The world’s air has reached what scientists call a troubling new milestone for carbon dioxide, the main global warming pollutant.
Monitoring stations across the Arctic this spring are measuring more than 400 parts per million of the heat-trapping gas in the atmosphere. The number isn’t quite a surprise, because it’s been rising at an accelerating pace.
Years ago, it passed the 350ppm mark that many scientists say is the highest safe level for carbon dioxide. It now stands globally at 395. ..
For more than 60 years, readings have been in the 300s, except in urban areas, where levels are skewed. The burning of fossil fuels, such as coal for electricity and oil for gasoline, has caused the overwhelming bulk of the man-made increase in carbon in the air, scientists say. ..
So far, only the Arctic has reached that 400 level, but the rest of the world will follow soon.
For more on this story, visit: Greenhouse gas levels pass symbolic 400ppm CO2 milestone | Environment | guardian.co.uk.