Sea surface temperature increased during the 20th century and continues to rise. From 1901 through 2020, temperature rose at an average rate of 0.14°F per decade (see Figure 1).Sea surface temperature has been consistently higher during the past three decades than at any other time since reliable observations began in 1880 (see Figure 1).Based on the historical record, increases in sea surface temperature have largely occurred over two key periods: between 1910 and 1940, and from about 1970 to the present. Sea surface temperature appears to have cooled between 1880 and 1910 (see Figure 1).Changes in sea surface temperature vary regionally. While most parts of the world’s oceans have seen temperature rise, a few areas have actually experienced cooling—for example, parts of the North Atlantic (see Figure 2).Background
