The average atmospheric carbon dioxide level was above 400 parts per million for the month of February, according to a Scientific American article. That’s two months earlier than 2014, when the month of April was the first to average carbon dioxide levels above 400 ppm.
Carbon dioxide concentrations topped 400 ppm for the first time in recorded history in 2013. The last time carbon dioxide levels were this high was about 23 million years ago, according to Climate Central.
Scientists report that Earth’s carbon dioxide levels typically vacillated between 170 and 280 ppm based on records of air bubbles suspended in ice. Carbon dioxide concentrations have increased by around 2 ppm each year as a result of carbon emission from cars, coal-fueled power plants and deforestation. Researchers warn that continued increase in carbon dioxide levels could increase global temperatures by as much as 6 degrees Celsius.
Top image: Carbon dioxide concentrations top 400 ppm. (Credit: NASA)