CO2 Levels Reach New Terrifying Levels

“As scientists expected, April became the first month in human history to have an average concentration of carbon dioxide — the main long-lived global warming gas — above 400 parts per million (ppm), according to data from a National Oceanic and Atmospheric Administration (NOAA) observatory, which sits atop a 11,000-foot-tall Hawaiian volcano.

This is a symbolic but grim milestone for those who are fighting to lower global greenhouse emissions to reduce manmade global warming; as carbon dioxide levels climb, so do the risks of triggering dangerous climate change, such as the melting of land-based ice sheets and flooding of coastal cities.

Mashable