AMS Publishes State of the Climate Report for 2019

[donsutherland1]

The American Meteorological Society (AMS) just published the state of the climate report for 2019. Excerpts:

All major greenhouse gases released into Earth’s atmosphere reached new record high concentrations in 2019. 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. Greenhouse gases, along with several halogenated gases, have contributed to a 45% increase in net forcing compared to 1990. Carbon dioxide is responsible for nearly two-thirds of this increase.

A weak El Niño early in the year transitioned to ENSO-neutral conditions by mid-year, yet the annual global surface temperature across land and ocean surfaces was still among the three highest on record. July became the hottest month in records dating to the mid- to late-1800s. Each decade since 1980 is warmer than its preceding decade, with 2010–19 being around 0.2°C warmer than 2000–09.

In 2019, there were a record high number of extreme warm days (temperatures above the 90th percentile) over global land surfaces. There were also a low number of extreme cool days (temperatures below the 10th percentile) compared to the last 70 years, but there were more cool days compared to the average of just the past decade. A new indicator introduced this year to the report—marine heat waves—indicates that the number of strong marine heatwaves surpassed the number of more moderate marine heat waves for the sixth consecutive year. Lake temperatures increased on average across the globe in 2019; observed Northern Hemisphere lakes were covered in ice seven days fewer than the 1981–2010 average, accord- ing to phenological records. Over land, the growing season was an average of eight days longer than the 2000–10 average in the Northern Hemisphere. In colder regions, alpine glaciers around the world continued to lose mass for the 32nd consecutive year, while record high permafrost temperatures were observed at many observing sites across the high northern latitudes.

The complete report can be found here:

https://www.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/