in the atmosphere is significantly increasing at around 400 parts per million. This may not fall below that threshold ever again, according to scientists.

Ralph Keeling, the director of the Scripps Institute for Oceanography's carbon dioxide monitoring program in May explained how the carbon dioxide levels topped 400 ppm for this month. September is usually the time of year when the carbon dioxide is at its lowest, according to Huffington Post.

Keeling wrote that the low point reflects the transition between summer and fall when the uptake of CO2 by vegetation weakens and is overtaken by the release of CO2 from soils. "Is it possible that October 2016 will yield a lower monthly value than September and dip below 400 ppm? Almost impossible."

David Black, the associate professor in the School of Marine and Atmospheric Sciences at Stony Brook University in New York told the Christian Science Monitor that the last time the Earth saw 440 ppm carbon dioxide in the atmosphere was about 3.5 million years ago and the global climate was particularly different than today. He further explained that it took millions of years for the atmosphere to reach 400 ppm CO2 back then, and it took millions of years for the carbon dioxide level to fall to 280 ppm tight before the industrial revolution.

Keeling also said that it goes upwards and could reach 450 parts per million. He added that stabilizing before 500 parts per million is not going to be very easy.

Meanwhile, Dr. Damon Matthews, an environment professor at Concordia University in Montreal said the carbon dioxide concentration level is somewhat reversible because of plants absorption of carbon dioxide. He further said that the temperature that has resulted from that change is not reversible in the absence of direct human efforts.