Earth's Carbon Concentrations Have Soared to Levels Not Seen in 800,000 Years

As temperatures bust heat records across the globe and wildfires rage from California to the Arctic, a new report produced annually by more than 500 scientists worldwide found that last year, the carbon dioxide concentrations in the Earth’s atmosphere reached the highest levels “in the modern atmospheric measurement record and in ice core records dating back as far as 800,000 years.”

While the most significant jump was the global average for carbon dioxide (CO₂)—which, at 405.0 parts per million (ppm), saw a 2.2 ppm increase from the previous year—concentrations of other dominant planet-warming greenhouse gases, methane (CH₄) and nitrous oxide (N₂O), also hit “record highs,” according to State of the Climate in 2017 (pdf) released Wednesday.

Considering those rates, Greg Johnson, an oceanographer at the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory in Seattle, warned that even if humanity “stopped the greenhouse gases at their current concentrations today, the atmosphere would still continue to warm for next couple decades to maybe a century.”

The 332-page report—which was overseen by NOAA and published as a special supplement to the Bulletin of the American Meteorological Society—also notes that 2017 is among the three hottest years ever, taking the top spot for warmest non-El Niño year since scientists began measuring in the 1800s. However, NOAA data released last weekend shows that 2018 is on track to set a new record.