PLEA Network

5 September 2023, Copernicus CLIMATE BULLETINS UPDATE: Record high global sea surface temperatures continue in August. Global* average sea surface temperatures (SSTs) have been consistently high over the past five months, and remained at record high levels for the time of year throughout April, May, June and July 2023. This situation has continued into August, which saw both the highest daily global SST in the ERA5 record and the highest monthly average global SST. Typically, SSTs reach their highest level for the year in March and then begin to fall, before a slight increase again during July and August. Copernicus Climate Change Service (C3S**) data show this year to be atypical in that, after an initial sharp rise in early March and only a slight dip during April and May, global average SSTs have continued to rise to reach the highest value in the C3S ERA5 dataset of 21.02°C on 23 and 24 August. This is higher than the previous record of 20.95°C, set in March 2016. In fact, every day from 31 July to 31 August this year has been warmer than the previous record set in March 2016. As well as daily SSTs remaining consistently above average, last month saw the largest SST anomaly by far for any August in the dataset, at 0.55°C. The monthly average SST for August, at 20.98°C, was higher than the previous record of 20.89°C, set in March 2016 and reached again in July this year (see ‘30 warmest months’ figure below). Read more here