Ocean temperatures have been consistently rising for at least three decades. Scientists believe that global sea surface temperatures will continue to increase over the next decade as greenhouse gases build up in the atmosphere.
According to a report by the International Union for Conservation of Nature released last week, the Southern Hemisphere has experienced intense warming over the past decade, with strong heat accumulation in the midlatitude regions of the Pacific and Indian Oceans.
Natural patterns such as El Niño and La Niña can have year-to-year effects on temperatures. Individual storms can also influence ocean temperatures for months or longer. But the overall temperature trends by decade reveal a backdrop of human-caused warming.
Record High Annual Mean Surface Temperatures, 2015
Last year, nearly all observed ocean surface temperatures registered above average because naturally occurring conditions caused by El Niño combined with human-induced warming. About a quarter of those observations broke record highs.