To call what is happening in the oceans right now anomalous is an understatement. Since March, the mean sea surface temperature is soaring to record heightsas indicated by the darker line in the graph below.
Sean Berkell/University of Maine
Since this record-keeping began in the early 1980s (other dashes are earlier years), global mean global sea level has fluctuated seasonally between 19.7 and 21 degrees Celsius (67.5 and 69.8 degrees Fahrenheit). It fluctuates from time to time. Towards the end of March, the average temperature rose above the 21° mark and remained there for a month. (The most recent reading on April 26 was just below 21 degrees.) This temperature spike is not only unprecedented, it’s extreme.
Robert Lord, principal scientist at Berkeley Earth, a nonprofit that collects climate data, said: “Usually when certain warming events occur, they are slightly above previous records. Now, for a considerable period of time, they are well above past records for this time of year.”
Rohde notes that this week’s temperature was just under two-tenths of a degree warmer than the previous record. “Two-tenths doesn’t sound like a big deal, but he’s actually two-tenths a big deal because from an ocean perspective, it doesn’t warm up as quickly as the land,” he said. increase.
As you can see from the past record of the chart, March is the beginning of the average sea surface temperature every year. declineThis is due to the southern hemisphere transitioning from summer to fall. Its hemisphere is covered by more oceans than the northern hemisphere, which has a larger land mass. As the southern ocean cools, the average global sea surface temperature will drop.
But at the moment, temperature anomalies are spreading in oceans around the world. (Near real-time data comes from a network of satellites, buoys, and other ocean instruments.) “We’re above average temperatures almost everywhere,” says Rohde. “And there have been significant heatwaves in the North Pacific for months.”
