A UN report cautions emissions must be reduced by 60% by 2035

The World Meteorological Organization reported that annual mean levels of carbon dioxide (CO2), the most significant GHG in the atmosphere, increased by 2.3 parts per million (PPM) between 2022 and 2023, setting a new record for planet-warming GHG levels. The annual mean CO2 increased by more than 2 PPM for the 12th year in a row.

In 2023, the average worldwide surface concentrations of carbon dioxide, methane, and nitrous oxide (GHG) hit all-time highs, with CO2 reaching 420 parts per million. The WMO estimates that the earth’s CO2 concentration was last comparable 3–5 million years ago, when sea levels were 10–20 meters higher and temperatures were 2-3°C warmer than they are today.

According to the WMO, natural variability contributed to the 2022–2023 CO2 increase, which was somewhat greater than the 2021–2022 period but lower than the average yearly growth rate over the previous ten years.