Last year was the warmest year on record for the world’s oceans, part of a long-term warming trend, according to a study released Monday.

“If you look at the ocean heat content, 2019 is by far the hottest, 2018 is second, 2017 is third, 2015 is fourth, and then 2016 is fifth,” said Kevin E. Trenberth, a senior scientist at the National Center for Atmospheric Research and an author on the study

The study, published in the journal Advances in Atmospheric Sciences, follows an announcement last week by European scientists that Earth’s surface temperatures in 2019 were the second-hottest on record.

Since the middle of last century, the oceans have absorbed roughly 93 percent of the excess heat caused by greenhouse gases from human activities such as burning coal for electricity. That has shielded the land from some of the worst effects of rising emissions.