State of the Climate in 2019 Bulletin of the American Meteorological Society

In 2019, the dominant greenhouse gases released into Earth’s atmosphere continued to increase. The annual global average carbon dioxide concentration at Earth’s surface was 409.8 ± 0.1 ppm, an increase of 2.5 ± 0.1 ppm over 2018, and the highest in the modern instrumental record and in ice core records dating back 800 000 years. Combined, greenhouse gases and several halogenated gases contributed 3.14 W m−2 to radiative forcing, representing a 45% increase since 1990. Carbon dioxide is responsible for about 65% of this radiative forcing. The annual net global uptake of ~2.4 billion metric tons of carbon dioxide by oceans was the highest in the record dating to 1982 and 33% higher than the 1997–2017 average.