Air pollution
Credit: Axios

Atmospheric levels of the greenhouse gas carbon dioxide (CO2) reached the highest ever recorded in human history in 2018, the World Meteorological Organization (WMO) announced in a new report Monday. (emphasis added)

Why it matters: If the trend continues, as predicted, the impact of climate change will become even more severe, the intergovernmental organization warns. “The last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago,” WMO Secretary-General Petteri Taalas said in a statement accompanying the report.

• “Carbon dioxide is the most important long-lived greenhouse gas, with a single molecule lasting in the air for hundreds to around 1,000 years,” science journalist Andrew Freedman has noted for Axios. “The continued buildup of carbon dioxide due to human activities, such as burning fossil fuels for energy, is driving global temperatures up and instigating harmful impacts worldwide.”

By the numbers: The WMO’s Greenhouse Gas Bulletin reports that globally averaged concentrations of CO2 reached 407.8 parts per million last year. That means for every 1 million molecules […]