Ole Humlum, Professor of Physical Geography, University of Oslo, Norway: According to the instrumental temperature record (since about 1850), 2019 was a very warm year, but cooler than 2016. Since 2004, when detailed recording of ocean temperatures began, the global oceans above 1900 m depth have, on average, warmed somewhat. Since 1972, however, snow extent has been largely stable. Data from tide gauges all over the world suggest an average global sea-level rise of 1–1.5 mm/year, while the satellite record suggests a rise of about 3.2 mm/year, or more. The noticeable difference in rate (a ratio of at least 1:2) between the two data
sets still has no broadly accepted explanation. The focus in this report is on observations, and not on output from numerical models.
