Global sea surface temperatures have only been warming at a rate of about 0.06°C per decade since 1950.
According to Dieng et al., 2017, global sea surface temperatures (SST) cooled slightly (-0.006°C/decade) from 2003 to 2013. This reduced the overall 1950-2014 warming rate to 0.059°C per decade.
Image Source: Dieng et al., 2017
The NCAR/HadCRUT4 global SST record from buoys and ARGO floats also show only modest warming in the last 3 decades. The natural 2015-’16 Super El Nino event is mostly responsible for the overall increasing rate.
Image Source: NCAR
Since 1871 there has been only modest warming in the Pacific and Atlantic (Zanna et al., 2019). Perhaps the Indian Ocean has a clearly detectable warming trend.
Image Source: Zanna et al., 2019
According to the Oceans 2k (2015) collection of globally reconstructed sea surface temperatures over the last 2000 years, there has been no alarming rise in temperatures that stands out (like a hockey stick) during the 20th century either.
Image Source: McGregor et al., 2015 and Supplementary Information
On a deeper note, from 1955 to 201o the 0-2000 m ocean only warmed 0.09°C (Levitus et al., 2012).
Image Source: Levitus et al., 2012
So why, exactly, should we be panicked and alarmed about any of this?