In a special supplement, the Bulletin of the American Meteorological Society has published its “State of the Climate” for 2018. The 300-page report is an “annual physical of the climate system”, the authors say, which “endeavours to bring a comprehensive set of measurements to detail the status of the climate system and our capacity and willingness to observe it”. 2018 saw average atmospheric CO2 concentrations reach 407 parts per million, the authors say. This is “the highest in the modern instrumental record and in ice core records dating back 800,000 years”. The authors note: “With a weak La Niña in early 2018 transitioning to a weak El Niño by the year’s end, the global surface (land and ocean) temperature was the fourth highest on record, with only 2015 through 2017 being warmer.” The report is free to download.