According to the CAS Institute of Atmospheric Physics, the last five years have been the five warmest years in the oceans. The long-term warming trend driven by human activities continued unabatedly. The increase in ocean heat content in 2017 occurred in most regions of the world and causes ocean volume expansion, sea level rise, declining oxygen content, bleaching of coral reefs, and melting of sea ice and ice shelves.
CAS news release, January 18, 2018